Intra‐annual variability of heat wave episodes over the east coast of India

Sandeep, A.; Prasad, V. S.

doi:10.1002/joc.5395

Cited by 21 publications

(11 citation statements)

References 34 publications

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“…Heat waves in other parts of the world such as Europe (Trigo et al ., 2005; García‐Herrera et al ., 2010), Australia (Pezza et al ., 2012), China (Wang et al ., 2016), Brazil (Geirinhas et al ., 2018), Russia (Lau & Kim, 2012) and Iran (Darand et al ., 2018) are also found to be associated with anomalous blocking or anticyclonic flow. Persistence of anticyclonic blocking patterns can suppress convection (Ratnam et al ., 2016), enhance subsidence and increase adiabatic heating of the surface layers (Xoplaki et al ., 2003; Trigo et al ., 2005; Darand et al ., 2018; Sandeep & Prasad, 2018).…”

Section: Resultsmentioning

confidence: 99%

“…Drier soils imply that the incoming energy is used in heating the air and increasing its temperature (Van Oldenborgh et al ., 2018). Enhanced radiative warming of the lower troposphere by the surface due to depleted soil moisture and its impact on high‐temperature extremes is shown with reanalysis data products (Rohini et al ., 2016; Ghatak et al ., 2017; Van Oldenborgh et al ., 2018), satellite observations (Panda et al ., 2017), atmospheric model in global retrospective analysis (Sandeep and Prasad, 2018) and land surface model simulations (Ghatak et al ., 2017).…”

Section: Resultsmentioning

confidence: 99%

“…Although the definition of a heat wave is not unique, they comprise, most generally, of episodes of consecutive days with above normal high temperatures (Perkins et al ., 2012). Recent studies have investigated heat wave characteristics in India and observed changes therein (Pai et al ., 2013; Murari et al ., 2016; Ratnam et al ., 2016; Rohini et al ., 2016; Mazdiyasni et al ., 2017; Panda et al ., 2017; Sharma & Mujumdar, 2017; Dileepkumar et al ., 2018; Sandeep & Prasad, 2018; Van Oldenborgh et al ., 2018) or future projections thereof (Murari et al ., 2015; Im et al ., 2017; Mishra et al ., 2017). Others (Wehner et al ., 2016; Pattanaik et al ., 2017; Gouda et al ., 2017; Ghatak et al ., 2017; Van Oldenborgh et al ., 2018; Dodla et al ., 2017; Chandran et al ., 2017; Nair et al ., 2017) study particular heat wave episodes focusing mainly on the 2015 heat wave event that resulted in more than 2000 deaths in India.…”

Section: Introductionmentioning

confidence: 99%

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Absorbing aerosols and high‐temperature extremes in India: A general circulation modelling study

Mondal

Sah

Sharma

et al. 2020

Intl Journal of Climatology

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Heat waves in India during the pre-monsoon months have significant impacts on human health, productivity and mortality. While greenhouse gas-induced global warming is believed to accentuate high temperature extremes, anthropogenic aerosols predominantly constituted by radiation-scattering sulfate are believed to cause an overall cooling in most world regions. However, the Indian region is marked by an abundance of absorbing aerosols, such as black carbon (BC) and dust. The goal of this work was to understand the association between aerosols, particularly those that are absorbing in nature, and hightemperature extremes in north-central India during the pre-monsoon season. We use 30-year simulations from a chemistry-coupled atmosphere-only general circulation model (GCM), ECHAM6-HAM2, forced with evolving aerosol emissions in an interactive aerosol module, along with observed evolving SSTs. A composite of high-temperature extremes in the model simulations, compared to climatology, shows large-scale conditions conducive to heat waves. Importantly, it reveals concurrent positive anomalies of BC and dust aerosol optical depths. Changes in near-surface properties include a reduction in single scattering albedo (implying greater absorption) and enhancement in shortwave heating rate, compared to climatological conditions. Alterations in surface energy balance include reduced latent heat flux, but increased sensible heat flux, consistent with enhanced temperatures. Thus, chemistry-coupled GCM simulations capture an association of absorbing aerosols with hightemperature extremes in north India, arising from radiative heating in the surface layer. K E Y W O R D S absorbing aerosols, chemistry-coupled AGCM, ECHAM6-HAM2, extreme temperature, Indian heat wave, radiative forcing 1 | INTRODUCTION Extreme temperature and heat wave events in India during the pre-monsoon season (March-June) are critical in terms of their impact on human health, environment, agriculture and economy. Recent trends in extreme temperature are reported to be positive over India

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Absorbing aerosols and high‐temperature extremes in India: A general circulation modelling study

