Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation

A dry bias in climatological Central Indian rainfall plagues Indian summer monsoon (ISM) simulations in multiple generations of climate models. Here, using observations and regional climate modeling, we focus on a warm coastal Bay of Bengal sea surface temperature (SST) front and its impact on Centr...

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Main Authors: Samanta, Dhrubajyoti, Hameed, Saji N., Jin, Dachao, Thilakan, Vishnu, Ganai, Malay, Rao, Suryachandra A., Deshpande, Medha
Other Authors: Asian School of the Environment
Format: Article
Language:English
Published: 2019
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Online Access:https://hdl.handle.net/10356/81254
http://hdl.handle.net/10220/47446
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-812542023-02-28T16:41:03Z Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation Samanta, Dhrubajyoti Hameed, Saji N. Jin, Dachao Thilakan, Vishnu Ganai, Malay Rao, Suryachandra A. Deshpande, Medha Asian School of the Environment Indian Summer Monsoon DRNTU::Social sciences::Geography::Environmental sciences Sea Surface Temperature A dry bias in climatological Central Indian rainfall plagues Indian summer monsoon (ISM) simulations in multiple generations of climate models. Here, using observations and regional climate modeling, we focus on a warm coastal Bay of Bengal sea surface temperature (SST) front and its impact on Central Indian rainfall. The SST front, featuring sharp gradients as large as 0.5 °C/100 km, is colocated with a mixed layer depth (MLD) front, in a region where salinity variations are known to control MLD. Regional climate simulations coupling a regional atmospheric model with an ocean mixed layer model are performed. A simulation with observed MLD climatology reproduces SST, rainfall, and atmospheric circulation associated with ISM reasonably well; it also eliminates the dry bias over Central India significantly. Perturbing MLD structure in the simulations, we isolate the SST front’s impact on the simulated ISM climate state. This experiment offers insights into ISM climatological biases in the coupled NCEP Climate Forecast System version-2. We suggest that the warm SST front is essential to Central Indian rainfall as it helps to sustain deep and intense convection in its vicinity, which may be a source for the vortex cores seeding the monsoon low-pressure systems. Published version 2019-01-11T05:20:44Z 2019-12-06T14:26:38Z 2019-01-11T05:20:44Z 2019-12-06T14:26:38Z 2018 Journal Article Samanta, D., Hameed, S. N., Jin, D., Thilakan, V., Ganai, M., Rao, S. A., & Deshpande, M. (2018). Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation. Scientific Reports, 8(1), 17694-. doi:10.1038/s41598-018-35735-3 https://hdl.handle.net/10356/81254 http://hdl.handle.net/10220/47446 10.1038/s41598-018-35735-3 en Scientific Reports © 2018 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. 12 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Indian Summer Monsoon
DRNTU::Social sciences::Geography::Environmental sciences
Sea Surface Temperature
spellingShingle Indian Summer Monsoon
DRNTU::Social sciences::Geography::Environmental sciences
Sea Surface Temperature
Samanta, Dhrubajyoti
Hameed, Saji N.
Jin, Dachao
Thilakan, Vishnu
Ganai, Malay
Rao, Suryachandra A.
Deshpande, Medha
Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation
description A dry bias in climatological Central Indian rainfall plagues Indian summer monsoon (ISM) simulations in multiple generations of climate models. Here, using observations and regional climate modeling, we focus on a warm coastal Bay of Bengal sea surface temperature (SST) front and its impact on Central Indian rainfall. The SST front, featuring sharp gradients as large as 0.5 °C/100 km, is colocated with a mixed layer depth (MLD) front, in a region where salinity variations are known to control MLD. Regional climate simulations coupling a regional atmospheric model with an ocean mixed layer model are performed. A simulation with observed MLD climatology reproduces SST, rainfall, and atmospheric circulation associated with ISM reasonably well; it also eliminates the dry bias over Central India significantly. Perturbing MLD structure in the simulations, we isolate the SST front’s impact on the simulated ISM climate state. This experiment offers insights into ISM climatological biases in the coupled NCEP Climate Forecast System version-2. We suggest that the warm SST front is essential to Central Indian rainfall as it helps to sustain deep and intense convection in its vicinity, which may be a source for the vortex cores seeding the monsoon low-pressure systems.
author2 Asian School of the Environment
author_facet Asian School of the Environment
Samanta, Dhrubajyoti
Hameed, Saji N.
Jin, Dachao
Thilakan, Vishnu
Ganai, Malay
Rao, Suryachandra A.
Deshpande, Medha
format Article
author Samanta, Dhrubajyoti
Hameed, Saji N.
Jin, Dachao
Thilakan, Vishnu
Ganai, Malay
Rao, Suryachandra A.
Deshpande, Medha
author_sort Samanta, Dhrubajyoti
title Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation
title_short Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation
title_full Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation
title_fullStr Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation
title_full_unstemmed Impact of a narrow coastal Bay of Bengal sea surface temperature front on an Indian summer monsoon simulation
title_sort impact of a narrow coastal bay of bengal sea surface temperature front on an indian summer monsoon simulation
publishDate 2019
url https://hdl.handle.net/10356/81254
http://hdl.handle.net/10220/47446
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