Under global warming,understanding the impact of urbanization on the characteristics of different heatwaves is important for sustainable development.In this study,we investigated the changes of heatwaves characteristi...Under global warming,understanding the impact of urbanization on the characteristics of different heatwaves is important for sustainable development.In this study,we investigated the changes of heatwaves characteristics in the Yangtze River Delta urban agglomeration(YRDUG)and analyzed the influencing mechanisms of urbanization.Results showed that:(1)the duration,frequency,and intensity of NHWs(Nighttime Heatwaves)and CHWs(Daytime-nighttime compound Heatwaves)had shown a significant increase and the CHWs showed the greatest increasing trend.Furthermore,the NHWs exhibited higher durations,frequencies,and intensities compared to DHWs(Daytime Heatwaves);(2)Since 1990,the DHWs and CHWs were greater in urban areas than in rural areas,NHWs had been more pronounced in rural areas than in urban centers;and(3)Cloud cover,solar radiation,etc.affected heatwaves.Furthermore,in the process of urbanization,the increase in impervious area and the decrease in green land exacerbated heatwaves.Considering the combined effect of DHWs and NHWs,CHWs continued to increase.展开更多
India is highly vulnerable to climate change and is going to increase its average annual temperature over the next few decades.The impact of heatwaves and related mortality is a concern for the country.In this paper,w...India is highly vulnerable to climate change and is going to increase its average annual temperature over the next few decades.The impact of heatwaves and related mortality is a concern for the country.In this paper,we aim to study the heatwaves and heat stress-related Heat Index vulnerability using heat index temperature.In this analysis,a heat in-dex temperature is calculated based on temperature and relative humidity for six different states(Delhi,West Bengal,Punjab,Uttar Pradesh,Andhra Pradesh,and Madhya Pradesh)of India to determine the heat stress vulnerability for which heat cramps and heat strokes are possible.Our analysis shows that most of the heatwaves and severe heatwaves occurred during 2010 for all the states.The heatwaves are observed only in the summer months.All the states of our study reached the Extreme Caution category of the Heat Index showing the Danger to Extreme Danger category dur-ing April to June.Future projection scenarios show an increase in heat stress-related vulnerability.SSP2-4.5 scenario showed that Delhi,Punjab,and West Bengal reached an Extreme Danger state during June for which death due to heat strokes is possible under continued exposure to heatwaves.The HI related vulnerability of SSP5-8.5 is like SSP2-4.5 except for Andhra Pradesh which shows an Extreme Danger state in May and June during which heat strokes are possi-ble under continued exposure to heatwaves.This study provides spatial variability of heat stress and Heat Index vulner-ability which may help adopt future strategies for heat-related policy implication.展开更多
Marine heatwaves(MHWs)in the East China Sea(ECS),especially those occurring on the ocean bottom(referred to as bottom marine heatwaves,BMHWs),can significantly affect regional ecosystems.However,our understanding of t...Marine heatwaves(MHWs)in the East China Sea(ECS),especially those occurring on the ocean bottom(referred to as bottom marine heatwaves,BMHWs),can significantly affect regional ecosystems.However,our understanding of the seasonal variations in the MHWs in the ECS remains limited.This study investigates the characteristics of MHWs in the ECS in summer and winter using high-resolution oceanic reanalysis.Our analyses reveal distinct spatial patterns of BMHWs in these seasons.During summer,the Taiwan Warm Current plays a crucial role in transporting warm water northward,potentially leading to intense BMHWs on the central ECS shelf.These BMHW events usually occur independently of surface warming due to strong stratification in summer.Conversely,winter BMHWs are more prevalent in coastal regions under the influence of coastal currents and typically feature consistent warming from surface to bottom with a deepened mixed layer.These findings inform the coherent vertical structure and driving mechanisms of MHWs in the ECS,which are essential for predicting and managing these extreme events in the future.展开更多
Marine heatwaves(MHWs),which can exert devastating socioeconomic and ecological impacts,have attracted much public interest in recent years.In this study,we evaluate the sub-seasonal forecast skill of MHWs based on th...Marine heatwaves(MHWs),which can exert devastating socioeconomic and ecological impacts,have attracted much public interest in recent years.In this study,we evaluate the sub-seasonal forecast skill of MHWs based on the Nanjing University of Information Science&Technology Climate Forecast System version 1.1(NUIST CFS1.1)and analyze the related physical processes.Our results show that the model can accurately forecast the occurrence of MHWs on a global scale out to a lead time of 25 days.Notably,even at lead times of 51–55 days,the forecast skill in most tropical regions,as well as in the northeastern and southeastern Pacific,is superior to both random forecasts and persistence forecasts.Accurate predictions of sea level pressure,zonal currents,and mixed-layer depth are important for MHW forecasting.Furthermore,we also conduct forecast skill assessments for two well-documented MHW events.Due to its ability to correctly forecast the changes in heat flux anomalies at a lead time of 25 days,the model can accurately forecast the strong MHW event that occurred in the South China Sea in May–October 2020.However,the forecasting results were less than optimal for the strong MHW event that occurred along the Australian west coast in January–April 2011.Although the model accurately forecasts its occurrence,the forecast of its intensity is poor.Additionally,when the lead time exceeds 10 days,forecasts of the relevant physical processes of this MHW event are also inaccurate.展开更多
With the intensification of global warming,marine heatwaves(MHWs)have emerged as a significant extreme hazard,garnering widespread attention and creating a pressing need for accurate prediction.The development of arti...With the intensification of global warming,marine heatwaves(MHWs)have emerged as a significant extreme hazard,garnering widespread attention and creating a pressing need for accurate prediction.The development of artificial intelligence,particularly the application of deep learning to sea surface temperature(SST),has significantly improved the feasibility of predictions.This study utilizes SST and Outgoing Longwave Radiation(OLR)data to train a 3D U-Net model for predicting MHWs in the South China Sea(SCS)with lead times ranging from 1 to 7 days,based on the characteristics of intraseasonal weather processes.Analysis of MHWs occurrences from 1982 to 2023 reveals distinct seasonal patterns,with summer MHWs primarily concentrated in the northern and central SCS,and the highest temperature centers located in the Gulf of Tonkin and west of the Philippines.The 2023 MHW forecast results demonstrate that the 3D U-Net model achieves low error rates and high correlation coefficients with observational data.Incorporating OLR data enhances forecast accuracy compared to SST-only inputs,and training the model exclusively with summer data further improves prediction accuracy.These findings indicate that the proposed method can significantly enhance the accuracy of MHW forecasts.展开更多
