Objective To reduce health-related threats of heat waves, interventions have been implemented in many parts of the world. However, there is a lack of higher-level evidence concerning the intervention efficacy. This st...Objective To reduce health-related threats of heat waves, interventions have been implemented in many parts of the world. However, there is a lack of higher-level evidence concerning the intervention efficacy. This study aimed to determine the efficacy of an intervention to reduce the number of heat-related illnesses. Methods A quasi-experimental design was employed by two cross-sectional surveys in the year 2024 and 2015, including 2,240 participants and 2,356 participants, respectively. Each survey was designed to include one control group and one intervention group, which conducted in Licheng, China. A representative sample was selected using a multistage sampling method. Data, collected from questionnaires about heat waves in 2014 and 2015, were analyzed using a difference-in-difference analysis and cost effectiveness analysis. Outcomes included changes in the prevalence of heat-related illnesses and cost-effectiveness variables. Results Relative to the control participants, the prevalence of heat-related illness in the intervention participants decreased to a greater extent in rural areas than in urban areas （OR=0.495 vs. OR=2.282）. Moreover, the cost-effectiveness ratio in the intervention group was tess than that in the control group （usS25.06 vs. us$25.69 per participant）. Furthermore, to avoid one additional patient, the incremental cost-effectiveness ratio showed that an additional USS14.47 would be needed for the intervention compared to when no intervention was applied. Conclusion The intervention program may be considered a worthwhile investment for rural areas that are more likely to experience heat waves. Meanwhile, corresponding improving measures should be presented towards urban areas. Future research should examine whether the intervention strategies could be spread out in other domestic or international regions where heat waves are usually experienced.展开更多
We present a regional climate simulation for the Iberian Peninsula for a 60-year period (1950-2009) using the WRF-ARW model with a focus on the simulation of summer maximum temperatures and associated extreme heat wav...We present a regional climate simulation for the Iberian Peninsula for a 60-year period (1950-2009) using the WRF-ARW model with a focus on the simulation of summer maximum temperatures and associated extreme heat waves. The WRF model was designed at a 5 km horizontal resolution on a 5-month (May-September) seasonal scale, for every year, during the study period with initial/boundary conditions derived from NCEP 2.5 degree reanalysis. The comparison of simulated mean summer seasonal maximums and mean maximums of June, July, and August months with the corresponding E-OBS data sets indicates that the model is able to characterize the spatial variation of magnitudes of temperature change over the Iberian Peninsula. The mean extreme heat wave conditions during the climate period 1950-2009 are well simulated and match the observations well. The regional scale simulations clearly show the propagation of intense heat waves from the south west to north east of Iberia. The WRF-ARW model also simulated well the general trend of increase in heat waves over most parts of the Iberian Peninsula during the study period 1950-2009. The characteristics of the most severe heat waves years 2003 and 2006 are also well simulated by the model.展开更多
Heat waves have attracted increasing attention in recent years due to their frequent occurrence.The present study investigates the heat wave intensity and duration in China using daily maximum temperature from 753 wea...Heat waves have attracted increasing attention in recent years due to their frequent occurrence.The present study investigates the heat wave intensity and duration in China using daily maximum temperature from 753 weather stations from 1960 to 2010.In addition,its relationships with soil moisture local forcing on the ten-day period and monthly scales in spring and summer are analyzed using soil moisture data from weather stations and ERA40 reanalysis data.And finally,a mechanistic analysis is carried out using CAM5.1（Community Atmosphere Model,version 5.1） coupled with CLM2（Community Land Model,version 2）.It is found that the heat wave frequency and duration show a sandwich distribution across China,with high occurrence rates in Southeast China and Northwest China,where the maximum frequency and duration exceeded 2.1 times and 9 days per year,respectively.The increasing trends in both duration and intensity occurred to the north of 35°N.The relationships between heat wave frequency in northern China in July（having peak distribution） and soil moisture in the earlier stage（from March to June） and corresponding period（July） are further analyzed,revealing a strong negative correlation in March,June and July,and thus showing that soil moisture in spring and early summer could be an important contributor to heat waves in July via positive subtropical high anomalies.However,the time scales of influence were relatively short in the semi-humid and humid regions,and longer in the arid region.The contribution in the corresponding period took place via positive subtropical high anomalies and positive surface skin temperature and sensible heat flux anomalies.展开更多
The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity...The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity heated by a 2 kJ, ins laser pulse （0.35 μm）. The delayed breakout time of the radiation waves from the rear side of the foam is measured by a three-chromatic streaked x-ray spectrometer （TCS） consisting of a set of three-imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera （XSC）. With one shot, simultaneous measurements of the delays of the drive source and the radiation with two different energies （210 eV, 840 eV） through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation with an energy of 210 eV propagates at a lower velocity. The radiating heat wave propagates with a velocity that is larger than the sound speed. Using TGS, the transmitting spectrum was measured, and then lower limit of the optical depth which is more than 1, was obtained. The experimental data were in agreement with numerical simulations.展开更多
This study presents a new non-parametric measure of heat waves called heat wave norm (HWN), which allows quantifying and qualifying the magnitude of the summer heat wave events in the Bechar region located northwest o...This study presents a new non-parametric measure of heat waves called heat wave norm (HWN), which allows quantifying and qualifying the magnitude of the summer heat wave events in the Bechar region located northwest of the Algerian Sahara over the period 1951-2010. The index, based on the analysis of daily maximum and minimum temperatures by adding them, integrated two dimensions at the same time: the duration and the excess heat. The results show an increase in the intensity and frequency of extreme events. More specifically, from the 1980s, it is possible to observe the propagation of extreme and very extreme and super extreme heat waves in recent decades with maximum presence during the period 1990-2010. In general, it can be said that the trend of excessive warming is clearly displayed in the Algerian Sahara, generally classified as a hot region.展开更多
