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Michelle L. Bell - One of the best experts on this subject based on the ideXlab platform.
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Heat Waves in South Korea: differences of Heat Wave characteristics by thermal indices
Journal of Exposure Science & Environmental Epidemiology, 2019Co-Authors: Seulkee Heo, Michelle L. BellAbstract:Heat Wave warning systems and related research define Heat Waves using various indices and there exists no standard definition for a Heat Wave. Despite various weather forecast services for Heat stress in South Korea, it is unclear how different thermal indices affect the designation of Heat Waves and health effect estimates. We aimed to analyze trends of Heat Wave characteristics and mortality associations using various criteria for the warm season (June-September) in 2011–5 for the most populated two cities in South Korea, Seoul and Busan. Hourly weather monitoring data and daily mortality data in each city were obtained. The following indices were estimated to define Heat Waves: air temperature, Heat index (HI), humidex, apparent temperature (AT), effective temperature (ET), and wet-bulb globe temperature (WBGT). The thresholds of each index for Heat Wave definitions were obtained by statistical distribution (95th percentiles) and minimum mortality temperature (MMT). Thermal indices showed clustering of accumulation of excess Heat above thresholds for northeast regions in the cities while air temperature showed it for central regions. Compared to 95th percentiles, the MMTs resulted 14 times longer Heat Wave days for thermal indices except for air temperature. When MMTs were used, nine times larger excess mortality from Heat Waves occurred for all indices compared to that from Heat Waves defined by the 95th percentiles. The thermal indices with the highest association between Heat and mortality varied between the two cities: air temperature for Seoul and WBGT for Busan. Heat Wave warnings should be based on a thorough comparison of how different Heat Wave criteria will affect the public health impact of Heat Wave warnings in terms of identifying a Heat Wave and degree of health impacts due to it.
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the use of a quasi experimental study on the mortality effect of a Heat Wave warning system in korea
International Journal of Environmental Research and Public Health, 2019Co-Authors: Seulkee Heo, Tarik Benmarhnia, Francesca Dominici, Amruta Norisarma, Kwonsang Lee, Michelle L. BellAbstract:Many cities and countries have implemented Heat Wave warning systems to combat the health effects of extreme Heat. Little is known about whether these systems actually reduce Heat-related morbidity and mortality. We examined the effectiveness of Heat Wave alerts and health plans in reducing the mortality risk of Heat Waves in Korea by utilizing the discrepancy between the alerts and the monitored temperature. A difference-in-differences analysis combined with propensity score weighting was used. Mortality, weather monitoring, and Heat Wave alert announcement data were collected for 7 major cities during 2009-2014. Results showed evidence of risk reduction among people aged 19-64 without education (-0.144 deaths/1,000,000 people, 95% CI: -0.227, -0.061) and children aged 0-19 (-0.555 deaths/1,000,000 people, 95% CI: -0.993, -0.117). Decreased cardiovascular and respiratory mortality was found in several subgroups including single persons, widowed people, blue-collar workers, people with no education or the highest level of education (university or higher). No evidence was found for decreased all-cause mortality in the population (1.687 deaths/1,000,000 people per day; 95% CI: 1.118, 2.255). In conclusion, Heat Wave alerts may reduce mortality for several causes and subpopulations of age and socio-economic status. Further work needs to examine the pathways through which the alerts impact subpopulations differently.
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Advancing our understanding of Heat Wave criteria and associated health impacts to improve Heat Wave alerts in developing country settings
International journal of environmental research and public health, 2019Co-Authors: Amruta Nori-sarma, Tarik Benmarhnia, Ajit Rajiva, Gulrez Shah Azhar, Prakash C. Gupta, Mangesh S. Pednekar, Michelle L. BellAbstract:Health effects of Heat Waves with high baseline temperatures in areas such as India remain a critical research gap. In these regions, extreme temperatures may affect the underlying population's adaptive capacity; Heat Wave alerts should be optimized to avoid continuous high alert status and enhance constrained resources, especially under a changing climate. Data from registrars and meteorological departments were collected for four communities in Northwestern India. Propensity Score Matching (PSM) was used to obtain the relative risk of mortality and number of attributable deaths (i.e., absolute risk which incorporates the number of Heat Wave days) under a variety of Heat Wave definitions (n = 13) incorporating duration and intensity. Heat Waves' timing in season was also assessed for potential effect modification. Relative risk of Heat Waves (risk of mortality comparing Heat Wave days to matched non-Heat Wave days) varied by Heat Wave definition and ranged from 1.28 [95% Confidence Interval: 1.11-1.46] in Churu (utilizing the 95th percentile of temperature for at least two consecutive days) to 1.03 [95% CI: 0.87-1.23] in Idar and Himmatnagar (utilizing the 95th percentile of temperature for at least four consecutive days). The data trended towards a higher risk for Heat Waves later in the season. Some Heat Wave definitions displayed similar attributable mortalities despite differences in the number of identified Heat Wave days. These findings provide opportunities to assess the "efficiency" (or number of days versus potential attributable health impacts) associated with alternative Heat Wave definitions. Findings on both effect modification and trade-offs between number of days identified as "Heat Wave" versus health effects provide tools for policy makers to determine the most important criteria for defining thresholds to trigger Heat Wave alerts.
