The method linking general circulation models' (GCMs') outputs with crop growthsimulation models' inputs has been the first choice in the studies of impacts of climate change.Changes in climatic variabilit...The method linking general circulation models' (GCMs') outputs with crop growthsimulation models' inputs has been the first choice in the studies of impacts of climate change.Changes in climatic variability, however were not considered in most studies due to limitedknowledge concerned Changes in climatic means derived from a general circulation model DKRZOPYC were input into a stochastic weather generator WGEN run for synthetic daily climate scenarios.Monte Carlo stochastic sampling method was adopted to generate climate change scenarios withvarious possible climatic veriabilities. A dynamic simulation model for maize growth anddevelopment of MZMOD was used to assess the potenhal implication of the changes in both climaticmeans and variability nd the boacts of crop management in changing climate on maize productionin Northeast China. The results indicated that maize yield would be reduced to various degrees inmost of the sensitivity experiments of climatic variability associating with the shortening of theduration of phenological phase of different sowing dates. The Anpacts of the diverse distributions ofclimatic factors detetmined by multiple changes in climatic variability on maire production and itsvariation, however, are not identical and have distinct regional disparities. Yield reduction caused bychanges in climatic means may be alleviated or aggravated by didributions of certain climaticvariables in line with the corresponding climatic variability according to the sensitivity analyses.Consequently, the hypothesis keeping climatic variability constant in the traditional research imposesrestriction on the overall inveshgation of the impacts of climate change on maize production.展开更多
Aerosol dynamics in semi-arid cities are key to understanding air quality and climate interactions.This study examines the spatiotemporal variability of Aerosol Optical Depth(AOD)over Jaipur,India,from 2018 to 2024 us...Aerosol dynamics in semi-arid cities are key to understanding air quality and climate interactions.This study examines the spatiotemporal variability of Aerosol Optical Depth(AOD)over Jaipur,India,from 2018 to 2024 using MODIS observations at 470,500,and 550 nm,combined with meteorological data and ground-based air quality records.The Mann–Kendall test identified a statistically significant decreasing trend at 500 nm(slope=–2.07,p<0.05),while 470 and 550 nm showed weak,nonsignificant declines.AOD peaked in April–June,declined during the monsoon,and rose again in October–November due to burning and festivals.Correlation analysis demonstrated strong positive associations with PM_(2.5),PM_(10),and temperature,with minimum temperature emerging as the most influential predictor,whereas relative humidity showed weak or negative relationships.Anomaly detection confirmed episodic high-AOD events during dust storms,winter inversions,and agricultural burning.Predictive modelling using Multiple Linear Regression(MLR)and Random Forest highlighted the complementary roles of linear drivers.Nonlinear dynamics,with Random Forest achieving high predictive accuracy(R^(2)=0.892 for training,0.588 for testing).These findings demonstrate that aerosol variability in Jaipur is governed by a dual influence of natural dust and anthropogenic emissions,with wavelength-specific responses.The results provide scientific evidence for integrating satellite monitoring,ground observations,and predictive models into urban air quality management and climate adaptation strategies in semi-arid regions.展开更多
In recent years,the water level in the Mekong Delta(MD)has undergone changes,attributed to the impacts of anthropogenic activities and climate change.Declining water levels have had implications for various aspects of...In recent years,the water level in the Mekong Delta(MD)has undergone changes,attributed to the impacts of anthropogenic activities and climate change.Declining water levels have had implications for various aspects of life and aquatic ecosystems in the lower basin water bodies.Analyzing long-term trends in rainfall and water levels is crucial for enhancing our understanding.This study aims to examine the evolving patterns of water level and rainfall in the region.Data on water levels and rainfall from observation stations were gathered from the National Center for Hydrometeorological Forecasting,Vietnam,spanning from 2000 to 2014.The assessment of homogeneity and identification of trend changes were conducted using the Standard Normal Homogeneity Test(SNHT)and the Mann-Kendall test.The results indicate that changes in water levels at the Tan Chau and Chau Doc stations have been observed since 2010 due to the operation of flow-regulating structures in the upper Mekong River.Following the commencement of upstream dam operations,the water level at the headwater stations of the Mekong River has been higher than the long-term average during the dry season and lower than the average during the flood season.The study findings highlight the influence of altered rainfall patterns under the impact of climate variability(ICC)on water level trends in the study area.While rainfall plays a significant role in increasing water levels during the flood season,the operation of hydropower dams(UHDs)stands out as the primary factor driving water level reductions in the study area.展开更多
Climate changes are affecting water resources around the world and the Mo Basin (MB) in Togo is no exception to this observation. This study aims at analyzing the influence of hydro-climatical data in the Mo Basin. To...Climate changes are affecting water resources around the world and the Mo Basin (MB) in Togo is no exception to this observation. This study aims at analyzing the influence of hydro-climatical data in the Mo Basin. To achieve this, Pettit’s stationarity break tests, Hubert’s segmentation, Nicholson’s [1] reduced centered index, Lamb [2] and flow coefficients have been applied. In addition, temperature, precipitation, evapotranspiration, relative humidity and discharge data from 1961 to 2018 have been used for this purpose. While rainfall is decreasing despite an increase of 22.8% at the Fazao station and 2.8% at Sotouboua station, the flow coefficients evolve synchronously with the precipitation data and show a strong link between both parameters. The climatic balance sheet is positive six months in the year (May to October), throughout the period of observation (1961-2018). Only 1962 and 1963 recorded an annual rainfall greater than the annual evapotranspiration. The other years undergo a climatic drought, increasingly pronounced, which strongly impacts the hydrology of rivers. This has a strong impact on water resources and food security and resources of the Fazao-Malfakassa reserve in the region.展开更多
In the Sahel region, the population depends largely on rain-fed agriculture. In West Africa in particular, climate models turn out to be unable to capture some basic features of present-day climate variability. This s...In the Sahel region, the population depends largely on rain-fed agriculture. In West Africa in particular, climate models turn out to be unable to capture some basic features of present-day climate variability. This study proposes a contribution to the analysis of the evolution of agro-climatic risks in the context of climate variability. Some statistical tests are used on the main variables of the rainy season to determine the trends and the variabilities described by the data series. Thus, the paper provides a statistical modeling of the different agro-climatic risks while the seasonal variability of agro-climatic parameters was analyzed as well as their inter annual variability. The study identifies the probability distributions of agroclimatic risks and the characterization of the rainy season was clarified.展开更多
Climate variability significantly impacts agricultural water resources,particularly in regions like Vietnam's Plain of Reeds that heavily utilize rain-fed conditions.This study employs the FAO-AquaCrop model to es...Climate variability significantly impacts agricultural water resources,particularly in regions like Vietnam's Plain of Reeds that heavily utilize rain-fed conditions.This study employs the FAO-AquaCrop model to estimate current and future irrigation water needs for rice cultivation in this critical subregion,aiming to identify optimal sowing schedules(OSS)that enhance rainwater utilization and reduce irrigation dependency.The model was driven by current climate data and future projections(2041-2070 and 2071-2099)derived from downscaled Global Circulation Models under RCP4.5 and RCP8.5 scenarios.The AquaCrop model demonstrated robust performance during validation and calibration,with d-values(0.82-0.93)and R²values(0.85-0.92)indicating strong predictive accuracy for rice yield.Simulation results for efficient irrigation water potential(IWP)under RCP4.5 revealed that strategic shifts in sowing dates can substantially alter water requirements;for instance,advancing the winter-spring sowing to December 5th decreased IWP by 15.6%in the 2041-2070 period,while delaying summer-autumn crop sowing to April 20th increased IWP by 48.6%due to greater reliance on irrigation as rainfall patterns shift.Similar dynamic responses were observed for the 2071-2099 period and for autumn-winter crops.These findings underscore that AquaCrop modeling can effectively predict future irrigation needs and that adjusting cultivation calendars presents a viable,low-cost adaptation strategy.This approach allows farmers in the Plain of Reeds to optimize rainwater use,thereby reducing dependency on supplementary irrigation and mitigating the adverse impacts of climate variability,contributing to more sustainable agricultural water management.展开更多