Background:Hepatitis E virus(HEV)causes substantial morbidity globally,with frequent outbreaks in low-resource settings due to fecal-oral transmission.Temperature and extreme heat may influence waterborne pathogens,bu...Background:Hepatitis E virus(HEV)causes substantial morbidity globally,with frequent outbreaks in low-resource settings due to fecal-oral transmission.Temperature and extreme heat may influence waterborne pathogens,but their impact on HEV risk is unclear.Methods:We performed a time-stratified case-crossover study using 42,481 laboratoryconfirmed hepatitis E cases reported in Jiangsu Province(2010-2023).Daily mean,maximum,and minimum temperatures were obtained from fixed-site monitoring data.We examined associations of short-term temperature(single-day and cumulative lags up to 21 days)and heat wave episodes with hepatitis E risk using conditional logistic regression.Heat waves were defined using percentile-based thresholds for consecutive days.Analyses were adjusted for relative humidity and time trends,and stratified by sex,age,residence,and occupation.Sensitivity analyses used alternative heat wave definitions and lag structures.-Results:Higher ambient temperature was associated with increases in hepatitis E risk.Each 1◦C rise in daily mean temperature(lag 0-1 days)was linked to a 0.6%higher odds of hepatitis E(OR 1.006,95%CI 1.002-1.010).Similar associations were observed for maximum and minimum temperatures(e.g.OR 1.005[1.002-1.009]per 1◦C at lag 0-1 for max temperature;OR 1.009[1.004-1.014]at lag 0-3 for min temperature).Heat waves defined by more extreme and prolonged thresholds showed stronger effects.For example,a three-day daytime heat wave above the 95th percentile(Day_HW95_3d)was associated with an 18%higher hepatitis E risk(OR 1.18,95%CI 1.08-1.29),and a four-day compound heat wave>90th percentile had an OR of 1.14(95%CI 1.04-1.24).Conclusions:Short-term exposure to higher ambient temperatures and heat wave events was associated with increased risk of hepatitis E in Jiangsu,China.These results suggest that climate warming and extreme heat may elevate transmission of HEV,underscoring the need for strengthened water and sanitation interventions and targeted public health planning during hot weather.展开更多
Emerging evidence suggests that heat waves and ozone(O_(3))contribute to increased mortality risks.Since widowhood is a common event that can increase individuals'susceptibility to the environment,it is of great i...Emerging evidence suggests that heat waves and ozone(O_(3))contribute to increased mortality risks.Since widowhood is a common event that can increase individuals'susceptibility to the environment,it is of great importance and interest to elucidate the widowhood disparity in mortality attributable to heat waves and O_(3).We therefore conducted a case-crossover study of 1,214,763 nonaccidental deaths in Jiangsu Province,China,during 2015–2021 to investigate the independent and interactive associations of exposure to heat waves and O_(3) with mortality by widowhood status.Grid-level heat waves were defined by multiple combinations of apparent temperature thresholds and durations.Residential heat waves and O_(3) exposures were assessed using validated grid datasets.Conditional logistic regression models were applied for exposure-response analyses and evalua-tions of additive interactions.Exposure to heat waves and O_(3) was significantly associated with increased odds of mortality in both widowed(odds ratio for heat waves,1.25;O_(3),1.06 per interquartile range increase)and married subjects(1.08;1.03),and these associations were higher in widowed subjects.A significant synergistic interaction was observed between heat waves and O_(3),which was stronger in widowed subjects(relative excess odds due to interaction,0.14 vs.0.03).Up to 6.43%and 3.56%of deaths were attributable to heat waves,O_(3) pollution,and their compound events in widowed and married subjects,respectively.Our findings suggest that widowed individuals are more susceptible to heat waves and O_(3) and highlight the need to consider differences associated with widowhood disparities in preventing premature deaths due to heat waves and O_(3) exposures.展开更多
The future increased frequency and intensity of heat waves(HWs)across China will exacerbate adverse effects on society and the environment.However,changes in socioeconomic exposure remain underexplored.In this study,c...The future increased frequency and intensity of heat waves(HWs)across China will exacerbate adverse effects on society and the environment.However,changes in socioeconomic exposure remain underexplored.In this study,climate model outputs from the Coupled Model Intercomparison Project Phase 6(CMIP6),together with population and gross domestic product(GDP)projections were used to investigate projected heat stress and socioeconomic exposure across China and its eight subregions under four shared socioeconomic pathway(SSP)scenarios(SSP1–2.6,SSP2–4.5,SSP3–7.0,and SSP5–8.5)over three periods(2021–2040,2051–2070,and 2081–2100).Our results indicate a consistent upward trend in the Universal Thermal Climate Index(UTCI)across all scenarios,with intensifying increases over time,peaking at>6°C.This suggests a continuous increase in the number of extreme heat events(EHEs)in China.Population exposure to EHEs across the four UTCI thresholds(>26°C,>32°C,>38°C,and>46°C)shows an increasing trend.Projections indicate a∼14-fold increase nationwide,500-fold increase in Northwest China(NWC),and a 1000-fold in Southwest China(SWC2)under SSP5–8.5 by2081–2100 compared with current levels.The eastern and southeastern regions,especially the Yangtze River and Pearl River Delta,show significant GDP exposure increases under SSP3–7.0 and SSP5–8.5.Population exposure is mainly driven by climatic effects under severe scenarios,whereas GDP exposure is influenced by interaction effects,particularly under SSP5–8.5 and during the 2090s.This study's findings offer actionable insights for targeted adaptation in China's diverse geographies.展开更多
Using daily maximum temperature(Tmax)data from 516 observation stations in eastern China from 1981 to 2020,this study employed a relative threshold method to define short-and long-lived heat waves(HWs)by considering r...Using daily maximum temperature(Tmax)data from 516 observation stations in eastern China from 1981 to 2020,this study employed a relative threshold method to define short-and long-lived heat waves(HWs)by considering regional climate differences to investigate the spatial characteristics and evolution of large-scale circulation during summer HWs.The results demonstrated spatial disparities in the frequency distribution of HWs of different durations and differences in the magnitude of duration and intensity between short-and long-lived HWs.Empirical orthogonal function analysis revealed three dominant spatial modes for both short-and long-lived HWs.The first mode showed that short-lived HWs occur prominently in both northern and southern regions,whereas long-lived HWs mainly occur in the northern region.The second mode was characterized by a meridional dipole pattern in both cases.The third mode exhibited a quadrupole pattern for short-lived HWs and a tripole pattern for long-lived HWs.Differences in the center locations of anomalies in the 500-hPa geopotential height and 850-hPa wind fields significantly influenced the temperature and precipitation anomaly distribution of typical HWs by affecting the warm column in the lower troposphere,cloud distribution,and moisture transport.Moreover,the atmospheric circulation evolution processes of typical HWs associated with the different modes of long-and short-lived HWs were linked to distinct teleconnection patterns.During the three modes of long-lived(short-lived)HWs,there was stronger(weaker)wave flux activity with multiple(single)propagation paths.Stronger westward Atlantic wave train activity at 300 hPa triggered the synergistic action of meridional and zonal wave fluxes,favoring the strengthening and maintenance of positive anomalies in geopotential height of 500 hPa.This may have contributed to the formation of long-lived HWs.These findings provide valuable insights to enhance our understanding and prediction of summer HWs.展开更多
Based on combined thresholds of daily maximum and minimum temperatures, a compound heat wave is defined, and then changes in multiple aspects of such heat waves in China are estimated between 1961 and 2015. Our result...Based on combined thresholds of daily maximum and minimum temperatures, a compound heat wave is defined, and then changes in multiple aspects of such heat waves in China are estimated between 1961 and 2015. Our results intriguingly indicate that severe compound heat waves in northern China are characterized by excessively high in- tensity within short duration, while long duration determines great disaster-causing potential of severe events in the south. In the past few decades, large areas of China have experienced longer, stronger, and more frequent compound heat waves. Northern China has witnessed dramatic intensity increases, with a maximum amplification over 5~C dec- ade-~; while remarkable lengthening in duration has been mostly recorded in the south, with a maximum trend over 1 day decade-1. The spatial extent affected by compound heat waves has significantly expanded since the 1960s, with the largest expanding rate over 6% decade-1 detected in North China and Northeast China. These systematic assess- ments serve to deepen our understanding of observed changes in compound heat waves across China, and may fur- ther shed some light on future adaptations and mitigations against an increasingly wanning climate.展开更多
