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A record-breaking precipitation event, with a maximum 24-h (1-h) precipitation of 624 mm (201.9 mm) observed at Zhengzhou Weather Station, occurred in Henan Province, China, in July 2021. However, all global operational forecast models failed to predict the intensity and location of maximum precipitation for this event. The unexpected heavy rainfall caused 398 deaths and 120.06 billion RMB of economic losses. The high-societal-impact of this event has drawn much attention from the research community. This article provides a research review of the event from the perspectives of observations, analysis, dynamics, predictability, and the connection with climate warming and urbanization. Global reanalysis data show that there was an anomalous large-scale circulation pattern that resulted in abundant moisture supply to the region of interest. Three mesoscale systems (a mesoscale low pressure system, a barrier jet, and downslope gravity current) were found by recent high-resolution model simulation and data assimilation studies to have contributed to the local intensification of the rainstorm. Furthermore, observational analysis has suggested that an abrupt increase in graupel through microphysical processes after the sequential merging of three convective cells contributed to the record-breaking precipitation. Although these findings have aided in our understanding of the extreme rainfall event, preliminary analysis indicated that the practical predictability of the extreme rainfall for this event was rather low. The contrary influences of climate warming and urbanization on precipitation extremes as revealed by two studies could add further challenges to the predictability. We conclude that data sharing and collaboration between meteorological and hydrological researchers will be crucial in future research on high-impact weather events. [ABSTRACT FROM AUTHOR]

Snow depth is an important parameter to characterize the characteristics of snow cover, and it is also one of the most sensitive response factors to regional climate change. However, the extent of snow depth variability and its driving mechanisms are still unknown in China. Therefore, in this study, we used the regression analysis, root-mean-square error analysis, anomalous year analysis, and correlation analysis methods to explore the spatiotemporal variation characteristics of snow depth in China from 1979 to 2019 based on the reanalysis snow depth dataset. The results show that (1) the snow distribution in China is obviously spatially heterogeneous, and the southeastern, western, and southern regions of the Qinghai-Tibet Plateau, northern Xinjiang, and northeastern China have high values of snow depth; (2) the high-value regions are also the sensitive regions for anomalous variations in snow depth in China; (3) in the past 41 years, the interannual variability of snow depth in China has shown a significantly decreasing trend, and the linear tendency of snow depth is − 0.093 cm/10 a (p < 0.01) and the snow depth in four seasons showed a decreasing trend (p < 0.05); and (4) the driving factors of snow heterogeneity are dissimilar in different regions and seasons. In temperate zones, average air temperature is the main factor affecting snow depth in cold temperature, mid temperature, and warm temperature zones; the maximum air temperature is the main factor affecting snow depth in mid temperate and warm temperate zones. Both the minimum air temperature and the average land-surface temperature are important factors affecting the snow depth in the cold temperate, mid temperate and warm temperate zones, and all passed the significance test of 0.01. [ABSTRACT FROM AUTHOR]

From July 19 to 21, 2021, Henan, a province in northern China (NC), was affected by severe flooding (referred to hereafter as "21·7") caused by a prolonged record-breaking extreme precipitation (EP) event. Understanding the extremes of the large-scale circulation pattern during "21·7" is essential for predicting EP events and preventing future disasters. In this study, daily atmospheric large-scale circulations over NC in the summers from 1979 to 2021 were investigated using the circulation classification method of an obliquely rotated principal component analysis in T-mode (PCT). The geopotential height at 500 hPa and 925 hPa were applied successively in classification. Among the nine summer circulation patterns at 500 hPa were found, the 3 days of "21·7" belonged to the Type 8 pattern, which had the second highest probability of EP days among all patterns. It was characterized by a southeasterly wind toward North China Plain driven by a dipole geopotential height field, with the West Pacific subtropical high (WPSH) extending far north to 30°N and low to the south near NC. Tropical cyclones (TCs) occurred on 72.5% of EP days, in which larger amounts of precipitation and a longer duration of EP days were found along the mountains in NC, as compared with other patterns. The distribution of EP events under this pattern was mainly influenced by the location of the low at 925 hPa in the dipole. The subtype 8−3 circulation, with lows in the east of Taiwan Island, included "21·7" and accounted for 1.6% of all summer days. Typhoon In-fa, together with the WPSH, gave rise to intense column integrated moisture flux convergence (IMFC) via the southeasterly wind to Henan, which occurred continuously during the 3 days of "21·7", resulting in the largest (second largest) mean IMFC among 3 consecutive EP days under type 8 (all types) during the past 43 summers in NC. Further analysis revealed that the large-scale dynamic process could not completely explain the record-breaking EP during "21·7", indicating possible contributions of other dynamic processed related to meso-scale convective storms. [ABSTRACT FROM AUTHOR]

The emergent highly pathogenic avian influenza A (H7N9) (HPAI) virus is a major public concern in China. Therefore, it is crucially important to develop an effective vaccine against this virus. In this study, we constructed a baculovirus vaccine expressing the hemagglutinin (HA) of H7N9 strain A/Chicken/Jiaxing/148/2014 (JX148). The recombinant baculovirus (rBac-JX148HA) generated in this study showed good growth in insect cells and good safety, and it stably expressed the HA protein. We compared the immunogenicity and efficacy of the inactivated whole-virus vaccine JX148 and rBac-JX148HA. One chicken in the JX148-treated group died on day 4 post-challenge, and three chickens had typical clinical symptoms (survival rate, 90%; morbidity, 40%). However, no chickens immunized with rBac-JX148HA showed clinical signs during the 14-day observation period. An analysis of viral shedding and viral replication demonstrated that rBac-JX148HA more efficiently inhibited viral shedding and viral replication than the inactivated whole-virus vaccine. Taken together, these results indicate that the inactivated recombinant baculovirus vaccine induces a high hemagglutination inhibition antibody titer, provides complete protection against challenge with the highly pathogenic H7N9 virus, and effectively inhibits viral shedding. Therefore, the candidate vaccine has potential utility in the prevention and control of H7N9 avian influenza and is also appropriate for veterinary vaccines using cell suspension culture technology. [ABSTRACT FROM AUTHOR]

The rheology and printability of the mixture from carboxymethyl tamarind gum (CTG) and carboxymethyl starch (CMS) with different mixture ratios were studied to explore the availability on double-sided printing of georgette fabric. The rheological properties of the mixture from CTG and CMS (TS) were investigated by steady-shear, dynamic oscillatory and transient tests. The printing performances of the printed georgette fabric using TS as thickener were evaluated by quality-determining parameters. The results showed that with the increasing proportion of CMS, the flowability and elasticity of TS gradually increased and the weak gel structure appeared little by little in company with more deviation from the Cox-Merz rule. The flow models and mechanical models were used to fit the rheological data. In comparison with CTG and CMS, TS had better double-sided printing performances on georgette fabric, including better colour yield, penetrability, levelness, handle, colour fastness and outline sharpness. Especially TS with a mixture ratio CTG:CMS = 4:6 exhibited the highest colour yield and penetration, and possessed the great potential as thickener on double-sided printing of georgette fabric. [ABSTRACT FROM AUTHOR]