Optimizing sowing dates(SDs)represents a viable strategy for adapting maize production to climate change and enhancing yield.However,research remains limited regarding the integrated effects of lodging and yield in re...Optimizing sowing dates(SDs)represents a viable strategy for adapting maize production to climate change and enhancing yield.However,research remains limited regarding the integrated effects of lodging and yield in relation to climatic variables across different SDs.This study examines the patterns and distribution of key climatic variables during maize growth seasons,their influence on yield and lodging,and the critical factors affecting lodging at crucial growth stages under various SD scenarios.The research evaluated climate change impacts on yield and lodging through field experiments spanning 5 years(2015,2016,2019-2021),incorporating 25 SDs in the Sichuan Basin,China.Results indicated that lodging rate significantly affected the coefficient of variation(CV,3.31-10.50%)of maize yield.Each 1%increase in lodging rate resulted in a yield reduction of 58.05 kg ha^(-1).SD modifications notably influenced solar radiation(Sr)from emergence to silking(E-R1).The study determined that Sr accounted for 34.7%of lodging rate variation in E-R1.Analysis of historical meteorological data revealed significant inter-annual Sr variations,showing a decline of-8.7763 MJ m^(-2)yr^(-1)from 1990 to 2021,particularly evident from late May to early July.Variation partitioning analysis(VPA)demonstrated that climatic variables during emergence to physiological maturity(E-R6)and E-R1 explained 43.9 and 53.2%of yield variation across SDs,respectively,while contributing 56.0 and 45.4%to lodging.Random forest(RF)analysis established that SD changes primarily influenced lodging rates through modifications in basal internode morphology,explaining 69.79%of the variation.The research identified optimal sowing dates between late March and mid-April for achieving consistent high yields,attributed to increased Sr during E-R1.This study provides critical insights into climate change effects on stalk lodging and offers practical guidance for SD adjustment to reduce maize lodging rates.展开更多
[Objective] The research aimed to study the variability and variation characteristics of climate in northern winter wheat zone during 1961-2004.[Method] Based on the meteorological data (temperature,precipitation and ...[Objective] The research aimed to study the variability and variation characteristics of climate in northern winter wheat zone during 1961-2004.[Method] Based on the meteorological data (temperature,precipitation and sunshine) of 55 meteorological stations in northern winter wheat zone during 1961-2004 and the yield data of winter wheat,by using the linear regression,correlated coefficient and climatic tendency rate,the spatial and temporal evolution characteristics of agricultural climatic resources (sunshine hours,temperature and precipitation) in northern winter wheat zone were analyzed.[Result] The annual average temperature,precipitation and sunshine hours in northern winter wheat zone during 1961-2004 all presented certain zonal distribution in the space.The precipitation and temperature gradually decreased from south to north.The sunshine hours gradually increased from south to north.The annual average temperature overall presented rise trend in northern winter wheat zone in 44 years,but the rise rate had difference in the different areas.The rise of annual average temperature in the high-latitude zone was more obvious than that in the low-latitude zone.The annual rainfall overall presented decrease trend,and the tendency rate of annual precipitation had significant difference in the different areas.The decrease rates of rainfalls in the central and western areas were bigger than that in other areas.The annual sunshine hours overall presented decline trend.In most areas,the tendency rate of annual sunshine hours was negative.But there was certain difference in the different areas.The zones where the decrease amplitude was smaller scattered in the west,and included central Shaanxi,south of Shanxi and some areas in southeast of Shandong.The decrease amplitudes were bigger in south of Henan,northwest of Shandong and south of Hebei.[Conclusion] The research provided theoretical basis for understanding the historical evolution of climate in northern winter wheat zone.展开更多
Climate in China's Mainland can be divided into the monsoon region in the southeast and the westerly region in the northwest as well as the intercross zone, i.e., the monsoon northernmost marginal active zone that...Climate in China's Mainland can be divided into the monsoon region in the southeast and the westerly region in the northwest as well as the intercross zone, i.e., the monsoon northernmost marginal active zone that is oriented from Southwest China to the upper Yellow River, North China, and Northeast China. In the three regions, dry-wet climate changes are directly linked to the interaction of the southerly monsoon flow on the east side of the Tibetan Plateau and the westerly flow on the north side of the Plateau from the inter-annual to inter-decadal timescales. Some basic features of climate variability in the three regions for the last half century and the historical hundreds of years are reviewed in this paper. In the last half century, an increasing trend of summer precipitation associated with the enhancing westerly flow is found in the westerly region from Xinjiang to northern parts of North China and Northeast China. On the other hand, an increasing trend of summer precipitation along the Yangtze River and a decreasing trend of summer precipitation along the monsoon northernmost marginal active zone are associated with the weakening monsoon flow in East Asia. Historical documents are widely distributed in the monsoon region for hundreds of years and natural climate proxies are constructed in the non-monsoon region, while two types of climate proxies can be commonly found over the monsoon northernmost marginal active zone. In the monsoon region, dry-wet variation centers are altered among North China, the lower Yangtze River, and South China from one century to another. Dry or wet anomalies are firstly observed along the monsoon northernmost marginal active zone and shifted southward or southeastward to the Yangtze River valley and South China in about a 70-year timescale. Severe drought events are experienced along the monsoon northernmost marginal active zone during the last 5 centuries. Inter-decadal dry-wet variations are depicted by natural proxies for the last 4-5 centuries in several areas over the non-monsoon region. Some questions, such as the impact of global warming on dry-wet regime changes in China, complex interactions between the monsoon and westerly flows in Northeast China, and the integrated multi-proxy analysis throughout all of China, are proposed.展开更多
A wide variety of studies have estimated the magnitude of global terrestrial net primary production （NPP）, but its variations, both spatially and temporally, still remain uncertain. By using an improved process-base...A wide variety of studies have estimated the magnitude of global terrestrial net primary production （NPP）, but its variations, both spatially and temporally, still remain uncertain. By using an improved process-based terrestrial ecosystem model （DLEM, Dynamic Land Ecosystem Model）, we provide an estimate of global terrestrial NPP induced by multiple environmental factors and examine the response of terrestrial NPP to climate variability at biome and global levels and along latitudes throughout the first decade of the 21st century. The model simulation estimates an average global terrestrial NPP of 54.6 Pg C yr-1 during 2000-2009, varying from 52.8 Pg C yr-1 in the dry year of 2002 to 56.4 Pg C yr-1 in the wet year of 2008. In wet years, a large increase in terrestrial NPP compared to the decadal mean was prevalent in Amazonia, Africa and Australia. In dry years, however, we found a 3.2% reduction in global terrestrial NPP compared to the decadal mean, primarily due to limited moisture supply in tropical regions. At a global level, precipitation explained approximately 63% of the variation in terrestrial NPP, while the rest was attributed to changes in temperature and other environmental factors. Precipitation was the major factor determining inter-annual variation in terrestrial NPP in low-latitude regions. However, in midand high-latitude regions, temperature variability largely controlled the magnitude of terrestrial NPP. Our results imply that pro- jected climate warming and increasing climate extreme events would alter the magnitude and spatiotemporal patterns of global terrestrial NPP.展开更多
