Against the backdrop of global warming,China has been facing increasingly frequent and severe extreme weather and climate events,with a prominent risk of compound extreme events induced by interactions among multiple ...Against the backdrop of global warming,China has been facing increasingly frequent and severe extreme weather and climate events,with a prominent risk of compound extreme events induced by interactions among multiple climate drivers and/or hazards.The present study first reviews the definition and classification of compound extreme events in China.Then,it summarizes research progress on the evolutionary characteristics,formation mechanisms,and future projections of different types of compound extreme events.The potential risks and possible impact pathways of three specific event types—namely,continuous day–night hot extremes,temperature–humidity compound events,and high-temperature–ozone compound events—on the health of the Chinese population are then explored.Finally,a framework for assessing the hazard risk of compound extreme events is constructed,accompanied by response strategies based on carbon neutrality targets.Building on existing research achievements,five future research directions are proposed:(1)identifying the risk chains of compound events;(2)addressing the constraints of observational records and coupled model performances;(3)attributing and understanding the drivers of compound extreme events;(4)finding optimal pathways for carbon reduction and air quality improvement;and(5)promoting inter-disciplinary,multi-regional,and cross-sectoral collaboration.Strengthening research in these directions will deepen our understanding of compound extreme events and provide technological support for climate change adaptation and health risk responses in China.展开更多
In a warming world,climate extremes tend to be more frequent and intense.The exceptional response of ecosystems triggered by extreme climate events under a warmer and wetter climate in northwest China(NWC)has aroused ...In a warming world,climate extremes tend to be more frequent and intense.The exceptional response of ecosystems triggered by extreme climate events under a warmer and wetter climate in northwest China(NWC)has aroused growing concern.However,understanding the responses of vegetation to climate extremes from the compound events perspective remains challenging.In this study,we identify the climate dynamics in NWC during 1971–2020 based on daily meteorological observations,focusing on the changes in compound hot-dry events(CHDEs)during the warmer and wetter period.We further explore the effects of CHDEs on vegetation by examining vegetation anomalies and recovery time using daily gross primary productivity(GPP)data.The results show a clear warmer and wetter period in NWC during 2000–2020.No signs of a hiatus in CHDEs increase are observed during this period,and even the duration of CHDEs in western NWC keeps showing an increasing tendency.Vegetation in eastern NWC,with a lower probability of GPP anomalies,exhibits stronger resistance of ecosystems to CHDEs than in western NWC.In NWC,vegetation typically returns to its normal state in 5.50 days on average,but exhibits greater resilience in the western region,where it takes less recovery time(4.82 days).Vegetation in the central region shows the lowest probability of GPP anomalies and relatively longer recovery time,likely due to its higher altitudes.Our research underscores the imperative to address the considerable impacts of CHDEs on vegetation growth even as the regional climate becomes increasingly warmer and wetter.展开更多
The increasing frequency of compound extreme events under ongoing climate change threatens global food security.Compared to individual extreme events,the simultaneous occurrence of multiple extreme events can exacerba...The increasing frequency of compound extreme events under ongoing climate change threatens global food security.Compared to individual extreme events,the simultaneous occurrence of multiple extreme events can exacerbate crop yield reductions,yet comprehensive assessments of these compound effects remain limited.To bridge this gap,we applied a linear mixed-effects model to quantify the impacts of individual extreme events(cold days(CD)and killing degree days(KDD))and triple compound extreme events(heatwave and low precipitation(HWLP)and hot-dry-windy(HDW))on the global yields of winter wheat,soybeans,and maize from 1982 to 2016.Our analysis indicated that regions severely impacted by extreme events(exceeding the 95%threshold)experienced total crop yield losses of more than 9.16,24.89,26.69,and 7.12%due to CD,KDD,HWLP,and HDW,respectively.The adverse effects of compound events were particularly pronounced during critical growth stages.HWLP results in yield losses of 9.4%for winter wheat and 6.8%for maize per 10 hours of exposure during the heading to harvesting stages,while soybean yields declined by 8.8%per 10 hours during the planting to three-true-leaf stage.Similarly,KDD caused a 7.4%yield reduction in winter wheat per 10°C day during the heading to harvesting stages,a 9.5%reduction in maize per 10°C day during the planting to jointing stages,and a 3.8%reduction in soybean per 10°C day during the planting to three-true-leaf stages.These findings underscore the substantial contribution of compound extreme events,which are often overlooked in existing risk assessments,in determining the global yields of major staple crops.展开更多
Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global scales.However,the association between heatwaves and dus...Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global scales.However,the association between heatwaves and dust storms is poorly known.In this study,we describe the association between heatwaves and dust events and propose a mechanism for such compound events in the TD.The results show that,from 1993 to 2022,the frequency and intensity of heatwaves in the TD have increased at a rate of 0.21 days year^(-1)and 0.02℃ year^(-1),respectively.More than 40% of heatwaves existed with dust events,which significantly lagged behind heatwaves.Mechanically,the higher the air temperature,the hotter and drier the soil,leading to more dust emissions in the TD.In high-occurrence heatwave years,a large-scale wave train of“cyclone-anticyclone-cyclone”in the northwest-southeast direction was found,with the anticyclone of which hovered over the TD region.The anomalous anticyclones favored the formation and maintenance of heatwaves,and subsequent anomalous cyclones in the wave train triggered strong dust events followed by heatwaves.With climate warming,the compound events of heatwave and dust storm are becoming bigger hazards threatening the socioeconomic and ecological security in the TD,the profound study of which is critical to understanding regional extreme responses.展开更多
Compound extreme climate events involving multiple meteorological elements usually have a more severe impact on the environment and human health than single-element extreme events.However,the current definition of mul...Compound extreme climate events involving multiple meteorological elements usually have a more severe impact on the environment and human health than single-element extreme events.However,the current definition of multi-element compound extreme events is proposed from meteorological and statistical perspectives,without integrating health data,making the conclusions less practical for guiding health risk prevention.This study identified the threshold for hot–dry compound extreme events with high mortality risks(HMHDs)in China,using daily mortality data and temperature–humidity data from 278 districts or counties,and explored the interdecadal change and driving mechanisms of HMHD frequency in China from 1979 to 2021.The results show a significant increase in annual HMHD frequency in China after 2000,mainly occurring in summer(June,July,August).The northwestern to western regions of China(Xinjiang,Inner Mongolia,Gansu),and from the southwestern to the areas south of the Yangtze River(Sichuan,Hubei,Hunan,Jiangxi,Fujian,Guizhou,Yunnan),experience an increase of>10 days.The authors find that the interdecadal abrupt change in HMHD frequency can be attributed to the shift of the Atlantic Multidecadal Oscillation from a negative to a positive phase by affecting the Silk Road teleconnection.展开更多
