Defining and Predicting Heat Waves in Bangladesh

AbstractThis paper proposes a heat-wave definition for Bangladesh that could be used to trigger preparedness measures in a heat early warning system (HEWS) and explores the climate mechanisms associated with heat waves. A HEWS requires a definition of heat waves that is both related to human health outcomes and forecastable. No such definition has been developed for Bangladesh. Using a generalized additive regression model, a heat-wave definition is proposed that requires elevated minimum and maximum daily temperatures over the 95th percentile for 3 consecutive days, confirming the importance of nighttime conditions for health impacts. By this definition, death rates increase by about 20% during heat waves; this result can be used as an argument for public-health interventions to prevent heat-related deaths. Furthermore, predictability of these heat waves exists from weather to seasonal time scales, offering opportunities for a range of preparedness measures. Heat waves are associated with an absence of normal premonsoonal rainfall brought about by anomalously strong low-level westerly winds and weak southerlies, detectable up to approximately 10 days in advance. This circulation pattern occurs over a background of drier-than-normal conditions, with below-average soil moisture and precipitation throughout the heat-wave season from April to June. Low soil moisture increases the odds of heat-wave occurrence for 10–30 days, indicating that subseasonal forecasts of heat-wave risk may be possible by monitoring soil-moisture conditions.

Download Full-text

European heat waves: observational characterization attending to climatic zones and modelled sensitivity to spring precipitation deficit.

10.5194/ems2021-397 ◽

2021 ◽

Author(s):

Samira Khodayar Pardo

Keyword(s):

Soil Moisture ◽

Iberian Peninsula ◽

Central Europe ◽

Heat Wave ◽

Heat Waves ◽

Hot Spot ◽

Spring Precipitation ◽

Climatic Zones ◽

Positive Tendency ◽

Moisture Conditions

In a changing climate an increase in frequency, intensity, and duration of heat extremes in Europe is predicted, accompanied by a decrease in mean precipitation, soil moisture and evapotranspiration. Over the last century, an increase in the duration of the heat waves and the number of hot days and warm nights was observed in Europe. One of the main &#8220;hot-spot&#8221; in this intensification of weather extremes is the Mediterranean due to the strong decrease in mean precipitation and increase in mean temperature. In the last two decades Europe has been frequently affected by extreme heat waves with record-breaking temperatures and large impacts on the natural, social system or on human health. During such heat-wave periods the daily mortality rate reached anomalies of about +70 %, causing for example additional 70,000 heat-related deaths in Europe in summer 2003. European cities are highly vulnerable to such events due to the urban heat effect.Despite the significant impact of heat waves on society and the projected increase in the frequency and intensity of these phenomena in Europe, the local-to-regional characteristics and the physical processes that contribute to their occurrence are not yet sufficiently understood.In this study, we investigate two relevant aspects of this extreme phenomena, (a) the evolution observed from the 1950-to-present in three different climatic zones in Europe, the Iberian Peninsula, France, and Central Europe, and (b) the sensitivity to preceding winter-spring precipitation and particularly spring soil moisture conditions.Despite a general positive tendency towards higher number and intensity of heat waves in all climatic zones, relevant differences were also found. Wet winter seasons are correlated to a decrease in the number of heat days and heat wave events during summer periods. Furthermore, extreme dry/wet spring soil moisture conditions over the Iberian Peninsula contribute up to 30% to changes in summer temperature in central Europe. In this presentation, the above mentioned and additional key results will be further discussed in detail.