Marine heatwaves(MHWs)are extreme ocean events characterized by anomalously warm upper-ocean temperatures,posing significant threats to marine ecosystems.While various factors driving MHWs have been extensively studie...Marine heatwaves(MHWs)are extreme ocean events characterized by anomalously warm upper-ocean temperatures,posing significant threats to marine ecosystems.While various factors driving MHWs have been extensively studied,the role of ocean salinity remains poorly understood.This study investigates the influence of salinity on the major 2013-2014 MHW event in the Northeast Pacific using reanalysis data and climate model outputs.Our results show that salinity variabilities are crucial for the development of the MHW event.Notably,a significant negative correlation exists between sea surface temperature anomalies(SSTAs)and sea surface salinity anomalies(SSSAs)during the MHW,with the SSSAs emerging simultaneously with SSTAs in the same area.Negative salinity anomalies(SAs)result in a shallower mixed layer,which suppresses vertical mixing and thus sustains the upper-ocean warming.Moreover,salinity has a greater impact on mixed layer depth anomalies than temperature.Model sensitivity experiments further demonstrate that negative SAs during MHWs amplify positive SSTAs by enhancing upper-ocean stratification,intensifying the MHW.Additionally,our analysis indicates that the SAs are predominantly driven by local freshwater flux anomalies,which are mainly induced by positive precipitation anomalies during the MHW event.展开更多
Using complex network methods,we construct undirected and directed heatwave networks to systematically analyze heatwave events over China from 1961 to 2023,exploring their spatiotemporal evolution patterns in differen...Using complex network methods,we construct undirected and directed heatwave networks to systematically analyze heatwave events over China from 1961 to 2023,exploring their spatiotemporal evolution patterns in different regions.The findings reveal a significant increase in heatwaves since the 2000s,with the average occurrence rising from approximately 3 to 5 times,and their duration increasing from 15 to around 30 days,nearly doubling.An increasing trend of“early onset and late withdrawal”of heatwaves has become more pronounced each year.In particular,eastern regions experience heatwaves that typically start earlier and tend to persist into September,exhibiting greater interannual variability compared to western areas.The middle and lower reaches of the Yangtze River and Xinjiang are identified as high-frequency heatwave areas.Complex network analysis reveals the dynamics of heatwave propagation,with degree centrality and synchronization distance indicating that the middle and lower reaches of the Yangtze River,Northeast China,and Xinjiang are key nodes in heatwave spread.Additionally,network divergence analysis shows that Xinjiang acts as a“source”area for heatwaves,exporting heat to surrounding regions,while the central region functions as a major“sink,”receiving more heatwave events.Further analysis from 1994 to 2023 indicates that heatwave events exhibit stronger network centrality and more complex synchronization patterns.These results suggest that complex networks provide a refined framework for depicting the spatiotemporal dynamics of heatwave propagation,offering new avenues for studying their occurrence and development patterns.展开更多
We chose a definition of heatwaves (HWs) that has ~4-year recurrence frequency at world hot spots. We first examined the 1940-2022 HWs climatology and trends in lifespan, severity, spatial extent, and recurrence frequ...We chose a definition of heatwaves (HWs) that has ~4-year recurrence frequency at world hot spots. We first examined the 1940-2022 HWs climatology and trends in lifespan, severity, spatial extent, and recurrence frequency. HWs are becoming more frequent and more severe for extratropical mid- and low-latitudes. To euphemize HWs, we here propose a novel clean energy-tapping concept that utilizes the available nano-technology, micro-meteorology knowledge of temperature distribution within/without buildings, and radiative properties of earth atmosphere. The key points for a practical electricity generation scheme from HWs are defogging, insulation, and minimizing the absorption of infrared downward radiation at the cold legs of the thermoelectric generators. One sample realization is presented which, through relay with existing photovoltaic devices, provides all-day electricity supply sufficient for providing air conditioning requirement for a residence (~2000-watt throughput). The provision of power to air conditioning systems, usually imposes a significant stress on traditional city power grids during heatwaves.展开更多
Using monthly observations and ensemble hindcasts of the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS1.0) for the period 1983–2020, this study investigates the forecast s...Using monthly observations and ensemble hindcasts of the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS1.0) for the period 1983–2020, this study investigates the forecast skill of marine heatwaves(MHWs) over the globe and the predictability sources of the MHWs over the tropical oceans. The MHW forecasts are demonstrated to be skillful on seasonal-annual time scales, particularly in tropical oceans. The forecast skill of the MHWs over the tropical Pacific Ocean(TPO) remains high at lead times of 1–24 months, indicating a forecast better than random chance for up to two years. The forecast skill is subject to the spring predictability barrier of El Nino-Southern Oscillation(ENSO). The forecast skills for the MHWs over the tropical Indian Ocean(TIO), tropical Atlantic Ocean(TAO), and tropical Northwest Pacific(NWP) are lower than that in the TPO. A reliable forecast at lead times of up to two years is shown over the TIO, while a shorter reliable forecast window(less than 17 months) occurs for the TAO and NWP.Additionally, the forecast skills for the TIO, TAO, and NWP are seasonally dependent. Higher skills for the TIO and TAO appear in boreal spring, while a greater skill for the NWP emerges in late summer-early autumn. Further analyses suggest that ENSO serves as a critical source of predictability for MHWs over the TIO and TAO in spring and MHWs over the NWP in summer.展开更多
This study evaluates the performance of 16 models sourced from the coupled model intercomparison project phase 6(CMIP6)in simulating marine heatwaves(MHWs)in the South China Sea(SCS)during the historical period(1982−2...This study evaluates the performance of 16 models sourced from the coupled model intercomparison project phase 6(CMIP6)in simulating marine heatwaves(MHWs)in the South China Sea(SCS)during the historical period(1982−2014),and also investigates future changes in SCS MHWs based on simulations from three shared socioeconomic pathway(SSP)scenarios(SSP126,SSP245,and SSP585)using CMIP6 models.Results demonstrate that the CMIP6 models perform well in simulating the spatial-temporal distribution and intensity of SCS MHWs,with their multi-model ensemble(MME)results showing the best performance.The reasonable agreement between the observations and CMIP6 MME reveals that the increasing trends of SCS MHWs are attributed to the warming sea surface temperature trend.Under various SSP scenarios,the year 2040 emerges as pivotal juncture for future shifts in SCS MHWs,marked by distinct variations in changing rate and amplitudes.This is characterized by an accelerated decrease in MHWs frequency and a notably heightened increase in mean intensity,duration,and total days after 2040.Furthermore,the projection results for SCS MHWs suggest that the spatial pattern of MHWs remains consistent across future periods.However,the intensity shows higher consistency only during the near-term period(2021−2050),while notable inconsistencies are observed during the medium-term(2041−2070)and long-term(2071−2100)periods under the three SSP scenarios.During the nearterm period,the SCS MHWs are characterized by moderate and strong events with high frequencies and relatively shorter durations.In contrast,during the medium-term period,MHWs are also characterized by moderate and strong events,but with longer-lasting and more intense events under the SSP245 and SSP585 scenarios.However,in the long-term period,extreme MHWs become the dominant feature under the SSP585 scenario,indicating a substantial intensification of SCS MHWs,effectively establishing a near-permanent state.展开更多
