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Elderly people in regions of China with hot summers and cold winters have significantly higher heat sensitivity than people in other regions and are ambiguous in their subjective perceptions of temperature, humidity, and solar radiation. This makes the elderly more vulnerable to the heat; consequently, when they engage in outdoor activities during the summer wearing light clothing, their diminished thermal perception increases the risk of heat stress injuries. Therefore, to more accurately evaluate the outdoor thermal comfort perception of the elderly in summer, this study used traditional field meteorological measurements, a questionnaire survey, physiological data, and machine learning prediction methods, to establish an outdoor thermal benchmark for retirement communities in hot summer and cold winter regions. Findings from the study reveal that the neutral universal thermal climate index (NUTCI) and the neutral universal thermal climate index range are 25.94°C and 22.23°C to 29.66°C respectively, and that the thermal comfort threshold is 35.39°C. It was also found that for 80% of elderly residents in the two retirement communities studied, the thermal acceptable range is from 19.41°C to 35.07°C. Using these findings as a guide, the thermal categories proposed are neutral 22.23°C to 33.08°C, slightly warm 33.08°C to 39.68°C, warm 39.68°C to 43.52°C, and hot above 43.52°C, with a preferred UTCI of 27.02°C. [ABSTRACT FROM AUTHOR]

Winter precipitation over eastern China displays remarkable interannual variability, which has been suggested to be closely related to El Niño–Southern Oscillation (ENSO). This study finds that ENSO impacts on eastern China precipitation patterns exhibit obvious differences in early (November–December) and late (January–February) winter. In early winter, precipitation anomalies associated with ENSO are characterized by a monopole spatial distribution over eastern China. In contrast, the precipitation anomaly pattern in late winter remarkably changes, manifesting as a dipole spatial distribution. The noteworthy change in precipitation responses from early to late winter can be largely attributed to the seasonally varying Kuroshio anticyclonic anomalies. During the early winter of El Niño years, anticyclonic circulation anomalies appear both over the Philippine Sea and Kuroshio region, enhancing water vapor transport to the entirety of eastern China, thus contributing to more precipitation there. During the late winter of El Niño years, the anticyclone over the Philippine Sea is further strengthened, while the one over the Kuroshio dissipates, which could result in differing water vapor transport between northern and southern parts of eastern China and thus a dipole precipitation distribution. Roughly the opposite anomalies of circulation and precipitation are displayed during La Niña winters. Further analysis suggests that the seasonally-varying Kuroshio anticyclonic anomalies are possibly related to the enhancement of ENSO-related tropical central-eastern Pacific convection from early to late winter. These results have important implications for the seasonal-to-interannual predictability of winter precipitation over eastern China. [ABSTRACT FROM AUTHOR]

Integrated Multi-satellitE Retrievals for GPM (Global Precipitation Measurement) (IMERG) is the primary high spatiotemporal resolution precipitation product of the GPM era. To assess the applicability of the latest released IMERG_V07 in mainland China, this study systematically evaluates the error characteristics of IMERG_V07 from the perspective of different seasons, precipitation intensity, topography, and climate regions on an hourly scale. Ground-based meteorological observations are used as the reference, and the performance improvement of IMERG_V07 relative to IMERG_V06 is verified. Error evaluation is conducted in terms of precipitation amount and precipitation frequency, and an improved error component procedure is utilized to trace the error sources. The results indicate that IMERG_V07 exhibits a smaller RMSE in mainland China, especially with significant improvements in the southeastern region. IMERG_V07 shows better consistency with ground station data. IMERG_V07 shows an overall improvement of approximately 4% in capturing regional average precipitation events compared to IMERG_V06, with the northwest region showing particularly notable enhancement. The error components of IMERG_V06 and IMERG_V07 exhibit similar spatial distributions. IMERG_V07 outperforms V06 in terms of lower Missed bias but slightly underperforms in Hit bias and False bias compared to IMERG_V06. IMERG_V07 shows improved ability in capturing precipitation frequency for different intensities, but challenges remain in capturing heavy precipitation events, missing light precipitation, and winter precipitation events. Both IMERG_V06 and IMERG_V07 exhibit notable topography dependency in terms of Total bias and error components. False bias is the primary error source for both versions, except in winter, where high-altitude regions (DEM > 1200 m) primarily contribute to Missed bias. IMERG_V07 has enhanced the accuracy of precipitation retrieval in high-altitude areas, but there are still limitations in capturing precipitation events. Compared to IMERG_V06, IMERG_V07 demonstrates more concentrated error component values in the four climatic regions, with reduced data dispersion and significant improvement in Missed bias. The algorithm improvements in IMERG_V07 have the most significant impact in arid regions. False bias serves as the primary error source for both satellite-based precipitation estimations in the four climatic regions, with a secondary contribution from Hit bias. The evaluation results of this study offer scientific references for enhancing the algorithm of IMERG products and enhancing users' understanding of error characteristics and sources in IMERG. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen (N) mineralization and immobilization are two important N biogeochemical processes in estuarine and coastal sediments. However, the changes of those two processes in sediment following Spartina alterniflora (S. alterniflora) invasions into mangrove wetlands under aerobic and anaerobic conditions remain limited. Methods: We used a 15N stable isotope dilution technique to investigate sediment gross N mineralization (GNM) and NH4+ immobilization (GAI) under aerobic and anaerobic conditions in mangrove communities, mangrove communities mixed with S. alterniflora, and pure S. alterniflora communities in the Zhangjiang Estuary, China. Results: GNM and GAI rates varied spatially and seasonally. Summer N mineralization and immobilization rates under aerobic and anaerobic conditions were both significantly higher than those in winter, and the high rates were observed mainly in mangrove sediments and decreased with S. alterniflora invasion. GNM rates in aerobic conditions were significantly higher than those in anaerobic conditions, while GAI rates in aerobic conditions were less than those in anaerobic conditions. GNM and GAI rates were related closely to temperature, water content and organic matter. S. alterniflora invasion can weaken GNM and GAI rates by reducing organic matter accumulation, and S. alterniflora invasion could have reduced sediment N mineralization (2.10 × 103 t N yr−1) and immobilization (1.46 × 103 t N yr−1) in mangrove wetlands of China from 1980 to 2020. Conclusions: Our results highlight the importance of S. alterniflora invasion and hydrological conditions in controlling N mineralization and immobilization processes in mangrove sediments and are essential for the evaluation of N-balance in this N-limited ecosystem. [ABSTRACT FROM AUTHOR]

Recently, nitrate (NO3–) levels in winter pollution in eastern China have been increasing yearly and have become the main component of PM2.5. The factors contributing to this rise in surface NO3– concentrations remain unclear, complicating the development of targeted pollution control measures. This study utilizes observational data from Shanghai during the winter 2019, alongside box model simulations, to recreate the NO3− pollution event and identify the key factors in the growth process. The analysis demonstrated that a rise in winter ozone levels significantly promotes NO3– production by facilitating NOx conversion via gas-phase and heterogeneous reactions. These findings could explain the correlation between the synchronous increase of surface ozone and NO3− in recent years. Furthermore, simulation of control strategies for NOx and volatile organic compounds (VOCs) identified an approach centered on ozone reduction as notably effective in mitigating winter NO3– pollution in the Yangtze River Delta. [ABSTRACT FROM AUTHOR]

This study investigated the potential effects of changes in inorganics on aerosol water uptake and, thus, on secondary organic aerosol (SOA) formation in wintertime haze based on the size-resolved measurements of non-refractory fine particulate matter (NR-PM 2.5) in Xi'an, northwestern China. The composition of inorganic aerosol showed significant changes in winter 2018–2019 compared to winter 2013–2014, shifting from a sulfate-rich profile to a nitrate-rich profile. In particular, the fraction of sulfate and chloride decreased, but that of nitrate increased in the entire size range, while ammonium mainly increased at larger particle sizes. These changes thus resulted in a size-dependent evolution in water uptake. Increased water uptake was observed in most cases, mainly associated with enhanced contributions of both nitrate and ammonium, with the highest increase ratio reaching 5 %–35 % at larger particle sizes and higher relative humidity (RH>70 %). The non-negligible influence of chloride on aerosol water uptake was also emphasized. The random forest analysis coupled with a Shapley additive explanation algorithm (SHAP) further showed an enhanced relative importance of aerosol water in impacting SOA formation. Aerosol water exhibited a significant contribution to SOA formation during winter 2018–2019, particularly at larger particle sizes. The SHAP value of aerosol water increased alongside higher levels of aerosol water, indicating an enhanced contribution of aerosol water to SOA formation. This implies that the majority of enhanced aerosol water uptake at larger particle sizes and high RH might facilitate the efficient aqueous-phase SOA formation. This study highlights the key role of aerosol water as a medium to link inorganics and organics in their multiphase processes. As challenges to further improve China's air quality remain and because SOA plays an increasing role in haze pollution, these results provide insight into the size-resolved evolution characteristics and offer guidance for future controls. [ABSTRACT FROM AUTHOR]

As an important hub on the East Asian-Australian Flyway (EAAF), Hongze Lake is an important migratory stopover and wintering site for hundreds of thousands of birds. However, research on bird community diversity in this area is still lacking. We conducted a bird survey from July 2020 to June 2021 using the line transect method on the terrestrial habitat, as well as the fixed-point method in the lake wetland at the Sihong Hongze Lake Wetland National Nature Reserve located in northwestern Hongze Lake, and analyzed the temporal-spatial variation in the bird community. The results showed that a total of 170432 detections of 215 bird species belonging to 18 orders and 55 families were recorded. In terms of species composition, the proportion of terrestrial birds was relatively high, followed by waterfowl richness, with high numbers of Anatidae species and shorebirds. For bird species abundance, waterfowl had the highest abundance of common coot (Fulica atra), belonging to the Rallidae family, followed by Anatidae and Ardeidae species. The abundance of shorebirds was extremely low, and that of non-waterfowl was also low. In terms of temporal patterns, the number of bird species and richness index were higher in spring and autumn but lower in winter and summer. The bird abundance was the highest in winter, and the remaining three seasons were similar in terms of bird abundance. The diversity index and evenness index were higher in spring, summer and autumn, and lowest in winter. For the spatial pattern, the open water in the western part of the reserve included the most densely distributed areas for birds, and the number of bird species and their abundance were both the highest in that part. There were significant differences in the bird community structures among the four habitats. The species number and richness index of birds in the reed habitat were the highest, and the bird abundance was also high, but the diversity index and evenness index were low. Although the bird abundance in the lake habitat was much higher than in the other habitats, the diversity index, evenness index and richness index were the lowest. The numbers of bird species and individuals in tourist attraction land and farmland were low, but the diversity index, evenness index and richness index were high. Our results reveal the spatial and temporal patterns of bird species diversity and abundance in Sihong Hongze Lake Wetland National Nature Reserve, and reflect the effects of different habitat types on bird diversity. [ABSTRACT FROM AUTHOR]