This study investigates the extreme compound cold-wet event in southern China during January–February 2024,which was the second most extreme event recorded since 1960.Two cold-wet processes occurred during this perio...This study investigates the extreme compound cold-wet event in southern China during January–February 2024,which was the second most extreme event recorded since 1960.Two cold-wet processes occurred during this period.The first process,from 22 January to 23 January,exhibited a more intense cold surge,while the second,from 1 February to 7 February,featured more extreme precipitation and longer duration.This extreme cold-wet event was attributed to the combined effects of El Niño and positive North Atlantic Oscillation(NAO)in winter,coupled with intense convection in the western tropical Indian Ocean associated with a positive Indian Ocean Dipole(IOD)from the preceding autumn.El Niño and the Indian Ocean Basin mode in winter are conductive to enhanced anticyclone over the western North Pacific.Over the western tropical Indian Ocean,the enhanced convection associated with the warm sea surface temperature in winter and the positive IOD in preceding autumn can trigger an anomalous upper-level anticyclone over the Arabian Sea,enhancing the subtropical jet and deepening the India-Myanmar trough.The deepened India-Myanmar trough and the strengthened subtropical anticyclone over the western North Pacific enhance water vapor transport and subsequent extreme precipitation in southern China.Moreover,positive NAO and strengthened westerly jet stream induce widespread cooling in subtropical Eurasia,including southern China.Analysis from the backward trajectories using the HYSPLIT model confirms that moisture from the west and cold air from northern China at the near surface favored the compound cold-wet event in southern China.The extreme conditions of ENSO and NAO in winter and IOD in autumn jointly contributed to this extreme compound event.展开更多
The escalation of compound extreme events has resulted in noteworthy economic and property losses.Recognizing the intricate interconnections among these events has become imperative.To tackle this challenge,we have fo...The escalation of compound extreme events has resulted in noteworthy economic and property losses.Recognizing the intricate interconnections among these events has become imperative.To tackle this challenge,we have formulated a comprehensive framework for the systematic analysis of their dependencies.This framework consists of three steps.(1)Define extreme events using Mahalanobis distance thresholds.(2)Represent dependencies among multiple extreme events through a point process-based method.(3)Verify dependencies with residual tail coefficients,determining thefinal dependency structure.Applying this framework to assess the extreme dependence of precipitation on wind speed and temperature in China,revealed four distinct dependency structures.In northern,Jianghuai,and southern China,precipitation heavily relies on wind speed,while tempera-tures maintain relative independence.In northeastern and northwestern China,precipitation exhibits relative independence,yet a notable dependence exists between temperatures and wind speed.In southwestern China,precipitation strongly depends on temperature,while wind speed remains relatively indepen-dent.The Qinghai–Tibet Plateau region displays a significant dependence relationship among precipitation,wind speed,and temperature,with weaker dependence between extreme wind speed and temperature.This framework is instrumental for analyzing dependencies among extreme values in compound events.展开更多
Under the influence of global warming,the increasing intensity of compound hot drought events(CHDEs)presents a substantial threat to human society.However,the interdecadal variability and driving factors of CHDEs in N...Under the influence of global warming,the increasing intensity of compound hot drought events(CHDEs)presents a substantial threat to human society.However,the interdecadal variability and driving factors of CHDEs in Northern East Asia(NEA)remain insufficiently understood.Employing the multivariate copula method to characterize CHDEs,this study investigates the characteristics and mechanisms in this region during July.Our findings reveal two notable interdecadal shifts in the intensity and frequency of CHDEs during 1940-2022,occurring in the mid-1950s and the mid-1990s.These shifts correspond to periods of interdecadal weakening and intensification of CHDEs,respectively.The primary driver of this interdecadal variability has been identified as the Atlantic Multidecadal Oscillation(AMO).During the positive phase of the AMO,anomalously warm sea surface temperatures(SSTs)in the Atlantic Ocean influence wave trains that propagate along great circle routes,subsequently altering regional atmospheric circulation patterns in NEA.Concurrently,the upper-level subtropical westerly jet experiences a northward shift and intensification.These conditions foster the development of anomalously high pressure and downward vertical motion,leading to reduced precipitation and elevated temperatures,which in turn increase the intensity and frequency of CHDEs in NEA during this period.The Atlantic pacemaker simulations further corroborate these findings,highlighting the significant role of the AMO phase in driving interdecadal variations of CHDEs.This research provides essential insights for future interdecadal predictions of CHDEs in NEA,thereby contributing to the broader understanding of climate variability and its implications for societal resilience.展开更多
In the Mei-yu region,there has been noticeable increase in the occurrence of compound hot drought(CHD)events in recent years.However,the underlying causes of these occurrences remain poorly understood.To address this ...In the Mei-yu region,there has been noticeable increase in the occurrence of compound hot drought(CHD)events in recent years.However,the underlying causes of these occurrences remain poorly understood.To address this knowledge gap,we conducted a comprehensive study utilizing observational datasets,reanalysis datasets,and four numerical experiments to investigate the associated physical mechanisms.Our findings indicated that the prevalence of CHD events in the Mei-yu region is influenced strongly by two key factors:the decline in Barents Sea ice during February and the presence of a La Ni?alike pattern of sea surface temperature(SST)in April.The decline in Barents Sea ice generates an anomalous Rossby wave in the Arctic that propagates southeastward.The La Ni?a-like SST pattern regulates a Rossby wave over western America,propagating along the subtropical jet stream.These two Rossby waves induce northward movement and strengthened intensity of the subtropical westerly jet in East Asia.The local circulation patterns in the Mei-yu region are influenced by the position and intensity of the subtropical jet,leading to downward motion in accordance with the secondary circulation theory for high-altitude jet streams.Consequently,these local circulation patterns might contribute to occurrence of CHD events.Moreover,our analysis revealed that the impact of Barents Sea ice and the La Nina-like SST pattern can explain approximately two-thirds of the mild CHD events in the Mei-yu region,and that the influence of each is relatively independent.This research underscores influences of polartropical systems on climate extremes in eastern Asia.展开更多