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Comparison of health risks by Heat Wave definition: Applicability of wet-bulb globe temperature for Heat Wave criteria
Environmental research, 2018Co-Authors: Seulkee Heo, Michelle L. Bell, Jong-tae LeeAbstract:Abstract Despite the active applications of thermal comfort indices for Heat Wave definitions, there is lack of evaluation for the impact of extended days of high temperature on health outcomes using many of the indices. This study compared the impact of Heat Waves on health outcomes among different Heat Wave definitions based on thermal comfort and air temperature. We compared Heat Waves in South Korea (cities and provinces) for the warm season for 2011–2014, using air temperature, Heat index (HI), and web-bulb globe temperature (WBGT). Heat Waves were defined as days with daily maximum values of each index at a specified threshold (literature-based, the 90th and 95th percentiles) or above. Distributed lag non-linear models and meta-analysis were used to estimate risk of mortality and hospitalization for all-causes, cardiovascular causes, respiratory causes and Heat disorders during Heat Wave days compared to non-Heat Wave days. WBGT identified 1.15 times longer maximum Heat Wave duration for the study periods than air temperature when the thresholds were based on 90th and 95th percentiles. Over the study period, for Heat Waves defined by WBGT and HI, the Southwestern region showed the highest total number of Heat Wave days, whereas for air temperature the longest Heat Wave days were identified in the southeastern region. The highest and most significant impact of Heat Waves were found by WBGT for hospitalization from Heat disorders (Relative risk = 2.959, 95% CI: 1.566–5.594). In sensitivity analyses using different structure of lags and temperature metrics (e.g., daily mean and minimum), the impacts of Heat Waves on most health outcomes substantially increased by using WBGT for Heat Wave definitions. As a result, WBGT and its thresholds can be used to relate Heat Waves and Heat-related diseases to improve the prevention effectiveness of Heat Wave warnings and give informative health guidelines according to the range of WBGT thresholds.
Seulkee Heo - One of the best experts on this subject based on the ideXlab platform.
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Heat Waves in South Korea: differences of Heat Wave characteristics by thermal indices
Journal of Exposure Science & Environmental Epidemiology, 2019Co-Authors: Seulkee Heo, Michelle L. BellAbstract:Heat Wave warning systems and related research define Heat Waves using various indices and there exists no standard definition for a Heat Wave. Despite various weather forecast services for Heat stress in South Korea, it is unclear how different thermal indices affect the designation of Heat Waves and health effect estimates. We aimed to analyze trends of Heat Wave characteristics and mortality associations using various criteria for the warm season (June-September) in 2011–5 for the most populated two cities in South Korea, Seoul and Busan. Hourly weather monitoring data and daily mortality data in each city were obtained. The following indices were estimated to define Heat Waves: air temperature, Heat index (HI), humidex, apparent temperature (AT), effective temperature (ET), and wet-bulb globe temperature (WBGT). The thresholds of each index for Heat Wave definitions were obtained by statistical distribution (95th percentiles) and minimum mortality temperature (MMT). Thermal indices showed clustering of accumulation of excess Heat above thresholds for northeast regions in the cities while air temperature showed it for central regions. Compared to 95th percentiles, the MMTs resulted 14 times longer Heat Wave days for thermal indices except for air temperature. When MMTs were used, nine times larger excess mortality from Heat Waves occurred for all indices compared to that from Heat Waves defined by the 95th percentiles. The thermal indices with the highest association between Heat and mortality varied between the two cities: air temperature for Seoul and WBGT for Busan. Heat Wave warnings should be based on a thorough comparison of how different Heat Wave criteria will affect the public health impact of Heat Wave warnings in terms of identifying a Heat Wave and degree of health impacts due to it.