A new algorithm is proposed to estimate the cooling amplitude over North China induced by each Ural blocking event. Taking full account of potential transient temperature rises during the cooling process and the lag time of cooling relative to the blocking, this algorithm provides more detailed analysis which should not be possible by using former methods. The amplitude of the Ural blocking-related cooling events is found to have a broad distribution. Further, although most Ural blocking events lead to severe cold surges over North China, the number of Ural blocking events that do not induce significant cooling over North China cannot be ignored. The possible reasons for the wide range in cooling amplitude are explored in terms of the lifetimes and geographical centers of the blocking highs, the circulation patterns preceding the onset of the cooling events, and the snowfall associated with cooling events. Larger amplitude cooling events occur in Ural blocking highs that have longer lifetimes and northwestward displacements of their geographical centers. The northward displacement of a Ural blocking center favors the advection of extremely cold air from the Arctic regions, which accumulates in West Siberia and subsequently gives rise to the most severe cold surges over North China. The lack of activities of cold surges before the blocking-related cooling events not only amplifies the cooling amplitude directly, but also increases the occurrence probabilities of snowfalls through its modulation on the local specific humidity. The increased albedo and subsequent snow-melt induced cooling further amplify the cooling amplitude. [ABSTRACT FROM AUTHOR]

The indoor thermal history of residents in the hot summer and cold winter climate zone in China have undergone a significant change in recent years, which also changes their seasonal thermal adaptations and this has formed feed-back effects to the increasing usage of air conditioning units in this area. To study the seasonal variations of thermal adaptation, the thermal comfort experiments were conducted on two groups of participants. Each groups included 20 participants who had indoor history mainly with natural ventilation (NV group) and air-conditioning (AC group), respectively. The results demonstrated that the thermal sensation vote (TSV) in warm environments did not differ between AC and NV subjects in summer. However, the TSV of AC subjects were much lower than that of NV subjects in the same standard effective temperature and skin temperature in a cold environment in winter. Overall, the participants who spent most of their time in AC space in winter showed a low level of thermal adaptation with a narrower acceptable skin temperature range of 32.6 - 33.5 °C. Thus, this study presents the basic information regarding the seasonal effects on human thermal adaptation due to different long-term indoor thermal histories. [ABSTRACT FROM AUTHOR]

Passive house standard buildings (PHSBs), characterized by exceptional airtightness, present a promising technology for attaining carbon neutrality by 2060. The level of building airtightness is closely associated with air infiltration, which significantly impacts building energy consumption. However, there has been insufficient analysis of air infiltration in highly airtight buildings across diverse climatic regions. The present study involves the numerical simulation of the air infiltration rate (AIR) in an airtight building under varying design conditions during winter and summer, followed by a comprehensive analysis of the corresponding energy demand associated with air infiltration. The simulation results indicate that the building's AIR ranges from 125 to 423 m3/h, with an average of 189 m3/h under summer design conditions, and from 40 to 344 m3/h, with an average of 198 m3/h under winter design conditions. The statistical findings demonstrate distinct distribution patterns for AIR and energy demand across various climatic regions, exhibiting significant variations in values. The discussion emphasizes the substantial heating load associated with air infiltration, even at a building airtightness level of 0.5 h−1, highlighting the necessity of considering its impact in the design of highly airtight buildings. Furthermore, it is recommended to establish specific airtightness limits for buildings in different climatic regions of China. This study offers theoretical guidance for the airtightness design of highly airtight buildings. [ABSTRACT FROM AUTHOR]

Building energy consumption in China accounts for 45% of the total national energy consumption, with air conditioning energy consumption representing approximately two-thirds of that. Therefore, energy efficiency in buildings is of utmost importance. This study focuses on a chemical industrial park located along the Fujiang River and compares three heating and cooling supply schemes: the river water source heat pump system, which utilizes river water as the heat source and heat sink; the water cooling unit and boiler system, which uses water-cooled electric compression chillers for cooling and an oil-fired boiler system for heating; and the split air conditioning and gas water heater scheme, which relies on refrigerants such as fluorine-containing compounds for cooling and a gas water heater for heating. By calculating the energy consumption of the above three schemes and conducting a comparative analysis, it is found that the river water source heat pump system exhibits significantly higher energy efficiency throughout the year compared to the water cooling unit and boiler system and the split air conditioning and gas water heater scheme. This highlights the notable energy efficiency advantage of the river water source heat pump system. [ABSTRACT FROM AUTHOR]

The biogeographical range shift of insect pests is primarily governed by temperature. However, the range shift of seasonal long-distance migratory insects may be very different from that of sedentary insects. Nilaparvata lugens (BPH), a serious rice pest, can only overwinter in tropical-to-subtropical regions, and some populations migrate seasonally to temperate zones with the aid of low-level jet stream air currents. This study utilized the CLIMEX model to project the overwintering area under the climate change scenarios of RCP2.6 and RCP8.5, both in 2030s and 2080s. The overwintering boundary is predicted to expand poleward and new overwintering areas are predicted in the mid-latitude regions of central-to-eastern China and mid-to-southern Australia. With climate change, the habitable areas remained similar, but suitability decreased substantially, especially in the near-equatorial regions, owing to increasing heat stress. The range shift is similar between RCP2.6-2030s, RCP2.6-2080s, and RCP8.5-2030s, but extreme changes are projected under RCP8.5-2080s with marginal areas increasing from 27.2 to 38.8% and very favorable areas dropping from 27.5 to 3.6% compared to the current climate. These findings indicate that climate change will drive range shifts in BPH and alter regional risks differently. Therefore, international monitoring programs are needed to effectively manage these emerging challenges. [ABSTRACT FROM AUTHOR]

Simple Summary: Since the 1990s, the golden cuttlefish (Sepia esculenta) has become the dominant cuttlefish fisheries target in the seas around China. In this paper, we aim to determine the current resource status and spatio-seasonal variation in the population in the East China Sea region. We found more juveniles at latitudes of 27.50–28.00° N and 29.00° N and more subadult individuals at 28.50° N in autumn, exhibiting different growth rates and resource densities. In addition, we found the majority of the catches were composed of parent groups in spring, while in autumn, the majority of the catches were composed of juvenile groups. We concluded that the subadult groups might have dispersed widely for feeding and growth along the latitude of 30.00° N and to the south in summer, and the southern area of the Yangtze River extending north was the spawning ground in spring. The groups of S. esculenta preferred to stay in areas with a stable water temperature of ~20.00 °C, and many S. esculenta juveniles might have adapted to endure the negative influence of the low oxygen content in summer. The depth range of the S. esculenta population was 10.00–133.00 m from spring to autumn, but this shrank to 66.00–107.00 m in winter. The golden cuttlefish (Sepia esculenta) is an important cephalopod species with a lifespan of approximately one year. The species plays a crucial role in marine ecological support services and is commercially valuable in fisheries. In the seas around China, this species has emerged as the main target for cuttlefish fisheries, replacing Sepiella maindroni since the 1990s. Variations in oceanographic conditions associated with global warming could significantly impact the temporal-spatial distribution of the species. In this study, we performed bottom trawling surveys with four cruises during 2018–2019 in the East China Sea region to determine the current resource status and seasonal-spatial variations in S. esculenta. We found that the average individual weight (AIW) values were 4.87 and 519.00 g/ind at stations located at 30.50° N, 124.00° E and 30.50° N, 124.50° E, respectively, with the aggregation of larvae and parent groups in spring. The species was not distributed north of 32.00° N in summer. The catch per unit effort by weight (CPUEw) value decreased in the order of 2772.50→2575.20→503.29→124.36 g/h, corresponding to latitudes of 34.50° N→34.00° N→33.50° N→32.50° N 121.50° E in autumn. The most suitable fishing areas were the south of the East China Sea region in spring; the south of the East China Sea region extending to the center and outer parts of the East China Sea region in summer; the south of the Yellow Sea close to the Haizhou Bay fishing ground and the forbidden fishing line region of the Lusi and Dasha fishing grounds in autumn; and the south and center of the East China Sea region in winter. The most suitable sea bottom temperature (SBT) values from spring to winter were 14.76–20.53 °C, 19.54–22.98 °C, 11.79–17.64 °C, and 16.94–20.36 °C, respectively. The most suitable sea bottom salinity (SBS) values were 31.53–34.80‰ in spring, 32.95–34.68‰ in summer, 31.51–34.77‰ in autumn, and 33.82–34.51‰ in winter. We concluded the following: (1) the southern and northern areas of the East China Sea region are spawning and nursery grounds, respectively, in spring; (2) the central distribution is located at a latitude of 28.00° N in autumn and winter; and (3) the southern area of the Yangtze River to the north is a spawning ground in spring, and the areas located at 29.00–34.50° N, 124.00–124.50° E, and 28.00–30.50° N, 125.50–126.50° E are nursery grounds. The results of this study provide useful guidance for appropriate fisheries management, thereby avoiding a collapse in the S. esculenta population, which has been experienced in other species in this area. [ABSTRACT FROM AUTHOR]