Growing evidence indicates that extreme heat and rain may occur in succession within short time periods and cause greater impacts than individual events separated in time and space.Therefore,many studies have examined...Growing evidence indicates that extreme heat and rain may occur in succession within short time periods and cause greater impacts than individual events separated in time and space.Therefore,many studies have examined the impacts of compound hazard events on the social-ecological system at various scales.The definition of compound events is fundamental for such research.However,there are no existing studies that support the determination of time interval between individual events of a compound rainstorm and heatwave(CRH)event,which consists of two or more potentially qualifying component heatwave and rainstorm events.To address the deficiency in defining what individual events can constitute a CRH event,this study proposed a novel method to determine the maximum time interval for CRH events through the change in CRH event frequency with increasing time interval between individual events,using southern China as a case study.The results show that the threshold identified by the proposed method is reasonable.For more than 90%of the meteorological stations,the frequency of CRH events has reached a maximum when the time interval is less than or equal to the threshold.This study can aid in time interval selection,which is an important step for subsequent study of CRH events.展开更多
Extreme heat events over both lands and oceans have increased in frequency and intensity,and exerted profound impacts on human and natural systems.More impactful is their concurrence,leading to larger losses in health...Extreme heat events over both lands and oceans have increased in frequency and intensity,and exerted profound impacts on human and natural systems.More impactful is their concurrence,leading to larger losses in health,food,economy,and ecosystem,but receiving far less attention.Understanding the mechanism for such marine–terrestrial compound heatwaves is a prerequisite to prediction and disaster prevention.Based on air particle trajectory analysis,we identified 87 compound heatwaves in China and adjacent oceans in summers of 1982–2021,with the connection between marine and terrestrial heatwaves particularly prominent between the oceans to Northeast Philippines and the lands in South/Southeast China.Through composite and case analysis,it is found that the connection is established by simultaneous governance of(i)the western Pacific subtropical high(WPSH),(ii)a dipole circulation pattern constituted by the WPSH and weak tropical cyclones(TCs),or(iii)strong and closer-to-coast TCs,each of which causes anomalously strong descending motion,increased incoming solar radiation,and strengthened adiabatic heating on lands.The marine heatwaves act to supply more moisture through enhanced evaporation,and/or intensify TCs that pass the region.The air particle tracking shows that these moister air masses are then advected by the WPSH and/or TCs to South/Southeast China,converting the adiabatic heating-caused dry heatwaves there into humid ones and thus adding to the heat stress.These diagnoses provide new insight into the mechanistic understanding and forecast precursors for terrestrial heatwaves,through the lens of compound events.展开更多
Northeastern China has experienced a significant increase in summer compound hot and dry events(CHDEs),posing a threat to local agricultural production and sustainable development.This study investigates the detectabl...Northeastern China has experienced a significant increase in summer compound hot and dry events(CHDEs),posing a threat to local agricultural production and sustainable development.This study investigates the detectable anthropogenic signal in the long-term trend of CHDE and quantifies the contribution of different external forcings.A probability-based index(PI)is constructed through the joint probability distribution to measure the severity of CHDE,with lower values representing more severe cases.Response of CHDE to external forcing was assessed with simulations from the Coupled Model Intercomparison Project phase 6(CMIP6).The results show a significant increase in the severity of CHDE over northeastern China during the past decades.The trend of regional averaged PI is-0.28(90%confidence interval:-0.43 to-0.13)per 54 yr and it is well reproduced in the historical forcing simulations.The attribution method of optimal fingerprinting was firstly applied to a two-signal configuration with anthropogenic forcing and natural forcing;the anthropogenic impact was robustly detected and it explains most of the observed trend of PI.Similarly,three-signal analysis further demonstrated that the anthropogenic greenhouse gases dominantly contribute to the observed change,while the anthropogenic aerosol and natural forcing have almost no contribution to the observed changes.For a compound event concurrently exceeding the 95 th percentile of surface air temperature and precipitation reversal in the current period,its likelihood exhibits little change at 1.5℃global warming,but almost doubled at 2.0℃global warming.展开更多
The extraordinarily high temperatures experienced during the summer of 2022 on the Tibetan Plateau(TP)demand attention when compared with its typical climatic conditions.The absence of precipitation alongside the elev...The extraordinarily high temperatures experienced during the summer of 2022 on the Tibetan Plateau(TP)demand attention when compared with its typical climatic conditions.The absence of precipitation alongside the elevated temperatures resulted in 2022 being the hottest and driest summer on record on the TP since at least 1961.Recognizing the susceptibility of the TP to climate change,this study employed large-ensemble simulations from the HadGEM3-A-N216 attribution system,together with a copula-based joint probability distribution,to investigate the influence of anthropogenic forcing,primarily global greenhouse gas emissions,on this unprecedented compound hot and dry event(CHDE).Findings revealed that the return period for the 2022 CHDE on the TP exceeds 4000 years,as determined from the fitted joint distributions derived using observational data spanning 1961-2022.This CHDE was directly linked to large-scale circulation anomalies,including the control of equivalent-barotropic high-pressure anomalies and the northward displacement of the subtropical westerly jet stream.Moreover,anthropogenic forcing has,to some extent,promoted the surface warming and increased variability in precipitation on the TP in summer,establishing conditions conducive for the 2022 CHDE from a long-term climate change perspective.The return period for a 2022-like CHDE on the TP was estimated to be approximately 283 years(142-613 years)by the large ensemble forced by both anthropogenic activities and natural factors.Contrastingly,ensemble simulations driven solely by natural forcing indicated that the likelihood of occurrence of a 2022-like CHDE was almost negligible.These outcomes underscore that the contribution of anthropogenic forcing to the probability of a 2022-like CHDE was 100%,implying that without anthropogenically induced global warming,a comparable CHDE akin to that observed in 2022 on the TP would not be possible.展开更多
