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The recent evolution of dune landforms and its environmental indications in the mid-latitude desert area(Hexi Corridor)

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Journal of Geographical Sciences 2022年第4期32卷 617-644页

作者： ZHU Bingqi Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China

The history of dune landform changes and dust activity at mid-latitudes is a good archive for exploring environmental changes and related landscape response.In this study,the dynamic changes,material sources,dust activity history and the influencing factors of typical sand dunes in the Hexi Corridor were comprehensively analyzed from the aspects of aeolian geomorphology,grain-size sedimentology,geochemistry and climatology.The results show that in the past half century,the typical crescent-shaped dunes and chains of crescent-shaped dunes in the study area have moved or swayed greatly,with an average speed ranging from 0.8 m/a(Dunhuang)to 6.2 m/a(Minqin).The dynamic changes of sand dunes are mainly affected by annual precipitation,annual average wind speed and annual gale days,which indicates that climate is the primary influencing factor of dune landform changes.The three-stage grain-size curve model of dune sands is obviously different from that of gobi sediments(two-stage),revealing the“immaturity”of the latter in sedimentology,while the former has experienced efficiently aeolian differentiation and non-local origin.The comprehensive evidences of paleogeography,sedimentology and geochemistry reveal that the source materials of sand dunes are mainly alluvial/proluvial and palaeo-fluvial sediments,including clastic sediments in the denudation/erosion zones of the north and south piedmonts.Indicators such as the proportion of surface fine particles,the coverage of surface salt crusts,and the content of erodible sandy materials indicate that the western gobi areas are not the main source areas of wind-blown dust in the central and eastern parts of the Hexi Corridor.The spatial distribution of the movement direction of sand dunes is similar to that of the regional dominant wind direction,which indicates that the difference in the dynamic evolution of dune landforms between the east and west of the Hexi Corridor should be controlled by the regional-scale wind system,that is,controlled by the dynamic mechanism rather

关键词： dune landform Gobi landform grain size sedimentology elemental geochemistry global warming desertification mid-latitude deserts

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Diagnosing the Dynamic and Thermodynamic Effects for the Exceptional 2020 Summer Rainy Season in the Yangtze River Valley

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Journal of Meteorological Research 2022年第1期36卷 26-36页

作者： Na WEN Shujie LIU Laurent Z.X.LI College of Atmospheric Sciences Nanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science&TechnologyNanjing 210044China Qingdao Engineering Technology Research Center for Meteorological Disaster Prevention Qingdao Meteorological BureauQingdao 266003China Laboratoire de Météorologie Dynamique Centre National de la Recherche ScientifiqueSorbonne UniversitéEcole Normale SupérieureEcole PolytechniqueParis 75252France

An exceptional rainy season occurred in the Yangtze River valley of eastern China in June-July 2020.The relative importance of the dynamic and thermodynamic effects on this unusual event is evaluated through the budget equations of moisture and moist static energy(MSE).The moisture budget analysis suggests that the thermodynamic effect contributes to the precipitation anomaly by 8.5%through the advection of abnormal water vapor by mean vertical motion,while the dynamic effect,related to water vapor advection by anomalous vertical motion,has the dominant contribution.The MSE budget analysis further reveals that the anomalous vertical motion is both constrained by the dynamic effect related to changes in atmospheric circulation and the thermodynamic effect related to changes of the atmospheric thermal state,with a ratio of thermodynamic versus total effects estimated at 45.3%.The dynamic effect is linked to the advection of warm and humid air by the abnormal southwesterly wind,which is related with an anomalous anticyclone over the Philippine Sea.The thermodynamic effect is partly induced by the positive advection of anomalous MSE(mainly latent energy)by the mean vertical motion.This analysis of the dynamic and thermodynamic effects is useful to understand the underlying physical mechanisms leading to the unusual rainy season in the Yangtze River valley in summer 2020.It is also helpful to put forward a few speculations on the potential role of global warming whose primary effect is,after all,to change the thermal state of the atmosphere.