Atmospheric visibility profoundly impacts daily life, and accurate prediction is crucial, particularly in conditions of low visibility characterized by high aerosol loading and humidity. This study employed the WRF‐Chem model to simulate a severe wintertime haze pollution episode that transpired from January 17 to 19, 2010, in Central‐East China (112–122° E, 34–42° N). The results reveal that excluding aerosol–meteorology interactions led to underestimated PM2.5 concentrations and relative humidity in comparison with ground‐based measurement data, accompanied by a significant overestimation of visibility. Aerosols can engage with meteorological elements, particularly humidity, resulting in positive feedback. Upon considering these feedback interactions, the simulation results showed an increase of 5.17% and 1.99% in PM2.5 concentration and relative humidity, respectively, compared with the original simulation. This adjustment narrowed the bias between simulated and measured data. The overestimation of simulated visibility was reduced by 16% and 25% for the entire study period and the severe haze pollution period, respectively. These findings underscore the vital role of incorporating aerosol–meteorology interactions in visibility simulations using the WRF‐Chem model. Notably, the inclusion of aerosol–meteorological feedback significantly enhances the accuracy of visibility predictions, particularly during heavily polluted periods. [ABSTRACT FROM AUTHOR]

During the boreal spring, extratropical cyclones in East Asia exhibit the highest frequency of occurrence in northeastern China. These cyclones are characterized by a distinct cold core, which is commonly referred to as the northeastern China cold vortex (NCCV), and most of NCCV events are usually accompanied by complex and hazardous weather, significantly impacting the regional climate in northeastern China. In this study, an automatic algorithm was employed to identify spring NCCVs from 1979 to 2022 using ERA5 reanalysis dataset, and a notable annual periodicity of 3–4 years was observed based on the defined spring NCCV intensity index (NCCVI). Through the analysis of anomalous strong/weak NCCVI years, it was found that the consistent heating (cooling) in the middle and lower troposphere of central Asia (northeastern China), along with a corresponding negative anomaly of geopotential height, as well as the enhanced cyclonic circulation in northeastern China, all contribute to the intensification and maintenance of NCCV activities. Furthermore, the winter snow cover in central Asia plays a vital role in local atmospheric heating and is associated with anomalous quasi-stationary Rossby waves that propagate eastward into northeastern China. The thermal forcing caused by preceding (DJF) snow cover anomalies in central Asia was somewhat replicated in ECHAM 4.6 model simulations. However, the simulations underestimated the contribution of snow cover anomalies to the eastward propagating Rossby wave trains. [ABSTRACT FROM AUTHOR]

In regions of China experiencing severe cold, the duration of the winter heating season significantly contributes to elevated heating energy consumption in rural dwellings. This study focuses on typical brick-and-concrete rural homes in the Wusu area. Utilizing the Rhino–Grasshopper parametric modeling platform, it aims to minimize heating-related carbon emissions and the overall costs associated with retrofitting. The approach involves improving the insulation properties of the building envelope to reduce energy requirements. Additionally, the study incorporates solar photovoltaic systems atop rural homes, building upon low-carbon, passive, energy-efficient design principles. By examining the influence of various factors on rural housing energy consumption, the research employs the entropy weight method to identify the most effective design solutions. The goal is to explore strategies for the energy-efficient retrofitting of rural dwellings in areas faced with harsh winter conditions, aligning with the objectives and preferences of Applied Sciences. The simulation results reveal the following: (1). In comparison with the baseline scenario, 42.2% of the optimized solutions within the Pareto frontier satisfy the current standards for 75% energy savings in energy-efficient residential design. (2). The lowest recorded thermal consumption index for the buildings can reach 12.427 W/m2, at which point the rate of energy savings is elevated to 79.5%. (3). Within the solutions identified by the Pareto frontier, 80% exhibit initial investments that are lower than the cost savings over the lifecycle due to reduced energy consumption ( d C g < 0), demonstrating the economic feasibility of the proposed retrofitting strategies. [ABSTRACT FROM AUTHOR]

Efficient carbon emission reduction technologies in buildings are necessary for achieving the "Dual carbon" goal in China. In this study, a comprehensive evaluation model is proposed to assess the effect of carbon emission reduction based on the analytic hierarchy process–entropy weight–coefficient of variation model which takes newly built residential buildings in Zhuzhou City as the research object. The results show that the preferred materials for the roof and exterior walls of the building's envelope structure were flame-retardant extruded polystyrene boards, and porous shale bricks were preferred as the main materials for the exterior walls. In addition, the rooftop solar photovoltaic system and energy-saving air conditioning technology were suitable in terms of being renewable and were better utilized. In the end, carbon emissions were significantly reduced when using the building decarbonization technologies. This study provides a new reference for choosing materials and technologies for the design of residential buildings in Hunan Province and even other regions with hot summers and cold winters. [ABSTRACT FROM AUTHOR]

Heating buildings with solar energy is challenged by the seasonal mismatch between solar availability and heating demand. Thermochemical energy storage is a promising technology to overcome this challenge because of its high energy density. In building applications, space requirement is also an important consideration. Therefore, both the storage space and collector areas are important considerations, with only the latter often being neglected in previous studies. This paper proposes a novel two-stage thermochemical heat pump heating system based on the working pair of NaOH/H2O. We demonstrate that this system can work with a concentration difference (70% wt–30% wt) for the climate in hot summer and cold winter regions in China. The energy storage density based on the discharged solution is 363 kWh/m3. With this solar-driven thermochemical heat pump heating system, 35.13 m2 of collectors and 10.48 tons of 70% wt NaOH solution are sufficient to complete a full charge–discharge cycle and meet the heating demand of a single-family house (winter space heating + DHW: 9370 kWh, summer DHW: 2280 kWh). The theoretical maximum storage for solution (discharged + water tank) is 32.47 m3. Compared with the sensible seasonal storage alternative, the collector area is reduced by 12.5% and the storage space is reduced by 59%, with a possible further reduction through optimization. With the potential to be further optimized for space saving, the two-stage solar–NaOH heat pump heating system is an energy-efficient and space-efficient heating system for buildings in the hot summer and cold winter regions of China. [ABSTRACT FROM AUTHOR]

The air quality in China has improved significantly in the last decade and, correspondingly, the characteristics of PM 2.5 have also changed. We studied the interannual variation of PM 2.5 in Chengdu, one of the most heavily polluted megacities in southwest China, during the most polluted season (winter). Our results show that the mass concentrations of PM 2.5 decreased significantly year-by-year, from 195.8 ± 91.0 µg/m3 in winter 2016 to 96.1 ± 39.3 µg/m3 in winter 2020. The mass concentrations of organic matter (OM), SO 4 2−, NH 4 + and NO 3 − decreased by 49.6%, 57.1%, 49.7% and 28.7%, respectively. The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO 3 − and there was a larger contribution from mobile sources. The contribution of OM and NO 3 − not only increased with increasing levels of pollution, but also increased year-by-year at the same level of pollution. Four sources of PM 2.5 were identified: combustion sources, vehicular emissions, dust and secondary aerosols. Secondary aerosols made the highest contribution and increased year-by-year, from 40.6% in winter 2016 to 46.3% in winter 2020. By contrast, the contribution from combustion sources decreased from 14.4% to 8.7%. Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants (e.g., OM and NO 3 −) and sources (secondary aerosols and vehicular emissions) in future policies for the reduction of pollution in Chengdu during the winter months. [ABSTRACT FROM AUTHOR]

Using the ERA‐5 reanalysis datasets, NCEP/NCAR sea ice concentration (SIC) and observed winter surface wind speed (WSWS) in northwest China during 1979–2020, this study examined the regime shift of the leading mode of observed WSWS in northwest China and investigated its possible link with the winter Barents–Kara Sea (BKS) SIC. The leading mode of observed WSWS in northwest China showed negative anomalies in southern and northeastern Xinjiang, Gansu, western and northern Shaanxi Provinces, and positive anomalies in northwestern and middle Xinjiang, Qinghai and Ningxia Provinces. The signs of WSWS in the leading mode is generally opposite to their trends during 1979–2020. Leading principal component (PC1) of observed WSWS in northwest China underwent an obvious decreasing regime shift in 2003/04, as well as the winter BKS SIC. There are significant correlations between PC1 and BKS SIC on both interdecadal and interannual timescales. Decadal decrease of BKS SIC is accompanied with a positive phase of Scandinavia pattern (SP) with positive anomalies of 500‐hPa geopotential height over subtropical North Atlantic, Arctic‐Ural region and southern Asia, and negative anomalies over northern North Atlantic‐West Europe and Siberia regions. BKS SIC and SP significantly influenced the Northern China Wind Index (NCWI) at 200 hPa on interdecadal timescale, which was related to the PC1 on both interdecadal and interannual timescales after removing the signal of Arctic Oscillation. Meridional configuration of Siberian cyclonic anomaly and southern Asian anticyclonic anomaly associated with the winter BKS SIC could enhance the intensity of NCWI, which favoured the increase of observed WSWS in northwest China and thereby may contribute to the regime shift in 2003/04 of the leading mode. However, there were still some stations showing decreasing regime shift, which mainly located at the region of steeping terrain. These decreasing changes of WSWS may be related to circumfluence effect of terrain, urbanization and local microclimate, and these reasons still need further detailed study. [ABSTRACT FROM AUTHOR]

Simple Summary: Harmonia axyridis (Pallas) is a widely distributed predatory natural enemy insect in North China but its application is limited in greenhouses owing to a low daily average temperature from December to February of next year in greenhouses and the facultative diapause of adult H. axyridis. Owing to the sensitivity of H. axyridis to photoperiod, it is of great importance to explore the feasibility of using the photoperiod to regulate the life parameters and predation ability of this ladybird in greenhouses during the winter, but the effects of photoperiods on life parameters and predation by H. axyridis are not well understood so far. In this study, development, reproduction, and population parameters were studied by constructing two-sex life tables, and effects of photoperiod on predation were tested by predation experiments in both laboratory and greenhouse settings. The results from this article may provide a basis for utilizing H. axyridis in greenhouses during the winter. To explore the feasibility of adjusting the photoperiod to regulate the life parameters and predation ability of Harmonia axyridis Pallas in greenhouses during the winter, life tables were constructed for H. axyridis under the three following photoperiods: 9L:15D (light/dark), 12L:12D, and 16L:8D at 15 °C, an average greenhouse temperature during the winter when aphids severely damage vegetables. The effects of photoperiods on predation by this ladybird were tested in both laboratory and greenhouse settings. The results showed that increased illumination promoted the development and reproduction of H. axyridis; under medium and long photoperiods, the pre-adult periods were 3.61 days and 4.34 days shorter than that under the short photoperiod, respectively, and the fecundity increased by 1.78 and 2.41 times. Population parameters r, λ, and R0 increased as illumination time increased, whereas T decreased. Increased illumination also increased the predation by third- and fourth-instar larvae and adults. The amounts of predation by fourth-instar larvae and adults increased by 22.16% and 75.09% under the medium photoperiod, and those under the long photoperiod increased by 71.96% and 89.64%, respectively. The numbers of Myzus persicae Sulzer predated by H. axyridis under the long photoperiod were higher than those under the short photoperiod in a greenhouse, and the predation parameters were influenced. [ABSTRACT FROM AUTHOR]

