Influence of the Arabian Sea on the Indian summer monsoon

Ghosh, Sujit K.; Pant, M. C.; Dewan, B. N.

doi:10.3402/tellusa.v30i2.10324

Cited by 51 publications

(7 citation statements)

References 7 publications

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“…This increased moisture availability can be attributed to the stronger cross‐equatorial flow in the ISLAB run which brings in more moisture to the system. The Q profile in Figure k shows the enhanced moisture availability in the ISLAB run particularly over the Arabian Sea, which is an important moisture source for ISMR [ Ghosh et al ., ; Levine and Turner , ]. Enhanced moisture over the Arabian Sea during LPS days highlights the importance of this moisture source in context of monsoon LPS (Figure ).…”

Section: Resultsmentioning

confidence: 99%

Structure, characteristics, and simulation of monsoon low‐pressure systems in CFSv2 coupled model

Srivastava

Rao

et al. 2017

JGR Oceans

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Indian Summer Monsoon (ISM) synoptic scale systems (low‐pressure systems, LPS) are known to produce increased rainfall over central India (CI). Fidelity of the Climate Forecast System version 2 (CFSv2) at simulating the LPS and their characteristics is evaluated in this study using a feature tracking algorithm. The model is able to reproduce the clustering of LPS by monsoon intraseasonal oscillations and the associated precipitation over eastern‐central India. It is found that mean biases in circulation and moisture stem from cold sea surface temperature (SST) bias in the model which results in weak LPS linked rainfall events over central India. Two sensitivity experiments were carried out to study the effect of coupled dynamics of tropical basins on LPS. Suppression of active dynamics of the tropical Indian Ocean in CFSv2 causes a reduction in cold SST bias and enhanced cyclogenesis in the northern Bay of Bengal. The reduced low‐level anticyclonic bias and enhanced moisture availability result in a better simulation of LPS structure, and associated precipitation over CI. Suppression of active ocean dynamics in tropical Pacific Ocean causes a perennial El‐Niño type bias which restricts LPS propagation over the Indian landmass, possibly due to time‐mean subsidence induced by remote El‐Niño forcing. Sensitivity experiments indicate the need for improvements in the representation of tropical Indian Ocean coupled dynamics as well as convective parameterization schemes in the model for subsequent improvements in the simulation of ISM at various time scales.

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Section: Resultsmentioning

confidence: 99%

Structure, characteristics, and simulation of monsoon low‐pressure systems in CFSv2 coupled model

Srivastava

Rao

et al. 2017

JGR Oceans

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“…Viewing the integrated moisture transport during the monsoon season in Figure a creates the notion that most of the moisture that precipitates along the Himalayas during the monsoon stems from the Bay of Bengal, the Arabian Sea, or as far as south of the equator. Focusing on moisture sources for the Indian subcontinent, this has in fact been shown in multiple studies which describe the magnitude of the moisture uptake over the ocean (Cadet & Greco, ; Cadet & Reverdin, ; Ghosh et al, ; Wang, , Chapters 1 and 4). Their findings are based on a moisture budget approach investigating vertically integrated moisture fluxes or comparing evaporation with precipitation deducted from measurements.…”

Section: Atmospheric Circulation and Moisture Sources For Nepal Durinmentioning

confidence: 93%

“…However, various studies investigated the origin of moisture for the Indian subcontinent. Ghosh et al () derived water vapor flux from airborne measurements along different transects in the Arabian Sea concluding that evaporation along the Arabian Sea is a major moisture source. Cadet and Reverdin () investigated surface water vapor transport for the 1975 summer monsoon season using a budget approach based on cross sections.…”

Section: Introductionmentioning

confidence: 99%

Synoptic Conditions and Moisture Sources Actuating Extreme Precipitation in Nepal

2017

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Despite the vast literature on heavy‐precipitation events in South Asia, synoptic conditions and moisture sources related to extreme precipitation in Nepal have not been addressed systematically. We investigate two types of synoptic conditions—low‐pressure systems and midlevel troughs—and moisture sources related to extreme precipitation events. To account for the high spatial variability in rainfall, we cluster station‐based daily precipitation measurements resulting in three well‐separated geographic regions: west, central, and east Nepal. For each region, composite analysis of extreme events shows that atmospheric circulation is directed against the Himalayas during an extreme event. The direction of the flow is regulated by midtropospheric troughs and low‐pressure systems traveling toward the respective region. Extreme precipitation events feature anomalous high abundance of total column moisture. Quantitative Lagrangian moisture source diagnostic reveals that the largest direct contribution stems from land (approximately 75%), where, in particular, over the Indo‐Gangetic Plain moisture uptake was increased. Precipitation events occurring in this region before the extreme event likely provided additional moisture.

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“…Several authors (Pisharoty, 1965;Saha and Bavadekar, 1973: Ghosh et al. 1978: Cadet and Reverdin, 1981Howland and Sikdar, 1983;Murakami ef nl., 1984;Cadet and Greco, 1987;Sadhuram and Ramesh Kumar, 1988) have studied the moisture budget over the Arabian Sea during the summer monsoon.…”

Section: Introductionmentioning

confidence: 99%

Estimation of bulk transfer coefficient for latent heat flux (Ce)

Sadhuram

1991

Boundary-Layer Meteorol

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The bulk transfer coefficient for latent heat flux (Ce) has been estimated over the Arabian Sea from the moisture budget during the pre-monsoon season of 1Y88.The computations have been made over two resion5 (A: OL8'N: 60-68" E: B: O-4" N: 56-60" E) with the upper computational boundary fixed at the 300 mb level. The precipitation amount (P) \\a\ negligible for region A while the observed values of P have been used for region B. The Ce estimates have been compared with those obtained with other available scheme5 (Kondo, lY7.5: Bunker. IY76). which are based on wind speed and atmospheric stability within the surface layer. Our value of Ce i\ higher in region A and lower in region B than the other estimates.

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Influence of the Arabian Sea on the Indian summer monsoon

Cited by 51 publications

References 7 publications

Structure, characteristics, and simulation of monsoon low‐pressure systems in CFSv2 coupled model

Structure, characteristics, and simulation of monsoon low‐pressure systems in CFSv2 coupled model

Synoptic Conditions and Moisture Sources Actuating Extreme Precipitation in Nepal

Estimation of bulk transfer coefficient for latent heat flux (Ce)

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