As the largest wetland in the North China Plain （NCP）, the Baiyangdian Lake plays an important role in maintaining water balance and ecological health of NCP. Ir the past few decades, the decreasing streamflow in th...As the largest wetland in the North China Plain （NCP）, the Baiyangdian Lake plays an important role in maintaining water balance and ecological health of NCP. Ir the past few decades, the decreasing streamflow in the Baiyangdian Basin associated with climate vari- ability and human activities has caused a series of water and eco-environmer,tal issues. In this study, we quantified the impacts of climate variability and human activities on streamflow in the water source area of the Baiyangdian Lake, based on analyses of hydrologic changes of the upper Tanghe river catchment （a sub-basin of the Baiyangdian Basin） from 1960 to 2008. Climate elasticity method and hydrological modeling method were used to distinguish the effects of climate variability and human activities. The results showed that the annual streamflow decreased significantly （P〉0.05） by 1.7 mm/a and an abrupt change was identi- fied around the year 1980. The quantification results indicated that climate variations ac- counted for 38%-40% of decreased streamflow, while human activities accounted for 60%--62%. Therefore, the effect of human activities played a dominant role on the decline of the streamflow in the water source area of the Baiyangdian Lake. To keep the ecosystem health of the Baiyangdian Lake, we suggest that minimum ecological water demand and in- tegrated watershed management should be guaranteed in the future.展开更多
The Qinghai-Xizang Plateau, or Tibetan Plateau, is a sensitive region for climate change, where the manifestation of global warming is particularly noticeable. The wide climate variability in this region significantly...The Qinghai-Xizang Plateau, or Tibetan Plateau, is a sensitive region for climate change, where the manifestation of global warming is particularly noticeable. The wide climate variability in this region significantly affects the local land ecosystem and could consequently lead to notable vegetation changes. In this paper, the interannual variations of the plateau vegetation are investigated using a 21-year normalized difference vegetation index （NDVI） dataset to quantify the consequences of climate warming for the regional ecosystem and its interactions. The results show that vegetation coverage is best in the eastern and southern plateau regions and deteriorates toward the west and north. On the whole, vegetation activity demonstrates a gradual enhancement in an oscillatory manner during 1982-2002. The temporal variation also exhibits striking regional differences： an increasing trend is most apparent in the west, south, north and southeast, whereas a decreasing trend is present along the southern plateau boundary and in the central-east region. Covariance analysis between the NDVI and surface temperature/precipitation suggests that vegetation change is closely related to climate change. However, the controlling physical processes vary geographically. In the west and east, vegetation variability is found to be driven predominantly by temperature, with the impact of precipitation being of secondary importance. In the central plateau, however, temperature and precipitation factors are equally important in modulating the interannual vegetation variability.展开更多
A coupled earth system model（ESM） has been developed at the Nanjing University of Information Science and Technology（NUIST） by using version 5.3 of the European Centre Hamburg Model（ECHAM）, version 3.4 of the Nu...A coupled earth system model（ESM） has been developed at the Nanjing University of Information Science and Technology（NUIST） by using version 5.3 of the European Centre Hamburg Model（ECHAM）, version 3.4 of the Nucleus for European Modelling of the Ocean（NEMO）, and version 4.1 of the Los Alamos sea ice model（CICE）. The model is referred to as NUIST ESM1（NESM1）. Comprehensive and quantitative metrics are used to assess the model＇s major modes of climate variability most relevant to subseasonal-to-interannual climate prediction. The model＇s assessment is placed in a multi-model framework. The model yields a realistic annual mean and annual cycle of equatorial SST, and a reasonably realistic precipitation climatology, but has difficulty in capturing the spring–fall asymmetry and monsoon precipitation domains. The ENSO mode is reproduced well with respect to its spatial structure, power spectrum, phase locking to the annual cycle, and spatial structures of the central Pacific（CP）-ENSO and eastern Pacific（EP）-ENSO; however, the equatorial SST variability,biennial component of ENSO, and the amplitude of CP-ENSO are overestimated. The model captures realistic intraseasonal variability patterns, the vertical-zonal structures of the first two leading predictable modes of Madden–Julian Oscillation（MJO）, and its eastward propagation; but the simulated MJO speed is significantly slower than observed. Compared with the T42 version, the high resolution version（T159） demonstrates improved simulation with respect to the climatology, interannual variance, monsoon–ENSO lead–lag correlation, spatial structures of the leading mode of the Asian–Australian monsoon rainfall variability, and the eastward propagation of the MJO.展开更多
Time-variable gravity data from the Gravity Recovery and Climate Experiment （GRACE） satellite mission are used to study terrestrial water storage （TWS） changes over the Pearl River Basin （PRB） for the period 200...Time-variable gravity data from the Gravity Recovery and Climate Experiment （GRACE） satellite mission are used to study terrestrial water storage （TWS） changes over the Pearl River Basin （PRB） for the period 2003-Nov. 2014. TWS estimates from GRACE generally show good agreement with those from two hydrological models GLDAS and WGHM. But they show different capability of detecting significant TWS changes over the PRB. Among them, WGHM is likely to underestimate the seasonal variability of TWS, while GRACE detects long- term water depletions over the upper PRB as was done by hydrological models, and observes significant water increases around the Longtan Reservoir （LTR） due to water impoundment. The heavy drought in 2011 caused by the persistent precipitation deficit has resulted in extreme low surface runoff and water level of the LTR. Moreover, large variability of summer and autumn precipitation may easily trigger floods and droughts in the rainy season in the PRB, especially for summer, as a high correlation of 0.89 was found between precipitation and surface runoff. Generally, the PRB TWS was negatively correlated with El Nifio-Southern Oscillation （ENSO） events. However, the modulation of the Pacific Decadal Oscillation （PDO） may impact this relationship, and the significant TWS anomaly was likely to occur in the peak of PDO phase as they agree well in both of the magnitude and timing of peaks. This indicates that GRACE-based TWS could be a valuable parameter for studying climatic in- fluences in the PRB.展开更多
Studies of the multi-scale climate variability of the Asian monsoon are essential to an advanced understanding of the physical processes of the global climate system.In this paper,the progress achieved in this field i...Studies of the multi-scale climate variability of the Asian monsoon are essential to an advanced understanding of the physical processes of the global climate system.In this paper,the progress achieved in this field is systematically reviewed,with a focus on the past several years.The achievements are summarized into the following topics:(1)the onset of the South China Sea summer monsoon;(2)the East Asian summer monsoon;(3)the East Asian winter monsoon;and(4)the Indian summer monsoon.Specifically,new results are highlighted,including the advanced or delayed local monsoon onset tending to be synchronized over the Arabian Sea,Bay of Bengal,Indochina Peninsula,and South China Sea;the basic features of the record-breaking mei-yu in 2020,which have been extensively investigated with an emphasis on the role of multi-scale processes;the recovery of the East Asian winter monsoon intensity after the early 2000s in the presence of continuing greenhouse gas emissions,which is believed to have been dominated by internal climate variability(mostly the Arctic Oscillation);and the accelerated warming over South Asia,which exceeded the tropical Indian Ocean warming,is considered to be the main driver of the Indian summer monsoon rainfall recovery since 1999.A brief summary is provided in the final section along with some further discussion on future research directions regarding our understanding of the Asian monsoon variability.展开更多