Download Full-text

Northern Eurasian Heat Waves and Droughts

Journal of Climate ◽

10.1175/jcli-d-13-00360.1 ◽

2014 ◽

Vol 27 (9) ◽

pp. 3169-3207 ◽

Cited By ~ 101

Author(s):

Siegfried D. Schubert ◽

Hailan Wang ◽

Randal D. Koster ◽

Max J. Suarez ◽

Pavel Ya. Groisman

Keyword(s):

Soil Moisture ◽

Heat Wave ◽

Extreme Events ◽

Decadal Variability ◽

Heat Waves ◽

Precipitation Variability ◽

Northern Eurasia ◽

Temperature And Precipitation ◽

Warming World

Abstract This article reviews the understanding of the characteristics and causes of northern Eurasian summertime heat waves and droughts. Additional insights into the nature of temperature and precipitation variability in Eurasia on monthly to decadal time scales and into the causes and predictability of the most extreme events are gained from the latest generation of reanalyses and from supplemental simulations with the NASA Goddard Earth Observing System model, version 5 (GEOS-5). Key new results are 1) the identification of the important role of summertime stationary Rossby waves in the development of the leading patterns of monthly Eurasian surface temperature and precipitation variability (including the development of extreme events such as the 2010 Russian heat wave); 2) an assessment of the mean temperature and precipitation changes that have occurred over northern Eurasia in the last three decades and their connections to decadal variability and global trends in SST; and 3) the quantification (via a case study) of the predictability of the most extreme simulated heat wave/drought events, with some focus on the role of soil moisture in the development and maintenance of such events. A literature survey indicates a general consensus that the future holds an enhanced probability of heat waves across northern Eurasia, while there is less agreement regarding future drought, reflecting a greater uncertainty in soil moisture and precipitation projections. Substantial uncertainties remain in the understanding of heat waves and drought, including the nature of the interactions between the short-term atmospheric variability associated with such extremes and the longer-term variability and trends associated with soil moisture feedbacks, SST anomalies, and an overall warming world.

Download Full-text

Modeling Antecedent Soil Moisture to Constrain Rainfall Thresholds for Shallow Landslides Occurrence

Landslides - Investigation and Monitoring ◽

10.5772/intechopen.92730 ◽

2020 ◽

Author(s):

Maurizio Lazzari ◽

Marco Piccarreta ◽

Ram L. Ray ◽

Salvatore Manfreda

Keyword(s):

Soil Moisture ◽

Rainfall Intensity ◽

Shallow Landslide ◽

Rainfall Thresholds ◽

Antecedent Soil Moisture ◽

Correct Definition ◽

Triggering Conditions ◽

Definition Of ◽

Moisture Conditions ◽

Traditional Approaches

Rainfall-triggered shallow landslide events have caused losses of human lives and millions of euros in damage to property in all parts of the world. The need to prevent such hazards combined with the difficulty of describing the geomorphological processes over regional scales led to the adoption of empirical rainfall thresholds derived from records of rainfall events triggering landslides. These rainfall intensity thresholds are generally computed, assuming that all events are not influenced by antecedent soil moisture conditions. Nevertheless, it is expected that antecedent soil moisture conditions may provide critical support for the correct definition of the triggering conditions. Therefore, we explored the role of antecedent soil moisture on critical rainfall intensity-duration thresholds to evaluate the possibility of modifying or improving traditional approaches. The study was carried out using 326 landslide events that occurred in the last 18 years in the Basilicata region (southern Italy). Besides the ordinary data (i.e., rainstorm intensity and duration), we also derived the antecedent soil moisture conditions using a parsimonious hydrological model. These data have been used to derive the rainfall intensity thresholds conditional on the antecedent saturation of soil quantifying the impact of such parameters on rainfall thresholds.

Download Full-text

Severe summer heat waves over Georgia: trends, patterns and driving forces

Earth System Dynamics Discussions ◽

10.5194/esdd-6-2273-2015 ◽

2015 ◽

Vol 6 (2) ◽

pp. 2273-2322 ◽

Cited By ~ 1

Author(s):

I. Keggenhoff ◽

M. Elizbarashvili ◽

L. King

Keyword(s):