This study focuses on the interannual variability of winter mean surface air temperature (SAT) and subseasonal SAT reversal in North China, which have profound impacts on national life and economic activities. The analysis explores the temporal and spatial distribution characteristics of these variations and their relationship with the Eurasian Zonal Circulation (EZ). The findings reveal distinct interdecadal changes in North China's winter mean SAT, along with a general subseasonal reversal of cold and warm conditions. In comparison to the North Atlantic oscillation/Arctic Oscillation, the EZ has a more significant influence on the interannual variability of winter and subseasonal reversals. Strong EZ years are associated with the weakening of the Siberian High and the Ural Blocking High, causing the East Asian Trough to move eastward, which leads to the retention of cold air from the north and increased SAT in North China. Conversely, weak EZ years exhibit opposite circulation patterns. The winter mean EZ is influenced by preceding autumn Arctic sea ice concentrations (SIC). Reduced autumn SIC results in decreased heat flux and reduced eddy energy, leading to substantial attenuation of the winter storm track across Scandinavia and Western Asia. This attenuation, mediated through the interaction between eddies and mean flow, triggers a slowdown of Eurasian zonal circulation and intensification of the Siberian High. These conditions favor a positive phase of the winter Scandinavia pattern, facilitating the transport of cold Arctic air into North China. Likewise, subseasonal reversals in SIC influence corresponding alterations in the EZ. Plain Language Summary: The winter surface air temperatures (SAT) in North China exhibit notable interdecadal variations and distinct intra‐seasonal changes. These intra‐seasonal variations lead to subseasonal reversals, where early winter may be unusually warm, followed by later winter turning unusually cold, or vice versa. These subseasonal SAT fluctuations are influenced by atmospheric circulation anomalies. In this study, we investigate the spatial and temporal patterns of the mean winter SAT and subseasonal SAT reversals in North China, focusing on their interannual variability. We emphasize the significant impact of anomalous zonal circulation over the middle and high latitudes in Eurasia and explore the relative influence of the Arctic as a boundary forcing factor in circulation anomalies. Key Points: The winter surface air temperature (SAT) and subseasonal SAT reversal in North China have noteworthy interannual variationsThe Eurasian Zonal Circulation (EZ) strongly influences winter SAT and subseasonal reversal variabilityThe physical mechanisms linking autumn Arctic sea ice concentrations to EZ is examined [ABSTRACT FROM AUTHOR]

Online volatile organic compounds (VOCs) were continuous monitored before and after the Omicron policy change at an urban site in polluted Zhengzhou from December 1, 2022, to January 31, 2023. The characteristics and sources of VOCs were explored. The daily average concentration of PM2.5 and total VOCs (TVOCs) ranged from 54 to 239 µg/m3andfrom 15.6 to 57.1 ppbv with an average value of 112 ± 45 µg/m3 and 36.1 ± 21.0 ppbv, respectively during the entire period. The values of PM2.5 and TVOCs in Case 3 (pollution episode after the abolishment of "Nucleic Acid Screening Measures for all staff" policy) were 1.3 and 1.8 times of the values in the Case 1 (pollution episode during "Nucleic Acid Screening Measures for all staff" policy). The concentration of TVOCs in Case 1 and Case 3 were 48.4 ± 20.4 and 67.6 ± 19.6 ppbv, respectively, increased by 63 % and 188 % compared with values during clean days. Alkanes were found to be the most abundant compounds during the entire period. Equivalent volume contribution of halogenated hydrocarbon and oxygenated VOCs (15 %) were found the most in Case 3, followed by alkenes (10 %). Though the volume contributions of aromatics were the lowest (6 % in Case 1 and 7 % in Case 3), the highest increasing ratio was found from clean days to polluted episodes. Positive Matrix Factor model results showed that the main source of VOCs during the observation period was industrial emissions, which accounted for 30 % of the TVOCs, followed by vehicular emission (24 %) and combustion (23 %). The vehicular emission became the largest source during Case 1 (40 %) and Case 3 (29 %), consisting of large numbers of people going out after the blockade. Secondary organic aerosol formation potential (SOAFP) values were 37 and 109 µg/m3, respectively with the highest SOAFP contribution (17–19 μg/m3and 31–51 %) from vehicular emission both in Case 1 and Case 3. Solvent usage sources had the second highest SOAFP value (9 and 16 μg/m3) with the contributions of 23 and 31 % in Case 1 and Case 3 respectively. The control of vehicular emission, and solvent usage should be focused in Zhengzhou, and combustion was also important for the control of PM2.5 pollution in winter. [ABSTRACT FROM AUTHOR]

There have been fruitful publications on thermal comfort of urban residential buildings in China. However, there is a lack of reviews on this topic to perform a comprehensive analysis and find opportunities to meet occupants' thermal comfort needs while improving building energy efficiencies. This paper addresses this issue by presenting a systematic review on the advancements in research on thermal comfort in urban residential buildings in China. Firstly, two common thermal comfort research approaches, i.e., field studies and laboratory studies, are discussed. Secondly, eleven main thermal comfort evaluation indicators are summarized. Finally, this paper analyzes the thermal comfort survey data from different researchers, discusses the impacts of adaptive behaviors on human thermal comfort, and provides recommendations for future research on urban residential thermal comfort. It was found that people have higher and higher requirements for their indoor thermal environment as time goes by, especially in the winter; the thermoneutral temperature is higher in warmer climate regions in the summer but lower in the winter than in colder climate regions; the thermoneutral temperature tends to increase with the indoor air temperature due to an adaptation to the indoor thermal environment. The outcomes of this paper provide valuable information on thermal comfort behaviors of urban residents in different climate zones in China, which can serve as a resource for the academic community conducting future research on thermal comfort and assist policymakers in enhancing building energy efficiencies without compromising the occupants' comfort. [ABSTRACT FROM AUTHOR]

To improve the utilization of satellite-based data and promote their development, this analysis comprehensively evaluates the performance of GSMaP Near-real-time Gauge-adjusted Rainfall Product version 6 (GSMaP_GNRT6) data in depicting precipitation over China from 2001 to 2020 by comparing four precipitation indices—accumulated precipitation, number of rainy days and rainstorm days, and precipitation maxima—with daily precipitation data from 2419 stations across China on monthly and annual time scales. The results show that the GSMaP-GNRT6 data effectively capture the overall spatial pattern of the four precipitation indices, but biases in the spatial distribution of the number of rainy days from July to September and the precipitation maxima during the wintertime are evident. A general underestimation of GSMaP-GNRT6 data is observed in the average for China. The annual precipitation amount, the number of rainy days and rainstorm days, and the precipitation maxima based on the GSMaP-GNRT6 data are 17.6%, 35.5%, 31.6% and 11.8% below the station observations, respectively. The GSMaP-GNRT6 data better depict the precipitation in eastern China, with the errors almost halved. And obvious overestimation of the number of rainstorm days and precipitation maxima occurs in western China, reaching up to 60%. Regarding the accumulated precipitation, the number of rainstorm days and the precipitation maxima, the GSMaP-GNRT6 data show an almost consistent interannual variation and increasing trends that are consistent with the station observations. However, the magnitude of the increasing trend based on the GSMaP-GNRT6 data is larger, especially at the beginning of the 21st century. Conversely, a considerable discrepancy in the annual variation and an almost opposite trend can be observed in the number of rainy days between the GSMaP-GNRT6 data and the station observations. [ABSTRACT FROM AUTHOR]

Tuta absoluta (Lepidoptera: Gelechiidae) originates from the South American tropics but has become a major invasive pest of tomato and other Solanaceae crops worldwide. Agricultural protected facilities (APFs) such as greenhouses and plastic tunnels may provide thermal conditions that allow the survival of T. absoluta in temperate zones with cold winters. In this study, a CLIMEX model was used to investigate the dual effects of increasing use of APFs and climate warming on the potential distribution and seasonal dynamics of T. absoluta in China. Our model showed that the northern boundary for year-round population persistence in China, ignoring APFs, was approximately 30°N, covering about 21% of China's area suitable under current climate. The modelled suitable area increased to 31% and northern boundary for year-round population persistence shifted to 40°N in 2080 under global warming. When APF refuges are included, the potential suitable area was 78% under the current climate and 79% under global warming. This suggests that, in the future, the increasing use of APFs will increase the areas at risk of T. absoluta invasion significantly more than global warming because APFs effectively protect T. absoluta from harsh northern winters. In addition, vegetable production in surrounding open fields will be at risk of invasion during milder seasons when APFs are opened and T. absoluta can disperse. Therefore, the micro-climate of APFs should be considered as part of the invasion process, and Integrated Pest Management should be simultaneously implemented inside and outside APFs for the rational management T. absoluta. [ABSTRACT FROM AUTHOR]