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the use of a quasi experimental study on the mortality effect of a Heat Wave warning system in korea
International Journal of Environmental Research and Public Health, 2019Co-Authors: Seulkee Heo, Tarik Benmarhnia, Francesca Dominici, Amruta Norisarma, Kwonsang Lee, Michelle L. BellAbstract:Many cities and countries have implemented Heat Wave warning systems to combat the health effects of extreme Heat. Little is known about whether these systems actually reduce Heat-related morbidity and mortality. We examined the effectiveness of Heat Wave alerts and health plans in reducing the mortality risk of Heat Waves in Korea by utilizing the discrepancy between the alerts and the monitored temperature. A difference-in-differences analysis combined with propensity score weighting was used. Mortality, weather monitoring, and Heat Wave alert announcement data were collected for 7 major cities during 2009-2014. Results showed evidence of risk reduction among people aged 19-64 without education (-0.144 deaths/1,000,000 people, 95% CI: -0.227, -0.061) and children aged 0-19 (-0.555 deaths/1,000,000 people, 95% CI: -0.993, -0.117). Decreased cardiovascular and respiratory mortality was found in several subgroups including single persons, widowed people, blue-collar workers, people with no education or the highest level of education (university or higher). No evidence was found for decreased all-cause mortality in the population (1.687 deaths/1,000,000 people per day; 95% CI: 1.118, 2.255). In conclusion, Heat Wave alerts may reduce mortality for several causes and subpopulations of age and socio-economic status. Further work needs to examine the pathways through which the alerts impact subpopulations differently.
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Comparison of health risks by Heat Wave definition: Applicability of wet-bulb globe temperature for Heat Wave criteria
Environmental research, 2018Co-Authors: Seulkee Heo, Michelle L. Bell, Jong-tae LeeAbstract:Abstract Despite the active applications of thermal comfort indices for Heat Wave definitions, there is lack of evaluation for the impact of extended days of high temperature on health outcomes using many of the indices. This study compared the impact of Heat Waves on health outcomes among different Heat Wave definitions based on thermal comfort and air temperature. We compared Heat Waves in South Korea (cities and provinces) for the warm season for 2011–2014, using air temperature, Heat index (HI), and web-bulb globe temperature (WBGT). Heat Waves were defined as days with daily maximum values of each index at a specified threshold (literature-based, the 90th and 95th percentiles) or above. Distributed lag non-linear models and meta-analysis were used to estimate risk of mortality and hospitalization for all-causes, cardiovascular causes, respiratory causes and Heat disorders during Heat Wave days compared to non-Heat Wave days. WBGT identified 1.15 times longer maximum Heat Wave duration for the study periods than air temperature when the thresholds were based on 90th and 95th percentiles. Over the study period, for Heat Waves defined by WBGT and HI, the Southwestern region showed the highest total number of Heat Wave days, whereas for air temperature the longest Heat Wave days were identified in the southeastern region. The highest and most significant impact of Heat Waves were found by WBGT for hospitalization from Heat disorders (Relative risk = 2.959, 95% CI: 1.566–5.594). In sensitivity analyses using different structure of lags and temperature metrics (e.g., daily mean and minimum), the impacts of Heat Waves on most health outcomes substantially increased by using WBGT for Heat Wave definitions. As a result, WBGT and its thresholds can be used to relate Heat Waves and Heat-related diseases to improve the prevention effectiveness of Heat Wave warnings and give informative health guidelines according to the range of WBGT thresholds.
Erich M Fischer - One of the best experts on this subject based on the ideXlab platform.