2019 was one of the hottest years in recent decades,with widespread heatwaves over many parts of the world,including Africa.However,as a developing and vulnerable region,the understanding of recent heatwave events in ...2019 was one of the hottest years in recent decades,with widespread heatwaves over many parts of the world,including Africa.However,as a developing and vulnerable region,the understanding of recent heatwave events in Africa is limited.Here,the authors incorporated different climate datasets,satellite observations,and population estimates to investigate patterns and hotspots of major heatwave events over Africa in 2019.Overall,2019 was one of the years that experienced the strongest heatwaves in terms of intensity and duration since 1981 in Africa.Heatwave hotspots were clearly identified across western-coastal,northeastern,southern,and equatorial Africa,where major cities and human populations are located.The proportion of urban agglomerations(population)exposed to extreme(99 th percentile)heatwaves in the Northern Hemisphere and Southern Hemisphere rose from 4%(5 million people)and 15%(17 million people),respectively,in the baseline period of 1981-2010 to36%(43 million people)and 57%(53 million people),respectively,in 2019.Heatwave patterns and hotspots in 2019 were related to anomalous seasonal change in atmospheric circulation and above-normal sea surface temperature.Without adaptation to minimize susceptibility to the effects of heatwave events,the risks they pose in populated areas may increase rapidly in Africa.展开更多
The propagation of HF waves in IAR can produce many nonlinear effects, including the modulation effect of IAR on HF waves and the Doppler effect. To start with the dependence of the ionospheric electron temperature va...The propagation of HF waves in IAR can produce many nonlinear effects, including the modulation effect of IAR on HF waves and the Doppler effect. To start with the dependence of the ionospheric electron temperature variations on the Alfvén resonant field, We discuss the mechanism of the modulation effect and lucubrate possible reasons for the Doppler effect. The results show that the Alfvén resonant field can have an observable modulation effect on HF waves while its mechanism is quite different from that of Schumann resonant field on HF waves. The depth of modulation of IAR on HF waves has a quasi\|quadratic relation with the Alfvén field, which directly inspires the formation of cross\|spectrum between ULF waves and HF waves and results in spectral peaks at some gyro\|frequencies of IAR. With respect to the Doppler effect during the propagation of HF waves in IAR, it is mainly caused by the motion of the high\|speed flyer and the drifting electrons and the frequency shift from the phase variation of the reflected waves can be neglected when the frequency of HF incident wave is high enough.展开更多
Objective Heat wave exposure significantly impacts human health.Nevertheless,studies on the long-term effects of heat wave exposure during adolescence on adverse pregnancy outcomes(APOs)are rare.This study aimed to in...Objective Heat wave exposure significantly impacts human health.Nevertheless,studies on the long-term effects of heat wave exposure during adolescence on adverse pregnancy outcomes(APOs)are rare.This study aimed to investigate the relationship between the long-term effects of heat wave exposure during adolescence and APOs.Methods We analyzed data from 3,376 female and 3,013 male participants across 31 provinces in China.All adolescents(10–19 years old),early adolescents(10–14),and late adolescents(15–19)were chosen as exposure windows.Heat waves were defined as periods lasting 2‒4 consecutive days with the daily temperature exceeding the 75th,90th,and 92.5th percentiles.We employed multivariate logistic regression models to assess the associations between exposure to heat waves during adolescence and APOs.Results The results revealed significant associations between male exposure to heat wave events during late adolescence and spontaneous abortion(P<0.05),which was more pronounced in South China.In contrast,no statistically significant associations were detected between males’exposure to heat wave events during adolescence and their partners’preterm birth(P>0.05 for all comparisons).The exposure of females to heat waves during adolescence was not significantly associated with subsequent spontaneous abortion or preterm birth(P>0.05 for all comparisons).Conclusions This study demonstrates that spontaneous abortion in females is associated with heat wave exposure in their male partner during adolescence.展开更多
Marine heat waves(MHWs), characterized by extreme warm sea surface temperature events, frequently occur in Chinese marginal seas. However, the seasonal variation and joint distribution of MHWs in the Bohai Sea have no...Marine heat waves(MHWs), characterized by extreme warm sea surface temperature events, frequently occur in Chinese marginal seas. However, the seasonal variation and joint distribution of MHWs in the Bohai Sea have not been fully described. Therefore, we conducted a systematic investigation of MHWs in this region. Our findings indicate that the frequency of MHW is low during winter, with long duration and weak intensity, while in summer, it is opposite, being high in the frequency, and shorter but stronger. Notably, in summer, the Laizhou and Liaodong bays exhibit a relatively long total day of MHWs compared to other areas in the Bohai Sea. Furthermore, our analysis of the joint distribution of MHWs, considering both duration and intensity, reveals significant seasonal variations. To provide practical insights for marine ranching, we have also investigated time series of MHWs at several specific stations and computed the correlation coefficients between MHW intensity and potential influential factors. Results suggest that sea surface height, cloud cover, wind stress, and wind stress curl are significantly correlated with MHW intensity, although these relationships vary geographically and seasonally. Overall, these findings elucidate the seasonal variation and potential influential factors of MHWs in the Bohai Sea and offer insights for decision-making and planning in marine ranching.展开更多
This study takes"ocean heat waves"as a typical case to study the scientific definition,driving mechanisms,multi-dimensional impacts,and response strategies of extreme climate events.The definition of extreme...This study takes"ocean heat waves"as a typical case to study the scientific definition,driving mechanisms,multi-dimensional impacts,and response strategies of extreme climate events.The definition of extreme events requires a comprehensive consideration of statistical thresholds and social impacts.It is mainly driven by global warming caused by human emissions of greenhouse gases,and is also influenced by the interaction of natural variations such as ENSO.Extreme events cause systematic and cascading impacts on human health,infrastructure,agricultural economy,and ecosystems(especially marine ecosystems).Advanced technologies such as satellite remote sensing,climate models,and artificial intelligence have significantly enhanced their monitoring and prediction capabilities.However,effective responses still require a parallel strategy of mitigation and adaptation,and international cooperation is strengthened through the framework of the Paris Agreement.展开更多