Due to global climate anomalies,the intensity and spatial extent of weather and climate extremes have increased notably.Therefore,extreme events must be studied to ensure agricultural production.In this study,the grow...Due to global climate anomalies,the intensity and spatial extent of weather and climate extremes have increased notably.Therefore,extreme events must be studied to ensure agricultural production.In this study,the growing season accumulated temperature above 10°C(GSAT 10)was used as the climate regionalization index for maize in the Songliao Plain region,and the study area was divided into three climate zones.The standardized precipitation requirement index(SPRI)and standardized temperature index(STI)were introduced to analyze the spatial and temporal patterns of drought,waterlogging,and heat during the maize growing season from May to September using meteorological station data from the Songliao Plain between 1991 and 2020.The compound event magnitude indices were constructed by modeling the marginal distribution to detect the patterns of compound drought and heat events(CDHEs)and compound waterlogging and heat events(CWHEs),and to assess their potential impacts on maize production.The results show that:(1)The major meteorological disasters in the Songliao Plain region were drought and heat.The areas with prolonged high temperatures were similar to the areas with higher severity of temperature extremes,and were mainly concentrated in the central and southern parts of the study area(Zone 3).(2)The CWHEs mainly occurred in the northern part of the study area(Zones 1 and 2),and the CDHEs predominantly occurred in the central and southern parts of the study area.(3)For most sites on the Songliao Plain,the duration,severity,and intensity of compound extreme events were positively correlated with relative meteorological yield(Y_(w)).Maize yield reduction was signifi cantly affected by the CDHEs.展开更多
In late July 2018, a compound drought and heat event(CDHE) occurred in the middle of the Yangtze River basin(MYRB) and caused great damage to the national economy. The CDHE over the MYRB has been documented to be link...In late July 2018, a compound drought and heat event(CDHE) occurred in the middle of the Yangtze River basin(MYRB) and caused great damage to the national economy. The CDHE over the MYRB has been documented to be linked with intraseasonal oscillations(ISOs) from different regions. However, specific roles of different ISOs on the development of the CDHE cannot be separated in the observational analysis. By using partial lateral forcing experiments driven by ISO in the Weather Research and Forecasting(WRF) model, we found that the midlatitude ISO generated by a westerly wave train in the upper troposphere played an important role in this heatwave and drought event in the northern MYRB, causing a regional average temperature rise of 1.65°C and intensification of drought over23.49% of the MYRB area. On the other hand, the ISO associated with the Pacific-Japan(PJ)-like teleconnection wave train in the lower troposphere induced a more pronounced impact on the event, causing an average temperature rise of 2.44°C, intensifying drought over 29.62% of the MYRB area. The MYRB was mainly affected by northward warm advection driven by the westward extension of the western North Pacific subtropical high in the early period of the CDHE development. In the late period, because of the establishment of a deep positive geopotential height field through the troposphere leading to intensive local subsidence, there was a remarkable temperature rise and moisture decrease in the MYRB. The results will facilitate a better understanding of the occurrence of CDHE and provide empirical precursory signals for subseasonal forecast of CDHE.展开更多
Owing to the complexity and variability of global climate,the study of extreme events to ensure food security is particularly critical.The standardized precipitation requirement index(SPRI)and chilling injury index(I_...Owing to the complexity and variability of global climate,the study of extreme events to ensure food security is particularly critical.The standardized precipitation requirement index(SPRI)and chilling injury index(I_(Ci))were introduced using data from agrometeorological stations on the Songliao Plain between 1981 and 2020 to identify the spatial and temporal variability of drought,waterlogging,and low-temperature cold damage during various maize growth periods.Compound drought and low-temperature cold damage events(CDLEs)and compound waterlogging and low-temperature cold damage events(CWLEs)were then identified.To measure the intensity of compound events,the compound drought and low-temperature cold damage magnitude index(CDLMI),and compound waterlogging and low-temperature cold damage magnitude index(CWLMI)were constructed by fitting marginal distributions.Finally,the effects of extreme events of various intensities on maize output were examined.The findings demonstrate that:(1)There were significant differences in the temporal trends of the SPRI and ICiduring different maize growth periods.Drought predominated in the middle growth period(MP),waterlogging predominated in the early growth period(EP)and late growth period(LP),and both drought and waterlogging tended to increase in intensity and frequency.The frequency of low-temperature cold damage showed a decreasing trend in all periods.(2)The CDLMI and CWLMI can effectively determine the intensity of CDLEs and CWLEs in the study area;these CDLEs and CWLEs had higher intensity and frequency in the late growth period.(3)Compared to single events,maize relative meteorological yield had a more significant negative correlation with the CDLMI and CWLMI.展开更多
基金the National Natural Science Foundation of China[grant numbers 42141019 and 42261144687]An Investigation Research Program between Ecological Environment and Human Health in Wuyi Mountain[grant number 20242120035]Natural Science Foundation of Hubei Province,China[grant number 2024AF-B115]。
文摘Against the backdrop of global warming,China has been facing increasingly frequent and severe extreme weather and climate events,with a prominent risk of compound extreme events induced by interactions among multiple climate drivers and/or hazards.The present study first reviews the definition and classification of compound extreme events in China.Then,it summarizes research progress on the evolutionary characteristics,formation mechanisms,and future projections of different types of compound extreme events.The potential risks and possible impact pathways of three specific event types—namely,continuous day–night hot extremes,temperature–humidity compound events,and high-temperature–ozone compound events—on the health of the Chinese population are then explored.Finally,a framework for assessing the hazard risk of compound extreme events is constructed,accompanied by response strategies based on carbon neutrality targets.Building on existing research achievements,five future research directions are proposed:(1)identifying the risk chains of compound events;(2)addressing the constraints of observational records and coupled model performances;(3)attributing and understanding the drivers of compound extreme events;(4)finding optimal pathways for carbon reduction and air quality improvement;and(5)promoting inter-disciplinary,multi-regional,and cross-sectoral collaboration.Strengthening research in these directions will deepen our understanding of compound extreme events and provide technological support for climate change adaptation and health risk responses in China.