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a review of the european summer Heat Wave of 2003
Critical Reviews in Environmental Science and Technology, 2010Co-Authors: Ricardo Garciaherrera, Jürg Luterbacher, Julio Diaz, Ricardo M Trigo, Erich M FischerAbstract:This paper reviews the European summer Heat Wave of 2003, with special emphasis on the first half of August 2003, jointly with its significant societal and environmental impact across Western and Central Europe. We show the pattern of record-breaking temperature anomalies, discuss it in the context of the past, and address the role of the main contributing factors responsible for the occurrence and persistence of this event: blocking episodes, soil moisture deficit, and sea surface temperatures. We show that the anticyclonic pattern corresponds more to an anomalous northern displacement of the North Atlantic subtropical high than a canonical blocking structure, and that soil moisture deficit was a key factor to reach unprecedented temperature anomalies. There are indications that the anomalous Mediterranean Sea surface temperatures (SSTs) have contributed to the Heat Wave of 2003, whereas the role of SST anomalies in other oceanic regions is still under debate. There are methodological limitations to evaluate excess mortality due to excessive temperatures; however, the different studies available in the literature allow us to estimate that around 40,000 deaths were registered in Europe during the Heat Wave, mostly
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soil moisture atmosphere interactions during the 2003 european summer Heat Wave
Journal of Climate, 2007Co-Authors: Erich M Fischer, Sonia I Seneviratne, Pier Luigi Vidale, Daniel Luthi, Christoph ScharAbstract:The role of land surface–related processes and feedbacks during the record-breaking 2003 European summer Heat Wave is explored with a regional climate model. All simulations are driven by lateral boundary conditions and sea surface temperatures from the ECMWF operational analysis and 40-yr ECMWF ReAnalysis (ERA-40), thereby prescribing the large-scale circulation. In particular, the contribution of soil moisture anomalies and their interactions with the atmosphere through latent and sensible Heat fluxes is investigated. Sensitivity experiments are performed by perturbing spring soil moisture in order to determine its influence on the formation of the Heat Wave. A multiyear regional climate simulation for 1970–2000 using a fixed model setup is used as the reference period. A large precipitation deficit together with early vegetation green-up and strong positive radiative anomalies in the months preceding the extreme summer event contributed to an early and rapid loss of soil moisture, which exceeded the multiyear average by far. The exceptionally high temperature anomalies, most pronounced in June and August 2003, were initiated by persistent anticyclonic circulation anomalies that enabled a dominance of the local Heat balance. In this experiment the hottest phase in early August is realistically simulated despite the absence of an anomaly in total surface net radiation. This indicates an important role of the partitioning of net radiation in latent and sensible Heat fluxes, which is to a large extent controlled by soil moisture. The lack of soil moisture strongly reduced latent cooling and thereby amplified the surface temperature anomalies. The evaluation of the experiments with perturbed spring soil moisture shows that this quantity is an important parameter for the evolution of European Heat Waves. Simulations indicate that without soil moisture anomalies the summer Heat anomalies could have been reduced by around 40% in some regions. Moreover, drought conditions are revealed to influence the tropospheric circulation by producing a surface Heat low and enhanced ridging in the midtroposphere. This suggests a positive feedback mechanism between soil moisture, continental-scale circulation, and temperature.
Joel Schwartz - One of the best experts on this subject based on the ideXlab platform.
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Accounting for adaptation and intensity in projecting Heat Wave-related mortality.
Environmental research, 2018Co-Authors: Yan Wang, Francesco Nordio, John Nairn, Antonella Zanobetti, Joel SchwartzAbstract:Abstract Background How adaptation and intensity of Heat Waves affect Heat Wave-related mortality is unclear, making health projections difficult. Methods We estimated the effect of Heat Waves, the effect of the intensity of Heat Waves, and adaptation on mortality in 209 U.S. cities with 168 million people during 1962–2006. We improved the standard time-series models by incorporating the intensity of Heat Waves using excess Heat factor (EHF) and estimating adaptation empirically using interactions with yearly mean summer temperature (MST). We combined the epidemiological estimates for Heat Wave, intensity, and adaptation with the Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model dataset to project Heat Wave-related mortality by 2050. Results The effect of Heat Waves increased with its intensity. Adaptation to Heat Waves occurred, which was shown by the decreasing effect of Heat Waves with MST. However, adaptation was lessened as MST increased. Ignoring adaptation in projections would result in a substantial overestimate of the projected Heat Wave-related mortality (by 277–747% in 2050). Incorporating the empirically estimated adaptation into projections would result in little change in the projected Heat Wave-related mortality between 2006 and 2050. This differs regionally, however, with increasing mortality over time for cities in the southern and western U.S. but decreasing mortality over time for the north. Conclusions Accounting for adaptation is important to reduce bias in the projections of Heat Wave-related mortality. The finding that the southern and western U.S. are the areas that face increasing Heat-related deaths is novel, and indicates that more regional adaptation strategies are needed.
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using forecast and observed weather data to assess performance of forecast products in identifying Heat Waves and estimating Heat Wave effects on mortality
Environmental Health Perspectives, 2014Co-Authors: Kai Zhang, Yeh Hsin Chen, Joel Schwartz, Richard B Rood, Marie S OneillAbstract:Background: Heat Wave and health warning systems are activated based on forecasts of health-threatening hot weather.Objective: We estimated Heat–mortality associations based on forecast and observe...