Marine heatwaves(MHWs)can cause irreversible damage to marine ecosystems and livelihoods.Appropriate MHW characterization remains difficult,because the choice of a sea surface temperature(SST)temporal baseline strongl...Marine heatwaves(MHWs)can cause irreversible damage to marine ecosystems and livelihoods.Appropriate MHW characterization remains difficult,because the choice of a sea surface temperature(SST)temporal baseline strongly influences MHW identification.Following a recent work suggesting that there should be a communicating baseline for long-term ocean temperature trends(LTT)and MHWs,we provided an effective and quantitative solution to calculate LTT and MHWs simultaneously by using the ensemble empirical mode decomposition(EEMD)method.The long-term nonlinear trend of SST obtained by EEMD shows superiority over the traditional linear trend in that the data extension does not alter prior results.The MHWs identified from the detrended SST data exhibited low sensitivity to the baseline choice,demonstrating the robustness of our method.We also derived the total heat exposure(THE)by combining LTT and MHWs.The THE was sensitive to the fixed-period baseline choice,with a response to increasing SST that depended on the onset time of a perpetual MHW state(identified MHW days equal to the year length).Subtropical areas,the Indian Ocean,and part of the Southern Ocean were most sensitive to the long-term global warming trend.展开更多
Concurrent extreme weather events in geographically distant areas potentially cause high-end risks for societies.By using network analysis,the present study managed to identify significant nearly-simultaneous occurren...Concurrent extreme weather events in geographically distant areas potentially cause high-end risks for societies.By using network analysis,the present study managed to identify significant nearly-simultaneous occurrences of heatwaves between the grid cells in East Asia and Eastern Europe,even though they are geographically far away from each other.By further composite analysis,this study revealed that hot events first occurred in Eastern Europe,typically with a time lag of3-4 days before the East Asian heatwave events.An eastward propagating atmospheric wave train,known as the circumglobal teleconnection(CGT)pattern,bridged the sequent occurrences of extreme events in these two remote regions.Atmospheric blockings,amplified by surface warming over Eastern Europe,not only enhanced local heat extremes but also excited a CGT-like pattern characterized by alternative anomalies of high and low pressures.Subsequent downstream anticyclones in the middle and upper troposphere reduced local cloud cover and increased downward solar radiation,thereby facilitating the formation of heatwaves over East Asia.Nearly half of East Asian heatwave events were preceded by Eastern European heatwave events in the 10-day time range before East Asian heatwave events.This investigation of heatwave teleconnection in the two distant regions exhibits strong potential to improve the prediction accuracy of East Asian heatwaves.展开更多
Based on the reforecast data(1999–2010)of three operational models[the China Meteorological Administration(CMA),the National Centers for Environmental Prediction of the U.S.(NCEP)and the European Centre for Medium-Ra...Based on the reforecast data(1999–2010)of three operational models[the China Meteorological Administration(CMA),the National Centers for Environmental Prediction of the U.S.(NCEP)and the European Centre for Medium-Range Weather Forecasts(ECMWF)]that participated in the Subseasonal to Seasonal Prediction(S2S)project,we identified the major sources of subseasonal prediction skill for heatwaves over the Yangtze River basin(YRB).The three models show limited prediction skills in terms of the fraction of correct predictions for heatwave days in summer;the Heidke Skill Score drops quickly after a 5-day forecast lead and falls down close to zero beyond the lead time of 15 days.The superior skill of the ECMWF model in predicting the intensity and duration of the YRB heatwave is attributable to its fidelity in capturing the phase evolution and amplitude of high-pressure anomalies associated with the intraseasonal oscillation and the dryness of soil moisture induced by less precipitation via the land–atmosphere coupling.The effects of 10–30-day and 30–90-day circulation prediction skills on heatwave predictions are comparable at shorter forecast leads(10 days),while the biases in 30–90-day circulation amplitude prediction show close connection with the degradation of heatwave prediction skill at longer forecast leads(>15–20 days).The biases of intraseasonal circulation anomalies further affect precipitation anomalies and thus land conditions,causing difficulty in capturing extremely hot days and their persistence in the S2S models.展开更多
Marine heatwaves(MHWs)are prolonged high-temperature extreme events in the ocean that can be devastating to marine life and seriously impact climate systems and economies.This paper describes the accessibility,content...Marine heatwaves(MHWs)are prolonged high-temperature extreme events in the ocean that can be devastating to marine life and seriously impact climate systems and economies.This paper describes the accessibility,content,characteristics,and potential applications of an MHW dataset to facilitate its use in scientific research.Daily intensities of global MHWs from 1982 to 2020 were analyzed using gridded SST data sourced from the National Oceanic and Atmospheric Administration(NOAA)Optimum Interpolation(OI)SST V2 high-resolution(0.25°)dataset.The analysis shows a linear increase in the frequency of MHWs in most ocean regions of the world as well as significant interdecadal changes.This data product can be used as a basic dataset to study the seasonal to decadal changes in extreme ocean events and explore the effects of global warming on the surface layers of oceans during the last 40 years.展开更多
Under global warming,understanding the long-term variation in different types of heatwaves is vital for China’s preparedness against escalating heat stress.This study investigates dry and wet heatwave shifts in easte...Under global warming,understanding the long-term variation in different types of heatwaves is vital for China’s preparedness against escalating heat stress.This study investigates dry and wet heatwave shifts in eastern China over recent decades.Spatial trend analysis displays pronounced warming in inland midlatitudes and the Yangtze River Valley,with increased humidity in coastal regions.EOF results indicate intensifying dry heatwaves in northern China,while the Yangtze River Valley sees more frequent dry heatwaves.On the other hand,Indochina and regions north of 25°N also experience intensified wet heatwaves,corresponding to regional humidity increases.Composite analysis is conducted based on different situations:strong,frequent dry or wet heatwaves.Strong dry heatwaves are influenced by anticyclonic circulations over northern China,accompanied by warming SST anomalies around the coastal midlatitudes of the western North Pacific(WNP).Frequent dry heatwaves are related to strong subsidence along with a strengthened subtropical high over the WNP.Strong and frequent wet heatwaves show an intensified Okhotsk high at higher latitudes in the lower troposphere,and a negative circumglobal teleconnection wave train pattern in the upper troposphere.Decaying El Niño SST patterns are observed in two kinds of wet heatwave and frequent dry heatwave years.Risk analysis indicates that El Niño events heighten the likelihood of these heatwaves in regions most at risk.As global warming continues,adapting and implementing mitigation strategies toward extreme heatwaves becomes crucial,especially for the aforementioned regions under significant heat stress.展开更多
