Extratropical anticyclonic Rossby wave breaking and Indian summer monsoon failure

Samanta, Dhrubajyoti; Dash, Mihir Kumar; Goswami, Bedartha; Pandey, P. C.

doi:10.1007/s00382-015-2661-7

Cited by 37 publications

(39 citation statements)

References 47 publications

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“…Subsequent work based on longer time series confirmed the existence of a significant relationship between the midlatitude zonal circulation and summer monsoon rainfall (Chattopadhyay et al, ; Ding & Wang, ; Srivastava et al, ). Others (e.g., Kripalani et al, ; Raman & Rao, ; Samanta et al, ; Yasunari, ) found strong correlations between large‐scale blockings over the Northern Caspian Sea and/or east Siberia and the monsoon breaks. Samanta et al () showed that in observations, blocking is not a climatological feature of the monsoon and is favored by Rossby wave breakings which allow the transport of low PV from the tropics toward north and the transport of high PV air toward the equator.…”

Section: Observational and Modeling Perspectivesmentioning

confidence: 97%

“…Others (e.g., Kripalani et al, 1997;Raman & Rao, 1981;Samanta et al, 2016;Yasunari, 1986) found strong correlations between large-scale blockings over the Northern Caspian Sea and/or east Siberia and the monsoon breaks. Samanta et al (2016) showed that in observations, blocking is not a climatological feature of the monsoon and is favored by Rossby wave breakings which allow the transport of low PV from the tropics toward north and the transport of high PV air toward the equator.…”

Section: Summer Monsoon Breaksmentioning

confidence: 99%

See 1 more Smart Citation

Review of Tropical‐Extratropical Teleconnections on Intraseasonal Time Scales

Stan

Straus

Frederiksen

et al. 2017

Reviews of Geophysics

267

214

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The interactions and teleconnections between the tropical and midlatitude regions on intraseasonal time scales are an important modulator of tropical and extratropical circulation anomalies and their associated weather patterns. These interactions arise due to the impact of the tropics on the extratropics, the impact of the midlatitudes on the tropics, and two‐way interactions between the regions. Observational evidence, as well as theoretical studies with models of complexity ranging from the linear barotropic framework to intricate Earth system models, suggest the involvement of a myriad of processes and mechanisms in generating and maintaining these interconnections. At this stage, our understanding of these teleconnections is primarily a collection of concepts; a comprehensive theoretical framework has yet to be established. These intraseasonal teleconnections are increasingly recognized as an untapped source of potential subseasonal predictability. However, the complexity and diversity of mechanisms associated with these teleconnections, along with the lack of a conceptual framework to relate them, prevent this potential predictability from being translated into realized forecast skill. This review synthesizes our progress in understanding the observed characteristics of intraseasonal tropical‐extratropical interactions and their associated mechanisms, identifies the significant gaps in this understanding, and recommends new research endeavors to address the remaining challenges.

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Section: Observational and Modeling Perspectivesmentioning

confidence: 97%

Section: Summer Monsoon Breaksmentioning

confidence: 99%

Review of Tropical‐Extratropical Teleconnections on Intraseasonal Time Scales

Stan

Straus

Frederiksen

et al. 2017

Reviews of Geophysics

267

214

View full text Add to dashboard Cite

show abstract

“…In particular, the daytime events have occurred over much of the northern and central India, depicting rationally the spatial orientation of the previous year's drought and soil water storage losses in Figure . This provides a robust evidence of the culmination of land‐atmosphere feedback, as no anticyclonic anomalies and the associated monsoon breaks occurred in 2010 [ Samanta et al ., ]. Note that there is a clear difference between the spatial orientation of HWN‐TX90p and HWF‐TX90p (Figures b and e).…”

Section: Concurrence Of Droughts and Heat Wavesmentioning

confidence: 99%

“…[] quantified that the 2010 soil moisture deficit alone contributed to a sixfold increase in risk of severe heat wave in western Russia. In India, a steady rise in rainfall failures since 1998 associated with anticyclonic Rossby wave breaking has led to moisture deficits over central and northwest parts, with NCEP/NCAR reanalysis data showing prominent wind field patterns in 2002 and 2009 [ Samanta et al ., ]. The same region also shows a strong soil moisture and temperature coupling, leading to a higher surface warming during break periods [ Miralles et al ., ; Ramarao et al ., ].…”

Section: Concurrence Of Droughts and Heat Wavesmentioning

confidence: 99%

Increasing heat waves and warm spells in India, observed from a multiaspect framework