Soil Moisture ◽

Heat Wave ◽

Driving Forces ◽

Heat Waves ◽

Longwave Radiation ◽

Meridional Wind ◽

Surface Heating ◽

Ural Mountains ◽

Summer Heat ◽

Excess Heat Factor

Abstract. During the last 50 years Georgia experienced a rising number of severe summer heat waves causing increasing heat-health impacts. In this study, the 10 most severe heat waves between 1961 and 2010 and recent changes in heat wave characteristics have been detected from 22 homogenized temperature minimum and maximum series using the Excess Heat Factor (EHF). A composite and Canonical Correlation Analysis (CCA) have been performed to study summer heat wave patterns and their relationships to the selected predictors: mean Sea Level Pressure (SLP), Geopotential Height at 500 mb (Z500), Sea Surface Temperature (SST), Zonal (u-wind500) and Meridional Wind at 500 mb (v-wind500), Vertical Velocity at 500 mb (O500), Outgoing Longwave Radiation (OLR), Relative Humidity (RH500), Precipitation (RR) and Soil Moisture (SM). Most severe heat events during the last 50 years are identified in 2007, 2006 and 1998. Largest significant trend magnitudes for the number, intensity and duration of low and high-impact heat waves have been found during the last 30 years. Significant changes in the heat wave predictors reveal that all relevant surface and atmospheric patterns contributing to heat waves have been intensified between 1961 and 2010. Composite anomalies and CCA patterns provide evidence of a large anticyclonic blocking pattern over the southern Ural Mountains, which attracts warm air masses from the Southwest, enhances subsidence and surface heating, shifts the African Intertropical Convergence Zone (ITCZ) northwards, and causes a northward shift of the subtropical jet. Moreover, pronounced precipitation and soil moisture deficiency throughout Georgia contribute to the heat wave formation and persistence over Georgia. Due to different large- to mesoscale circulation patterns and the local terrain, heat wave effects over Eastern Georgia are dominated by subsidence and surface heating, while convective rainfall and cooling are observed in the West.

Download Full-text

Efficacy of Heat Wave Warning System in Reducing Mortality Risk of Heat Waves in South Korea, Utilizing Difference-in-Difference and Propensity Score Weighting approaches

Environmental Epidemiology ◽

10.1097/01.ee9.0000609132.52259.56 ◽

2019 ◽

Vol 3 ◽

pp. 290

Author(s):

Heo S ◽

Nori-Sarma A ◽

Lee K ◽

Benmarhnia T ◽

Dominici F ◽

...

Keyword(s):

Propensity Score ◽

South Korea ◽

Heat Wave ◽

Mortality Risk ◽

Heat Waves ◽

Warning System ◽

Difference In Difference ◽

Propensity Score Weighting

Download Full-text

How Important is Vegetation Phenology for European Climate and Heat Waves?

Journal of Climate ◽

10.1175/jcli-d-13-00040.1 ◽

2013 ◽

Vol 26 (24) ◽

pp. 10077-10100 ◽

Cited By ~ 14

Author(s):

Ruth Lorenz ◽

Edouard L. Davin ◽

David M. Lawrence ◽

Reto Stöckli ◽

Sonia I. Seneviratne

Keyword(s):

Soil Moisture ◽

Heat Wave ◽

Climate Model ◽

Heat Waves ◽

Daily Maximum ◽

Vegetation Phenology ◽

Area Index ◽

Summer Climate ◽

European Climate ◽

The Impact

Abstract It has been hypothesized that vegetation phenology may play an important role for the midlatitude climate. This study investigates the impact of interannual and intraseasonal variations in phenology on European climate using regional climate model simulations. In addition, it assesses the relative importance of interannual variations in vegetation phenology and soil moisture on European summer climate. It is found that drastic phenological changes have a smaller effect on mean summer and spring climate than extreme changes in soil moisture (roughly ¼ of the temperature anomaly induced by soil moisture changes). However, the impact of phenological anomalies during heat waves is found to be more important. Generally, late and weak greening has amplifying effects and early and strong greening has dampening effects on heat waves; however, regional variations are found. The experiments suggest that in the extreme hot 2003 (western and central Europe) and 2007 (southeastern Europe) summers the decrease in leaf area index amplified the heat wave peaks by about 0.5°C for daily maximum temperatures (about half of the effect induced by soil moisture deficit). In contrast to earlier hypotheses, no anomalous early greening in spring 2003 is seen in the phenological dataset employed here. Hence, the results indicate that vegetation feedbacks amplified the 2003 heat wave but were not responsible for its initiation. In conclusion, the results suggest that phenology has a limited effect on European mean summer climate, but its impact can be as important as that induced by soil moisture anomalies in the context of specific extreme events.