This study was designed to determine the fragmentation of sub-lakes in winter and its effects on wintering waterbirds in Poyang Lake. Poyang Lake becomes fragmented in winter, which forms many seasonal sub-lakes every year, and have different environmental characteristics. These sub-lakes significantly impact winter bird habitats and result in susceptibility to various changes, because birds have different distribution responses. A total of 24 sub-lakes were surveyed from one to five vantage points using point count methods in each sub-lake with binoculars, monocular, and a spotting scope for four consecutive winter seasons. The multi-site dissimilarity Sorensen index measures overlapped between two populations, and the R software "iNEXT" package was used to evaluate the sample coverage test of the study area. We observed 58 wintering waterbird species belonging to 9 orders and 15 families from 2016 to 2020. Spearman correlation analysis showed that the species richness of wintering waterbirds was significantly positively correlated with the sub-lake areas and associated with the richness of habitat type. The WNODF analyses were considerably correlated for sites of waterbirds, mainly with the abundance of forage and conservation of habitat form. The outcomes of this study showed that Maying Lake has the highest local beta diversity, whereas Dacha Lake has the lowest local beta diversity contribution (0.007). This study's findings demonstrate Poyang Lake's role in waterbird the habitat suitability of waterbirds, especially for foraging and conservation. [ABSTRACT FROM AUTHOR]

Against the background of global warming, trees in high-latitude and high-altitude areas are more sensitive to rapid warming. Revealing the response patterns of trees at different altitudes to rapid warming in typical alpine mountain environments can help to predict the future distribution of forests in the region and the associated changes in the timberline. This study used tree-ring width data (band sampling) from Dahurian larch (Larix gmelinii Rupr.) along an altitudinal gradient (970–1409 m) on Oakley Mountain to establish 10 chronologies and to analyze the growth–climate response of larch to warming and altitudinal changes along a gradient. The results showed that before rapid warming, larch growth was strongly influenced mainly by precipitation in July–August, while after warming, the growth was controlled mainly by precipitation (snowfall) in winter (October–April) and showed a significant positive correlation with the SPEI in winter and a negative correlation with temperature in February–April (early spring). This indicates that the rapid warming event led to a drastic change in the water heat balance during the pre-growth period of the trees in the study area, which shifted the tree growth from being restricted by drought in the growing season before warming to being restricted by winter drought (i.e., the lagged effect of snowfall in the pre-growing season) after warming and that the trees at low altitudes suffered from more severe winter drought. In the future, as the global climate warms further, the growth of mountain larch at low altitudes (below 1200 m) will continue to decrease, and the coupling of winter snowfall and seasonal (February–April) warming will increase the upper altitude limit at which winter drought occurs for larch in the study area; additionally, larch at higher altitudes will be able to cope with this ecological process better. [ABSTRACT FROM AUTHOR]

In winter, the water transfer channel of the Middle Route of South-to-North Water Transfer Project (MR-StNWTP) in China always encounters ice problems. The preciously simulation and prediction of water temperature is essential for analyzing the ice condition, which is important for the safety control of the water transfer channel in winter. Due to the difference of specific heat between water and air, when the air temperature rises and falls dramatically, the range of change of water temperature is relatively small and has a lag, which often affects the accuracy of simulation and prediction of water temperature based on air temperature. In the present study, a new approach for simulating and predicting water temperature in water transfer channels in winter has been proposed. By coupling the neural network theory to equations describing water temperature, a model has been developed for predicting water temperature. The temperature data of prototype observations in winter are preprocessed through the wavelet decomposition and noise reduction. Then, the wavelet soft threshold denoising method is used to eliminate the fluctuation of certain temperature data of prototype observations, and the corresponding water temperature is calculated afterward. Compared to calculation results using both general neural network and multiple regression approaches, the calculation results using the proposed model agree well with those of prototype measurements and can effectively improve the accuracy of prediction of water temperature. [ABSTRACT FROM AUTHOR]

The pollution of atmospheric ozone in China shows an obvious upward trend in the past decade. However, the studies on the atmospheric oxidation capacity and O 3 formation in four seasons in the southeastern coastal region of China with the rapid urbanization remain limited. Here, a four-season field observation was carried out in a coastal city of southeast China, using an observation-based model combining with the Master Chemical Mechanism, to explore the atmospheric oxidation capacity (AOC), radical chemistry, O 3 formation pathways and sensitivity. The results showed that the average net O 3 production rate (14.55 ppbv/hr) in summer was the strongest, but the average O 3 concentrations in autumn was higher. The AOC and RO x levels presented an obvious seasonal pattern with the maximum value in summer, while the OH reactivity in winter was the highest with an average value of 22.75 sec−1. The OH reactivity was dominated by oxygenated VOCs (OVOCs) (30.6%-42.8%), CO (23.2%-26.8%), NO 2 (13.6%-22.0%), and alkenes (8.4%-12.5%) in different seasons. HONO photolysis dominated OH primary source on daytime in winter, while in other seasons, HONO photolysis in the morning and ozone photolysis in the afternoon contributed mostly. Sensitivity analysis indicated that O 3 production was controlled by VOCs in spring, autumn and winter, but a VOC-limited and NO x -limited regime in summer, and alkene and aromatic species were the major controlling factors to O 3 formation. Overall, the study characterized the atmospheric oxidation capacity and elucidated the controlling factors for O 3 production in the coastal area with the rapid urbanization in China. [ABSTRACT FROM AUTHOR]

The Yangtze River Delta (YRD) is an important economic region in China. Heavy winter rainfall may pose serious threats to city operations. To ensure the safe operation of the city, meteorological departments need to provide forecast results for the Spring Festival travel rush weather service. Therefore, the extended-range forecast of winter rainfall is of considerable importance. To solve this problem, based on the analysis of low-frequency rainfall and the intra-seasonal oscillation of atmospheric circulation, an extended-range forecast model for winter rainfall is developed using spatiotemporal projection methods and is applied to a case study from 2020. The results show that: (1) The precipitation in the YRD during the winter has a significant intra-seasonal oscillation (ISO) with a periodicity of 10–30 d. (2) The atmospheric circulations associated with winter rainfall in the YRD have a significant characteristic of low-frequency oscillation. From a 30-day to a 0-day lead, large modifications appear in the low-frequency atmospheric circulations at low, mid, and high latitudes. At low latitudes, strong wet convective activity characterized by a negative OLR combined with a positive RH700 correlation coefficient moves northwestward and covers the entire YRD. Meanwhile, the Western Pacific subtropical high (WPSH) characterized by a positive Z500 anomaly enhances and lifts northward. At mid and high latitudes, the signal of negatively correlated Z500 northwest of Lake Balkhash propagates southeastward, indicating the cold is air moving southward. Multiple circulation factors combine together and lead to the precipitation process in the YRD. (3) Taking the intra-seasonal dynamical evolution process of the atmospheric circulation as the prediction factor, the spatiotemporal method is used to build the model for winter mean extended-range precipitation anomaly tendency in the YRD. The hindcast for the recent 10 years shows that the ensemble model has a higher skill that can reach up to 20 days. In particular, the skill of the eastern part of the YRD can reach 25 days. (4) The rainfall in the 2019/2020 winter has a significant ISO. The ensemble model could forecast the most extreme precipitation for 20 days ahead. [ABSTRACT FROM AUTHOR]

The mid‐high latitude intraseasonal oscillation (ISO) has remarkable impacts on the Northern Hemisphere. However, the interannual variance of the mid‐high latitude ISO and its underlying mechanism are rarely explored. Here, we find that the tropical stratospheric Quasi‐Biennial Oscillation (QBO) has notable impacts. A statistically significant contrast in the interannual variability of intraseasonal 2‐m temperature (T2m) over northern Eurasia is detected between the easterly (EQBO) and westerly (WQBO) QBO phase. The influence of the QBO could be attributed to the interactions of ISO perturbation and QBO‐related winter‐mean flow. Specifically, the ISO perturbation is more efficient in extracting kinetic and potential energy from the winter‐mean flow in EQBO. Additionally, the northern Eurasia ISO propagates southeastward and exert effects on China. Due to this, the subseasonal forecast system of NUIST (NUIST CFS1.1) displays higher skill in predicting the T2m in China during EQBO phase at 3, 4, and 5 pentads in advance. Plain Language Summary: Extreme weather and climate in winter, such as cold waves, snowstorms, and prolonged low temperature, have severe impacts on the society, therefore it is of great value to improve subseasonal prediction of 2‐m temperature (T2m). In this study, we find that the variability of intraseasonal T2m over northern Eurasia varies from year to year during boreal winter, which is negatively correlated with the tropical stratospheric Quasi‐Biennial Oscillation (QBO). The variability of intraseasonal T2m is enhanced during QBO easterly phase (EQBO). In accordance with the higher variance of intraseasonal T2m, the extreme temperature events display higher frequency and stronger intensity in EQBO. We also find that the intraseasonal oscillation (ISO) in the northern Eurasia is not stationary, it often propagates southeastward, impacting the weather and climate in China. This has implications for the prediction of intraseasonal T2m in China. These results help understanding the relationship between the tropical QBO and mid‐high latitude ISO and provide a potential way to improve the subseasonal forecasts. Key Points: The interannual variability of intraseasonal 2‐m temperature (T2m) is amplified during easterly Quasi‐Biennial Oscillation (EQBO) in winterThe likelihood of extreme temperature events, particularly cold extreme events with intensified high‐pressure systems, is enhanced in EQBOThe southeastward propagation of the intraseasonal oscillation over northern Eurasia has impacts on winter temperature in China [ABSTRACT FROM AUTHOR]

Climate warming has induced significant shifts in spring phenology over both temperate and boreal forests. The timing of bud growth resuming from dormancy is crucial for predicting spring phenology. However, the mechanisms by which environmental cues, other than chilling accumulation, initiate bud growth remains unclear. By constructing a revised process-based spring phenology model incorporating photoperiod and temperature triggers of bud growth, we simulated the first leaf unfolding and first flowering dates of four deciduous forest trees during 1981-2014 at 102 stations across China’s monsoon regions. Then, we revealed spatial patterns of the two triggers. Moreover, we compared fitting precision and robustness of the revised model with three mainstream models. Results show that the revised models can effectively simulate all spring phenology time series. Growth initiation of foliar and floral buds was induced by photoperiod lengthening in 80.8% and 77.7% of time series, and by temperature increasing in remaining 19.2% and 22.3% of time series, respectively. The proportions of time series with photoperiod- and temperatureinitiated bud growth significantly increase and decrease from northern to southern climatic zones, respectively. Chilling exposure controls the predominant bud growth triggers in different climate zones. Specifically, in regions with long and severe winters where chilling requirement is easily fulfilled, rising temperature in spring alleviates the cold constraint and initiate bud growth. Conversely, in regions with short and mild winters, prolonged daylength in spring compensates the lack of chilling exposure to initiate bud growth. These findings suggest that photoperiod may limit spring phenology response to temperature in low-latitudes. Overall, our model slightly outperforms other models in terms of efficiency, accuracy, and robustness in modeling leaf unfolding and flowering dates. Therefore, this study deepens our understanding of the mechanisms of spring phenology, and improves the predicting capability of spring phenology models in the face of ongoing global warming. [ABSTRACT FROM AUTHOR]