关键词： exceptional rainfall Yangtze River valley global warming dynamic and thermodynamic effects

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Modeling the effect of time delay in implementation of mitigation policies on the control of atmospheric greenhouse gases

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生物数学学报:英文版 2023年第8期16卷 75-108页

作者： Alok Kumar Verma Maitri Verma Department of Mathematics School of Physical and Decision Science Babasaheb Bhimrao Ambedkar University Lucknow India

Mitigation of the enhanced greenhouse gas(GHG)concentrations in the Earth's atmosphere is imperative to meet the climate change mitigation objective.Governments of many countries are developing and implementing various mitigation strategies to reduce their GHG emissions.However,a time delay between the formulation and implementation of these mitigation policies can affect their effectiveness in controlling greenhouse gas levels in the atmosphere.This work presents a nonlinear mathematical model to investigate the effect of application of mitigation strategies and the delay involved in their implementation over the reduction of atmospheric greenhouse gases.In model formulation,it is assumed that the mitigation strategies work two-fold;first they reduce the GHG emission rate from the anthropogenic source and second they increase the removal rate of greenhouse gas from the atmosphere.A comprehensive stability analysis of the proposed model system is made to examine its long-term behavior.The model analysis shows that an increase in the implementation rate of mitigation strategies and their efficiencies to cut down the GHG emission rate from point sources and increase the GHG uptake rate lead to reduction in equilibrium GHG concentration.It is found that a long delay in the execution of mitigation policies can destabilize the system dynamics and leads to the generation of periodic oscillations.The expression for the threshold value of the delay parameter at which periodic oscillations arise via Hopf-bifurcation is determined.The stability and direction of bifurcating periodic solutions are discussed.A sensitivity analysis is performed to investigate the effect of changes in key parameters over system dynamics.

关键词： Mathematical model greenhouse gases global warming mitigation strategies time delay Hopf-bifurcation

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Future Changes in the Relationship Between the South and East Asian Summer Monsoons in CMIP6 Models

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Journal of Tropical Meteorology 2023年第2期29卷 191-203页

作者：陈虹静杨崧魏维 School of Atmospheric Sciences Sun Yat-sen UniversityZhuhaiGuangdong 519082 China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) ZhuhaiGuangdong 519000 China Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Sun Yat-sen UniversityZhuhaiGuangdong 519082 China

The future changes in the relationship between the South Asian summer monsoon(SASM)and the East Asian summer monsoon(EASM)are investigated by using the high-emissions Shared Socioeconomic Pathway 5-8.5(SSP5-8.5)experiments from 26 coupled models that participated in the phase 6 of the Coupled Model Intercomparison Project(CMIP6).Six models,selected based on their best performance in simulating the upper-and lower-level pathways related to the SASM-EASM teleconnection in the historical run,can capture the positive relationship between the SASM and the rainfall over northern China.In the future scenario,the upper-level teleconnection wave pattern connecting the SASM and the EASM exhibits a significant weakening trend,due to the rainfall anomalies decrease over the northern Indian Peninsula in the future.At the lower level,the western North Pacific anticyclone is projected to strengthen in the warming climate.The positive(negative)rainfall anomalies associated with positive(negative)SASM rainfall anomalies are anticipated to extend southward from northern China to the Yangtze-Huai River valley,the Korea Peninsula,and southern Japan.The connection in the lower-level pathway may be strengthened in the future.

关键词： CMIP6 global warming South Asian monsoon East Asian monsoon future projection

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warming‑induced changes of broccoli head to cauliflower‑like curd in Brassica oleracea are regulated by DNA methylation as revealed by methylome and transcriptome co‑profiling

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Molecular Horticulture 2022年第1期2卷 318-332页

作者： Zilei Yao Lu Yuan Ke Liu Tingjin Wang Bin Liu Yan Zhao Susheng Gan Liping Chen Department of Horticulture College of Agriculture and BiotechnologyZhejiang UniversityHangzhou 310058China Plant Biology Section School of Integrative Plant ScienceCornell UniversityIthacaNY 14853USA Present address:College of Agronomy and Biotechnology Yunnan Agricultural UniversityKunming 650201China

Increasingly warming temperature impacts on all aspects of growth and development in plants.Flower development is a complex process that is very sensitive to ambient temperature,and warming temperatures often lead to abnor-mal flower development and remarkably reduce the quality and yield of inflorescent vegetables and many other crops,which can be exemplified by Brassica oleracea cv.Green Harmony F1,a broccoli cultivar,whose floral develop-ment is ceased at inflorescence meristem(at 28℃)or floral primordium stage(at 22℃),forming a cauliflower-like curd(28℃)or intermediate curd(22℃)instead of normal broccoli head at 16℃.However,the underlying molecular regulatory mechanisms are not well understood.Here we report that warming temperature(28℃ or 22℃)induced hypermethylation of the genome,especially the promoter regions of such sets of genes as ribosome biogenesis-related and others,leading to the suppression of the apex-highly-expressed distinctive genes,subsequently resulting in the abnormal floral development,as revealed by methylome and transcriptome co-profiling.The regulation of warming-induced abnormal floral development in broccoli was further verified by the fact that the DNA methylation inhibitor 5-azacytidine(5-azaC)released the expression of genes from the warming temperature-induced suppres-sion,and restored the broccoli development to normalcy at warming temperature.The research provided new approaches to breeding broccoli and other crops for growing in wider or warmer temperature zones.