During the hot summer season,using electricity systems increases the local anthropogenic heat emission,further increasing the temperature.Regarding anthropogenic heat sources,electric energy consumption,heat generatio...During the hot summer season,using electricity systems increases the local anthropogenic heat emission,further increasing the temperature.Regarding anthropogenic heat sources,electric energy consumption,heat generation,indoor and outdoor heat transfer,and exchange in buildings play a critical role in the change in the urban thermal environment.Therefore,the Weather Research and Forecasting(WRF)Model was applied in this study to investigate the heat generation from an indoor electricity system and its influence on the outdoor thermal environment.Through the building effect parameterization(BEP)of a multistorey urban canopy scheme,a building energy model(BEM)to increase the influence of indoor air conditioning on the electricity consumption system was proposed.In other words,the BEP+BEM urban canopy parameterization scheme was set.High temperatures and a summer heat wave were simulated as the background weather.The results show that using the BEP+BEM parameterization scheme of indoor and outdoor energy exchange in the WRF model can better simulate the air temperature near the surface layer on a sunny summer.During the day,the turning on the air conditioning and other electrical systems have no obvious effect on the air temperature near the surface layer in the city,whereas at night,the air temperature generally increases by 0.6℃,especially in densely populated areas,with a maximum temperature rise of approximately 1.2℃from 22:00 to 23:00.When the indoor air conditioning target temperature is adjusted to 25-27℃,the total energy release of the air conditioning system is reduced by 12.66%,and the temperature drops the most from 13:00 to 16:00,with an average of approximately 1℃.Further,the denser the building is,the greater the temperature drop.展开更多
Objective To assess the impact of the heat wave in 2005 on mortality among the residents in Guangzhou and to identify susceptible subpopulations in Guangzhou, China. Methods The data of daily number of deaths and mete...Objective To assess the impact of the heat wave in 2005 on mortality among the residents in Guangzhou and to identify susceptible subpopulations in Guangzhou, China. Methods The data of daily number of deaths and meteorological measures from 2003 to 2006 in Guangzhou were used in this study. Heat wave was defined as 〉7 consecutive days with daily maximum temperature above 35.0 ~C and daily mean temperature above the 97th percentile during the study period. The excess deaths and rate ratio （RR） of mortality in the case period compared with the reference period in the same summer were calculated. Results During the study period, only one heat wave in 2005 was identified and the total number of excess deaths was 145 with an average of 12 deaths per day. The effect of the heat wave on non-accidental mortality （RR=l.23, 95% CI： 1.11-1.37） was found with statistically significant difference. Also, greater effects were observed for cardiovascular mortality （RR=l.34, 95% Cl： 1.13-1.59） and respiratory mortality （RR=I.31, 95% CI： 1.02-1.69）. Females, the elderly and people with lower socioeconomic status were at significantly higher risk of heat wave-associated mortality. Conclusion The 2005 heat wave had a substantial impact on mortality among the residents in Guangzhou, particularly among some susceptible subpopulations. The findings from the present study may provide scientific evidences to develop relevant public health policies and prevention measures aimed at reduction of preventable mortality from heat waves.展开更多
In late July and early August 2018,Northeast China suffered from extremely high temperatures,with the maxium temperature anomaly exceeding 6°C.In this study,the large-scale circulation features associated with th...In late July and early August 2018,Northeast China suffered from extremely high temperatures,with the maxium temperature anomaly exceeding 6°C.In this study,the large-scale circulation features associated with this heat wave over Northeast China are analyzed using station temperature data and NCEP–NCAR reanalysis data.The results indicate that strong anomalous positive geopotential height centers existed from the lower to upper levels over Northeast China,and the related downward motions were directly responsible for the extreme high-temperature anomalies.The northwestward shift of the western Pacific subtropical high(WPSH)and the northeastward shift of the South Asian high concurrently reinforced the geopotential height anomalies and descending flow over Northeast China.In addition,an anomalous Pacific–Japan pattern in the lower troposphere led to the northwestward shift of the WPSH,jointly favoring the anomalous geopotential height over Northeast China.Two wave trains emanating from the Atlantic region propagated eastwards along high latitudes and midlatitudes,respectively,and converged over Northeast China,leading to the enhancement of the geopotential height anomalies.展开更多
In the summer of 2013, an unprecedented heat wave was experienced over a vast area of southern China. The great areal extent, duration, and strength of this high temperature are very rare. For the 2013 hot spell, the ...In the summer of 2013, an unprecedented heat wave was experienced over a vast area of southern China. The great areal extent, duration, and strength of this high temperature are very rare. For the 2013 hot spell, the major and direct influence mostly came from the anomaly of the western Pacific subtropical high(WPSH). The abnormally strong and stable WPSH was associated with specific surrounding circulations. The eastward extension of a stronger Qinghai-Xizang high favored the westward extension of the WPSH. The weaker cold air activity from the polar region led to the northward shift of the WPSH and helped it to remain stable. In the tropics, the western segment of the ITCZ was abnormally strong in the period, and supported the maintenance of the WPSH from the south. In addition, the interdecadal variation of the WPSH provided a decadal background for the anomaly variation of the WPSH that summer.展开更多
The authors previous study reported the important role of extratropical intraseasonal oscillation(ISO)on the occurrence of a typical heatwave event over the Yangtze River Valley.Based on the ECMWF subseasonal reforeca...The authors previous study reported the important role of extratropical intraseasonal oscillation(ISO)on the occurrence of a typical heatwave event over the Yangtze River Valley.Based on the ECMWF subseasonal reforecast database,this follow-up study evaluates the extended-range prediction skill of the heatwave event and further unravels the close link between the ISO and extended-range prediction of the event.With a two-week lead time,this heatwave event fails to occur in the reforecast because the predicted surface temperature is signi cantly underesti-mated.More detailed analysis demonstrates that the biases for both the intensity and the location of the warming region are primarily attributable to the inaccurate extratropical intrasea-sonal traveling signals.This work strongly indicates that accurately capturing the extratropical intraseasonal signal from the Eurasian continent is indispensable for extended-range prediction of East Asian extreme heatwave events.展开更多
基金supported by National Basic Research Program of China(973 Program)(Grant No.2012CB955504)
文摘Objective To reduce health-related threats of heat waves, interventions have been implemented in many parts of the world. However, there is a lack of higher-level evidence concerning the intervention efficacy. This study aimed to determine the efficacy of an intervention to reduce the number of heat-related illnesses. Methods A quasi-experimental design was employed by two cross-sectional surveys in the year 2024 and 2015, including 2,240 participants and 2,356 participants, respectively. Each survey was designed to include one control group and one intervention group, which conducted in Licheng, China. A representative sample was selected using a multistage sampling method. Data, collected from questionnaires about heat waves in 2014 and 2015, were analyzed using a difference-in-difference analysis and cost effectiveness analysis. Outcomes included changes in the prevalence of heat-related illnesses and cost-effectiveness variables. Results Relative to the control participants, the prevalence of heat-related illness in the intervention participants decreased to a greater extent in rural areas than in urban areas （OR=0.495 vs. OR=2.282）. Moreover, the cost-effectiveness ratio in the intervention group was tess than that in the control group （usS25.06 vs. us$25.69 per participant）. Furthermore, to avoid one additional patient, the incremental cost-effectiveness ratio showed that an additional USS14.47 would be needed for the intervention compared to when no intervention was applied. Conclusion The intervention program may be considered a worthwhile investment for rural areas that are more likely to experience heat waves. Meanwhile, corresponding improving measures should be presented towards urban areas. Future research should examine whether the intervention strategies could be spread out in other domestic or international regions where heat waves are usually experienced.