Much attention has recently been focused on the effects of climate variability and human activities on the runoff. In this study, we analyzed 56-yr(1957–2012) runoff change and patterns in the Jinghe River Basin(JRB)...Much attention has recently been focused on the effects of climate variability and human activities on the runoff. In this study, we analyzed 56-yr(1957–2012) runoff change and patterns in the Jinghe River Basin(JRB) in the arid region of northwest China. The nonparametric Mann–Kendall test and the precipitation-runoff double cumulative curve(PRDCC) were used to identify change trend and abrupt change points in the annual runoff. It was found that the runoff in the JRB has periodically fluctuated in the past 56 yr. Abrupt change point in annual runoff was identified in the JRB, which occurred in the years around 1964 and 1996 dividing the long-term hydrologic series into a natural period(1957 – 1964) and a climate and man-induced period(1965 – 1996 and 1997 – 2012). In the 1965 – 1996 period, human activities were the main factor that decreased runoff with contribution of 88.9%, while climate variability only accounted for 11.1%. However,the impact of climate variability has been increased from 11.1% to 47.5% during 1997 – 2012, showing that runoff in JRB is more sensitive to climate variability during global warming. This study distinguishes theeffect of climate variability from human activities on runoff, which can do duty for a reference for regional water resources assessment and management.展开更多
Taoer River Basin, which is located in the west of Northeast China, is an agropastoral ecotone. In recent years, the hydrological cycle and water resources have changed significantly with the deterioration of the envi...Taoer River Basin, which is located in the west of Northeast China, is an agropastoral ecotone. In recent years, the hydrological cycle and water resources have changed significantly with the deterioration of the environment. Many water problems such as river blanking, wetland shrinking and salinization have occurred in this region. All of these phenomena were directly caused by changes in stream flow under climate variability and human actiities. In light of the situation, the impact of climate variability and human activities on stream flow should be identified immediately to identify the primary driving factors of basin hydrological processes. To achieve this, statistical tests were applied to identify trends in variation and catastrophe points in mean annual stream flow from 1961 to 2011. A runoff sensitive coefficients method and a SIMHYD model were applied to assess the impacts of stream flow variation. The following conclusions were found： 1 ） The years 1985 and 2000 were confirmed to be catastrophe points in the stream flow series. Thus, the study period could be divided into three periods, from 1961 to 1985 （Period I）, 1986 to 2000 （Period II） and 2001 to 2011 （Period III）. 2） Mean annual observed stream flow was 31.54 mm in Period I, then increased to 65.60 mm in Period II and decreased to 2.92 mm in Period III. 3） Using runoff sensitive coefficients, the contribution of climate variability was 41.93% and 43.14% of the increase in stream flow during Periods II and III, suggesting that the contribution of human activities to the increase was 58.07% and 56.86%, respectively. 4） Climate variability accounted for 42.57% and 44.30% of the decrease in stream flow, while human activities accounted for 57.43% and 55.70% of the decrease, according to the SIMHYD model. 5） In comparison of these two methods, the primary driving factors of stream flow variation could be considered to be human activities, which contributed about 15% more than climate variability. It is hoped that these conclusions will .benefit future regional planning and sustainable development.展开更多
A new modeling concept, referred to as Modeling Surgery, has been recently developed at University of Wisconsin-Madison. It is specifically designed to diagnose coupled feedbacks between different climate components a...A new modeling concept, referred to as Modeling Surgery, has been recently developed at University of Wisconsin-Madison. It is specifically designed to diagnose coupled feedbacks between different climate components as well as climatic teleconnections within a specific component through systematically modifying the coupling configurations and teleconnective pathways. It thus provides a powerful means for identifying the causes and mechanisms of low-frequency variability in the Earth's climate system. In this paper, we will give a short review of our recent progress in this new area.展开更多
Understanding how alien species assemble is crucial for predicting changes to community structure caused by biological invasions and for directing management strategies for alien species,but patterns and drivers of al...Understanding how alien species assemble is crucial for predicting changes to community structure caused by biological invasions and for directing management strategies for alien species,but patterns and drivers of alien species assemblages remain poorly understood relative to native species.Climate has been suggested as a crucial filter of invasion-driven homogenization of biodiversity.However,it remains unclear which climatic factors drive the assemblage of alien species.Here,we compiled global data at both grid scale(2,653 native and 2,806 current grids with a resolution of 2°x 2°)and administrative scale(271 native and 297 current nations and sub-nations)on the distributions of 361 alien amphibians and reptiles(herpetofauna),the most threatened vertebrate group on the planet.We found that geographical distance,proxy for natural dispersal barriers,was the dominant variable contributing to alien herpetofaunal assemblage in native ranges.In contrast,climatic factors explained more unique variation in alien herpetofaunal assemblage after than before invasions.This pattern was driven by extremely high temperatures and precipitation seasonality,2 hallmarks of global climate change,and bilateral trade which can account for the alien assemblage after invasions.Our results indicated that human-assisted species introductions combined with climate change may accelerate the reorganization of global species distributions.展开更多
Ommastrephes bartramii is an ecologically dependent species and has great commercial values among the AsiaPacific countries. This squid widely inhabits the North Pacific, one of the most dynamic marine environments in...Ommastrephes bartramii is an ecologically dependent species and has great commercial values among the AsiaPacific countries. This squid widely inhabits the North Pacific, one of the most dynamic marine environments in the world, subjecting to multi-scale climatic events such as the Pacific Decadal Oscillation（PDO）. Commercial fishery data from the Chinese squid-jigging fleets during 1995-2011 are used to evaluate the influences of climatic and oceanic environmental variations on the spatial distribution of O. bartramii. Significant interannual and seasonal variability are observed in the longitudinal and latitudinal gravity centers（LONG and LATG） of fishing ground of O. bartramii. The LATG mainly occurred in the waters with the suitable ranges of environmental variables estimated by the generalized additive model. The apparent north-south spatial shift in the annual LATG appeares to be associated with the PDO phenomenon and is closely related to the sea surface temperature（SST）and sea surface height（SSH） on the fishing ground, whereas the mixed layer depth（MLD） might contribute limited impacts to the distribution pattern of O. bartramii. The warm PDO regimes tend to yield cold SST and low SSH, resulting in a southward shift of LATG, while the cold PDO phases provid warm SST and elevated SSH,resulting in a northward shift of LATG. A regression model is developed to help understand and predict the fishing ground distributions of O. bartramii and improve the fishery management.展开更多
文摘The method linking general circulation models' (GCMs') outputs with crop growthsimulation models' inputs has been the first choice in the studies of impacts of climate change.Changes in climatic variability, however were not considered in most studies due to limitedknowledge concerned Changes in climatic means derived from a general circulation model DKRZOPYC were input into a stochastic weather generator WGEN run for synthetic daily climate scenarios.Monte Carlo stochastic sampling method was adopted to generate climate change scenarios withvarious possible climatic veriabilities. A dynamic simulation model for maize growth anddevelopment of MZMOD was used to assess the potenhal implication of the changes in both climaticmeans and variability nd the boacts of crop management in changing climate on maize productionin Northeast China. The results indicated that maize yield would be reduced to various degrees inmost of the sensitivity experiments of climatic variability associating with the shortening of theduration of phenological phase of different sowing dates. The Anpacts of the diverse distributions ofclimatic factors detetmined by multiple changes in climatic variability on maire production and itsvariation, however, are not identical and have distinct regional disparities. Yield reduction caused bychanges in climatic means may be alleviated or aggravated by didributions of certain climaticvariables in line with the corresponding climatic variability according to the sensitivity analyses.Consequently, the hypothesis keeping climatic variability constant in the traditional research imposesrestriction on the overall inveshgation of the impacts of climate change on maize production.