Simple Summary: The critically endangered Siberian crane (Grus leucogeranus) relies on Poyang Lake's wetlands in China for wintering. Rapid changes in these wetlands, driven by climate shifts and human activities, affect habitat and food availability for these birds. Our study investigated Poyang Lake's hydrological dynamics over the past two decades and assessed the impact of related variables on crane populations. Employing advanced modeling, we predicted how varying water levels influence suitable habitats for Siberian cranes. Our findings revealed that a summer-inundated area exerted a notable influence on population fluctuations in crane species in the natural habitats of Poyang Lake. The scarcity of food, resulting from summer floods, compels cranes to adapt by exploring alternative food sources and new foraging grounds, including artificial habitats. During the dry season, the size of the inundated area primarily impacts the food availability for Siberian cranes, thereby influencing both their population size and distribution pattern, and a moderate water level of 8–10 m provides the highest amount of good habitat. Persistent winter droughts exacerbate the unsuitability of habitats, and the shortage of food in natural habitats may become a recurring occurrence in the future. This study emphasizes the importance of managing both natural and artificial habitats to support Siberian crane conservation amid environmental changes. To assess the Siberian crane (Grus leucogeranus)'s response to changing water levels and habitat quality at Poyang Lake, we analyzed the lake's hydrological trends over the past two decades with the Mann-Kendall and Sen slope methods. Additionally, we explored the link between the crane population size and hydrological conditions at the lake from 2011 to 2019. Meanwhile, five environmental factors, including habitat type, distance from shallow lakes, human footprint index, elevation and normalized vegetation index were selected, and the distribution patterns of suitable habitats for the Siberian crane under 10 water level gradients with intervals of about 1 m (5.3–14.2 m) were simulated by using an improved habitat suitability index model that determines the weights of evaluating factors based on the MaxEnt model. The results showed that the overall trend of the inundated area in Poyang Lake was shrinking in the last 20 years, with a significant increase in the area of exposed floodland during the early wintering period (Z = −2.26). The prolonged drought resulting from this will force vegetation succession, thereby diminishing the food resources for cranes in their natural habitat. The mean inundated area in June demonstrated a significant negative correlation with the population of Siberian cranes in natural habitats (r = −0.75, p = 0.02). Shortage of the Siberian crane-preferred Vallisneria tuber due to June flooding was the primary driver of the crane's altered foraging strategy and habitat shift. In years with relatively normal June inundation, indicating abundant Vallisneria resources, the relationship between the inundated area during the dry season and the crane population fit well, with a quadratic curve (R2 = 0.92, p = 0.02). The dry season's inundated area primarily affected the crane population and distribution pattern by influencing the availability of food resources, and both excessive and insufficient inundation areas were unfavorable for crane survival. The modeling results for habitat suitability indicated that as the water level decreased, the trend of the area of good habitat for the Siberian crane showed an inverted bell shape, peaking at a water level of 8.8 m, with optimal conditions occurring between 8 and 10 m. The combined effects of climate and human activities have made the shortage of food resources in Poyang Lake the new normal. The degradation of natural habitats has led to a decline in the quality of Siberian crane habitats, and artificial habitats can only be used as refuges to a certain extent. Thus, formulating strategies to restore natural habitats and enhance the management of artificial habitats is crucial for the conservation efforts of Siberian cranes. [ABSTRACT FROM AUTHOR]

The nitrate radical (NO 3) is a critical nocturnal atmospheric oxidant in the troposphere, which widely affects the fate of air pollutants and regulates air quality. Many previous works have reported the chemistry of NO 3 in inland regions of China, while fewer studies target marine regions. Here, we present a field measurement of the NO 3 reservoir, dinitrogen pentoxide (N 2 O 5), and related species at a typical marine site (Da Wan Shan Island) located in the South China Sea in the winter of 2021. Two patterns of air masses were captured during the campaign, including the dominant airmass from inland China (IAM) with a percentage of ∼ 84 %, and the airmass from eastern coastal areas (CAM) with ∼ 16 %. During the IAM period, the NO 3 production rate reached 1.6 ± 0.9 ppbv h -1 due to the transportation of the polluted urban plume with high NO x and O 3. The average nocturnal N 2 O 5 and the calculated NO 3 mixing ratios were 119.5 ± 128.6 and 9.9 ± 12.5 pptv, respectively, and the steady-state lifetime of NO 3 was 0.5 ± 0.7 min on average, indicating intensive nighttime chemistry and rapid NO 3 loss at this site. By examining the reaction of NO 3 with volatile organic compounds (VOCs) and N 2 O 5 heterogeneous hydrolysis, we revealed that these two reaction pathways were not responsible for the NO 3 loss (< 20 %) since the NO 3 reactivity (k (NO 3)) towards VOCs was small (5.2×10-3 s -1) and the aerosol loading was low. Instead, NO was proposed to significantly contribute to nocturnal NO 3 loss at this site, despite the nocturnal NO concentration always below the parts per billion by volume level and near the instrument detection limit. This might be from the local soil emission or something else. We infer that the nocturnal chemical NO 3 reactions would be largely enhanced once without NO emission in the open ocean after the air mass passes through this site, thus highlighting the strong influences of the urban outflow to the downwind marine areas in terms of nighttime chemistry. During the CAM period, nocturnal ozone was higher, while NO x was much lower. The NO 3 production was still very fast, with a rate of 1.2 ppbv h -1. With the absence of N 2 O 5 measurement in this period, the NO 3 reactivity towards VOCs and N 2 O 5 uptake were calculated to assess NO 3 loss processes. We showed that the average k (NO 3) from VOCs (56.5 %, 2.6 ± 0.9 × 10 -3 s -1) was higher than that from N 2 O 5 uptake (43.5 %, 2.0 ± 1.5 × 10 -3 s -1) during the CAM period, indicating a longer NO 3 / N 2 O 5 lifetime than that during IAM period. This study improves the understanding of the nocturnal NO 3 budget and environmental impacts with the interaction of anthropogenic and natural activities in marine regions. [ABSTRACT FROM AUTHOR]

Isodon xiaoluzhiensis, a new species of the tribe Ocimeae in family Lamiaceae, is described and illustrated. The new species is known only from the type locality, Xiaoluzhi village in Luzhijang dry-hot valley of Yimen County, central Yunnan, southwest China. It is characterized by having a procumbent habit, gracile stems and branches, relatively small leaves and flowers, and the phenology of flowering in winter. The morphological comparisons with its putative closest relatives (I. adenanthus and I. hsiwenii) are also presented. [ABSTRACT FROM AUTHOR]

Simple Summary: Due to the fact that rabbit meat possesses high levels of proteins and polyunsaturated fatty acids with low contents of fat and cholesterol that can meet the urgent demand for a healthy diet in modern life, the meat rabbit industry in China has been rapidly developed in recent years. However, rabbits are more sensitive to seasonal changes owing to their specific physiological characteristics, such as few sweat glands, thick coats of fur, high metabolic rate, and high growth rate. In this study, we investigated the variations in productivity, health status, and gut microbiota of meat rabbits reared in semi-confined conditions between summer and winter. In the summer season, the relative high ambient temperature and humidity could trigger disturbance of the gut microbiome, potential heat stress, reduced antioxidant defense, and increased inflammation risk, which consequently deteriorated production performance. In the winter season, changes in energy demand, photoperiod, and feeding pattern should be regarded as important factors that affect the productivity of meat rabbits. Based on our findings, we not only proposed several realistic strategies to alleviate the unfavorable influences of seasonal alterations on the productivity and well-being of meat rabbits but also pointed out the future directions for this study of molecular mechanisms in adaptation physiology. In this study, we investigated the variations in production performance, health status, and gut microbiota of meat rabbits raised in the semi-confined barn during summer and winter. Compared to summer, rabbits reared in winter possessed significantly higher slaughter weight and carcass weight. Rabbits fed in the summer were more vulnerable to different stressors, which led to increased protein levels of HSP90, IL-1α, IL-1β, IL-2, and concentrations of MDA, but declined GSH and SOD activities. Additionally, significant differences in gut microbial communities were observed. Compared to the winter, rabbits fed in the summer had significantly lower and higher alpha and beta diversity. Both Firmicutes and Verrucomicrobiota were the dominant phyla, and they accounted for greater proportions in the winter than in the summer. At lower microbial taxa levels, several seasonal differentially enriched microbes were identified, such as Akkermansia muciniphila, the Oscillospiraceae NK4A214 group, the Christensenellaceae R-7 group, Alistipes, and Muribaculaceae. Functional capacities linked to microbial proliferation, nutrient metabolism, and environmental adaptive responses exhibited significantly different abundances between summer and winter. Moreover, strong interactions among different indicators were presented. Based on our findings, we not only proposed several potential strategies to ameliorate the undesirable effects of seasonal changes on the productivity and health of meat rabbits but also underscored the directions for future mechanistic studies of adaptation physiology. [ABSTRACT FROM AUTHOR]

Folk residence in the cold region of Northeast China is an integral part of China's traditional folk residence, with significant geographical representation. In this paper, we take the residential compounds of villages and towns in the cold region of Northeast China as the research object, summarize four typical layout forms of residential compounds of villages and towns in the cold region of Northeast China, simulate the wind environment of combinations of different layout forms in winter using the computer numerical simulation software Fluent, and then analyze and evaluate the wind environment of the compounds, including the evaluation standard of the wind speed ratio and considering the area of wind shadows, number of vortices, and other factors. [ABSTRACT FROM AUTHOR]