Download Full-text

Impact of different heat wave definitions on daily mortality in Bandafassi, Senegal

PLoS ONE ◽

10.1371/journal.pone.0249199 ◽

2021 ◽

Vol 16 (4) ◽

pp. e0249199

Author(s):

Mbaye Faye ◽

Abdoulaye Dème ◽

Abdou Kâ Diongue ◽

Ibrahima Diouf

Keyword(s):

Heat Wave ◽

Heat Waves ◽

Age Groups ◽

Additive Model ◽

Total Mortality ◽

Warning System ◽

Decision Makers ◽

Maximum Temperature ◽

Climate Services ◽

The Impact

Objective The aim of this study is to find the most suitable heat wave definition among 15 different ones and to evaluate its impact on total, age-, and gender-specific mortality for Bandafassi, Senegal. Methods Daily weather station data were obtained from Kedougou situated at 17 km from Bandafassi from 1973 to 2012. Poisson generalized additive model (GAM) and distributed lag non-linear model (DLNM) are used to investigate the effect of heat wave on mortality and to evaluate the nonlinear association of heat wave definitions at different lag days, respectively. Results Heat wave definitions, based on three or more consecutive days with both daily minimum and maximum temperatures greater than the 90th percentile, provided the best model fit. A statistically significant increase in the relative risk (RRs 1.4 (95% Confidence Interval (CI): 1.2–1.6), 1.7 (95% CI: 1.5–1.9), 1.21 (95% CI: 1.08–1.3), 1.2 (95% CI: 1.04–1.5), 1.5 (95% CI: 1.3–1.8), 1.4 (95% CI: 1.2–1.5), 1.5 (95% CI: 1.07–1.6), and 1.5 (95% CI: 1.3–1.8)) of total mortality was observed for eight definitions. By using the definition based on the 90th percentile of minimum and maximum temperature with a 3-day duration, we also found that females and people aged ≥ 55 years old were at higher risks than males and other different age groups to heat wave related mortality. Conclusion The impact of heat waves was associated with total-, age-, gender-mortality. These results are expected to be useful for decision makers who conceive of public health policies in Senegal and elsewhere. Climate parameters, including temperatures and humidity, could be used to forecast heat wave risks as an early warning system in the area where we conduct this research. More broadly, our findings should be highly beneficial to climate services, researchers, clinicians, end-users and decision-makers.

Download Full-text

Heat wave–related mortality in Sweden: A case-crossover study investigating effect modification by neighbourhood deprivation

Scandinavian Journal of Public Health ◽

10.1177/1403494818801615 ◽

2018 ◽

Vol 48 (4) ◽

pp. 428-435 ◽

Cited By ~ 6

Author(s):

Daniel Oudin Åström ◽

Christofer Åström ◽

Bertil Forsberg ◽

Ana M. Vicedo-Cabrera ◽

Antonio Gasparrini ◽

...