文摘Aerosol dynamics in semi-arid cities are key to understanding air quality and climate interactions.This study examines the spatiotemporal variability of Aerosol Optical Depth(AOD)over Jaipur,India,from 2018 to 2024 using MODIS observations at 470,500,and 550 nm,combined with meteorological data and ground-based air quality records.The Mann–Kendall test identified a statistically significant decreasing trend at 500 nm(slope=–2.07,p<0.05),while 470 and 550 nm showed weak,nonsignificant declines.AOD peaked in April–June,declined during the monsoon,and rose again in October–November due to burning and festivals.Correlation analysis demonstrated strong positive associations with PM_(2.5),PM_(10),and temperature,with minimum temperature emerging as the most influential predictor,whereas relative humidity showed weak or negative relationships.Anomaly detection confirmed episodic high-AOD events during dust storms,winter inversions,and agricultural burning.Predictive modelling using Multiple Linear Regression(MLR)and Random Forest highlighted the complementary roles of linear drivers.Nonlinear dynamics,with Random Forest achieving high predictive accuracy(R^(2)=0.892 for training,0.588 for testing).These findings demonstrate that aerosol variability in Jaipur is governed by a dual influence of natural dust and anthropogenic emissions,with wavelength-specific responses.The results provide scientific evidence for integrating satellite monitoring,ground observations,and predictive models into urban air quality management and climate adaptation strategies in semi-arid regions.
基金funded by the University of Science,VNU-HCM under grant number T2022-10 project entitled“Water level variability in the Mekong Delta under the impacts of anthropogenic and climatic factors”.
文摘In recent years,the water level in the Mekong Delta(MD)has undergone changes,attributed to the impacts of anthropogenic activities and climate change.Declining water levels have had implications for various aspects of life and aquatic ecosystems in the lower basin water bodies.Analyzing long-term trends in rainfall and water levels is crucial for enhancing our understanding.This study aims to examine the evolving patterns of water level and rainfall in the region.Data on water levels and rainfall from observation stations were gathered from the National Center for Hydrometeorological Forecasting,Vietnam,spanning from 2000 to 2014.The assessment of homogeneity and identification of trend changes were conducted using the Standard Normal Homogeneity Test(SNHT)and the Mann-Kendall test.The results indicate that changes in water levels at the Tan Chau and Chau Doc stations have been observed since 2010 due to the operation of flow-regulating structures in the upper Mekong River.Following the commencement of upstream dam operations,the water level at the headwater stations of the Mekong River has been higher than the long-term average during the dry season and lower than the average during the flood season.The study findings highlight the influence of altered rainfall patterns under the impact of climate variability(ICC)on water level trends in the study area.While rainfall plays a significant role in increasing water levels during the flood season,the operation of hydropower dams(UHDs)stands out as the primary factor driving water level reductions in the study area.
文摘Climate changes are affecting water resources around the world and the Mo Basin (MB) in Togo is no exception to this observation. This study aims at analyzing the influence of hydro-climatical data in the Mo Basin. To achieve this, Pettit’s stationarity break tests, Hubert’s segmentation, Nicholson’s [1] reduced centered index, Lamb [2] and flow coefficients have been applied. In addition, temperature, precipitation, evapotranspiration, relative humidity and discharge data from 1961 to 2018 have been used for this purpose. While rainfall is decreasing despite an increase of 22.8% at the Fazao station and 2.8% at Sotouboua station, the flow coefficients evolve synchronously with the precipitation data and show a strong link between both parameters. The climatic balance sheet is positive six months in the year (May to October), throughout the period of observation (1961-2018). Only 1962 and 1963 recorded an annual rainfall greater than the annual evapotranspiration. The other years undergo a climatic drought, increasingly pronounced, which strongly impacts the hydrology of rivers. This has a strong impact on water resources and food security and resources of the Fazao-Malfakassa reserve in the region.
文摘In the Sahel region, the population depends largely on rain-fed agriculture. In West Africa in particular, climate models turn out to be unable to capture some basic features of present-day climate variability. This study proposes a contribution to the analysis of the evolution of agro-climatic risks in the context of climate variability. Some statistical tests are used on the main variables of the rainy season to determine the trends and the variabilities described by the data series. Thus, the paper provides a statistical modeling of the different agro-climatic risks while the seasonal variability of agro-climatic parameters was analyzed as well as their inter annual variability. The study identifies the probability distributions of agroclimatic risks and the characterization of the rainy season was clarified.
文摘Climate variability significantly impacts agricultural water resources,particularly in regions like Vietnam's Plain of Reeds that heavily utilize rain-fed conditions.This study employs the FAO-AquaCrop model to estimate current and future irrigation water needs for rice cultivation in this critical subregion,aiming to identify optimal sowing schedules(OSS)that enhance rainwater utilization and reduce irrigation dependency.The model was driven by current climate data and future projections(2041-2070 and 2071-2099)derived from downscaled Global Circulation Models under RCP4.5 and RCP8.5 scenarios.The AquaCrop model demonstrated robust performance during validation and calibration,with d-values(0.82-0.93)and R²values(0.85-0.92)indicating strong predictive accuracy for rice yield.Simulation results for efficient irrigation water potential(IWP)under RCP4.5 revealed that strategic shifts in sowing dates can substantially alter water requirements;for instance,advancing the winter-spring sowing to December 5th decreased IWP by 15.6%in the 2041-2070 period,while delaying summer-autumn crop sowing to April 20th increased IWP by 48.6%due to greater reliance on irrigation as rainfall patterns shift.Similar dynamic responses were observed for the 2071-2099 period and for autumn-winter crops.These findings underscore that AquaCrop modeling can effectively predict future irrigation needs and that adjusting cultivation calendars presents a viable,low-cost adaptation strategy.This approach allows farmers in the Plain of Reeds to optimize rainwater use,thereby reducing dependency on supplementary irrigation and mitigating the adverse impacts of climate variability,contributing to more sustainable agricultural water management.