基金funded through the Integrated Program of IC&DT Call No.1/SAESCTN/ALENT-07-0224-FEDER-001755funding by the Geophysics Centre,University of Evora,Portugal,under the contract with Portuguese FCT,and PEst-OE/CTE/UI0078/2011
文摘We present a regional climate simulation for the Iberian Peninsula for a 60-year period (1950-2009) using the WRF-ARW model with a focus on the simulation of summer maximum temperatures and associated extreme heat waves. The WRF model was designed at a 5 km horizontal resolution on a 5-month (May-September) seasonal scale, for every year, during the study period with initial/boundary conditions derived from NCEP 2.5 degree reanalysis. The comparison of simulated mean summer seasonal maximums and mean maximums of June, July, and August months with the corresponding E-OBS data sets indicates that the model is able to characterize the spatial variation of magnitudes of temperature change over the Iberian Peninsula. The mean extreme heat wave conditions during the climate period 1950-2009 are well simulated and match the observations well. The regional scale simulations clearly show the propagation of intense heat waves from the south west to north east of Iberia. The WRF-ARW model also simulated well the general trend of increase in heat waves over most parts of the Iberian Peninsula during the study period 1950-2009. The characteristics of the most severe heat waves years 2003 and 2006 are also well simulated by the model.
基金supported by the National Natural Science Foundation of China(Grant Nos.41375155 and 91437107)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Heat waves have attracted increasing attention in recent years due to their frequent occurrence.The present study investigates the heat wave intensity and duration in China using daily maximum temperature from 753 weather stations from 1960 to 2010.In addition,its relationships with soil moisture local forcing on the ten-day period and monthly scales in spring and summer are analyzed using soil moisture data from weather stations and ERA40 reanalysis data.And finally,a mechanistic analysis is carried out using CAM5.1（Community Atmosphere Model,version 5.1） coupled with CLM2（Community Land Model,version 2）.It is found that the heat wave frequency and duration show a sandwich distribution across China,with high occurrence rates in Southeast China and Northwest China,where the maximum frequency and duration exceeded 2.1 times and 9 days per year,respectively.The increasing trends in both duration and intensity occurred to the north of 35°N.The relationships between heat wave frequency in northern China in July（having peak distribution） and soil moisture in the earlier stage（from March to June） and corresponding period（July） are further analyzed,revealing a strong negative correlation in March,June and July,and thus showing that soil moisture in spring and early summer could be an important contributor to heat waves in July via positive subtropical high anomalies.However,the time scales of influence were relatively short in the semi-humid and humid regions,and longer in the arid region.The contribution in the corresponding period took place via positive subtropical high anomalies and positive surface skin temperature and sensible heat flux anomalies.
基金The project supported by National High Technique Development Project (863) No.2002AA843130Scientific Fund of CAEP No. 20030214
文摘The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity heated by a 2 kJ, ins laser pulse （0.35 μm）. The delayed breakout time of the radiation waves from the rear side of the foam is measured by a three-chromatic streaked x-ray spectrometer （TCS） consisting of a set of three-imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera （XSC）. With one shot, simultaneous measurements of the delays of the drive source and the radiation with two different energies （210 eV, 840 eV） through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation with an energy of 210 eV propagates at a lower velocity. The radiating heat wave propagates with a velocity that is larger than the sound speed. Using TGS, the transmitting spectrum was measured, and then lower limit of the optical depth which is more than 1, was obtained. The experimental data were in agreement with numerical simulations.
文摘This study presents a new non-parametric measure of heat waves called heat wave norm (HWN), which allows quantifying and qualifying the magnitude of the summer heat wave events in the Bechar region located northwest of the Algerian Sahara over the period 1951-2010. The index, based on the analysis of daily maximum and minimum temperatures by adding them, integrated two dimensions at the same time: the duration and the excess heat. The results show an increase in the intensity and frequency of extreme events. More specifically, from the 1980s, it is possible to observe the propagation of extreme and very extreme and super extreme heat waves in recent decades with maximum presence during the period 1990-2010. In general, it can be said that the trend of excessive warming is clearly displayed in the Algerian Sahara, generally classified as a hot region.
基金supported by the Public Health Professional Training Supporting Project(No.01063)Chinese Field Epidemiology Training Program.