Keyword(s):

Heat Wave ◽

Heat Waves ◽

Warning System ◽

Daily Maximum ◽

Neighbourhood Deprivation ◽

Deprived Neighbourhoods ◽

Case Crossover ◽

All Cause Mortality ◽

Maximum Temperatures ◽

The Impact

Aims: The present study aimed to investigate if set thresholds in the Swedish heat-wave warning system are valid for all parts of Sweden and if the heat-wave warning system captures a potential increase in all-cause mortality and coronary heart disease (CHD) mortality. An additional aim was to investigate whether neighbourhood deprivation modifies the relationship between heat waves and mortality. Methods: From 1990 until 2014, in 14 municipalities in Sweden, we collected data on daily maximum temperatures and mortality for the five warmest months. Heat waves were defined according to the categories used in the current Swedish heat-wave warning system. Using a case-crossover approach, we investigated the association between heat waves and mortality in Sweden, as well as a modifying effect of neighbourhood deprivation. Results: On a national as well as a regional level, heat waves significantly increased both all-cause mortality and CHD mortality by approximately 10% and 15%, respectively. While neighbourhood deprivation did not seem to modify heat wave–related all-cause mortality, CHD mortality did seem to modify the risk. Conclusions: It may not be appropriate to assume that heat waves in Sweden will have the same impact in a northern setting as in a southern, or that the impact of heat waves will be the same in affluent and deprived neighbourhoods. When designing and implementing heat-wave warning systems, neighbourhood, regional and national information should be incorporated.

Download Full-text

Definition of temperature thresholds: the example of the French heat wave warning system

International Journal of Biometeorology ◽

10.1007/s00484-012-0530-1 ◽

2012 ◽

Vol 57 (1) ◽

pp. 21-29 ◽

Cited By ~ 28

Author(s):

Mathilde Pascal ◽

Vérène Wagner ◽

Alain Le Tertre ◽

Karine Laaidi ◽

Cyrille Honoré ◽

...

Keyword(s):

Heat Wave ◽

Warning System ◽

Temperature Thresholds ◽

Definition Of

Download Full-text

A Study on the Operation of Early Warning System for Heat Waves in Gwangju Based on the Urban Climatic Environment Assessment Model System

10.5194/egusphere-egu2020-3238 ◽

2020 ◽

Author(s):

Byoungchull Oh ◽

Cheolho Hwang ◽

Won-tae Yun ◽

Jongha Kim

Keyword(s):

Heat Wave ◽

Early Warning ◽

Heat Waves ◽

Warning System ◽

Scientific Basis ◽

Model System ◽

Assessment Model ◽

Environment Assessment ◽

Climatic Environment ◽

The City

Damages in cities resulting from climate change are made irregularly and untypically, thus difficult to predict due to heavily concentrated buildings and population, etc. This study aims to introduce the results of our Urban Climatic Environment Assessment Model System(Model System hereinafter) as well as its construction, which is designed to provide impact assessment of heat waves in cities, to reduce damages, and to build capacities against it.Our Model System is based on the Unified Model(UM : an integrated model of Korea Meteorological Administration), and satellite data is necessary to verify the Model System. However, we have developed high resolution (10m ~ 100m) urban assessment model to analyze the impacts of heat waves in city of Gwangju to help local government by developing and implementing environmental policies. The outputs of our Model System will contribute to the decision making.Following two approaches were considered for impact assesment. Firstly, high spatial resolution model (in 10m to 100m level) using ensemble and down-scaling techniques can help identification of vulnerable areas in the city. Also, analyzed data can be linked to local GIS and land use map for analysis and assessment of the heat waves, which enables to make 48h heat wave forecast.Secondly, CFD micro-scale analysis using super-computer enables to analyze the vulnerable areas with components of : temperature, wind, humidity, solar radiation quantity, cloud cover, etc. Data achieved via our Model System will be used as objective and scientific basis for developing heat wave policies. It will also give guidance for heat wave early warning.It is expected that local governments can utilize our Model System to identify and analyze patterns and characteristics of heat waves in the city, and make decisions and develop environment-related policies on the objective and scientific basis preemptive response for vulnerable areas in the region.Keywords : heat waves, Urban Climatic Environment Assessment Model System, spatial resolution, ensemble average, down-scaling, CFD, micro-scale, Early warning system&#160;* This research was supported by a grant from Research Program funded by International Climate & Environment Center(ICEC).

Download Full-text