基金supported by the National Key Research and Development Program of China(2022YFD190160304)the Key Program of Natural Science Foundation of Sichuan Province,China(2022NSFSC0013)+1 种基金the Sichuan Maize Innovation Team Construction Project,China(SCCXTD-2023-02)the National Science and Technology Support Projects,China(2015BAC05B05)。
文摘Optimizing sowing dates(SDs)represents a viable strategy for adapting maize production to climate change and enhancing yield.However,research remains limited regarding the integrated effects of lodging and yield in relation to climatic variables across different SDs.This study examines the patterns and distribution of key climatic variables during maize growth seasons,their influence on yield and lodging,and the critical factors affecting lodging at crucial growth stages under various SD scenarios.The research evaluated climate change impacts on yield and lodging through field experiments spanning 5 years(2015,2016,2019-2021),incorporating 25 SDs in the Sichuan Basin,China.Results indicated that lodging rate significantly affected the coefficient of variation(CV,3.31-10.50%)of maize yield.Each 1%increase in lodging rate resulted in a yield reduction of 58.05 kg ha^(-1).SD modifications notably influenced solar radiation(Sr)from emergence to silking(E-R1).The study determined that Sr accounted for 34.7%of lodging rate variation in E-R1.Analysis of historical meteorological data revealed significant inter-annual Sr variations,showing a decline of-8.7763 MJ m^(-2)yr^(-1)from 1990 to 2021,particularly evident from late May to early July.Variation partitioning analysis(VPA)demonstrated that climatic variables during emergence to physiological maturity(E-R6)and E-R1 explained 43.9 and 53.2%of yield variation across SDs,respectively,while contributing 56.0 and 45.4%to lodging.Random forest(RF)analysis established that SD changes primarily influenced lodging rates through modifications in basal internode morphology,explaining 69.79%of the variation.The research identified optimal sowing dates between late March and mid-April for achieving consistent high yields,attributed to increased Sr during E-R1.This study provides critical insights into climate change effects on stalk lodging and offers practical guidance for SD adjustment to reduce maize lodging rates.
基金Supported by Special Item of Public Welfare Industry Science Research ( GYHY201006025)
文摘[Objective] The research aimed to study the variability and variation characteristics of climate in northern winter wheat zone during 1961-2004.[Method] Based on the meteorological data (temperature,precipitation and sunshine) of 55 meteorological stations in northern winter wheat zone during 1961-2004 and the yield data of winter wheat,by using the linear regression,correlated coefficient and climatic tendency rate,the spatial and temporal evolution characteristics of agricultural climatic resources (sunshine hours,temperature and precipitation) in northern winter wheat zone were analyzed.[Result] The annual average temperature,precipitation and sunshine hours in northern winter wheat zone during 1961-2004 all presented certain zonal distribution in the space.The precipitation and temperature gradually decreased from south to north.The sunshine hours gradually increased from south to north.The annual average temperature overall presented rise trend in northern winter wheat zone in 44 years,but the rise rate had difference in the different areas.The rise of annual average temperature in the high-latitude zone was more obvious than that in the low-latitude zone.The annual rainfall overall presented decrease trend,and the tendency rate of annual precipitation had significant difference in the different areas.The decrease rates of rainfalls in the central and western areas were bigger than that in other areas.The annual sunshine hours overall presented decline trend.In most areas,the tendency rate of annual sunshine hours was negative.But there was certain difference in the different areas.The zones where the decrease amplitude was smaller scattered in the west,and included central Shaanxi,south of Shanxi and some areas in southeast of Shandong.The decrease amplitudes were bigger in south of Henan,northwest of Shandong and south of Hebei.[Conclusion] The research provided theoretical basis for understanding the historical evolution of climate in northern winter wheat zone.
基金supported by the National Natural Science Foundation of China(Nos40890053,90502001,and 90711003)
文摘Climate in China's Mainland can be divided into the monsoon region in the southeast and the westerly region in the northwest as well as the intercross zone, i.e., the monsoon northernmost marginal active zone that is oriented from Southwest China to the upper Yellow River, North China, and Northeast China. In the three regions, dry-wet climate changes are directly linked to the interaction of the southerly monsoon flow on the east side of the Tibetan Plateau and the westerly flow on the north side of the Plateau from the inter-annual to inter-decadal timescales. Some basic features of climate variability in the three regions for the last half century and the historical hundreds of years are reviewed in this paper. In the last half century, an increasing trend of summer precipitation associated with the enhancing westerly flow is found in the westerly region from Xinjiang to northern parts of North China and Northeast China. On the other hand, an increasing trend of summer precipitation along the Yangtze River and a decreasing trend of summer precipitation along the monsoon northernmost marginal active zone are associated with the weakening monsoon flow in East Asia. Historical documents are widely distributed in the monsoon region for hundreds of years and natural climate proxies are constructed in the non-monsoon region, while two types of climate proxies can be commonly found over the monsoon northernmost marginal active zone. In the monsoon region, dry-wet variation centers are altered among North China, the lower Yangtze River, and South China from one century to another. Dry or wet anomalies are firstly observed along the monsoon northernmost marginal active zone and shifted southward or southeastward to the Yangtze River valley and South China in about a 70-year timescale. Severe drought events are experienced along the monsoon northernmost marginal active zone during the last 5 centuries. Inter-decadal dry-wet variations are depicted by natural proxies for the last 4-5 centuries in several areas over the non-monsoon region. Some questions, such as the impact of global warming on dry-wet regime changes in China, complex interactions between the monsoon and westerly flows in Northeast China, and the integrated multi-proxy analysis throughout all of China, are proposed.
基金NSF Decadal and Regional Climate Prediction using Earth System Models,No.AGS-1243220NSF Dynamics of Coupled Natural and Human Systems,No.1210360+2 种基金NSF Computer and Network Systems,No.CNS-1059376NASA Land Cover/Land Use Change Program,No.NNX08AL73G S01NASA Interdisciplinary Science Program,No.NNX10AU06G,No.NNX11AD47G
文摘A wide variety of studies have estimated the magnitude of global terrestrial net primary production （NPP）, but its variations, both spatially and temporally, still remain uncertain. By using an improved process-based terrestrial ecosystem model （DLEM, Dynamic Land Ecosystem Model）, we provide an estimate of global terrestrial NPP induced by multiple environmental factors and examine the response of terrestrial NPP to climate variability at biome and global levels and along latitudes throughout the first decade of the 21st century. The model simulation estimates an average global terrestrial NPP of 54.6 Pg C yr-1 during 2000-2009, varying from 52.8 Pg C yr-1 in the dry year of 2002 to 56.4 Pg C yr-1 in the wet year of 2008. In wet years, a large increase in terrestrial NPP compared to the decadal mean was prevalent in Amazonia, Africa and Australia. In dry years, however, we found a 3.2% reduction in global terrestrial NPP compared to the decadal mean, primarily due to limited moisture supply in tropical regions. At a global level, precipitation explained approximately 63% of the variation in terrestrial NPP, while the rest was attributed to changes in temperature and other environmental factors. Precipitation was the major factor determining inter-annual variation in terrestrial NPP in low-latitude regions. However, in midand high-latitude regions, temperature variability largely controlled the magnitude of terrestrial NPP. Our results imply that pro- jected climate warming and increasing climate extreme events would alter the magnitude and spatiotemporal patterns of global terrestrial NPP.