关键词： Brassica oleracea DNA methylation Floral development cessation global warming Heat stress

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RESPONSE OF TIBETAN SNOW COVER TO global warming

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Journal of Geographical Sciences 1995年第3期5卷 69-76页

作者： Li Peiji(Lanchou Institute of Gaciology and Geocryology, CAS, Lanzhou 730000)People’s Ropublic of China

Daily snow depth records at 60 primary dimatc statons over the Tibetan Plateau for the penod 1957-1992 are used as basis for point and areal hme series developmat. A statistical lnodel consistng of a trend plus serially correated noise is fitted to the data to test for trend in time series of snow cover. Restilts of three trend estimatos based on difference of average, least squares fitting and slope AN (1) process imply that the increase in annual snow depth is a systematic developlnent as evidenced by the presence of a dotenniruStic trend. The spatial pattem of trend estimates convinced that the increase trends are almost onAnpresent over the wtire plateau. Further exandnation of interannual variation of snow cover over the Tiban Plateau and suffoce air tenrperature in winter over the nodriem hemisphere reveals a posihve correlation of +0.21 betWeen the two time series for period of 1957-1992.

关键词： snow cover global warming Tibetan Plateau

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CMIP6和CMIP5中哈德雷环流变化趋势的比较

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Science Bulletin 2020年第19期65卷 1667-1674,M0004页

作者：夏炎胡永云刘骥平 College of global Change and Earth System Science Beijing Normal UniversityBeijing 100875China Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100871China Department of Atmospheric and Environmental Sciences University at AlbanyState University of New YorkAlbanyNY 12222USA

近些年来,哈德雷环流变宽和副热带干旱区域向极地区域移动受到了气候变化领域高度的关注.本文使用第六次国际耦合气候模式比较计划(CMIP6)的模拟结果,分析了哈德雷环流宽度和强度的变化趋势,并且与CMIP5模拟结果进行了对比.分析表明,在C... 详细信息

近些年来,哈德雷环流变宽和副热带干旱区域向极地区域移动受到了气候变化领域高度的关注.本文使用第六次国际耦合气候模式比较计划(CMIP6)的模拟结果,分析了哈德雷环流宽度和强度的变化趋势,并且与CMIP5模拟结果进行了对比.分析表明,在CMIP6中包含了全部辐射强迫因子的历史模拟试验中,哈德雷环流在1970~2014年间平均每10年变宽0.13°±0.02°,与CMIP5的结果基本相当.关于哈德雷环流的强度,CMIP6给出的北支环流强度减弱比CMIP5大,而在南支环流则有变弱的加强趋势.CMIP6单个辐射强迫模拟试验表明,温室气体的增加导致南北半支哈德雷环流均变宽和变弱,而人类活动导致的气溶胶增加和平流层臭氧的变化使得南支哈德雷环流变弱的趋势加强.CMIP6未来模拟试验结果表明,哈德雷环流变宽和变弱的趋势均随辐射强迫的增强而加强.

关键词： Hadley circulation global warming Increasing greenhouse gases Stratospheric ozone Anthropogenic aerosols Coupled Model Intercomparison Project Phase-6(CMIP6)

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An observation-based perspective of winter haze days in four major polluted regions of China

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National Science Review 2019年第3期6卷 515-523页

作者： Lu Mao Run Liu Wenhui Liao Xuemei Wang Min Shao Shaw Chen Liu Yuanhang Zhang State Key Joint Laboratory of Environmental Simulation and Pollution Control Beijing Innovation Center for Engineering Science and Advanced Technology College of Environmental Sciences and Engineering Peking University Institute for Environmental and Climate Research Jinan University Guangdong University of Finance

An observation-based approach is used to examine key characteristics of winter haze days in four major polluted regions in China. Major findings in this study are: first, there was no significant trend in the number of winter haze days in most provinces and districts in eastern China from 1973 to 2012, contrary to the 2.5-fold increase in the emissions of particulate matter and its precursors(PM emissions) in the same period of time. Second, meteorological and climate conditions rather than PM emissions are in control of the interannual variabilities and trends of winter haze days. These interannual variabilities(ranging from 24 to 125%) pose a substantial masking effect that must be overcome by any control of PM emissions before its impact becomes statistically detectable. Finally, we find that global warming may have contributed significantly to the trend of winter haze days in eastern China.

