Interdecadal variability of summer precipitation in the Three River Source Region: Influences of SST and zonal shifts of the East Asian subtropical westerly jet

Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the influence of the East Asian westerly jet(EAWJ)on TRSR rainfall.A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index(JZPI)of the EAWJ from 1961 to 2019(R=0.619,p<0.01).During periods when a positive JZPI indicates a westward shift in the EAWJ,enhanced water vapor anomalies,warmer air,and low-level convergence anomalies contribute to increased TRSR summer precipitation.Using empirical orthogonal function and regression analyses,this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection(AEA)from the North Atlantic(NA).The interdecadal variability between the NA and central tropical Pacific(CTP)significantly affects TRSR precipitation.This influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ,and another south of 45°N.Moreover,the NA–CTP Opposite Phase Index(OPI),which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP,is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ.

Spatiotemporal Variability and Environmental Controls of Temperature Sensitivity of Ecosystem Respiration across the Tibetan Plateau

Warming-induced carbon loss via ecosystem respiration(R_(e))is probably intensifying in the alpine grassland ecosystem of the Tibetan Plateau owing to more accelerated warming and the higher temperature sensitivity of R_(e)(Q_(10)).However,little is known about the patterns and controlling factors of Q_(10)on the plateau,impeding the comprehension of the intensity of terrestrial carbon-climate feedbacks for these sensitive and vulnerable ecosystems.Here,we synthesized and analyzed multiyear observations from 14 sites to systematically compare the spatiotemporal variations of Q_(10)values in diverse climate zones and ecosystems,and further explore the relationships between Q_(10)and environmental factors.Moreover,structural equation modeling was utilized to identify the direct and indirect factors predicting Q_(10)values during the annual,growing,and non-growing seasons.The results indicated that the estimated Q_(10)values were strongly dependent on temperature,generally,with the average Q_(10)during different time periods increasing with air temperature and soil temperature at different measurement depths(5 cm,10 cm,20 cm).The Q_(10)values differentiated among ecosystems and climatic zones,with warming-induced Q_(10)declines being stronger in colder regions than elsewhere based on spatial patterns.NDVI was the most cardinal factor in predicting annual Q_(10)values,significantly and positively correlated with Q_(10).Soil temperature(Ts)was identified as the other powerful predictor for Q_(10),and the negative Q_(10)-Ts relationship demonstrates a larger terrestrial carbon loss potentiality in colder than in warmer regions in response to global warming.Note that the interpretations of the effect of soil moisture on Q_(10)were complicated,reflected in a significant positive relationship between Q_(10)and soil moisture during the growing season and a strong quadratic correlation between the two during the annual and non-growing season.These findings are conducive to improving our understanding of alpine grassland ecosystem carbon-climate feedbacks under warming climates.

Numerical simulation of the climate effect of high-altitude lakes on the Tibetan Plateau

Lakes regulate the water and heat exchange between the ground and the atmosphere on different temporal and spatial scales. However, studies of the lake effect in the high-altitude Tibetan Plateau(TP) rarely have been performed until recently, and little attention has been paid to modelling of frozen lakes. In this study, the Weather Research and Forecasting Model(WRF v. 3.6.1) is employed to conduct three numerical experiments in the Ngoring Lake Basin(the original experiment, an experiment with a tuned model, and a no-lake experiment) to investigate the influences of parameter optimization on the lake simulation and of the high-altitude lake on the regional climate. After the lake depth, the roughness lengths, and initial surface temperature are corrected in the model, the simulation of the air temperature is distinctly improved. In the experiment using a tuned model, the simulated sensible-heat flux(H) is clearly improved, especially during periods of ice melting(from late spring to early summer) and freezing(late fall). The improvement of latent-heat flux(LE) is mainly manifested by the sharp increase in the correlation coefficient between simulation and observation, whereas the improvement in the average value is small. The optimization of initial surface temperature shows the most prominent effect in the first year and distinctly weakens after a freezing period. After the lakes become grassland in the model, the daytime temperature clearly increases during the freezing and melting periods; but the nocturnal cooling appears in other stages, especially from September to October. The annual mean H increases by 6.4 times in the regions of the Ngoring Lake and the Gyaring Lake, and the LE declines by 56.2%. The sum of H and LE increases from 71.2 W/m2(with lake) to 84.6 W/m2(no lake). For the entire simulation region, the sum of H and LE also increases slightly. After the lakes are removed, the air temperature increases significantly from June to September over the area corresponding to the two lakes, and an abnormal convergence field appears; at the same time, the precipitation clearly increases over the two lakes and surrounding areas.