基金supported by the National Natural Science Foundation of China(Grant No.42371423)the Fundamental Research Funds for the Central Universities(Grant No.2042023kfyq04)+1 种基金the China Postdoctoral Science Foundation(Grant No.2023M742682)the Postdoctoral Fellowship Program of CPSF(Grant No.GZB20230539).
文摘In a warming world,climate extremes tend to be more frequent and intense.The exceptional response of ecosystems triggered by extreme climate events under a warmer and wetter climate in northwest China(NWC)has aroused growing concern.However,understanding the responses of vegetation to climate extremes from the compound events perspective remains challenging.In this study,we identify the climate dynamics in NWC during 1971–2020 based on daily meteorological observations,focusing on the changes in compound hot-dry events(CHDEs)during the warmer and wetter period.We further explore the effects of CHDEs on vegetation by examining vegetation anomalies and recovery time using daily gross primary productivity(GPP)data.The results show a clear warmer and wetter period in NWC during 2000–2020.No signs of a hiatus in CHDEs increase are observed during this period,and even the duration of CHDEs in western NWC keeps showing an increasing tendency.Vegetation in eastern NWC,with a lower probability of GPP anomalies,exhibits stronger resistance of ecosystems to CHDEs than in western NWC.In NWC,vegetation typically returns to its normal state in 5.50 days on average,but exhibits greater resilience in the western region,where it takes less recovery time(4.82 days).Vegetation in the central region shows the lowest probability of GPP anomalies and relatively longer recovery time,likely due to its higher altitudes.Our research underscores the imperative to address the considerable impacts of CHDEs on vegetation growth even as the regional climate becomes increasingly warmer and wetter.
基金supported by the National Natural Science Foundation of China(42371483,and 42401573)the Guangdong Basic and Applied Basic Research Foundation,China(2022B1515130001)+2 种基金the Natural Science Foundation of Guangdong Province,China(2024A1515012081 and 2025A1515010770)the Guangzhou Basic and Applied Basic Research Project,China(202201011666)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZB20240880).
文摘The increasing frequency of compound extreme events under ongoing climate change threatens global food security.Compared to individual extreme events,the simultaneous occurrence of multiple extreme events can exacerbate crop yield reductions,yet comprehensive assessments of these compound effects remain limited.To bridge this gap,we applied a linear mixed-effects model to quantify the impacts of individual extreme events(cold days(CD)and killing degree days(KDD))and triple compound extreme events(heatwave and low precipitation(HWLP)and hot-dry-windy(HDW))on the global yields of winter wheat,soybeans,and maize from 1982 to 2016.Our analysis indicated that regions severely impacted by extreme events(exceeding the 95%threshold)experienced total crop yield losses of more than 9.16,24.89,26.69,and 7.12%due to CD,KDD,HWLP,and HDW,respectively.The adverse effects of compound events were particularly pronounced during critical growth stages.HWLP results in yield losses of 9.4%for winter wheat and 6.8%for maize per 10 hours of exposure during the heading to harvesting stages,while soybean yields declined by 8.8%per 10 hours during the planting to three-true-leaf stage.Similarly,KDD caused a 7.4%yield reduction in winter wheat per 10°C day during the heading to harvesting stages,a 9.5%reduction in maize per 10°C day during the planting to jointing stages,and a 3.8%reduction in soybean per 10°C day during the planting to three-true-leaf stages.These findings underscore the substantial contribution of compound extreme events,which are often overlooked in existing risk assessments,in determining the global yields of major staple crops.
基金supported by the National Natural Science Foundation of China(Grant Nos.41991231 and 91937302)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2022-kb11)。
文摘Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global scales.However,the association between heatwaves and dust storms is poorly known.In this study,we describe the association between heatwaves and dust events and propose a mechanism for such compound events in the TD.The results show that,from 1993 to 2022,the frequency and intensity of heatwaves in the TD have increased at a rate of 0.21 days year^(-1)and 0.02℃ year^(-1),respectively.More than 40% of heatwaves existed with dust events,which significantly lagged behind heatwaves.Mechanically,the higher the air temperature,the hotter and drier the soil,leading to more dust emissions in the TD.In high-occurrence heatwave years,a large-scale wave train of“cyclone-anticyclone-cyclone”in the northwest-southeast direction was found,with the anticyclone of which hovered over the TD region.The anomalous anticyclones favored the formation and maintenance of heatwaves,and subsequent anomalous cyclones in the wave train triggered strong dust events followed by heatwaves.With climate warming,the compound events of heatwave and dust storm are becoming bigger hazards threatening the socioeconomic and ecological security in the TD,the profound study of which is critical to understanding regional extreme responses.
