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Hand, foot, and mouth disease (HFMD) is a global infectious disease severely threatening children's health. It has been recognized that climate factors play an important role in the transmission of HFMD. In this paper, the bootstrap test in the geographically weighted regression (GWR) literature is extended to geographically and temporally weighted regression (GTWR) models for identifying homogeneous explanatory variables and spatiotemporally heterogeneous ones. The resulting mixed GTWR model is then used to investigate spatiotemporal effect of climate factors on the HFMD incidence in Inner Mongolia, China, a provincial autonomous region with extensive area and different climatic conditions. The results demonstrate that the effect of relative humidity is global over space and time, while that of air temperature, air pressure and wind speed varies spatiotemporally. The extended bootstrap test provides a solid statistical basis for model selection. The findings from the study may provide not only a deep understanding of spatiotemporal variation characteristics of the climatic effect on the HFMD incidence, but also some useful evidences for taking measures of the disease prevention and control at the county level in different seasons. [ABSTRACT FROM AUTHOR]

Variability in East Asian summer monsoon precipitation during the Holocene remains of debate. In this study, we use a closed lake with well‐dated lake beach ridges located on the margin of the East Asian summer monsoon, a region highly sensitive to monsoon precipitation changes, to obtain a temporal sequence of water volume in North China. The elevation of each beach ridge calibrated to the modern lake level was surveyed. Optically stimulated luminescence dating of undisturbed sediments of beach ridges was performed. The lake area and water volume corresponding to each beach ridge were calculated using a digital elevation model. This study reveals relatively reduced monsoon precipitation from ~12 to 7 ka interrupted by strengthening of the monsoon circulation to a maximum from ~7 to ~5 ka and followed by greatly reduced monsoon intensity until the present day. These results demonstrate that changes in the East Asian summer monsoon precipitation may not be directly driven by global temperature or atmospheric CO2 content. Rather, we suggest that variation in the the monsoon margin precipitation is probably mainly driven by ice volume and subordinately by the summer solar insolation difference between mid‐latitude land and low‐latitude ocean. [ABSTRACT FROM AUTHOR]

Previous studies indicate that vegetation and lakes in arid and semi-arid regions are closely related to climate change. However, the responses of vegetation and lakes to climate-related variables have rarely been contrastively studied. The Hulun Lake (HLL) and its surrounding grasslands in Northeast Inner Mongolia of China comprise a semi-arid region that has experienced intense climate change over the last several decades. This study aims to understand the key factors that control the variations in the lake area and vegetation cover over the last five decades in the HLL region, as well as contrastively investigate the different responses of the lake area and vegetation cover to climate-related variables. Analysis results indicate that the variations with increasing change rates in the HLL area were mainly controlled by precipitation fluctuation. Moreover, an increase or decrease in the air temperature and relative humidity could affect the response time of the HLL area to the change in precipitation. The Normalized Difference Vegetation Index (NDVI) variations from 1990 to 1999 around the HLL region were mainly controlled by the intense local grazing rather than climatic restrictions. The fluctuation in NDVI after 1999 reflects the response of the vegetation cover to climatic change. The correlation analysis shows that the variations in the HLL area were closely related to the multi-year tendency of precipitation amount and to the Standardized Precipitation Evapotranspiration Index (SPEI) with a long timescale. However, NDVI is sensitive to changes in short-term precipitation amount, such as seasonal precipitation, and in SPEI with a monthly timescale. The soil moisture at shallow depths (< 0.1 m) was the key root–zone soil moisture that could influence NDVI, whereas soil moisture at depths of 0.4 to 1.0 m and the HLL area were closely related and had similar responses to climatic change. [ABSTRACT FROM AUTHOR]

In Inner Mongolia, China, semi-arid grasslands have strong winds and radiation in spring, but it is unclear how grazing management influences the connections between aerodynamic and energy balance during this time. During spring, we conducted measurements of radiation, wind speed, and air temperature, for both grazed and grazing-prohibited grasslands. From these results it was found that the temperature gradient differential (ΔT = T 0.4m -T 2m) between the ground level (T 0.4m) and the high height (T 2m) is normally negative at night and positive during the day. Grazed grassland was found to have very few negative ΔT values. Albedo and ΔT were higher on the grazed grasslands, while net radiation and aerodynamic roughness (Z 0) were lower on the grazed grasslands. According to structural equation modeling (SEM), the grazing prohibited and grazed had no effect on the relationship between surface albedo, air temperature, and humidity. Z 0 in grazed grassland exhibited a substantial positive correlation with net radiation (Rn), but was not correlated with albedo. The Z 0 of the grazing-prohibited grassland exhibited a substantial negative correlation with albedo, but not with Rn, and Z 0 had a significant negative correlation with air temperature. These findings explain how grazing measures affect the vertical variations of surface heat in air. [Display omitted] • Quantify the thermal and aerodynamic properties over the grass. • The vertical temperature difference (ΔT) is smaller in the prohibited grassland. • Higher aerodynamic impedance and net radiation in the prohibited grassland. • Grazing affects the relationship between radiation, aerodynamics and air temperature. [ABSTRACT FROM AUTHOR]