In this study, we constructed a ring-width chronology derived from Betula ermanii (BE) near the transitional zone between forests and tundra within the Changbai Mountain (CBM) region. This chronology was established utilizing 55 cores obtained from 30 trees. Our analysis of growth/climate responses underscores the pivotal role of the mean maximum winter temperature in influencing radial growth. Drawing upon these growth/climate associations, we reconstructed the mean maximum temperature series for December of the preceding year through January of the current year for the years 1787 and 2005 CE, employing a standardized chronology. During the calibration period (1960–2005), the reconstructed series exhibited an explained variance of 36%. This reconstruction provides crucial insights into historical temperature fluctuations within the study area. Our findings indicate that year-to-year temperature variations did not manifest synchronously along the altitude gradient of Changbai Mountain. Notably, the response to recent winter warming exhibited disparities with the altitude on Changbai Mountain. Specifically, the higher altitude range (1950–2000 m a.s.l.) displayed a response to warming around 1960, the mid-altitude range (765–1188 m a.s.l.) responded around 1975, and the lowest altitude (650 m a.s.l.) responded by 1977. Consequently, the paleotemperature research outcomes from Changbai Mountain alone may not adequately characterize climate change in this region. We recommend future high-resolution temperature records be obtained through sampling at various altitudes to enhance the comprehensiveness of our understanding. [ABSTRACT FROM AUTHOR]

In spring 2022, strong temperature whiplash events occurred in eastern China (EC), characterized by enhanced subseasonal variability in surface air temperature (SAT). Our results show that extreme temperature fluctuations are dominated by the amplified Eurasian wave train on a biweekly timescale as a possible response to increased sea ice concentrations (SICs) over the Barents‐Kara Seas (BK) in previous winter. Increased winter SICs weaken the upward planetary waves and enhance the stratospheric polar vortex. In spring, the downward propagation of enhanced polar vortex intensifies the polar front jet, increasing kinetic energy gain of the North Atlantic wave train and guiding it to travel farther eastward. The Eurasian wave train strengthens through an upstream development and enhanced local baroclinicity and enhances subseasonal SAT variability over EC. Therefore, the state of BK SICs in previous winter could be a useful signal for the enhanced likelihood of spring extreme temperature whiplash events. Plain Language Summary: In spring 2022, extremely cold and warm spells alternately affected eastern China (EC) and caused drastic temperature whiplash events, featured by the enhanced subseasonal variability of surface air temperature (SAT). We find the subseasonal SAT variability is directly associated with the Eurasian wave train, and its intensity is correlated with sea ice concentrations (SICs) over the Barents‐Kara Seas (BK) in previous winter. Increased SICs reduce the heat transfer from ocean to atmosphere, induce a cyclone anomaly aloft, and diminish the climatological planetary wavenumber‐1 component. The weakened upward wave activity flux strengthens the stratospheric polar vortex, which spreads downward until spring. Hence, the polar front jet in the North Atlantic is enhanced, and the meridional temperature gradient in northern Europe increases, providing a favorable background for atmospheric disturbance development. The North Atlantic wave train propagates farther eastward after gaining more kinetic energy from the accelerated jet and intensifies the following Eurasian wave train. Due to stronger local baroclinic energy conversion, the Eurasian wave train further strengthens, resulting in enhanced subseasonal SAT variability over EC. Therefore, the extremely increased winter BK SICs could be a useful initial signal for the probability of temperature whiplash events over EC in the following spring. Key Points: Record‐breaking subseasonal variability of surface air temperature (SAT) prevails in eastern China in spring 2022Sea ice concentrations over the Barents‐Kara Seas in previous winter strengthen mean state of North Atlantic circulation via the delayed role of the stratosphereThe upstream interaction between mean state and eddies reinforces the Eurasian wave train and enhances subseasonal SAT variability [ABSTRACT FROM AUTHOR]

Appropriate greening design can enhance the microclimate of residential areas. This study investigated different greening cases for residential buildings in hot summer–cold winter zones. Four sorts of greening layouts were tested in a residential area in Chongqing, China. Arbor–grass mix and arbor–shrub–grass mix showed effective cooling and humidifying effects, and were chosen for further study using the ENVI-met model. The simulations were conducted in Chongqing, comparing sixteen greening cases for determinant and enclosed building forms. Results indicate that the greening design for determinant layout should give priority to ensuring the greening area and shortening the distance from the sidewalk. While enclosed layout should concentrate greening in dense populations, using arbor–shrub–grass mix to improve the wind environment. In cases where the distribution of arbors and shrubs covers a ratio of 7:4, constituting 30% of the overall green space, there is a reduction in environmental temperature by 1.4 °C and in PET by 4.8 °C. This study provides the optimal greening layout for two types of residential areas in China's hot summer–cold winter zones, guiding landscape construction in these residential areas to optimize the microclimate. [ABSTRACT FROM AUTHOR]

Simple Summary: Predatory spider and epigaeic beetle assemblages are major natural enemies (NEs) in agricultural ecosystems. The effects of non-crop natural habitats in supporting predatory NEs are well known for summer crop systems; however, limited attention has been given to summer–winter crop rotation transaction systems and during overwintering periods, especially in small-scale farmland systems. Here, we examine the effect of winter planting regimes and landscape composition on the species diversity and functional diversity of ground predators (spiders and carabids) in eight gradient landscape sites in southern China over two consecutive winters (2019/2020 and 2020/2021). Our work reveal that the spiders were more abundant and had a higher activity density in fallow rice fields (FRs) than oilseed rape fields (OSRs); however, the ground beetles were more abundant in OSRs than that in FRs. The composition of spider assemblages was impacted by semi-natural habitats (SNHs) during overwintering, while ground beetle assemblages were influenced mainly by overwintering planting patterns. The results suggest that different planting regimes and SNHs are a strategic way to enhance these ground predators. To conserve and improve predator diversity during overwintering, we suggest maintaining a diversity of planting regimes and conserving local semi-natural habitats. The rotation patterns of summer rice–winter oil seed rape and summer rice–winter fallow are the main planting regimes in the rice ecosystem in southern China. However, the impact of local rotation patterns and landscape factors on the overwintering conservation of predators in spider and epigaeic beetle assemblages remains poorly understood. Here, we investigate the diversity and density of spiders and beetles over two consecutive winters (2019/2020 and 2020/2021), focusing on the impact of two rotation patterns (rice–fallow and rice–oilseed rape) and surrounding landscape compositions on predator diversity. The main findings of our research were that spiders were more abundant and had a higher activity density in the fallow rice fields (FRs) compared to the oilseed rape fields (OSRs), whereas ground beetles exhibited the opposite pattern. Specifically, fallow rice fields supported small and ballooning spiders (e.g., dominant spider: Ummeliata insecticeps), while OSRs supported larger ground beetles (e.g., dominant beetles: Agonum chalcomus and Pterostichus liodactylus). Moreover, the composition of spider assemblages were impacted by semi-natural habitats (SNHs) during overwintering, while ground beetle assemblages were influenced by overwinter planting patterns. Overall, our results suggest that different planting regimes and preserving semi-natural habitats are a strategic way to enhance species diversity and functional diversity of ground predators. It is, therefore, recommended that to conserve and improve predator diversity during overwintering, land managers and farmers should aim to maintain diverse planting regimes and conserve local semi-natural habitats. [ABSTRACT FROM AUTHOR]

The role of the Tibetan Plateau (TP) in Asian hydrological climate is crucial, yet there is a lack of quantitative estimates regarding its impact on snowfall in China. Some opinions suggest that the TP functions as a large barrier that obstructs cold outbreaks, protecting southern China from severe snowstorms. Through topography experiments with and without the TP, our study suggests that the TP's presence results in a 60% decrease in snowfall in northern China by significantly reducing moisture. In contrast, it promotes a 1500% increase in snowfall in southern China, particularly from November to March, by drawing cold air from the north and moisture from the south to southern China. The presence of TP significantly enhances winter relative humidity in southern China, causing discomfort for humans. This research refutes some trending views and improves our understanding of the TP's role in China's winter climate. [ABSTRACT FROM AUTHOR]

Simple Summary: The swordtip squid (Uroteuthis edulis) is both of commercial and ecological importance and vital in the coastal China ecosystem. However, the limited ecological research requires further investigations into its habitat preferences. To address this, we studied how the habitat of U. edulis varies and what environmental factors drive its movements across different seasons in the East China Sea (ECS) and southern Yellow Sea. The study found that U. edulis predominantly inhabited the central and southern regions of the ECS, with a slight shift in the geometric center of its habitat across seasons. The preferences for sea surface temperature, sea surface height, and depth were the primary factors affecting its distribution. During summer and autumn, the suitable habitats of U. edulis were larger and expanded northwards towards the coastline, but in spring and winter, they retreated southwards to waters near the edge of the ECS continental shelf. These patterns are likely influenced by the changing mixture of ocean currents and varying environmental conditions throughout the year. This study provides valuable insight into how U. edulis is distributed in response to the changing environment, which can help to better manage and protect their populations. Accurately modeling the distribution of keystone species is of utmost importance to gain a comprehensive understanding of their complex ecological dynamics and to develop effective strategies for sustainable scientific management. In the coastal China ecosystem, the swordtip squid (Uroteuthis edulis) stands out as a keystone species with significant commercial and ecological value. Despite its importance, research on the ecological dynamics of this species remains limited and requires further investigation. To investigate the spatial and temporal variability in the distribution of U. edulis and identify the key environmental drivers in the East China Sea (ECS) and southern Yellow Sea across different seasons, we generated ensemble models using oceanographic variables and fishery-independent scientific survey data collected from 2016 to 2018. Our results revealed that U. edulis predominantly inhabited the central and southern regions of the ECS throughout the year. The primary environmental variables driving its distribution varied by season, with the sea surface temperature being the most important in spring, sea surface height in summer and autumn, and depth in winter. During summer and autumn, the suitable habitats of U. edulis were found to be largest and extended northwards towards the coastline. However, they migrated southwards to the waters near the edge of the ECS continental shelf with smaller suitable areas in the spring and winter. These results suggested that U. edulis exhibited season-specific habitat preferences and responded to changing environmental conditions throughout the year. The observed seasonal distribution patterns were likely influenced by the fluctuating mixture of waters (ocean currents) from different sources, with varying physical and chemical characteristics throughout the year. Our study provides baseline data for comprehending the population dynamics of U. edulis and highlights the significance of considering species' habitat preferences in a dynamic environment. [ABSTRACT FROM AUTHOR]