The thermal state of seawater is a fundamental property of the ocean.Extreme changes in the ocean's thermal conditions can significantly impact the marine environment,climate system,ecosystems,and economic activit...The thermal state of seawater is a fundamental property of the ocean.Extreme changes in the ocean's thermal conditions can significantly impact the marine environment,climate system,ecosystems,and economic activities.Marine heatwaves(MHWs)are extreme high-temperature events occurring in the ocean at weather or short-to-medium-term climate scales,representing extreme variations in oceanic conditions(Pearce et al.,2011;Feng et al.,2013;Hobday et al.,2016).展开更多
Bottom marine heatwaves(BMHWs),i.e.,anomalous ocean warming at the seafloor,can happen without concurrent surface marine heatwaves(SMHWs),which pose a serious threat to marine ecosystems and present a challenge to det...Bottom marine heatwaves(BMHWs),i.e.,anomalous ocean warming at the seafloor,can happen without concurrent surface marine heatwaves(SMHWs),which pose a serious threat to marine ecosystems and present a challenge to detect and study them adequately.This type of event is called independent BMHWs.This study examines the summertime BMHWs on the continental shelf of the East China Sea(ECS)using oceanic reanalysis data from 1993 to 2020.Our results show that summertime BMHWs in the ECS are generally more intense than SMHWs,with some BMHW events occurring without surface expression.Through heat budget analyses of the 2016 SMHW event and the 2019 BMHW event,we investigated the drivers of independent summertime BMHWs.It is indicated that the occurrences of bottom temperature anomalies in summer are predominantly attributed to oceanic horizontal advection.Specifically,the summertime BMHWs on the central ECS shelf are closely related to the strengthening of the inshore branch of the Taiwan Warm Current(TWC)and the weakening of the offshore TWC branch.These findings provide important insights into the underlying physical processes and diagnostic tools for monitoring and managing independent BMHWs in the ECS.展开更多
Australia is a significant hotspot for heatwaves due to its geographical location and pronounced climatic variability,and heatwave exposure is expected to further increase in the future with anthropogenic climate chan...Australia is a significant hotspot for heatwaves due to its geographical location and pronounced climatic variability,and heatwave exposure is expected to further increase in the future with anthropogenic climate change.With the intent to support United Nations Sustainable Development Goals 3 (Good health and well-being) and 13 (Climate action),in this study we identified key challenges and opportunities for adapting to heatwaves,focusing on the most vulnerable members of our community-older adults.A naturalistic,qualitative approach was selected for this study.Data were collected via semistructured interviews.Key insights were captured through a series of semistructured interviews with key informants from local government agencies and community groups that provide care for older adults in New South Wales,Australia.Questions centered around current preventative measures adopted by the organization regarding heatwaves,level of heatwave knowledge of local residents,and common effects of heatwaves in the local community.The findings highlight four primary challenges:(1) increasing duration and intensity of heatwaves;(2) lack of knowledge among older adults regarding symptoms and the effect on the body;(3) the financial and social impacts of heatwaves;and (4) inadequate urban planning practices and building codes including the need for the creation of cool and green spaces.This study provides important insights for protecting our most vulnerable populations from the growing threat of heatwaves.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
Despite the prevalence of artificial separation of daytime and nighttime hot extremes, they may actually co-occur or occur sequentially. Considering their potential lead-lag configuration, this study identified an ent...Despite the prevalence of artificial separation of daytime and nighttime hot extremes, they may actually co-occur or occur sequentially. Considering their potential lead-lag configuration, this study identified an entire heatwave period as consecutive days with either daytime or nighttime hot extremes and investigated the changes of the prevalence and sequence of daytime and nighttime hot extremes during heatwaves over China from 1961 to 2017. It was found that the majority(82%) of heatwaves were compound heatwaves that had both daytime and nighttime hot extremes exceeding the 90 th percentile-based thresholds, while only 7%(11%) were purely daytime(nighttime) heatwaves that contained only daytime(nighttime) hot extremes. During the entire periods of compound heatwaves, daytime hot extremes usually occurred one day or a few days before nighttime hot extremes, which was in accordance with the daily variations in radiation and meteorological conditions, such as the increasing surface humidity and cloud cover, and decreasing solar radiation during the entire heatwave periods. From 1961 to2017, compound heatwave numbers exhibited the sharpest increase with a statistically significant trend of 0.44 times decade-1, in contrast to an insignificant trend of 0.00 times decade-1 for purely daytime heatwaves and a significant trend of 0.09 times decade-1 for purely nighttime heatwaves. Within the compound heatwave periods, hot nights were starting earlier and ending later, and numbers of concurrent daytime-nighttime hot extremes increased significantly at 0.20 days decade-1. In particular,urban area were not only subject to increasingly more frequent and longer compound heatwaves, but also to more occurrences of concurrent daytime-nighttime hot extremes with more serious impact. This study provides instructions for researchers to customize and select appropriate heatwave indices.展开更多
基金National Natural Science Foundation of China,No.42271037Natural Science Foundation of Anhui Province,No.2408085MD095+2 种基金Key Research and Development Program Project of Anhui Province,No.2022m07020011University Synergy Innovation Program of Anhui Province,No.GXXT-2021-048Science Foundation for Excellent Young Scholars of Anhui,No.2108085Y13。
文摘Under global warming,understanding the impact of urbanization on the characteristics of different heatwaves is important for sustainable development.In this study,we investigated the changes of heatwaves characteristics in the Yangtze River Delta urban agglomeration(YRDUG)and analyzed the influencing mechanisms of urbanization.Results showed that:(1)the duration,frequency,and intensity of NHWs(Nighttime Heatwaves)and CHWs(Daytime-nighttime compound Heatwaves)had shown a significant increase and the CHWs showed the greatest increasing trend.Furthermore,the NHWs exhibited higher durations,frequencies,and intensities compared to DHWs(Daytime Heatwaves);(2)Since 1990,the DHWs and CHWs were greater in urban areas than in rural areas,NHWs had been more pronounced in rural areas than in urban centers;and(3)Cloud cover,solar radiation,etc.affected heatwaves.Furthermore,in the process of urbanization,the increase in impervious area and the decrease in green land exacerbated heatwaves.Considering the combined effect of DHWs and NHWs,CHWs continued to increase.