文摘Background:Hepatitis E virus(HEV)causes substantial morbidity globally,with frequent outbreaks in low-resource settings due to fecal-oral transmission.Temperature and extreme heat may influence waterborne pathogens,but their impact on HEV risk is unclear.Methods:We performed a time-stratified case-crossover study using 42,481 laboratoryconfirmed hepatitis E cases reported in Jiangsu Province(2010-2023).Daily mean,maximum,and minimum temperatures were obtained from fixed-site monitoring data.We examined associations of short-term temperature(single-day and cumulative lags up to 21 days)and heat wave episodes with hepatitis E risk using conditional logistic regression.Heat waves were defined using percentile-based thresholds for consecutive days.Analyses were adjusted for relative humidity and time trends,and stratified by sex,age,residence,and occupation.Sensitivity analyses used alternative heat wave definitions and lag structures.-Results:Higher ambient temperature was associated with increases in hepatitis E risk.Each 1◦C rise in daily mean temperature(lag 0-1 days)was linked to a 0.6%higher odds of hepatitis E(OR 1.006,95%CI 1.002-1.010).Similar associations were observed for maximum and minimum temperatures(e.g.OR 1.005[1.002-1.009]per 1◦C at lag 0-1 for max temperature;OR 1.009[1.004-1.014]at lag 0-3 for min temperature).Heat waves defined by more extreme and prolonged thresholds showed stronger effects.For example,a three-day daytime heat wave above the 95th percentile(Day_HW95_3d)was associated with an 18%higher hepatitis E risk(OR 1.18,95%CI 1.08-1.29),and a four-day compound heat wave>90th percentile had an OR of 1.14(95%CI 1.04-1.24).Conclusions:Short-term exposure to higher ambient temperatures and heat wave events was associated with increased risk of hepatitis E in Jiangsu,China.These results suggest that climate warming and extreme heat may elevate transmission of HEV,underscoring the need for strengthened water and sanitation interventions and targeted public health planning during hot weather.
基金supported by the Natural Science Foundation of Guangdong Province(2025A1515011041)the Key Project of Medical Science Research of Jiangsu Provincial Health Commission(K2023045)the Shenzhen Medical Research Fund(A2302033).
文摘Emerging evidence suggests that heat waves and ozone(O_(3))contribute to increased mortality risks.Since widowhood is a common event that can increase individuals'susceptibility to the environment,it is of great importance and interest to elucidate the widowhood disparity in mortality attributable to heat waves and O_(3).We therefore conducted a case-crossover study of 1,214,763 nonaccidental deaths in Jiangsu Province,China,during 2015–2021 to investigate the independent and interactive associations of exposure to heat waves and O_(3) with mortality by widowhood status.Grid-level heat waves were defined by multiple combinations of apparent temperature thresholds and durations.Residential heat waves and O_(3) exposures were assessed using validated grid datasets.Conditional logistic regression models were applied for exposure-response analyses and evalua-tions of additive interactions.Exposure to heat waves and O_(3) was significantly associated with increased odds of mortality in both widowed(odds ratio for heat waves,1.25;O_(3),1.06 per interquartile range increase)and married subjects(1.08;1.03),and these associations were higher in widowed subjects.A significant synergistic interaction was observed between heat waves and O_(3),which was stronger in widowed subjects(relative excess odds due to interaction,0.14 vs.0.03).Up to 6.43%and 3.56%of deaths were attributable to heat waves,O_(3) pollution,and their compound events in widowed and married subjects,respectively.Our findings suggest that widowed individuals are more susceptible to heat waves and O_(3) and highlight the need to consider differences associated with widowhood disparities in preventing premature deaths due to heat waves and O_(3) exposures.
基金supported by the Third Xinjiang Scientific Expedition Program(Grant No.2023xjkk0101)the National Youth Talent Project(Grant No.E4150103)。
文摘The future increased frequency and intensity of heat waves(HWs)across China will exacerbate adverse effects on society and the environment.However,changes in socioeconomic exposure remain underexplored.In this study,climate model outputs from the Coupled Model Intercomparison Project Phase 6(CMIP6),together with population and gross domestic product(GDP)projections were used to investigate projected heat stress and socioeconomic exposure across China and its eight subregions under four shared socioeconomic pathway(SSP)scenarios(SSP1–2.6,SSP2–4.5,SSP3–7.0,and SSP5–8.5)over three periods(2021–2040,2051–2070,and 2081–2100).Our results indicate a consistent upward trend in the Universal Thermal Climate Index(UTCI)across all scenarios,with intensifying increases over time,peaking at>6°C.This suggests a continuous increase in the number of extreme heat events(EHEs)in China.Population exposure to EHEs across the four UTCI thresholds(>26°C,>32°C,>38°C,and>46°C)shows an increasing trend.Projections indicate a∼14-fold increase nationwide,500-fold increase in Northwest China(NWC),and a 1000-fold in Southwest China(SWC2)under SSP5–8.5 by2081–2100 compared with current levels.The eastern and southeastern regions,especially the Yangtze River and Pearl River Delta,show significant GDP exposure increases under SSP3–7.0 and SSP5–8.5.Population exposure is mainly driven by climatic effects under severe scenarios,whereas GDP exposure is influenced by interaction effects,particularly under SSP5–8.5 and during the 2090s.This study's findings offer actionable insights for targeted adaptation in China's diverse geographies.
基金Supported by the National Key Research and Development Program of China(2022YFF0801603).
文摘Using daily maximum temperature(Tmax)data from 516 observation stations in eastern China from 1981 to 2020,this study employed a relative threshold method to define short-and long-lived heat waves(HWs)by considering regional climate differences to investigate the spatial characteristics and evolution of large-scale circulation during summer HWs.The results demonstrated spatial disparities in the frequency distribution of HWs of different durations and differences in the magnitude of duration and intensity between short-and long-lived HWs.Empirical orthogonal function analysis revealed three dominant spatial modes for both short-and long-lived HWs.The first mode showed that short-lived HWs occur prominently in both northern and southern regions,whereas long-lived HWs mainly occur in the northern region.The second mode was characterized by a meridional dipole pattern in both cases.The third mode exhibited a quadrupole pattern for short-lived HWs and a tripole pattern for long-lived HWs.Differences in the center locations of anomalies in the 500-hPa geopotential height and 850-hPa wind fields significantly influenced the temperature and precipitation anomaly distribution of typical HWs by affecting the warm column in the lower troposphere,cloud distribution,and moisture transport.Moreover,the atmospheric circulation evolution processes of typical HWs associated with the different modes of long-and short-lived HWs were linked to distinct teleconnection patterns.During the three modes of long-lived(short-lived)HWs,there was stronger(weaker)wave flux activity with multiple(single)propagation paths.Stronger westward Atlantic wave train activity at 300 hPa triggered the synergistic action of meridional and zonal wave fluxes,favoring the strengthening and maintenance of positive anomalies in geopotential height of 500 hPa.This may have contributed to the formation of long-lived HWs.These findings provide valuable insights to enhance our understanding and prediction of summer HWs.