Severe PM2.5 pollution strikes winter eastern China, while its physical process associated with the atmospheric evolution from several days to weeks is not clear. This study uses weather types as intermediate agents between large‐scale atmospheric circulation and regional air pollution, to explore the whole circulation evolutionary chain related to wintertime PM2.5 pollution in eastern China. We extract objectively 6 weather types (WTs) for wintertime surface synoptic patterns in eastern China and analyze quantitatively the impacts of WTs on PM2.5 pollution. Then the preferred transitions between WTs are explored to explain potential weather process. We find a most frequently recurring circulation evolution corresponding to Mongolia high pressure that stretches southward to eastern China, referred as the WTs transition of YSH− > BLH− > MH, with PM2.5 increased in North China and dissipated as the high pressure moves southward. Further to establish intraseasonal connections between large‐scale circulation and regional synoptic patterns, several leading evolutionary chains are discovered among tropical Madden‐Julian Oscillation (MJO), extratropical teleconnections, and WTs of eastern China at an extended period. The positive or negative phase of teleconnections can indicate the WTs change 4–10 days in advance, while MJO further extends that indicative effect to 10–15 days. The intraseasonal oscillations of teleconnections such as conventional Eurasia, Scandinavia, Arctic Oscillation, Polar/Eurasia, Western Pacific and East Atlantic are associated with the transition of YSH− > BLH− > MH, and MJO may act as a precursor of teleconnection phases to extend effectively the prediction time for surface weather conditions and air pollution in eastern China. Plain Language Summary: Recently eastern China is experiencing severe PM2.5 pollution in winter, and meteorological conditions can play their roles in air pollution at multi timescale. The current most relevant researches focus on the influences of meteorology on air pollution at the seasonal and interannual timescales, but little effort has yet been made to investigate the intraseasonal variation of PM2.5 along with the day‐to‐day evolution rule of synoptic patterns. This study takes weather types as intermediate agents between the large‐scale circulation and the regional air pollution, to explore leading evolutionary chains among tropical Madden‐Julian Oscillation, extratropical teleconnections, and weather types of eastern China over an extended period. A most frequently recurring circulation evolution is detected that Mongolia high pressure stretches southward to eastern China, then PM2.5 pollution dissipate in the northern China. Multiple extratropical teleconnections in the Northern Hemisphere contribute their respective low‐frequency oscillation to impact the recurring circulation evolution in eastern China during winter. Key Points: A most frequently recurring circulation evolution is detected that Mongolia high pressure stretches southward to eastern ChinaTeleconnections can establish relationship with the frequently recurring circulation evolution related to wintertime PM2.5 in ChinaSeveral leading evolutionary chains are discovered to establish intraseasonal connections between large‐scale and regional circulations [ABSTRACT FROM AUTHOR]

Under the influence of global epidemics and the need for urban expansion, many outpatient buildings have been rapidly constructed, but the problem of high energy consumption has been neglected. There is a lack of research on the impact of outpatient building forms on energy consumption in different climate zones. Many studies have demonstrated that the energy consumption of a given building can be greatly reduced by adopting a reasonable spatial form design at the early stages of design. Therefore, if architects choose a reasonable spatial form, this could effectively reduce energy consumption. In this study, outpatient building cases in China were summarized, and three typical spatial forms were proposed: the centralized, corridor, and courtyard forms. The DesignBuilder tool was used to simulate and analyse the typical building energy consumption in different climate zones. The results showed that the corridor form (southwards) should be chosen in the severe cold zone, the centralized form (southwards) should be chosen in the cold zone and the hot summer and cold winter zone, the centralized form (northwards) should be chosen in the hot summer and warm winter zone, and the centralized or corridor form can be chosen in the warm zone. The results of this study could provide a reference for energy-efficient design of outpatient buildings in China and other regions with similar conditions and could help architects quickly select reasonable spatial forms at the early stages of design. [ABSTRACT FROM AUTHOR]

In this study, observational and model datasets are used to analyze winter precipitation and its leading empirical orthogonal function (EOF1) mode over Southeast China. EOF1 displays a dominant monosign pattern during the last 60 years; however, its major impacting factors have a decadal transition near the mid-1990s. The first principal component (PC1) is related to El Niño–Southern Oscillation (ENSO) after the mid-1990s and to the quasi-biennial oscillation (QBO) before the mid-1990s. An enhanced ENSO–precipitation relationship is associated with stronger ENSO-induced tropical zonal circulation and the westward shift of ENSO-induced SST over the tropical Pacific after the mid-1990s compared to before the mid-1990s. Negative correlation coefficients between QBO and precipitation are evident before the mid-1990s but are no longer statistically significant after the mid-1990s. This change originates from the interaction between QBO's subtropical influences and the Holton–Tan effect. The QBO's subtropical influence and the Holton–Tan effect lead to a zonal pressure gradient and meridional wind anomalies over East Asia before the mid-1990s, which further influence the meridional transport of water vapor and precipitation over Southeast China. However, the Holton–Tan effect is enhanced after the mid-1990s. Downward stratospheric polar vortex signals and the QBO's subtropical influence cause a meridional pressure gradient over East Asia, and thus the relevant moisture flux divergence lacks statistical significance. The above results indicate that the subtropical response to QBO and the Holton–Tan effect should be considered together when using the QBO signal to improve forecasts of winter precipitation over East Asia. Significance Statement: Southeast China winter precipitation (SCWP) is often attributed to variation in lower-atmospheric dynamics and sea surface temperature, such as El Niño–Southern Oscillation (ENSO). Few studies focus on the role of the mid- to upper atmosphere. In this study, we diagnose the influence of the stratospheric quasi-biennial oscillation (QBO) on SCWP. Both observational and modeling analyses indicate a strong decadal change in the QBO–SCWP relationship, which limits the use of the QBO in seasonal forecasts of SCWP. This decadal change originates from the strength of the QBO's modulation of the stratospheric polar vortex. Our results provide a new perspective on the use of the mid- to upper atmosphere in seasonal forecasts of SCWP. [ABSTRACT FROM AUTHOR]

Based on the daily temperature observation data at 1992 stations in China, this study investigates the intra‐seasonal variations and trends of extreme warm spells during 1981–2022. The results indicate that the nationwide extreme cold and warm spells have both increased rapidly since the 21st century. However, different from cold extremes which occur evenly in winter months, the nationwide super warm spells have distinct intra‐seasonal differences, with more occurrences in February. The number of nationwide extreme warm spells has increased from 8 during 1981–2001 to 14 during 2002–2022, and the intensity has also increased obviously. Due to the spatial differences, the study area is divided into three regions to reveal the detailed features. It is found that the warm spell frequencies in most of China increase from December to February while decrease in northeastern China. Results demonstrate that extreme warm spells are concentrated in late winter in most regions (stations). The significant increasing trends are widespread from northern China to most parts of southern China, and the areas with increasing trend exceeding +0.6 day/decade are concentrated in North China and the middle reaches of the Yangtze River. Linear trends indicate that the significantly increasing trends in late winter contribute a major part to the variation in the whole winter in China. [ABSTRACT FROM AUTHOR]

Prolonged low temperature significantly threatens transportation and planting in populous areas and is closely linked to slowly varying forcing such as sea surface temperature (SST). In this study, we reveal the impact of the north–south dipole pattern in extra-tropical North Atlantic SST (DNA) anomaly on surface air temperature (SAT) over southern China in February. The positive phase of the DNA is favorable for a positive North Atlantic Oscillation-like pattern at the troposphere via synoptic eddy vorticity forcing and triggers a southeastward-propagating Rossby wave train associated with the deepened East Asian trough and the strengthened Siberian high, which are conducive to enhancement of the East Asian winter monsoon. A stronger monsoon leads to lower-than-normal SAT over southern China by intensifying southward cold air outbreaks. Considerably, the extremely low temperature over southern China in February 2022 is explainable by this physical mechanism. Furthermore, experiments with a linear baroclinic model verify that the proposed downstream propagating Rossby wave train is mainly associated with the midlatitude North Atlantic SST anomaly. These results emphasize that the extra-tropical North Atlantic SST anomaly should be focused when interpreting and predicting the late winter SAT over southern China. [ABSTRACT FROM AUTHOR]

A single ozone (O 3) tracer mode was developed in this work to build the capability of the Goddard Earth Observing System model with Chemistry (GEOS-Chem) for rapid O 3 simulation. The single O 3 tracer simulation demonstrates consistency with the GEOS-Chem full chemistry simulation, with dramatic reductions in computational costs of approximately 91 %–94 %. The single O 3 tracer simulation was combined with surface and Ozone Monitoring Instrument (OMI) O 3 observations to investigate the changes in tropospheric O 3 over eastern China in 2015–2020. The assimilated O 3 concentrations demonstrate good agreement with O 3 observations because surface O 3 concentrations are 43.2, 41.8, and 42.1 ppb and tropospheric O 3 columns are 37.1, 37.9, and 38.0 DU in the simulations, assimilations, and observations, respectively. The assimilations indicate rapid rises in surface O 3 concentrations by 1.60 (spring), 1.16 (summer), 1.47 (autumn), and 0.80 ppb yr -1 (winter) over eastern China in 2015–2020, and the increasing trends are underestimated by the a priori simulations. More attention is suggested to the rapid increases in the O 3 pollution in spring and autumn. We find stronger rises in tropospheric O 3 columns over highly polluted areas due to larger local contributions, for example, 0.12 DU yr -1 (North China Plain) in contrast to -0.29 (Sichuan Basin) and -0.25 DU yr -1 (southern China). Furthermore, our analysis demonstrated noticeable contributions of the interannual variability in background O 3 to the trends in surface O 3 (particularly in the summer) and tropospheric O 3 columns over eastern China in 2015–2020. This work highlights the importance of rapid simulations and assimilations to extend and interpret atmospheric O 3 observations. [ABSTRACT FROM AUTHOR]