文摘India is highly vulnerable to climate change and is going to increase its average annual temperature over the next few decades.The impact of heatwaves and related mortality is a concern for the country.In this paper,we aim to study the heatwaves and heat stress-related Heat Index vulnerability using heat index temperature.In this analysis,a heat in-dex temperature is calculated based on temperature and relative humidity for six different states(Delhi,West Bengal,Punjab,Uttar Pradesh,Andhra Pradesh,and Madhya Pradesh)of India to determine the heat stress vulnerability for which heat cramps and heat strokes are possible.Our analysis shows that most of the heatwaves and severe heatwaves occurred during 2010 for all the states.The heatwaves are observed only in the summer months.All the states of our study reached the Extreme Caution category of the Heat Index showing the Danger to Extreme Danger category dur-ing April to June.Future projection scenarios show an increase in heat stress-related vulnerability.SSP2-4.5 scenario showed that Delhi,Punjab,and West Bengal reached an Extreme Danger state during June for which death due to heat strokes is possible under continued exposure to heatwaves.The HI related vulnerability of SSP5-8.5 is like SSP2-4.5 except for Andhra Pradesh which shows an Extreme Danger state in May and June during which heat strokes are possi-ble under continued exposure to heatwaves.This study provides spatial variability of heat stress and Heat Index vulner-ability which may help adopt future strategies for heat-related policy implication.
基金The National Natural Science Foundation of China under contract No.42030410the Laoshan Laboratory under contract Nos LSKJ202202404 and LSKJ202202403+2 种基金the Startup Foundation for Introducing Talent of Nanjing University of Information Science and TechnologyJiangsu Innovation Research Group under contract No.JSSCTD202346Jiangsu Funding Program for Excellent Postdoctoral Talent under contract No.2023ZB690。
文摘Marine heatwaves(MHWs)in the East China Sea(ECS),especially those occurring on the ocean bottom(referred to as bottom marine heatwaves,BMHWs),can significantly affect regional ecosystems.However,our understanding of the seasonal variations in the MHWs in the ECS remains limited.This study investigates the characteristics of MHWs in the ECS in summer and winter using high-resolution oceanic reanalysis.Our analyses reveal distinct spatial patterns of BMHWs in these seasons.During summer,the Taiwan Warm Current plays a crucial role in transporting warm water northward,potentially leading to intense BMHWs on the central ECS shelf.These BMHW events usually occur independently of surface warming due to strong stratification in summer.Conversely,winter BMHWs are more prevalent in coastal regions under the influence of coastal currents and typically feature consistent warming from surface to bottom with a deepened mixed layer.These findings inform the coherent vertical structure and driving mechanisms of MHWs in the ECS,which are essential for predicting and managing these extreme events in the future.
基金supported by National Natural Science Foundation of China(Grant Nos.42030605 and 42088101)National Key R&D Program of China(Grant No.2020YFA0608004)High Performance Computing of Nanjing University of Information Science&Technology for their support of this work。
文摘Marine heatwaves(MHWs),which can exert devastating socioeconomic and ecological impacts,have attracted much public interest in recent years.In this study,we evaluate the sub-seasonal forecast skill of MHWs based on the Nanjing University of Information Science&Technology Climate Forecast System version 1.1(NUIST CFS1.1)and analyze the related physical processes.Our results show that the model can accurately forecast the occurrence of MHWs on a global scale out to a lead time of 25 days.Notably,even at lead times of 51–55 days,the forecast skill in most tropical regions,as well as in the northeastern and southeastern Pacific,is superior to both random forecasts and persistence forecasts.Accurate predictions of sea level pressure,zonal currents,and mixed-layer depth are important for MHW forecasting.Furthermore,we also conduct forecast skill assessments for two well-documented MHW events.Due to its ability to correctly forecast the changes in heat flux anomalies at a lead time of 25 days,the model can accurately forecast the strong MHW event that occurred in the South China Sea in May–October 2020.However,the forecasting results were less than optimal for the strong MHW event that occurred along the Australian west coast in January–April 2011.Although the model accurately forecasts its occurrence,the forecast of its intensity is poor.Additionally,when the lead time exceeds 10 days,forecasts of the relevant physical processes of this MHW event are also inaccurate.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)。
文摘With the intensification of global warming,marine heatwaves(MHWs)have emerged as a significant extreme hazard,garnering widespread attention and creating a pressing need for accurate prediction.The development of artificial intelligence,particularly the application of deep learning to sea surface temperature(SST),has significantly improved the feasibility of predictions.This study utilizes SST and Outgoing Longwave Radiation(OLR)data to train a 3D U-Net model for predicting MHWs in the South China Sea(SCS)with lead times ranging from 1 to 7 days,based on the characteristics of intraseasonal weather processes.Analysis of MHWs occurrences from 1982 to 2023 reveals distinct seasonal patterns,with summer MHWs primarily concentrated in the northern and central SCS,and the highest temperature centers located in the Gulf of Tonkin and west of the Philippines.The 2023 MHW forecast results demonstrate that the 3D U-Net model achieves low error rates and high correlation coefficients with observational data.Incorporating OLR data enhances forecast accuracy compared to SST-only inputs,and training the model exclusively with summer data further improves prediction accuracy.These findings indicate that the proposed method can significantly enhance the accuracy of MHW forecasts.
基金The Laoshan Laboratory under contract Nos LSKJ202202403 and LSKJ202202402the National Natural Science Foundation of China under contract Nos 42030410 and 42406202+3 种基金the Natural Science Foundation of Jiangsu Province under contract No.BK20240718the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technologythe Jiangsu Innovation Research Group under contract No.JSSCTD202346the Jiangsu Funding Program for Excellent Postdoctoral Talent under contract No.2023ZB690.