基金National Basic Research Program of China,No.2010CB428406National Natural Science Foundation of China,No.40830636No.40971023
文摘As the largest wetland in the North China Plain （NCP）, the Baiyangdian Lake plays an important role in maintaining water balance and ecological health of NCP. Ir the past few decades, the decreasing streamflow in the Baiyangdian Basin associated with climate vari- ability and human activities has caused a series of water and eco-environmer,tal issues. In this study, we quantified the impacts of climate variability and human activities on streamflow in the water source area of the Baiyangdian Lake, based on analyses of hydrologic changes of the upper Tanghe river catchment （a sub-basin of the Baiyangdian Basin） from 1960 to 2008. Climate elasticity method and hydrological modeling method were used to distinguish the effects of climate variability and human activities. The results showed that the annual streamflow decreased significantly （P〉0.05） by 1.7 mm/a and an abrupt change was identi- fied around the year 1980. The quantification results indicated that climate variations ac- counted for 38%-40% of decreased streamflow, while human activities accounted for 60%--62%. Therefore, the effect of human activities played a dominant role on the decline of the streamflow in the water source area of the Baiyangdian Lake. To keep the ecosystem health of the Baiyangdian Lake, we suggest that minimum ecological water demand and in- tegrated watershed management should be guaranteed in the future.
基金supported by the foundation from:the program of the National Natural Science Foundation of China(40675037)the key program of the Sichuan Province Youth Science and Technology Fund(05ZQ026-023)the opening project of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences.
文摘The Qinghai-Xizang Plateau, or Tibetan Plateau, is a sensitive region for climate change, where the manifestation of global warming is particularly noticeable. The wide climate variability in this region significantly affects the local land ecosystem and could consequently lead to notable vegetation changes. In this paper, the interannual variations of the plateau vegetation are investigated using a 21-year normalized difference vegetation index （NDVI） dataset to quantify the consequences of climate warming for the regional ecosystem and its interactions. The results show that vegetation coverage is best in the eastern and southern plateau regions and deteriorates toward the west and north. On the whole, vegetation activity demonstrates a gradual enhancement in an oscillatory manner during 1982-2002. The temporal variation also exhibits striking regional differences： an increasing trend is most apparent in the west, south, north and southeast, whereas a decreasing trend is present along the southern plateau boundary and in the central-east region. Covariance analysis between the NDVI and surface temperature/precipitation suggests that vegetation change is closely related to climate change. However, the controlling physical processes vary geographically. In the west and east, vegetation variability is found to be driven predominantly by temperature, with the impact of precipitation being of secondary importance. In the central plateau, however, temperature and precipitation factors are equally important in modulating the interannual vegetation variability.
基金supported by the Research Innovation Program for college graduates of Jiangsu Province (CXLX13 487)
文摘A coupled earth system model（ESM） has been developed at the Nanjing University of Information Science and Technology（NUIST） by using version 5.3 of the European Centre Hamburg Model（ECHAM）, version 3.4 of the Nucleus for European Modelling of the Ocean（NEMO）, and version 4.1 of the Los Alamos sea ice model（CICE）. The model is referred to as NUIST ESM1（NESM1）. Comprehensive and quantitative metrics are used to assess the model＇s major modes of climate variability most relevant to subseasonal-to-interannual climate prediction. The model＇s assessment is placed in a multi-model framework. The model yields a realistic annual mean and annual cycle of equatorial SST, and a reasonably realistic precipitation climatology, but has difficulty in capturing the spring–fall asymmetry and monsoon precipitation domains. The ENSO mode is reproduced well with respect to its spatial structure, power spectrum, phase locking to the annual cycle, and spatial structures of the central Pacific（CP）-ENSO and eastern Pacific（EP）-ENSO; however, the equatorial SST variability,biennial component of ENSO, and the amplitude of CP-ENSO are overestimated. The model captures realistic intraseasonal variability patterns, the vertical-zonal structures of the first two leading predictable modes of Madden–Julian Oscillation（MJO）, and its eastward propagation; but the simulated MJO speed is significantly slower than observed. Compared with the T42 version, the high resolution version（T159） demonstrates improved simulation with respect to the climatology, interannual variance, monsoon–ENSO lead–lag correlation, spatial structures of the leading mode of the Asian–Australian monsoon rainfall variability, and the eastward propagation of the MJO.
基金supported by the National Natural Science Foundation of China (41174020, 41131067)the Fundamental Research Funds for the Central Universities (2014214020203)+1 种基金the open fund of Key Laboratory of Geospace Environment and Geodesy, Ministry of Education (14-02-011)the open fund of Guangxi Key Laboratory of Spatial Information and Geomatics (14-045-24-17)
文摘Time-variable gravity data from the Gravity Recovery and Climate Experiment （GRACE） satellite mission are used to study terrestrial water storage （TWS） changes over the Pearl River Basin （PRB） for the period 2003-Nov. 2014. TWS estimates from GRACE generally show good agreement with those from two hydrological models GLDAS and WGHM. But they show different capability of detecting significant TWS changes over the PRB. Among them, WGHM is likely to underestimate the seasonal variability of TWS, while GRACE detects long- term water depletions over the upper PRB as was done by hydrological models, and observes significant water increases around the Longtan Reservoir （LTR） due to water impoundment. The heavy drought in 2011 caused by the persistent precipitation deficit has resulted in extreme low surface runoff and water level of the LTR. Moreover, large variability of summer and autumn precipitation may easily trigger floods and droughts in the rainy season in the PRB, especially for summer, as a high correlation of 0.89 was found between precipitation and surface runoff. Generally, the PRB TWS was negatively correlated with El Nifio-Southern Oscillation （ENSO） events. However, the modulation of the Pacific Decadal Oscillation （PDO） may impact this relationship, and the significant TWS anomaly was likely to occur in the peak of PDO phase as they agree well in both of the magnitude and timing of peaks. This indicates that GRACE-based TWS could be a valuable parameter for studying climatic in- fluences in the PRB.
基金study was supported by the National Natural Science Foundation of China(Grant Nos.42230605 and 41721004).