Dataset of Comparative Observations for Land Surface Processes over the Semi-Arid Alpine Grassland against Alpine Lakes in the Source Region of the Yellow River

Thousands of lakes on the Tibetan Plateau(TP) play a critical role in the regional water cycle, weather, and climate. In recent years, the areas of TP lakes underwent drastic changes and have become a research hotspot. However, the characteristics of the lake-atmosphere interaction over the high-altitude lakes are still unclear, which inhibits model development and the accurate simulation of lake climate effects. The source region of the Yellow River(SRYR) has the largest outflow lake and freshwater lake on the TP and is one of the most densely distributed lakes on the TP. Since 2011,three observation sites have been set up in the Ngoring Lake basin in the SRYR to monitor the lake-atmosphere interaction and the differences among water-heat exchanges over the land and lake surfaces. This study presents an eight-year(2012–19), half-hourly, observation-based dataset related to lake–atmosphere interactions composed of three sites. The three sites represent the lake surface, the lakeside, and the land. The observations contain the basic meteorological elements,surface radiation, eddy covariance system, soil temperature, and moisture(for land). Information related to the sites and instruments, the continuity and completeness of data, and the differences among the observational results at different sites are described in this study. These data have been used in the previous study to reveal a few energy and water exchange characteristics of TP lakes and to validate and improve the lake and land surface model. The dataset is available at National Cryosphere Desert Data Center and Science Data Bank.

Advances in research of land surface evapotranspiration at home and abroad

Land surface evapotranspiration (ET) is an important part of the hydrologic cycle and energy balances.With the development of remote sensing technology,research on monitoring and estimating of evapotranspiration has made important progress.This paper summarizes advances in measuring and estimating regional evapotranspiration at home and abroad based on traditional methods and remote sensing.This summary includes such methods as Bowen,Gradient,Penman-Monteith,Water Balance,Eddy Correlation,SPAC,Energy Balance and Remote Sensing.Also,the evapotranspiration achievements in the Heihe River Basin are also discussed.Finally,the existing problems in regional evapotranspiration research and future development prospects are also discussed at the conclusion of this paper.

Inhibition of gasdermin D-dependent pyroptosis attenuates the progression of silica-induced pulmonary inflammation and fibrosis

Silicosis is a leading cause of occupational disease-related morbidity and mortality worldwide,but the molecular basis underlying its development remains unclear.An accumulating body of evidence supports gasdermin D(GSDMD)-mediated pyroptosis as a key component in the development of various pulmonary diseases.However,there is little experimental evidence connecting silicosis and GSDMD-driven pyroptosis.In this work,we investigated the role of GSDMD-mediated pyroptosis in silicosis.Single-cell RNA sequencing of healthy and silicosis human and murine lung tissues indicated that GSDMD-induced pyroptosis in macrophages was relevant to silicosis progression.Through microscopy we then observed morphological alterations of pyroptosis in macrophages treated with silica.Measurement of interleukin-1βrelease,lactic dehydrogenase activity,and real-time propidium iodide staining further revealed that silica induced pyroptosis of macrophages.Additionally,we verified that both canonical(caspase-1-mediated)and non-canonical(caspase-4/5/11-mediated)signaling pathways mediated silica-induced pyroptosis activation,in vivo and in vitro.Notably,Gsdmd knockout mice exhibited dramatically alleviated silicosis phenotypes,which highlighted the pivotal role of pyroptosis in this disease.Taken together,our results demonstrated that macrophages underwent GSDMD-dependent pyroptosis in silicosis and inhibition of this process could serve as a viable clinical strategy for mitigating silicosis.

Transcriptional landscape of cotton roots in response to salt stress at single-cell resolution

Increasing soil salinization has led to severe reductions in plant yield and quality,and investigating the mo-lecular mechanism of salt stress response is therefore an urgent priority.In this study,we systematically analyzed the response of cotton roots to salt stress using single-cell transcriptomics technology;56281 high-quality cells were obtained from 5-day-old lateral root tips of Gossypium arboreum under natural growth conditions and different salt treatments.Ten cell types with an array of novel marker genes were identified and confirmed by in situ RNA hybridization,and pseudotime analysis of some specific cell types revealed their potential differentiation trajectories.Prominent changes in cell numbers under salt stress were observed for outer epidermal and inner endodermal cells,which were significantly enriched in response to stress,amide biosynthetic process,glutathione metabolism,and glycolysis/gluconeogenesis.Analysis of differentially expressed genes identified in multiple comparisons revealed other functional ag-gregations concentrated on plant-type primary cell wall biogenesis,defense response,phenylpropanoid biosynthesis,and metabolic pathways.Some candidate differentially expressed genes encoding transcrip-tion factors or associated with plant hormones also responsive to salt stress were identified,and the func-tion of Ga03G2153,annotated as auxin-responsive GH3.6,was confirmed by virus-induced gene silencing.The GaGH3.6-silenced plants showed a severe stress-susceptible phenotype,and physiological and biochemical measurements indicated that they suffered more significant oxidative damage.These results suggest that GaGH3.6 might participate in cotton salt tolerance by regulating redox processes.We thus construct a transcriptional atlas of salt-stressed cotton roots at single-cell resolution,enabling us to explore cellular heterogeneity and differentiation trajectories and providing valuable insights into the mo-lecular mechanisms that underlie plant stress tolerance.