文摘Marine heatwaves(MHWs)are extreme ocean events characterized by anomalously warm upper-ocean temperatures,posing significant threats to marine ecosystems.While various factors driving MHWs have been extensively studied,the role of ocean salinity remains poorly understood.This study investigates the influence of salinity on the major 2013-2014 MHW event in the Northeast Pacific using reanalysis data and climate model outputs.Our results show that salinity variabilities are crucial for the development of the MHW event.Notably,a significant negative correlation exists between sea surface temperature anomalies(SSTAs)and sea surface salinity anomalies(SSSAs)during the MHW,with the SSSAs emerging simultaneously with SSTAs in the same area.Negative salinity anomalies(SAs)result in a shallower mixed layer,which suppresses vertical mixing and thus sustains the upper-ocean warming.Moreover,salinity has a greater impact on mixed layer depth anomalies than temperature.Model sensitivity experiments further demonstrate that negative SAs during MHWs amplify positive SSTAs by enhancing upper-ocean stratification,intensifying the MHW.Additionally,our analysis indicates that the SAs are predominantly driven by local freshwater flux anomalies,which are mainly induced by positive precipitation anomalies during the MHW event.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2022YFE0136000 and 2024YFC3013100)the Joint Meteorological Fund(Grant No.U2342211)+1 种基金the Joint Research Project for Meteorological Capacity Improvement(Grant No.22NLTSZ004)the National Meteorological Information Center(Grant No.NMICJY202301)。
文摘Using complex network methods,we construct undirected and directed heatwave networks to systematically analyze heatwave events over China from 1961 to 2023,exploring their spatiotemporal evolution patterns in different regions.The findings reveal a significant increase in heatwaves since the 2000s,with the average occurrence rising from approximately 3 to 5 times,and their duration increasing from 15 to around 30 days,nearly doubling.An increasing trend of“early onset and late withdrawal”of heatwaves has become more pronounced each year.In particular,eastern regions experience heatwaves that typically start earlier and tend to persist into September,exhibiting greater interannual variability compared to western areas.The middle and lower reaches of the Yangtze River and Xinjiang are identified as high-frequency heatwave areas.Complex network analysis reveals the dynamics of heatwave propagation,with degree centrality and synchronization distance indicating that the middle and lower reaches of the Yangtze River,Northeast China,and Xinjiang are key nodes in heatwave spread.Additionally,network divergence analysis shows that Xinjiang acts as a“source”area for heatwaves,exporting heat to surrounding regions,while the central region functions as a major“sink,”receiving more heatwave events.Further analysis from 1994 to 2023 indicates that heatwave events exhibit stronger network centrality and more complex synchronization patterns.These results suggest that complex networks provide a refined framework for depicting the spatiotemporal dynamics of heatwave propagation,offering new avenues for studying their occurrence and development patterns.
文摘We chose a definition of heatwaves (HWs) that has ~4-year recurrence frequency at world hot spots. We first examined the 1940-2022 HWs climatology and trends in lifespan, severity, spatial extent, and recurrence frequency. HWs are becoming more frequent and more severe for extratropical mid- and low-latitudes. To euphemize HWs, we here propose a novel clean energy-tapping concept that utilizes the available nano-technology, micro-meteorology knowledge of temperature distribution within/without buildings, and radiative properties of earth atmosphere. The key points for a practical electricity generation scheme from HWs are defogging, insulation, and minimizing the absorption of infrared downward radiation at the cold legs of the thermoelectric generators. One sample realization is presented which, through relay with existing photovoltaic devices, provides all-day electricity supply sufficient for providing air conditioning requirement for a residence (~2000-watt throughput). The provision of power to air conditioning systems, usually imposes a significant stress on traditional city power grids during heatwaves.
基金jointly supported by the National Natural Science Foundation of China (Grant Nos.42192562 and 42030605)。
文摘Using monthly observations and ensemble hindcasts of the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS1.0) for the period 1983–2020, this study investigates the forecast skill of marine heatwaves(MHWs) over the globe and the predictability sources of the MHWs over the tropical oceans. The MHW forecasts are demonstrated to be skillful on seasonal-annual time scales, particularly in tropical oceans. The forecast skill of the MHWs over the tropical Pacific Ocean(TPO) remains high at lead times of 1–24 months, indicating a forecast better than random chance for up to two years. The forecast skill is subject to the spring predictability barrier of El Nino-Southern Oscillation(ENSO). The forecast skills for the MHWs over the tropical Indian Ocean(TIO), tropical Atlantic Ocean(TAO), and tropical Northwest Pacific(NWP) are lower than that in the TPO. A reliable forecast at lead times of up to two years is shown over the TIO, while a shorter reliable forecast window(less than 17 months) occurs for the TAO and NWP.Additionally, the forecast skills for the TIO, TAO, and NWP are seasonally dependent. Higher skills for the TIO and TAO appear in boreal spring, while a greater skill for the NWP emerges in late summer-early autumn. Further analyses suggest that ENSO serves as a critical source of predictability for MHWs over the TIO and TAO in spring and MHWs over the NWP in summer.
基金The National Natural Science Foundation of China under contract Nos 42275024 and 42105040the Key R&D Program of China under contract No.2022YFE0203500+3 种基金the Guangdong Basic and Applied Basic Research Foundation under contract Nos 2023B1515020009 and 2024B1515040024the Youth Innovation Promotion Association CAS under contract No.2020340the Special Fund of South China Sea Institute of Oceanology of the Chinese Academy of Sciences under contract No.SCSIO2023QY01the Science and Technology Planning Project of Guangzhou under contract No.2024A04J6275.