• Snow cover exerted a weak effect on MSFD across China. • Regional differences in the effects of snow cover on MSFD were relatively large. • ASD has a greater influence on MSFD than does SCD. • Modified Stefan formula could improve MSFD estimation accuracy. Using 1980–2014 observation data of 378 meteorological stations, this study quantified the correlations between snow cover and the annual maximum seasonally freeze depth (MSFD) across China and the contributions of snow cover to MSFD. Snow cover exhibited a weak effect on MSFD across China, which may be related to the thinness and short duration of the snow cover. Regional differences in the effects of snow cover on MSFD were relatively large, and the effects of snow cover were more significant than those of air temperature (characterized by the air-freezing index) at stations in Northeast China, northeastern Inner Mongolia, and the north of the Tianshan Mountains. In regions with a thin snow cover or short snow cover duration (SCD), the cooling effect of snow cover can dominate, but it only slightly influences MSFD owing to the short SCD. With increasing average snow depth (ASD) and SCD, the relative contributions of snow cover to MSFD gradually increased, peaking at SCDs of 120–140 days or ASDs of 8–10 cm, which is attributable to the increasing insulating effect. However, with further increase in ASD and SCD, the insulating effect decreases because of high albedo and the latent heat effect of snow melting. This decrease resulted in declining MSFD–snow cover correlations and snow cover contributions to MSFD. Compared with SCD, ASD has a greater influence on MSFD. By adding an ASD variable to the Stefan formula, this modified formula outperformed the conventional formula in MSFD estimation at SCDs of 60–140 days. This study demonstrated the importance of snow cover variables for soil freeze depth analysis and simulation in areas with large snow cover and further elucidated the effects of snow cover on soil freeze depth. [ABSTRACT FROM AUTHOR]

• Experimental warming altered start of season (SOS) in grasslands. • Soil moisture regulated the magnitude of the warming-induced advance or delay in SOS. • Changes in soil N did not affect SOS, and regulate the effects of warming on SOS. Spring vegetation phenology is highly sensitive to global change. However, the effects of ongoing climate warming and N deposition on grassland spring phenology and how abiotic and biotic factors modulate such effects remain unclear. Here, we conducted a factorial field experiment of warming and N addition in three types of grasslands with varying aridity indices (0.20–0.39) in Inner Mongolia, China. Our results showed that warming and the combination of warming plus N addition had similar effects on start of season (SOS). These treatments delayed SOS by 3–5 weeks in low-, moderate and high-aridity grasslands in both wet (2018) and dry (2019) years, except that they advanced SOS by ∼1 week in low-aridity grassland in the wet year. N addition alone slightly advanced or delayed SOS by 2–5 days depending on the grassland type. The magnitude and direction of SOS response to warming and warming plus N addition were closely and linearly correlated to grassland soil moisture, but not to air temperature or soil N availability. Warming-induced reduction in soil moisture drove SOS by affecting species richness and/or functional group composition. By contrast, N addition–induced changes in species richness and functional group composition did not alter the SOS. These combined results indicate that temperature and soil water availability are primary factors regulating SOS in semiarid grasslands. Our findings suggest that annual variation and spatial distribution in soil moisture should be considered in future studies of climate warming and environmental effects on grassland phenology. [ABSTRACT FROM AUTHOR]

Abstract: In arid lands, the shifts in dominant plant types from grasses to shrubs can significantly alter the ecosystem function and biogeochemistry cycles. However, the magnitude of these alterations and its inherent mechanisms are still poorly understood. In this study, we measured soil respiration and NPP over two growing seasons in 2006–2007 in the co-occurring perennial grass and desert shrub ecosystems at the Ordos Plateau of Inner Mongolia, China. Over the two growing seasons, the desert shrub site presented higher aboveground biomass and NPP while lower soil respiration relative to the grass site (p < 0.05). In this paper, we can not determine that whether vegetation conversion or soil texture change drive the site difference in soil respiration because we did not control for soil texture. We suppose that the site difference in pulse response of soil respiration might play an essential role in regulating this soil respiration gap. In all the growing seasons, surface soil moisture (0–10 cm) was identified as the major driver of soil respiration at both sites. Compared to the linear soil moisture model, the integrated model incorporating both surface soil moisture and air temperature was performed better in predicting the dynamics of soil respiration. [Copyright &y& Elsevier]

Fire is one of the most widespread and destructive disasters, which causes property losses, casualties, and disruption of the balance of ecosystems. Therefore, it is highly necessary for firefighting to study the variations in fire and its climatic attributions. This study analyzed the characteristics of fire-burned area (BA) and its response to climatic factors in seven subregions of China from 2001 to 2018 using satellite remote sensing BA products. The results show that the BA in China and most of its subregions shows a decreasing trend. In general, it is negatively correlated with precipitation and positively correlated with air temperature and wind speed based on the regression and correlation analyses. Based on Pearson correlation and random forest methods, it is also found that the temperature is commonly an important factor contributing to BA in China, except for R2 (Inner Mongolia region), where wind speed is more important, and R5 (South China), where precipitation is more important, which coexists at annual and seasonal scales. Besides temperature, precipitation in spring and summer is the main driving factor, such as in R1 (Northeast China), R5, R6 (Northwest China) and R7 (Qinghai–Tibet Plateau) in spring and R4 (Central China), R5 and R7 in summer; and wind speed in autumn and winter is the main driving factor, such as in R2 and R4 in autumn and R2, R3, R5, R6 and R7 in winter. Finally, the distributions of BA with respect to each climatic factor were also analyzed to quantify the range of climatic factors with maximum BA occurrence. [ABSTRACT FROM AUTHOR]