文摘Studies of the multi-scale climate variability of the Asian monsoon are essential to an advanced understanding of the physical processes of the global climate system.In this paper,the progress achieved in this field is systematically reviewed,with a focus on the past several years.The achievements are summarized into the following topics:(1)the onset of the South China Sea summer monsoon;(2)the East Asian summer monsoon;(3)the East Asian winter monsoon;and(4)the Indian summer monsoon.Specifically,new results are highlighted,including the advanced or delayed local monsoon onset tending to be synchronized over the Arabian Sea,Bay of Bengal,Indochina Peninsula,and South China Sea;the basic features of the record-breaking mei-yu in 2020,which have been extensively investigated with an emphasis on the role of multi-scale processes;the recovery of the East Asian winter monsoon intensity after the early 2000s in the presence of continuing greenhouse gas emissions,which is believed to have been dominated by internal climate variability(mostly the Arctic Oscillation);and the accelerated warming over South Asia,which exceeded the tropical Indian Ocean warming,is considered to be the main driver of the Indian summer monsoon rainfall recovery since 1999.A brief summary is provided in the final section along with some further discussion on future research directions regarding our understanding of the Asian monsoon variability.
基金supported by the International S&T Cooperation Program of China (Grant No. 2010DFA92720-12)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-GJ04)+2 种基金the Natural Science Foundation of China (Grant Nos. 41130531, 41375101)the Ministry of Water Resources Special Funds for Scientific Research on Public Causes (Grant No. 201301103)the Program for Innovative Research Team in University (Grant No. IRT1180)
文摘Much attention has recently been focused on the effects of climate variability and human activities on the runoff. In this study, we analyzed 56-yr(1957–2012) runoff change and patterns in the Jinghe River Basin(JRB) in the arid region of northwest China. The nonparametric Mann–Kendall test and the precipitation-runoff double cumulative curve(PRDCC) were used to identify change trend and abrupt change points in the annual runoff. It was found that the runoff in the JRB has periodically fluctuated in the past 56 yr. Abrupt change point in annual runoff was identified in the JRB, which occurred in the years around 1964 and 1996 dividing the long-term hydrologic series into a natural period(1957 – 1964) and a climate and man-induced period(1965 – 1996 and 1997 – 2012). In the 1965 – 1996 period, human activities were the main factor that decreased runoff with contribution of 88.9%, while climate variability only accounted for 11.1%. However,the impact of climate variability has been increased from 11.1% to 47.5% during 1997 – 2012, showing that runoff in JRB is more sensitive to climate variability during global warming. This study distinguishes theeffect of climate variability from human activities on runoff, which can do duty for a reference for regional water resources assessment and management.
基金National Natural Science Foundation of China,No.91547114,No.41201568,No.41201572
文摘Taoer River Basin, which is located in the west of Northeast China, is an agropastoral ecotone. In recent years, the hydrological cycle and water resources have changed significantly with the deterioration of the environment. Many water problems such as river blanking, wetland shrinking and salinization have occurred in this region. All of these phenomena were directly caused by changes in stream flow under climate variability and human actiities. In light of the situation, the impact of climate variability and human activities on stream flow should be identified immediately to identify the primary driving factors of basin hydrological processes. To achieve this, statistical tests were applied to identify trends in variation and catastrophe points in mean annual stream flow from 1961 to 2011. A runoff sensitive coefficients method and a SIMHYD model were applied to assess the impacts of stream flow variation. The following conclusions were found： 1 ） The years 1985 and 2000 were confirmed to be catastrophe points in the stream flow series. Thus, the study period could be divided into three periods, from 1961 to 1985 （Period I）, 1986 to 2000 （Period II） and 2001 to 2011 （Period III）. 2） Mean annual observed stream flow was 31.54 mm in Period I, then increased to 65.60 mm in Period II and decreased to 2.92 mm in Period III. 3） Using runoff sensitive coefficients, the contribution of climate variability was 41.93% and 43.14% of the increase in stream flow during Periods II and III, suggesting that the contribution of human activities to the increase was 58.07% and 56.86%, respectively. 4） Climate variability accounted for 42.57% and 44.30% of the decrease in stream flow, while human activities accounted for 57.43% and 55.70% of the decrease, according to the SIMHYD model. 5） In comparison of these two methods, the primary driving factors of stream flow variation could be considered to be human activities, which contributed about 15% more than climate variability. It is hoped that these conclusions will .benefit future regional planning and sustainable development.
文摘A new modeling concept, referred to as Modeling Surgery, has been recently developed at University of Wisconsin-Madison. It is specifically designed to diagnose coupled feedbacks between different climate components as well as climatic teleconnections within a specific component through systematically modifying the coupling configurations and teleconnective pathways. It thus provides a powerful means for identifying the causes and mechanisms of low-frequency variability in the Earth's climate system. In this paper, we will give a short review of our recent progress in this new area.
基金supported by grants from National Science Foundation of China(31870507 and 31530088)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0501)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Y201920).
文摘Understanding how alien species assemble is crucial for predicting changes to community structure caused by biological invasions and for directing management strategies for alien species,but patterns and drivers of alien species assemblages remain poorly understood relative to native species.Climate has been suggested as a crucial filter of invasion-driven homogenization of biodiversity.However,it remains unclear which climatic factors drive the assemblage of alien species.Here,we compiled global data at both grid scale(2,653 native and 2,806 current grids with a resolution of 2°x 2°)and administrative scale(271 native and 297 current nations and sub-nations)on the distributions of 361 alien amphibians and reptiles(herpetofauna),the most threatened vertebrate group on the planet.We found that geographical distance,proxy for natural dispersal barriers,was the dominant variable contributing to alien herpetofaunal assemblage in native ranges.In contrast,climatic factors explained more unique variation in alien herpetofaunal assemblage after than before invasions.This pattern was driven by extremely high temperatures and precipitation seasonality,2 hallmarks of global climate change,and bilateral trade which can account for the alien assemblage after invasions.Our results indicated that human-assisted species introductions combined with climate change may accelerate the reorganization of global species distributions.
基金The National High-Tech R&D Program(863 Program)of China under contract No.2012AA092303the Project of Public Science and Technology Research Funds Projects of Ocean under contract No.20155014+3 种基金the National Key Technologies R&D Program of China under contract No.2013BAD13B00the Shanghai Universities First-Class Disciplines Project(Fisheries)the Funding Program for Outstanding Dissertations in Shanghai Ocean Universitythe Shanghai Ocean University International Center for Marine Studies
文摘Ommastrephes bartramii is an ecologically dependent species and has great commercial values among the AsiaPacific countries. This squid widely inhabits the North Pacific, one of the most dynamic marine environments in the world, subjecting to multi-scale climatic events such as the Pacific Decadal Oscillation（PDO）. Commercial fishery data from the Chinese squid-jigging fleets during 1995-2011 are used to evaluate the influences of climatic and oceanic environmental variations on the spatial distribution of O. bartramii. Significant interannual and seasonal variability are observed in the longitudinal and latitudinal gravity centers（LONG and LATG） of fishing ground of O. bartramii. The LATG mainly occurred in the waters with the suitable ranges of environmental variables estimated by the generalized additive model. The apparent north-south spatial shift in the annual LATG appeares to be associated with the PDO phenomenon and is closely related to the sea surface temperature（SST）and sea surface height（SSH） on the fishing ground, whereas the mixed layer depth（MLD） might contribute limited impacts to the distribution pattern of O. bartramii. The warm PDO regimes tend to yield cold SST and low SSH, resulting in a southward shift of LATG, while the cold PDO phases provid warm SST and elevated SSH,resulting in a northward shift of LATG. A regression model is developed to help understand and predict the fishing ground distributions of O. bartramii and improve the fishery management.