文摘This study evaluates the performance of 16 models sourced from the coupled model intercomparison project phase 6(CMIP6)in simulating marine heatwaves(MHWs)in the South China Sea(SCS)during the historical period(1982−2014),and also investigates future changes in SCS MHWs based on simulations from three shared socioeconomic pathway(SSP)scenarios(SSP126,SSP245,and SSP585)using CMIP6 models.Results demonstrate that the CMIP6 models perform well in simulating the spatial-temporal distribution and intensity of SCS MHWs,with their multi-model ensemble(MME)results showing the best performance.The reasonable agreement between the observations and CMIP6 MME reveals that the increasing trends of SCS MHWs are attributed to the warming sea surface temperature trend.Under various SSP scenarios,the year 2040 emerges as pivotal juncture for future shifts in SCS MHWs,marked by distinct variations in changing rate and amplitudes.This is characterized by an accelerated decrease in MHWs frequency and a notably heightened increase in mean intensity,duration,and total days after 2040.Furthermore,the projection results for SCS MHWs suggest that the spatial pattern of MHWs remains consistent across future periods.However,the intensity shows higher consistency only during the near-term period(2021−2050),while notable inconsistencies are observed during the medium-term(2041−2070)and long-term(2071−2100)periods under the three SSP scenarios.During the nearterm period,the SCS MHWs are characterized by moderate and strong events with high frequencies and relatively shorter durations.In contrast,during the medium-term period,MHWs are also characterized by moderate and strong events,but with longer-lasting and more intense events under the SSP245 and SSP585 scenarios.However,in the long-term period,extreme MHWs become the dominant feature under the SSP585 scenario,indicating a substantial intensification of SCS MHWs,effectively establishing a near-permanent state.
基金Supported by the National Natural Science Foundation of China(Nos.41821004,42276025)the Natural Science Foundation of Shandong Province(No.ZR2021MD027)+1 种基金the National Key Research and Development Program of China(No.2022YFE0140500)the Project of“Development of China-ASEAN blue partnership”started in 2021.
文摘Marine heatwaves(MHWs)can cause irreversible damage to marine ecosystems and livelihoods.Appropriate MHW characterization remains difficult,because the choice of a sea surface temperature(SST)temporal baseline strongly influences MHW identification.Following a recent work suggesting that there should be a communicating baseline for long-term ocean temperature trends(LTT)and MHWs,we provided an effective and quantitative solution to calculate LTT and MHWs simultaneously by using the ensemble empirical mode decomposition(EEMD)method.The long-term nonlinear trend of SST obtained by EEMD shows superiority over the traditional linear trend in that the data extension does not alter prior results.The MHWs identified from the detrended SST data exhibited low sensitivity to the baseline choice,demonstrating the robustness of our method.We also derived the total heat exposure(THE)by combining LTT and MHWs.The THE was sensitive to the fixed-period baseline choice,with a response to increasing SST that depended on the onset time of a perpetual MHW state(identified MHW days equal to the year length).Subtropical areas,the Indian Ocean,and part of the Southern Ocean were most sensitive to the long-term global warming trend.
基金Guangdong Major Project of Basic and Applied Basic Research (2020B0301030004)National Natural Science Foundation of China (42275020)+1 种基金Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (311021001)Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies (2020B1212060025)。
文摘Concurrent extreme weather events in geographically distant areas potentially cause high-end risks for societies.By using network analysis,the present study managed to identify significant nearly-simultaneous occurrences of heatwaves between the grid cells in East Asia and Eastern Europe,even though they are geographically far away from each other.By further composite analysis,this study revealed that hot events first occurred in Eastern Europe,typically with a time lag of3-4 days before the East Asian heatwave events.An eastward propagating atmospheric wave train,known as the circumglobal teleconnection(CGT)pattern,bridged the sequent occurrences of extreme events in these two remote regions.Atmospheric blockings,amplified by surface warming over Eastern Europe,not only enhanced local heat extremes but also excited a CGT-like pattern characterized by alternative anomalies of high and low pressures.Subsequent downstream anticyclones in the middle and upper troposphere reduced local cloud cover and increased downward solar radiation,thereby facilitating the formation of heatwaves over East Asia.Nearly half of East Asian heatwave events were preceded by Eastern European heatwave events in the 10-day time range before East Asian heatwave events.This investigation of heatwave teleconnection in the two distant regions exhibits strong potential to improve the prediction accuracy of East Asian heatwaves.
基金The authors would like to thank the anonymous reviewers for their comments,which helped improve the manuscript.This study was supported by the National Key R&D Program of China(Grant Nos.2018YFC1505804 and 2018YFC1507704)NSFC(Grant No.41625019).We appreciate the operational centers for providing their model outputs through the S2S database.
文摘Based on the reforecast data(1999–2010)of three operational models[the China Meteorological Administration(CMA),the National Centers for Environmental Prediction of the U.S.(NCEP)and the European Centre for Medium-Range Weather Forecasts(ECMWF)]that participated in the Subseasonal to Seasonal Prediction(S2S)project,we identified the major sources of subseasonal prediction skill for heatwaves over the Yangtze River basin(YRB).The three models show limited prediction skills in terms of the fraction of correct predictions for heatwave days in summer;the Heidke Skill Score drops quickly after a 5-day forecast lead and falls down close to zero beyond the lead time of 15 days.The superior skill of the ECMWF model in predicting the intensity and duration of the YRB heatwave is attributable to its fidelity in capturing the phase evolution and amplitude of high-pressure anomalies associated with the intraseasonal oscillation and the dryness of soil moisture induced by less precipitation via the land–atmosphere coupling.The effects of 10–30-day and 30–90-day circulation prediction skills on heatwave predictions are comparable at shorter forecast leads(10 days),while the biases in 30–90-day circulation amplitude prediction show close connection with the degradation of heatwave prediction skill at longer forecast leads(>15–20 days).The biases of intraseasonal circulation anomalies further affect precipitation anomalies and thus land conditions,causing difficulty in capturing extremely hot days and their persistence in the S2S models.
基金the Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-DQC010)the National Natural Science Foundation of China(Grant No.41876012)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB42000000)the National Key R&D Program of China 2018YFB0505000.NOAA High-Resolution SST data were provided by the NOAA/OAR/ESRL PSD,Boulder,Colorado,USA,from their Web site at http://www.esrl.noaa.gov/psd/.The authors wish to thank two anony-mous reviewers for their very helpful comments and suggestions.
文摘Marine heatwaves(MHWs)are prolonged high-temperature extreme events in the ocean that can be devastating to marine life and seriously impact climate systems and economies.This paper describes the accessibility,content,characteristics,and potential applications of an MHW dataset to facilitate its use in scientific research.Daily intensities of global MHWs from 1982 to 2020 were analyzed using gridded SST data sourced from the National Oceanic and Atmospheric Administration(NOAA)Optimum Interpolation(OI)SST V2 high-resolution(0.25°)dataset.The analysis shows a linear increase in the frequency of MHWs in most ocean regions of the world as well as significant interdecadal changes.This data product can be used as a basic dataset to study the seasonal to decadal changes in extreme ocean events and explore the effects of global warming on the surface layers of oceans during the last 40 years.