基金funded by the National Natural Science Foundation of China[grant number U2442202]the National Key Research and Development Program of China[grant number 2018YFA0606200]+1 种基金the Guangdong Major Project of Basic and Applied Basic Research[grant number 2020B0301030004]the Science and Technology Project of the Tibet Autonomous Region[grant number XZ202402ZD0006-06]。
文摘Compound extreme climate events involving multiple meteorological elements usually have a more severe impact on the environment and human health than single-element extreme events.However,the current definition of multi-element compound extreme events is proposed from meteorological and statistical perspectives,without integrating health data,making the conclusions less practical for guiding health risk prevention.This study identified the threshold for hot–dry compound extreme events with high mortality risks(HMHDs)in China,using daily mortality data and temperature–humidity data from 278 districts or counties,and explored the interdecadal change and driving mechanisms of HMHD frequency in China from 1979 to 2021.The results show a significant increase in annual HMHD frequency in China after 2000,mainly occurring in summer(June,July,August).The northwestern to western regions of China(Xinjiang,Inner Mongolia,Gansu),and from the southwestern to the areas south of the Yangtze River(Sichuan,Hubei,Hunan,Jiangxi,Fujian,Guizhou,Yunnan),experience an increase of>10 days.The authors find that the interdecadal abrupt change in HMHD frequency can be attributed to the shift of the Atlantic Multidecadal Oscillation from a negative to a positive phase by affecting the Silk Road teleconnection.
基金Guangdong Major Project of Basic and Applied Basic Research Foundation(2020B0301030004)National Natural Science Foundation of China(42375029)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2023A1515010908)Science and Technology Planning Project of Guangdong Province(2023B1212060019)Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2024SP012)。
文摘This study investigates the extreme compound cold-wet event in southern China during January–February 2024,which was the second most extreme event recorded since 1960.Two cold-wet processes occurred during this period.The first process,from 22 January to 23 January,exhibited a more intense cold surge,while the second,from 1 February to 7 February,featured more extreme precipitation and longer duration.This extreme cold-wet event was attributed to the combined effects of El Niño and positive North Atlantic Oscillation(NAO)in winter,coupled with intense convection in the western tropical Indian Ocean associated with a positive Indian Ocean Dipole(IOD)from the preceding autumn.El Niño and the Indian Ocean Basin mode in winter are conductive to enhanced anticyclone over the western North Pacific.Over the western tropical Indian Ocean,the enhanced convection associated with the warm sea surface temperature in winter and the positive IOD in preceding autumn can trigger an anomalous upper-level anticyclone over the Arabian Sea,enhancing the subtropical jet and deepening the India-Myanmar trough.The deepened India-Myanmar trough and the strengthened subtropical anticyclone over the western North Pacific enhance water vapor transport and subsequent extreme precipitation in southern China.Moreover,positive NAO and strengthened westerly jet stream induce widespread cooling in subtropical Eurasia,including southern China.Analysis from the backward trajectories using the HYSPLIT model confirms that moisture from the west and cold air from northern China at the near surface favored the compound cold-wet event in southern China.The extreme conditions of ENSO and NAO in winter and IOD in autumn jointly contributed to this extreme compound event.
基金National Key R&D Program of China,Grant/Award Number:2022YFC3002705National Natural Science Foundation of China,Grant/Award Number:5220904China Institute of Water Resources and Hydropower Research,Grant/Award Number:SKL2022TS11。
文摘The escalation of compound extreme events has resulted in noteworthy economic and property losses.Recognizing the intricate interconnections among these events has become imperative.To tackle this challenge,we have formulated a comprehensive framework for the systematic analysis of their dependencies.This framework consists of three steps.(1)Define extreme events using Mahalanobis distance thresholds.(2)Represent dependencies among multiple extreme events through a point process-based method.(3)Verify dependencies with residual tail coefficients,determining thefinal dependency structure.Applying this framework to assess the extreme dependence of precipitation on wind speed and temperature in China,revealed four distinct dependency structures.In northern,Jianghuai,and southern China,precipitation heavily relies on wind speed,while tempera-tures maintain relative independence.In northeastern and northwestern China,precipitation exhibits relative independence,yet a notable dependence exists between temperatures and wind speed.In southwestern China,precipitation strongly depends on temperature,while wind speed remains relatively indepen-dent.The Qinghai–Tibet Plateau region displays a significant dependence relationship among precipitation,wind speed,and temperature,with weaker dependence between extreme wind speed and temperature.This framework is instrumental for analyzing dependencies among extreme values in compound events.
基金supported by the National Natural Science Foundation of China(Grant No.42088101)supported by the Research Council of Norway funded project(MAPARC,Grant No.328943)。
文摘Under the influence of global warming,the increasing intensity of compound hot drought events(CHDEs)presents a substantial threat to human society.However,the interdecadal variability and driving factors of CHDEs in Northern East Asia(NEA)remain insufficiently understood.Employing the multivariate copula method to characterize CHDEs,this study investigates the characteristics and mechanisms in this region during July.Our findings reveal two notable interdecadal shifts in the intensity and frequency of CHDEs during 1940-2022,occurring in the mid-1950s and the mid-1990s.These shifts correspond to periods of interdecadal weakening and intensification of CHDEs,respectively.The primary driver of this interdecadal variability has been identified as the Atlantic Multidecadal Oscillation(AMO).During the positive phase of the AMO,anomalously warm sea surface temperatures(SSTs)in the Atlantic Ocean influence wave trains that propagate along great circle routes,subsequently altering regional atmospheric circulation patterns in NEA.Concurrently,the upper-level subtropical westerly jet experiences a northward shift and intensification.These conditions foster the development of anomalously high pressure and downward vertical motion,leading to reduced precipitation and elevated temperatures,which in turn increase the intensity and frequency of CHDEs in NEA during this period.The Atlantic pacemaker simulations further corroborate these findings,highlighting the significant role of the AMO phase in driving interdecadal variations of CHDEs.This research provides essential insights for future interdecadal predictions of CHDEs in NEA,thereby contributing to the broader understanding of climate variability and its implications for societal resilience.