基金Supported by the National Basic Research and Development(973)Program of China(2013CB430203 and 2012CB417205)China Meteorological Administration Special Public Welfare Research Fund(GYHY201306033)+2 种基金National Natural Science Foundation of China(41275073)Program of Science and Technology Development in Sichuan Meteorological Bureau(2014-09)Project for Postgraduate Scientific Research and Innovation of Jiangsu Province(KYLX16_0933)
文摘Based on combined thresholds of daily maximum and minimum temperatures, a compound heat wave is defined, and then changes in multiple aspects of such heat waves in China are estimated between 1961 and 2015. Our results intriguingly indicate that severe compound heat waves in northern China are characterized by excessively high in- tensity within short duration, while long duration determines great disaster-causing potential of severe events in the south. In the past few decades, large areas of China have experienced longer, stronger, and more frequent compound heat waves. Northern China has witnessed dramatic intensity increases, with a maximum amplification over 5~C dec- ade-~; while remarkable lengthening in duration has been mostly recorded in the south, with a maximum trend over 1 day decade-1. The spatial extent affected by compound heat waves has significantly expanded since the 1960s, with the largest expanding rate over 6% decade-1 detected in North China and Northeast China. These systematic assess- ments serve to deepen our understanding of observed changes in compound heat waves across China, and may fur- ther shed some light on future adaptations and mitigations against an increasingly wanning climate.
基金funded by the National Natural Science Foundation of China[grant numbers 41861124005 and 41675079]the first author was a recipient of a research studentship provided by the CAS-TWAS President fellowship。
文摘2019 was one of the hottest years in recent decades,with widespread heatwaves over many parts of the world,including Africa.However,as a developing and vulnerable region,the understanding of recent heatwave events in Africa is limited.Here,the authors incorporated different climate datasets,satellite observations,and population estimates to investigate patterns and hotspots of major heatwave events over Africa in 2019.Overall,2019 was one of the years that experienced the strongest heatwaves in terms of intensity and duration since 1981 in Africa.Heatwave hotspots were clearly identified across western-coastal,northeastern,southern,and equatorial Africa,where major cities and human populations are located.The proportion of urban agglomerations(population)exposed to extreme(99 th percentile)heatwaves in the Northern Hemisphere and Southern Hemisphere rose from 4%(5 million people)and 15%(17 million people),respectively,in the baseline period of 1981-2010 to36%(43 million people)and 57%(53 million people),respectively,in 2019.Heatwave patterns and hotspots in 2019 were related to anomalous seasonal change in atmospheric circulation and above-normal sea surface temperature.Without adaptation to minimize susceptibility to the effects of heatwave events,the risks they pose in populated areas may increase rapidly in Africa.
文摘The propagation of HF waves in IAR can produce many nonlinear effects, including the modulation effect of IAR on HF waves and the Doppler effect. To start with the dependence of the ionospheric electron temperature variations on the Alfvén resonant field, We discuss the mechanism of the modulation effect and lucubrate possible reasons for the Doppler effect. The results show that the Alfvén resonant field can have an observable modulation effect on HF waves while its mechanism is quite different from that of Schumann resonant field on HF waves. The depth of modulation of IAR on HF waves has a quasi\|quadratic relation with the Alfvén field, which directly inspires the formation of cross\|spectrum between ULF waves and HF waves and results in spectral peaks at some gyro\|frequencies of IAR. With respect to the Doppler effect during the propagation of HF waves in IAR, it is mainly caused by the motion of the high\|speed flyer and the drifting electrons and the frequency shift from the phase variation of the reflected waves can be neglected when the frequency of HF incident wave is high enough.
基金funded by the Key Project of the University Outstanding Youth Backbone Talented Person Foreign Visits Study Does Research of Anhui Province(No.gxgwfx2020025).
文摘Objective Heat wave exposure significantly impacts human health.Nevertheless,studies on the long-term effects of heat wave exposure during adolescence on adverse pregnancy outcomes(APOs)are rare.This study aimed to investigate the relationship between the long-term effects of heat wave exposure during adolescence and APOs.Methods We analyzed data from 3,376 female and 3,013 male participants across 31 provinces in China.All adolescents(10–19 years old),early adolescents(10–14),and late adolescents(15–19)were chosen as exposure windows.Heat waves were defined as periods lasting 2‒4 consecutive days with the daily temperature exceeding the 75th,90th,and 92.5th percentiles.We employed multivariate logistic regression models to assess the associations between exposure to heat waves during adolescence and APOs.Results The results revealed significant associations between male exposure to heat wave events during late adolescence and spontaneous abortion(P<0.05),which was more pronounced in South China.In contrast,no statistically significant associations were detected between males’exposure to heat wave events during adolescence and their partners’preterm birth(P>0.05 for all comparisons).The exposure of females to heat waves during adolescence was not significantly associated with subsequent spontaneous abortion or preterm birth(P>0.05 for all comparisons).Conclusions This study demonstrates that spontaneous abortion in females is associated with heat wave exposure in their male partner during adolescence.
基金Supported by the National Natural Science Foundation of China (Nos. 92358302, 42227901)。
文摘Marine heat waves(MHWs), characterized by extreme warm sea surface temperature events, frequently occur in Chinese marginal seas. However, the seasonal variation and joint distribution of MHWs in the Bohai Sea have not been fully described. Therefore, we conducted a systematic investigation of MHWs in this region. Our findings indicate that the frequency of MHW is low during winter, with long duration and weak intensity, while in summer, it is opposite, being high in the frequency, and shorter but stronger. Notably, in summer, the Laizhou and Liaodong bays exhibit a relatively long total day of MHWs compared to other areas in the Bohai Sea. Furthermore, our analysis of the joint distribution of MHWs, considering both duration and intensity, reveals significant seasonal variations. To provide practical insights for marine ranching, we have also investigated time series of MHWs at several specific stations and computed the correlation coefficients between MHW intensity and potential influential factors. Results suggest that sea surface height, cloud cover, wind stress, and wind stress curl are significantly correlated with MHW intensity, although these relationships vary geographically and seasonally. Overall, these findings elucidate the seasonal variation and potential influential factors of MHWs in the Bohai Sea and offer insights for decision-making and planning in marine ranching.
基金Supported by the School-level Project of Sichuan Minzu College(XYZB2017ZB).