Mondal

Sah

Sharma

et al. 2020

Intl Journal of Climatology

View full text Add to dashboard Cite

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“…Studies of heat waves focused on South Asia have mostly considered temperature alone (Bedekar et al, ; Dash & Mamgain, ; De et al, ; Khan et al, ; Murari et al, ; Pai et al, ; Rohini et al, ; Sandeep & Prasad, ; Zahid & Rasul, ). Dynamical aspects of these events have been examined by Ratnam et al (), who suggest that heat waves in northwest India are remotely initiated by extratropical blocking events in the North Atlantic region with subsequent Rossby wave propagation to South Asia.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Extreme Wet‐Bulb Temperature Events in Southern Pakistan

Monteiro

Caballero

2019

Geophysical Research Letters

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We study extreme wet‐bulb temperature (Tw) events in a regional hot spot of high Tw values in southwest Pakistan's Indus Valley. We focus on the May–June premonsoon months and employ a combination of station data, ERA‐Interim reanalysis, and trajectory calculations to analyze the extreme events. We find that the events are associated with anomalous influx of marine air from the Arabian Sea. The air flows in a shallow layer below 950 hPa and is heated and moistened by diabatic processes over land, arriving at the hot spot region with very high Tw. We surmise that surface evaporation within the strip of well‐irrigated land flanking the Indus River plays a major role in generating these extreme Tw values. Our results imply that studies of extreme Tw events in future, warmer climates must pay close attention to fine‐scale diabatic processes within the boundary layer, especially evaporation over land.

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“…HW events in the northwestern region are associated with an anti‐cyclonic circulation developing due to a quasi‐stationary anomalous Rossby wave train generated at North Africa (Ratnam et al ., 2016). These waves are generated due to stretching of vorticity by divergent winds, which propagates along with westerly jet streams over northwestern India causing a sinking motion that causes positive outgoing longwave radiation (OLR) and hence heat waves (Ratnam et al2016; Sandeep and Prasad, 2018).…”

Section: Resultsmentioning

confidence: 99%

Changing spatio‐temporal trends of heat wave and severe heat wave events over India: An emerging health hazard

Singh

Mall

Singh

2020

Intl Journal of Climatology

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Heat wave (HW) and severe heat wave (SHW) events are the manifestations of extreme temperature causing an array of impacts on health, ecosystem, and economy. Since the mid-20th century, an increasing trend in the characteristics of heat waves has been observed over India causing an increased rate in human mortality. Our study aimed to analyse monthly, seasonal, and decadal variations along with long-term trends of HW and SHW events for premonsoon (March-May) and early summer monsoon (June-July) season during 1951-2016. HW and SHW events were identified using revised criteria given by the India Meteorological Department (IMD) using daily gridded maximum temperature data at 0.5 × 0.5 resolution from IMD. The study found a Spatio-temporal shift in the occurrence of HW events with a significantly increasing trend in three prominent heat wave prone regions that is northwestern, central, and south-central India, the highest being in West Madhya Pradesh (0.80 events/year), while a significantly decreasing trend was observed over an eastern region that is Gangetic West Bengal (−0.13events/year). SHW events showed a southward expansion and a spatial surge during the decades of 2001-2010 and 2010-2016. Tri-decadal comparative assessment shows a decadal increase of around 12 HW and 5 SHW events post the 1980s. Statewise Pearson's correlation between HW/SHW events and observed mortality reveals that the eastern coastal states that are Odisha and Andhra Pradesh show a significant positive correlation of 0.62 and 0.73, respectively. This significantly increasing trend in HW and SHW events may pose a grave risk to human health, predominantly on the vulnerable sections of the society. Heat waves need to be recognized as a potential health risk and demand further study, robust preparedness, and policy intervention. K E Y W O R D S heat waves, long term trends, mortality, severe heat waves 1 | INTRODUCTION India, the second-most populous and seventh-largest country of the world is also the sixth most vulnerable country to the extreme events (Eckstein et al., 2017; Mall et al., 2019). The dynamics of climate-dependent mechanisms are changing at a great pace due to the rise in global mercury. Both man-made and natural ecosystems are at a risk to climate-related extreme events such as heat waves, extreme precipitation, droughts, wildfires,

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Intra‐annual variability of heat wave episodes over the east coast of India

Cited by 21 publications

References 34 publications

Absorbing aerosols and high‐temperature extremes in India: A general circulation modelling study

Absorbing aerosols and high‐temperature extremes in India: A general circulation modelling study

Characterization of Extreme Wet‐Bulb Temperature Events in Southern Pakistan

Changing spatio‐temporal trends of heat wave and severe heat wave events over India: An emerging health hazard

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