基金supported by the National Natural Science Foundation of China(42088101)the National Key Research and Development Program of China(2022YFF0801704)the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(316323005)。
文摘In the Mei-yu region,there has been noticeable increase in the occurrence of compound hot drought(CHD)events in recent years.However,the underlying causes of these occurrences remain poorly understood.To address this knowledge gap,we conducted a comprehensive study utilizing observational datasets,reanalysis datasets,and four numerical experiments to investigate the associated physical mechanisms.Our findings indicated that the prevalence of CHD events in the Mei-yu region is influenced strongly by two key factors:the decline in Barents Sea ice during February and the presence of a La Ni?alike pattern of sea surface temperature(SST)in April.The decline in Barents Sea ice generates an anomalous Rossby wave in the Arctic that propagates southeastward.The La Ni?a-like SST pattern regulates a Rossby wave over western America,propagating along the subtropical jet stream.These two Rossby waves induce northward movement and strengthened intensity of the subtropical westerly jet in East Asia.The local circulation patterns in the Mei-yu region are influenced by the position and intensity of the subtropical jet,leading to downward motion in accordance with the secondary circulation theory for high-altitude jet streams.Consequently,these local circulation patterns might contribute to occurrence of CHD events.Moreover,our analysis revealed that the impact of Barents Sea ice and the La Nina-like SST pattern can explain approximately two-thirds of the mild CHD events in the Mei-yu region,and that the influence of each is relatively independent.This research underscores influences of polartropical systems on climate extremes in eastern Asia.
基金funded by the Joint Funds of the National Natural Science Foundation of China(Grant No.U22B2011)the Ministry of Education and State Administration of Foreign Experts Aff airs,China(Grant No.BP0820003)the Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education(2023-KF-13)。
文摘Growing evidence indicates that extreme heat and rain may occur in succession within short time periods and cause greater impacts than individual events separated in time and space.Therefore,many studies have examined the impacts of compound hazard events on the social-ecological system at various scales.The definition of compound events is fundamental for such research.However,there are no existing studies that support the determination of time interval between individual events of a compound rainstorm and heatwave(CRH)event,which consists of two or more potentially qualifying component heatwave and rainstorm events.To address the deficiency in defining what individual events can constitute a CRH event,this study proposed a novel method to determine the maximum time interval for CRH events through the change in CRH event frequency with increasing time interval between individual events,using southern China as a case study.The results show that the threshold identified by the proposed method is reasonable.For more than 90%of the meteorological stations,the frequency of CRH events has reached a maximum when the time interval is less than or equal to the threshold.This study can aid in time interval selection,which is an important step for subsequent study of CRH events.
基金Supported by the National Natural Science Foundation of China(42375041)Joint Research Project for Meteorological Capacity Improvement(22NLTSZ002)China Meteorological Administration Youth Innovation Group(CMA2024QN06).
文摘Extreme heat events over both lands and oceans have increased in frequency and intensity,and exerted profound impacts on human and natural systems.More impactful is their concurrence,leading to larger losses in health,food,economy,and ecosystem,but receiving far less attention.Understanding the mechanism for such marine–terrestrial compound heatwaves is a prerequisite to prediction and disaster prevention.Based on air particle trajectory analysis,we identified 87 compound heatwaves in China and adjacent oceans in summers of 1982–2021,with the connection between marine and terrestrial heatwaves particularly prominent between the oceans to Northeast Philippines and the lands in South/Southeast China.Through composite and case analysis,it is found that the connection is established by simultaneous governance of(i)the western Pacific subtropical high(WPSH),(ii)a dipole circulation pattern constituted by the WPSH and weak tropical cyclones(TCs),or(iii)strong and closer-to-coast TCs,each of which causes anomalously strong descending motion,increased incoming solar radiation,and strengthened adiabatic heating on lands.The marine heatwaves act to supply more moisture through enhanced evaporation,and/or intensify TCs that pass the region.The air particle tracking shows that these moister air masses are then advected by the WPSH and/or TCs to South/Southeast China,converting the adiabatic heating-caused dry heatwaves there into humid ones and thus adding to the heat stress.These diagnoses provide new insight into the mechanistic understanding and forecast precursors for terrestrial heatwaves,through the lens of compound events.
基金Supported by the National Key Research and Development Program of China(2018YFC1507704,2017YFA0603804)National Natural Science Foundation of China(41905078)。
文摘Northeastern China has experienced a significant increase in summer compound hot and dry events(CHDEs),posing a threat to local agricultural production and sustainable development.This study investigates the detectable anthropogenic signal in the long-term trend of CHDE and quantifies the contribution of different external forcings.A probability-based index(PI)is constructed through the joint probability distribution to measure the severity of CHDE,with lower values representing more severe cases.Response of CHDE to external forcing was assessed with simulations from the Coupled Model Intercomparison Project phase 6(CMIP6).The results show a significant increase in the severity of CHDE over northeastern China during the past decades.The trend of regional averaged PI is-0.28(90%confidence interval:-0.43 to-0.13)per 54 yr and it is well reproduced in the historical forcing simulations.The attribution method of optimal fingerprinting was firstly applied to a two-signal configuration with anthropogenic forcing and natural forcing;the anthropogenic impact was robustly detected and it explains most of the observed trend of PI.Similarly,three-signal analysis further demonstrated that the anthropogenic greenhouse gases dominantly contribute to the observed change,while the anthropogenic aerosol and natural forcing have almost no contribution to the observed changes.For a compound event concurrently exceeding the 95 th percentile of surface air temperature and precipitation reversal in the current period,its likelihood exhibits little change at 1.5℃global warming,but almost doubled at 2.0℃global warming.
基金supported by the second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2022QZKK0101)。
文摘The extraordinarily high temperatures experienced during the summer of 2022 on the Tibetan Plateau(TP)demand attention when compared with its typical climatic conditions.The absence of precipitation alongside the elevated temperatures resulted in 2022 being the hottest and driest summer on record on the TP since at least 1961.Recognizing the susceptibility of the TP to climate change,this study employed large-ensemble simulations from the HadGEM3-A-N216 attribution system,together with a copula-based joint probability distribution,to investigate the influence of anthropogenic forcing,primarily global greenhouse gas emissions,on this unprecedented compound hot and dry event(CHDE).Findings revealed that the return period for the 2022 CHDE on the TP exceeds 4000 years,as determined from the fitted joint distributions derived using observational data spanning 1961-2022.This CHDE was directly linked to large-scale circulation anomalies,including the control of equivalent-barotropic high-pressure anomalies and the northward displacement of the subtropical westerly jet stream.Moreover,anthropogenic forcing has,to some extent,promoted the surface warming and increased variability in precipitation on the TP in summer,establishing conditions conducive for the 2022 CHDE from a long-term climate change perspective.The return period for a 2022-like CHDE on the TP was estimated to be approximately 283 years(142-613 years)by the large ensemble forced by both anthropogenic activities and natural factors.Contrastingly,ensemble simulations driven solely by natural forcing indicated that the likelihood of occurrence of a 2022-like CHDE was almost negligible.These outcomes underscore that the contribution of anthropogenic forcing to the probability of a 2022-like CHDE was 100%,implying that without anthropogenically induced global warming,a comparable CHDE akin to that observed in 2022 on the TP would not be possible.