关键词： haze visibility global warming

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warming Stimulated Soil Respiration in a Subalpine Meadow in North China

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Wuhan University Journal of Natural Sciences 2023年第1期28卷 77-87页

作者： LUO Shuzheng ZHANG Jianhua ZHANG Hufang ZHENG Qingrong GAO Yongping LI Meihong Department of Biological Sciences Xinzhou Teachers UniversityXinzhou 034000ShanxiChina Department of Geography Xinzhou Teachers UniversityXinzhou 034000ShanxiChina Shanxi Provincial Wutai Mountain State Forestry Administration Xinzhou 034000ShanxiChina Shanxi Provincial Nature Reserve of Abies nephrolepis Xinzhou 034000ShanxiChina

In order to explore the response of soil respiration in grassland to global warming,we carried out a warming experiment with open top chambers(OTCs)in the subalpine meadow,Mount Wutai in north China.Our results showed in the subalpine meadow across 2500-2700 m above the sea level(ASL),with OTCs,soil respiration increased by 2.00μmol·m^(-2)·s^(-1)as soil temperature increased by 1.25℃on average.warming decreased soil moisture over the experiment periods except in October 2019 when snow melted in OTCs.warming effect on soil respiration peaked at 178.31%in October 2019.In control and warming treatment,based on exponential regression equations,soil temperature alone accounted for 85.3%and 61.2%of soil respiration variation,respectively.In control treatment soil moisture alone explained 23.2%of soil respiration variation based on the power regression equation while in warming treatment they were not significantly correlated with each other.The response of soil respiration to warming relied on altitudes as well as the time of the year,but was not inhibited by soil moisture,labile carbon pool,and available nitrogen.We concluded soil temperature was the main factor influencing soil respiration,and global warming would stimulate soil respiration in the subalpine meadows of Mount Wutai in the future.Our analysis provided new data on characteristics and mechanisms of the response of soil respiration to warming,and helped to further understand the relationship between carbon cycle and climate change.

关键词： global warming soil respiration open top chambers(OTCs) the subalpine meadow Mount Wutai

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Long-term warming does not affect soil ecoenzyme activity and original microbial nutrient limitation on the Qinghai-Tibet Plateau

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Soil Ecology Letters 2022年第4期4卷 383-398页

作者： Yuanze Li Huakun Zhou Wenjing Chen Yang Wu Lei Lei Qiao ZiRan Yan GuoBin Liu Sha Xue State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Regions Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810000China State Key Laboratory of Plateau Ecology and Agriculture Qinghai UniversityXining 810000China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry Water ResourcesYangling 712100China College of Natural Resources and Environment Northwest A&F UniversityYangling 712100China

Microbes play an important role in the carbon cycle and nutrient flow of the soil ecosystem.However,the response of microbial activities to long-term warming over decades is poorly understood.To determine how warming changes ecoenzyme activity and microbial nutrient limitation,we conducted a long-term,21 years,experiment,on the Qinghai–Tibet Plateau.We selected typical grass-and shrub-covered plots,used fiberglass open-top chambers(OTCs)to raise the temperature,conducted soil sampling at different depths,studied the response of nutrient-acquiring enzyme activity and stoichiometry,and conducted vector analysis of stoichiometry.Our results showed that long-term warming did not have a notable effect on the activity of nutrient-acquiring enzymes or enzymatic stoichiometry.However,Spearman correlation analysis indicated a significant and positive correlation between ecoenzyme activity and the available nutrients and microbial biomass in soil.Vector analysis of stoichiometry showed phosphorus limitation for all soil microbes at different depths,regardless of whether the soil experienced warming.These changes in enzymatic stoichiometry and vector analysis suggested that microbial nutrient limitation was not alleviated substantially by long-term warming,and warming did not considerably affect the stratification of microbial nutrient limitation.Our research has also shown that long-term warming does not significantly change soil ecoenzyme activity and original microbial nutrient limitation at different soil depths within the OTUsʼimpact range.These results could help improve understanding of microbial thermal acclimation and response to future long-term global warming.

关键词： global warming Ecoenzymatic stoichiometry Microbial nutrient limitation Thermal acclimation Qinghai-Tibet Plateau

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