文摘This study takes"ocean heat waves"as a typical case to study the scientific definition,driving mechanisms,multi-dimensional impacts,and response strategies of extreme climate events.The definition of extreme events requires a comprehensive consideration of statistical thresholds and social impacts.It is mainly driven by global warming caused by human emissions of greenhouse gases,and is also influenced by the interaction of natural variations such as ENSO.Extreme events cause systematic and cascading impacts on human health,infrastructure,agricultural economy,and ecosystems(especially marine ecosystems).Advanced technologies such as satellite remote sensing,climate models,and artificial intelligence have significantly enhanced their monitoring and prediction capabilities.However,effective responses still require a parallel strategy of mitigation and adaptation,and international cooperation is strengthened through the framework of the Paris Agreement.
基金supported by Incubation Project of State Grid Jiangsu Electric Power Company“Research and application of key technology of intelligent forecasting and warning for electric power meteorological public service platform”(JF2021045).
文摘During the hot summer season,using electricity systems increases the local anthropogenic heat emission,further increasing the temperature.Regarding anthropogenic heat sources,electric energy consumption,heat generation,indoor and outdoor heat transfer,and exchange in buildings play a critical role in the change in the urban thermal environment.Therefore,the Weather Research and Forecasting(WRF)Model was applied in this study to investigate the heat generation from an indoor electricity system and its influence on the outdoor thermal environment.Through the building effect parameterization(BEP)of a multistorey urban canopy scheme,a building energy model(BEM)to increase the influence of indoor air conditioning on the electricity consumption system was proposed.In other words,the BEP+BEM urban canopy parameterization scheme was set.High temperatures and a summer heat wave were simulated as the background weather.The results show that using the BEP+BEM parameterization scheme of indoor and outdoor energy exchange in the WRF model can better simulate the air temperature near the surface layer on a sunny summer.During the day,the turning on the air conditioning and other electrical systems have no obvious effect on the air temperature near the surface layer in the city,whereas at night,the air temperature generally increases by 0.6℃,especially in densely populated areas,with a maximum temperature rise of approximately 1.2℃from 22:00 to 23:00.When the indoor air conditioning target temperature is adjusted to 25-27℃,the total energy release of the air conditioning system is reduced by 12.66%,and the temperature drops the most from 13:00 to 16:00,with an average of approximately 1℃.Further,the denser the building is,the greater the temperature drop.
基金supported by National Nature Science Foundation of China (81102207)Guangdong Nature Science Foundation (S2011040005355)
文摘Objective To assess the impact of the heat wave in 2005 on mortality among the residents in Guangzhou and to identify susceptible subpopulations in Guangzhou, China. Methods The data of daily number of deaths and meteorological measures from 2003 to 2006 in Guangzhou were used in this study. Heat wave was defined as 〉7 consecutive days with daily maximum temperature above 35.0 ~C and daily mean temperature above the 97th percentile during the study period. The excess deaths and rate ratio （RR） of mortality in the case period compared with the reference period in the same summer were calculated. Results During the study period, only one heat wave in 2005 was identified and the total number of excess deaths was 145 with an average of 12 deaths per day. The effect of the heat wave on non-accidental mortality （RR=l.23, 95% CI： 1.11-1.37） was found with statistically significant difference. Also, greater effects were observed for cardiovascular mortality （RR=l.34, 95% Cl： 1.13-1.59） and respiratory mortality （RR=I.31, 95% CI： 1.02-1.69）. Females, the elderly and people with lower socioeconomic status were at significantly higher risk of heat wave-associated mortality. Conclusion The 2005 heat wave had a substantial impact on mortality among the residents in Guangzhou, particularly among some susceptible subpopulations. The findings from the present study may provide scientific evidences to develop relevant public health policies and prevention measures aimed at reduction of preventable mortality from heat waves.
基金supported by the National Natural Science Foundation of China under Grant 41775073
文摘In late July and early August 2018,Northeast China suffered from extremely high temperatures,with the maxium temperature anomaly exceeding 6°C.In this study,the large-scale circulation features associated with this heat wave over Northeast China are analyzed using station temperature data and NCEP–NCAR reanalysis data.The results indicate that strong anomalous positive geopotential height centers existed from the lower to upper levels over Northeast China,and the related downward motions were directly responsible for the extreme high-temperature anomalies.The northwestward shift of the western Pacific subtropical high(WPSH)and the northeastward shift of the South Asian high concurrently reinforced the geopotential height anomalies and descending flow over Northeast China.In addition,an anomalous Pacific–Japan pattern in the lower troposphere led to the northwestward shift of the WPSH,jointly favoring the anomalous geopotential height over Northeast China.Two wave trains emanating from the Atlantic region propagated eastwards along high latitudes and midlatitudes,respectively,and converged over Northeast China,leading to the enhancement of the geopotential height anomalies.
基金supported by the Special Public Welfare Research Fund of China Meteorological Administration (Grant No. GYHY201406020)the National Natural Science Foundation of China (Grant No. 41375055)
文摘In the summer of 2013, an unprecedented heat wave was experienced over a vast area of southern China. The great areal extent, duration, and strength of this high temperature are very rare. For the 2013 hot spell, the major and direct influence mostly came from the anomaly of the western Pacific subtropical high(WPSH). The abnormally strong and stable WPSH was associated with specific surrounding circulations. The eastward extension of a stronger Qinghai-Xizang high favored the westward extension of the WPSH. The weaker cold air activity from the polar region led to the northward shift of the WPSH and helped it to remain stable. In the tropics, the western segment of the ITCZ was abnormally strong in the period, and supported the maintenance of the WPSH from the south. In addition, the interdecadal variation of the WPSH provided a decadal background for the anomaly variation of the WPSH that summer.
基金supported by the National Key R&D Program of China(Grant No.2018YFC1505903)the National Natural Science Foundation of China(Grant No.41775071)the National Key R&D Program of China(Grant No.2016YFA0602401)
文摘The authors previous study reported the important role of extratropical intraseasonal oscillation(ISO)on the occurrence of a typical heatwave event over the Yangtze River Valley.Based on the ECMWF subseasonal reforecast database,this follow-up study evaluates the extended-range prediction skill of the heatwave event and further unravels the close link between the ISO and extended-range prediction of the event.With a two-week lead time,this heatwave event fails to occur in the reforecast because the predicted surface temperature is signi cantly underesti-mated.More detailed analysis demonstrates that the biases for both the intensity and the location of the warming region are primarily attributable to the inaccurate extratropical intrasea-sonal traveling signals.This work strongly indicates that accurately capturing the extratropical intraseasonal signal from the Eurasian continent is indispensable for extended-range prediction of East Asian extreme heatwave events.