基金supported by the National K&D Program of China(2022YFD2300201)the National Natural Science Foundation of China(U21A2040)+3 种基金the National Natural Science Foundation of China(42077443)the Science and Technology Development Planning of Jilin Province(20210203153SF)the Key Scientific and Technology Research and Development Program of Jilin Province(20200403065SF)the Construction Project of the Science and Technology Innovation Center(20210502008ZP)。
文摘Due to global climate anomalies,the intensity and spatial extent of weather and climate extremes have increased notably.Therefore,extreme events must be studied to ensure agricultural production.In this study,the growing season accumulated temperature above 10°C(GSAT 10)was used as the climate regionalization index for maize in the Songliao Plain region,and the study area was divided into three climate zones.The standardized precipitation requirement index(SPRI)and standardized temperature index(STI)were introduced to analyze the spatial and temporal patterns of drought,waterlogging,and heat during the maize growing season from May to September using meteorological station data from the Songliao Plain between 1991 and 2020.The compound event magnitude indices were constructed by modeling the marginal distribution to detect the patterns of compound drought and heat events(CDHEs)and compound waterlogging and heat events(CWHEs),and to assess their potential impacts on maize production.The results show that:(1)The major meteorological disasters in the Songliao Plain region were drought and heat.The areas with prolonged high temperatures were similar to the areas with higher severity of temperature extremes,and were mainly concentrated in the central and southern parts of the study area(Zone 3).(2)The CWHEs mainly occurred in the northern part of the study area(Zones 1 and 2),and the CDHEs predominantly occurred in the central and southern parts of the study area.(3)For most sites on the Songliao Plain,the duration,severity,and intensity of compound extreme events were positively correlated with relative meteorological yield(Y_(w)).Maize yield reduction was signifi cantly affected by the CDHEs.
基金Supported by the National Natural Science Foundation of China(41875111 and 41975073)Special Program for Innovation and Development of China Meteorological Administration(CXFZ2022J031).
文摘In late July 2018, a compound drought and heat event(CDHE) occurred in the middle of the Yangtze River basin(MYRB) and caused great damage to the national economy. The CDHE over the MYRB has been documented to be linked with intraseasonal oscillations(ISOs) from different regions. However, specific roles of different ISOs on the development of the CDHE cannot be separated in the observational analysis. By using partial lateral forcing experiments driven by ISO in the Weather Research and Forecasting(WRF) model, we found that the midlatitude ISO generated by a westerly wave train in the upper troposphere played an important role in this heatwave and drought event in the northern MYRB, causing a regional average temperature rise of 1.65°C and intensification of drought over23.49% of the MYRB area. On the other hand, the ISO associated with the Pacific-Japan(PJ)-like teleconnection wave train in the lower troposphere induced a more pronounced impact on the event, causing an average temperature rise of 2.44°C, intensifying drought over 29.62% of the MYRB area. The MYRB was mainly affected by northward warm advection driven by the westward extension of the western North Pacific subtropical high in the early period of the CDHE development. In the late period, because of the establishment of a deep positive geopotential height field through the troposphere leading to intensive local subsidence, there was a remarkable temperature rise and moisture decrease in the MYRB. The results will facilitate a better understanding of the occurrence of CDHE and provide empirical precursory signals for subseasonal forecast of CDHE.
基金supported by the National K&D Program of China(2022YFD2300201)the National Natural Science Foundation of China(U21A2040)+4 种基金the Major Science and Technology Program of Jilin Province(YDZJ202303CGZH023)the National Natural Science Foundation of China(42077443)the Science and Technology Development Planning of Jilin Province(20210203153SF)the Key Scientific and Technology Research and Development Program of Jilin Province(20200403065 SF)the Construction Project of the Science and Technology Innovation Center(20210502008ZP).
文摘Owing to the complexity and variability of global climate,the study of extreme events to ensure food security is particularly critical.The standardized precipitation requirement index(SPRI)and chilling injury index(I_(Ci))were introduced using data from agrometeorological stations on the Songliao Plain between 1981 and 2020 to identify the spatial and temporal variability of drought,waterlogging,and low-temperature cold damage during various maize growth periods.Compound drought and low-temperature cold damage events(CDLEs)and compound waterlogging and low-temperature cold damage events(CWLEs)were then identified.To measure the intensity of compound events,the compound drought and low-temperature cold damage magnitude index(CDLMI),and compound waterlogging and low-temperature cold damage magnitude index(CWLMI)were constructed by fitting marginal distributions.Finally,the effects of extreme events of various intensities on maize output were examined.The findings demonstrate that:(1)There were significant differences in the temporal trends of the SPRI and ICiduring different maize growth periods.Drought predominated in the middle growth period(MP),waterlogging predominated in the early growth period(EP)and late growth period(LP),and both drought and waterlogging tended to increase in intensity and frequency.The frequency of low-temperature cold damage showed a decreasing trend in all periods.(2)The CDLMI and CWLMI can effectively determine the intensity of CDLEs and CWLEs in the study area;these CDLEs and CWLEs had higher intensity and frequency in the late growth period.(3)Compared to single events,maize relative meteorological yield had a more significant negative correlation with the CDLMI and CWLMI.