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the effect of the 1995 Heat Wave in chicago on all cause and cause specific mortality
American Journal of Public Health, 2007Co-Authors: Reinhard Kaiser, Joel Schwartz, Alain Le Tertre, Carol A Gotway, Randolph W Daley, Carol RubinAbstract:Objectives. We sought to reexamine the effects of the 1995 Chicago Heat Wave on all-cause and cause-specific mortality, including mortality displacement, using advanced time-series analysis methods.Methods. We used Poisson regression with penalized regression splines to model excess mortality and mortality displacement over a 50-day period centered on the day in which the Heat Wave temperature peaked, adjusting for meteorological and other variables. We controlled for temporal trends by using daily mortality data during 1993–1997. We estimated relative risks (RRs) with reference to the first day of the 50-day period.Results. We estimated that there were 692 excess deaths from June 21, 1995, to August 10, 1995; 26% of these deaths were owing to mortality displacement. RR for all-cause mortality on the day with peak mortality was 1.74 (95% confidence interval=1.67, 1.81). Risk of Heat-related death was significantly higher among Blacks, and mortality displacement was substantially lower.Conclusions. The 199...
Sonia I Seneviratne - One of the best experts on this subject based on the ideXlab platform.
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role of soil moisture versus recent climate change for the 2010 Heat Wave in western russia
Geophysical Research Letters, 2016Co-Authors: Mathias Hauser, Rene Orth, Sonia I SeneviratneAbstract:The severe 2010 Heat Wave in western Russia was found to be influenced by anthropogenic climate change. Additionally, soil moisture-temperature feedbacks were deemed important for the buildup of the exceptionally high temperatures. We quantify the relative role of both factors by applying the probabilistic event attribution framework and analyze ensemble simulations to distinguish the effect of climate change and the 2010 soil moisture conditions for annual maximum temperatures. The dry 2010 soil moisture alone has increased the risk of a severe Heat Wave in western Russia sixfold, while climate change from 1960 to 2000 has approximately tripled it. The combined effect of climate change and 2010 soil moisture yields a 13 times higher Heat Wave risk. We conclude that internal climate variability causing the dry 2010 soil moisture conditions formed a necessary basis for the extreme Heat Wave.
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soil moisture atmosphere interactions during the 2003 european summer Heat Wave
Journal of Climate, 2007Co-Authors: Erich M Fischer, Sonia I Seneviratne, Pier Luigi Vidale, Daniel Luthi, Christoph ScharAbstract:The role of land surface–related processes and feedbacks during the record-breaking 2003 European summer Heat Wave is explored with a regional climate model. All simulations are driven by lateral boundary conditions and sea surface temperatures from the ECMWF operational analysis and 40-yr ECMWF ReAnalysis (ERA-40), thereby prescribing the large-scale circulation. In particular, the contribution of soil moisture anomalies and their interactions with the atmosphere through latent and sensible Heat fluxes is investigated. Sensitivity experiments are performed by perturbing spring soil moisture in order to determine its influence on the formation of the Heat Wave. A multiyear regional climate simulation for 1970–2000 using a fixed model setup is used as the reference period. A large precipitation deficit together with early vegetation green-up and strong positive radiative anomalies in the months preceding the extreme summer event contributed to an early and rapid loss of soil moisture, which exceeded the multiyear average by far. The exceptionally high temperature anomalies, most pronounced in June and August 2003, were initiated by persistent anticyclonic circulation anomalies that enabled a dominance of the local Heat balance. In this experiment the hottest phase in early August is realistically simulated despite the absence of an anomaly in total surface net radiation. This indicates an important role of the partitioning of net radiation in latent and sensible Heat fluxes, which is to a large extent controlled by soil moisture. The lack of soil moisture strongly reduced latent cooling and thereby amplified the surface temperature anomalies. The evaluation of the experiments with perturbed spring soil moisture shows that this quantity is an important parameter for the evolution of European Heat Waves. Simulations indicate that without soil moisture anomalies the summer Heat anomalies could have been reduced by around 40% in some regions. Moreover, drought conditions are revealed to influence the tropospheric circulation by producing a surface Heat low and enhanced ridging in the midtroposphere. This suggests a positive feedback mechanism between soil moisture, continental-scale circulation, and temperature.