基金supported by the National Natural Science Foundation of China(Grant Nos.42120104001,42192563 and 42005010)the Hong Kong RGC General Research Fund 11300920.
文摘Under global warming,understanding the long-term variation in different types of heatwaves is vital for China’s preparedness against escalating heat stress.This study investigates dry and wet heatwave shifts in eastern China over recent decades.Spatial trend analysis displays pronounced warming in inland midlatitudes and the Yangtze River Valley,with increased humidity in coastal regions.EOF results indicate intensifying dry heatwaves in northern China,while the Yangtze River Valley sees more frequent dry heatwaves.On the other hand,Indochina and regions north of 25°N also experience intensified wet heatwaves,corresponding to regional humidity increases.Composite analysis is conducted based on different situations:strong,frequent dry or wet heatwaves.Strong dry heatwaves are influenced by anticyclonic circulations over northern China,accompanied by warming SST anomalies around the coastal midlatitudes of the western North Pacific(WNP).Frequent dry heatwaves are related to strong subsidence along with a strengthened subtropical high over the WNP.Strong and frequent wet heatwaves show an intensified Okhotsk high at higher latitudes in the lower troposphere,and a negative circumglobal teleconnection wave train pattern in the upper troposphere.Decaying El Niño SST patterns are observed in two kinds of wet heatwave and frequent dry heatwave years.Risk analysis indicates that El Niño events heighten the likelihood of these heatwaves in regions most at risk.As global warming continues,adapting and implementing mitigation strategies toward extreme heatwaves becomes crucial,especially for the aforementioned regions under significant heat stress.
基金Supported by the National Natural Science Foundation of China(No.42476016)the Laoshan Laboratory(No.LSKJ202202702)the Indo-Pacific Ocean and Climate Laboratory Project(No.424530)from Hohai University。
文摘The thermal state of seawater is a fundamental property of the ocean.Extreme changes in the ocean's thermal conditions can significantly impact the marine environment,climate system,ecosystems,and economic activities.Marine heatwaves(MHWs)are extreme high-temperature events occurring in the ocean at weather or short-to-medium-term climate scales,representing extreme variations in oceanic conditions(Pearce et al.,2011;Feng et al.,2013;Hobday et al.,2016).
基金Supported by the National Natural Science Foundation of China(No.42030410)the Laoshan Laboratory(Nos.LSKJ202202404,LSKJ202202403)+1 种基金the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology(NUIST),Jiangsu Innovation Research Group(No.JSSCTD202346)the Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2023ZB690)。
文摘Bottom marine heatwaves(BMHWs),i.e.,anomalous ocean warming at the seafloor,can happen without concurrent surface marine heatwaves(SMHWs),which pose a serious threat to marine ecosystems and present a challenge to detect and study them adequately.This type of event is called independent BMHWs.This study examines the summertime BMHWs on the continental shelf of the East China Sea(ECS)using oceanic reanalysis data from 1993 to 2020.Our results show that summertime BMHWs in the ECS are generally more intense than SMHWs,with some BMHW events occurring without surface expression.Through heat budget analyses of the 2016 SMHW event and the 2019 BMHW event,we investigated the drivers of independent summertime BMHWs.It is indicated that the occurrences of bottom temperature anomalies in summer are predominantly attributed to oceanic horizontal advection.Specifically,the summertime BMHWs on the central ECS shelf are closely related to the strengthening of the inshore branch of the Taiwan Warm Current(TWC)and the weakening of the offshore TWC branch.These findings provide important insights into the underlying physical processes and diagnostic tools for monitoring and managing independent BMHWs in the ECS.
文摘Australia is a significant hotspot for heatwaves due to its geographical location and pronounced climatic variability,and heatwave exposure is expected to further increase in the future with anthropogenic climate change.With the intent to support United Nations Sustainable Development Goals 3 (Good health and well-being) and 13 (Climate action),in this study we identified key challenges and opportunities for adapting to heatwaves,focusing on the most vulnerable members of our community-older adults.A naturalistic,qualitative approach was selected for this study.Data were collected via semistructured interviews.Key insights were captured through a series of semistructured interviews with key informants from local government agencies and community groups that provide care for older adults in New South Wales,Australia.Questions centered around current preventative measures adopted by the organization regarding heatwaves,level of heatwave knowledge of local residents,and common effects of heatwaves in the local community.The findings highlight four primary challenges:(1) increasing duration and intensity of heatwaves;(2) lack of knowledge among older adults regarding symptoms and the effect on the body;(3) the financial and social impacts of heatwaves;and (4) inadequate urban planning practices and building codes including the need for the creation of cool and green spaces.This study provides important insights for protecting our most vulnerable populations from the growing threat of heatwaves.
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 R&D Program(Grant No.2016YFA0601502)the National Natural Science Foundation of China(Grant Nos.41822503 and 41375092).
文摘Despite the prevalence of artificial separation of daytime and nighttime hot extremes, they may actually co-occur or occur sequentially. Considering their potential lead-lag configuration, this study identified an entire heatwave period as consecutive days with either daytime or nighttime hot extremes and investigated the changes of the prevalence and sequence of daytime and nighttime hot extremes during heatwaves over China from 1961 to 2017. It was found that the majority(82%) of heatwaves were compound heatwaves that had both daytime and nighttime hot extremes exceeding the 90 th percentile-based thresholds, while only 7%(11%) were purely daytime(nighttime) heatwaves that contained only daytime(nighttime) hot extremes. During the entire periods of compound heatwaves, daytime hot extremes usually occurred one day or a few days before nighttime hot extremes, which was in accordance with the daily variations in radiation and meteorological conditions, such as the increasing surface humidity and cloud cover, and decreasing solar radiation during the entire heatwave periods. From 1961 to2017, compound heatwave numbers exhibited the sharpest increase with a statistically significant trend of 0.44 times decade-1, in contrast to an insignificant trend of 0.00 times decade-1 for purely daytime heatwaves and a significant trend of 0.09 times decade-1 for purely nighttime heatwaves. Within the compound heatwave periods, hot nights were starting earlier and ending later, and numbers of concurrent daytime-nighttime hot extremes increased significantly at 0.20 days decade-1. In particular,urban area were not only subject to increasingly more frequent and longer compound heatwaves, but also to more occurrences of concurrent daytime-nighttime hot extremes with more serious impact. This study provides instructions for researchers to customize and select appropriate heatwave indices.