2017

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Recent heat waves have been a matter of serious concern for India because of potential impacts on agriculture, food security, and socioeconomic progress. This study examines the trends and variability in frequency, duration, and intensity of hot episodes during three time periods (1951–2013, 1981–2013 and 1998–2013) by defining heat waves based on the percentile of maximum, minimum, and mean temperatures. The study also explores heat waves and their relationships with hydroclimatic variables, such as rainfall, terrestrial water storage, Palmer drought severity index, and sea surface temperature. Results reveal that the number, frequency, and duration of daytime heat waves increased considerably during the post‐1980 dry and hot phase over a large area. The densely populated and agriculturally dominated northern half of India stands out as a key region where the nighttime heat wave metrics reflected the most pronounced amplifications. Despite the recent warming hiatus in India and other parts of the world, we find that both daytime and nighttime extreme measures have undergone substantial changes during or in the year following a dry year since 2002, with the probability distribution functions manifesting a hotter‐than‐normal climate during 1998–2013. This study shows that a few months preceding the 2010 record‐breaking heat wave in Russia, India experienced the largest hot episode in the country's history. Interestingly, both these mega events are comparable in terms of their evolution and amplification. These findings emphasize the importance of planning for strategies in the context of the rising cooccurrence of dry and hot events.

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“…From a different perspective, several studies have shown the association among extratropical circulation (i.e., southward intrusion of midlatitude westerly wave troughs), MISOs and monsoon breaks during ISM (e.g., Ramasamy, 1962;Ding and Wang, 2007;Samanta et al, 2016;Mahesh et al, 2018). The recent studies in this direction suggest the key-role of anticyclonic Rossby wave breaking over West Asia in causing monsoon breaks (Samanta et al, 2016) or in regulating MISO through extratropical eddy transport (Mahesh et al, 2018). However, Kripalani et al (1997) showed that the extratropical wave activity (with successive anomalous troughs and ridges intruding into the subtropics of the Asian domain) can also promote active monsoon conditions over north and central India, thus suggesting mutual interplay between midlatitude circulation and ISM (Ding and Wang, 2007).…”

Section: Introductionmentioning

confidence: 99%

Dynamics of rainfall extremes over India: A new perspective

Sooraj

Terray

Shilin

et al. 2020

Intl Journal of Climatology

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A comprehensive analysis of the role of Indo-Pakistan arid region (IPAR) in modulating the boreal summer heavy extreme rainfall events over monsoon core zone (MCZ over Indian subcontinent) at subseasonal to daily time scales is presented. The objective is to bring new perspectives on the dynamics of such rainfall extremes. Time-lagged composite analysis shows the clustering of Monsoon Intra-Seasonal Oscillation with monsoon rainfall daily extremes. However, our results additionally bring out the distinct role of surface thermal forcing and moist processes over IPAR as another potential and significant precursor, 16-10 days in advance, causing monsoon rainfall daily extremes over MCZ. Further analysis reveals that the warming over IPAR is initially found in the northern part of the domain, 20-15 days before the rainfall events over MCZ and is triggered by subtropical-midlatitude interactions characterized by the intrusion of a midlatitude (i.e., Eurasian) atmospheric wave train into the Asian domain. Our analysis further reveals strong moist static energy (MSE) build-up over the IPAR 12 days in advance, which is initially dominated by anomalous warming in the lower atmosphere, but with an incremental contribution of low-level specific humidity as we moved forward in time towards the rainfall event. Hydrodynamic-longwave radiative teleconnections are the primary mechanism for the persistence of the surface warming and MSE buildup over IPAR after the initial intrusion of the Eurasian wave train. The persistent warming over IPAR reinforces the land-sea contrast between the Middle East and western equatorial Indian Ocean to its south, and this subsequently leads to pressure anomalies and monsoon circulation changes through geostrophic wind adjustment, thus enhancing westerlies over Arabian Sea. All these factors lead to the development of a gigantic monsoon trough over central India thus causing the rainfall extremes over MCZ through the genesis of synoptic vortices.

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Extratropical anticyclonic Rossby wave breaking and Indian summer monsoon failure

Abstract: to be one of the major causes of dry spell/break episodes in ISM. Additionally, the presence of cold air over Central India reduces the north-south thermal contrast over the monsoon region thereby modifying the local Hadley circulation over the region.

Cited by 37 publications

References 47 publications

Review of Tropical‐Extratropical Teleconnections on Intraseasonal Time Scales

Review of Tropical‐Extratropical Teleconnections on Intraseasonal Time Scales

Increasing heat waves and warm spells in India, observed from a multiaspect framework

Dynamics of rainfall extremes over India: A new perspective

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