Observed air-sea interface conditions and a monsoon depression during MONEX-79

Seetaramayya, P.; Master, A. H.

doi:10.1007/bf02265431

Cited by 38 publications

(12 citation statements)

References 8 publications

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“…In the Indian Ocean, warm SST is generally found in three locations (Vinayachandran et al 2007): the western equatorial Indian Ocean, the southeastern Arabian Sea (SEAS), and eastern BOB, with the latter being warmest during April. At about 1 week before the Indian monsoon onset, a warm pool (SST [ 30.5°C) exists over the Arabian Sea (Seetaramayya and Master 1984). The warm SST in the SEAS leads to the formation of a vortex that affects the Indian monsoon onset over Kerala in early June (Joseph 1990;Shenoi et al 1999Shenoi et al , 2005.…”

Section: Introductionmentioning

confidence: 99%

Air–sea interaction and formation of the Asian summer monsoon onset vortex over the Bay of Bengal

Guan

Liu

et al. 2011

Clim Dyn

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In spring over the southern Bay of Bengal (BOB), a vortex commonly develops, followed by the Asian summer monsoon onset. An analysis of relevant data and a case study reveals that the BOB monsoon onset vortex is formed as a consequence of air-sea interaction over BOB, which is modulated by Tibetan Plateau forcing and the land-sea thermal contrast over the South Asian area during the spring season. Tibetan Plateau forcing in spring generates a prevailing cold northwesterly over India in the lower troposphere. Strong surface sensible heating is then released, forming a prominent surface cyclone with a strong southwesterly along the coastal ocean in northwestern BOB. This southwesterly induces a local offshore current and upwelling, resulting in cold sea surface temperatures (SSTs). The southwesterly, together with the near-equatorial westerly, also results in a surface anticyclone with descending air over most of BOB and a cyclone with ascending air over the southern part of BOB. In the eastern part of central BOB, where sky is clear, surface wind is weak, and ocean mixed layer is shallow, intense solar radiation and low energy loss due to weak surface latent and sensible heat fluxes act onto a thin ocean layer, resulting in the development of a unique BOB warm pool in spring. Near the surface, water vapor is transferred from northern BOB and other regions to southeastern BOB, where surface sensible heating is relatively high. The atmospheric available potential energy is generated and converted to kinetic energy, thereby resulting in vortex formation. The vortex then intensifies and moves northward, where SST is higher and surface sensible heating is stronger. Meanwhile, the zonal-mean kinetic energy is converted to eddy kinetic energy in the area east of the vortex, and the vortex turns eastward. Eventually, southwesterly sweeps over eastern BOB and merges with the subtropical westerly, leading to the onset of the Asian summer monsoon.

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Section: Introductionmentioning

confidence: 99%

Air–sea interaction and formation of the Asian summer monsoon onset vortex over the Bay of Bengal

Guan

Liu

et al. 2011

Clim Dyn

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“…The SE Arabian Sea is therefore a dominant tropical warm waters region in April-May within which a mini warm pool over the Lakshadweep area, is situated which was Vol. 162, 2005 Intraseasonal Variability During BOBMEX andARMEX 1499 first noticed by SEETARAMAYYA and MASTER (1984) and further studied by several workers (JOSEPH, 1990;VINAYCHANDRAN and SHETYE, 1991;SHENOI et al, 1999;RAO andSIVAKUMAR, 1999, 2000). SHANKAR and SHETYE (1997) examined the dynamics of the Lakshadweep SST high (mini-warm pool) and linked the preferential warming of the area to the intrusion of low salinity waters of the BOB into SE Arabian Sea, as a result of the westward moving Rossby waves from the BOB generated by downwelling coastal Kelvin waves between December to March.…”

Section: Armex-ii: Build-up Of the Se Arabian Sea Warm Pool And Onsetmentioning

confidence: 99%

“…In several studies collapse of the warm pool has been linked with the process of onset of the monsoon over the Lakshadweep Sea and Kerala Coast. The monsoon onset is brought about in many years (50% on the average) by the formation of an intense vortex (depression/ tropical storm) over the SE Arabian Sea towards the end of May/early June (SEETARAMAYYA and MASTER, 1984;JOSEPH, 1990;RAO and SIVAKUMAR, 1999). The warm pool collapses under the impact of the burst of the monsoon winds within about a week to fortnight of the invasion of the strong winds over the Lakshadweep Sea area.…”

Section: Armex-ii: Build-up Of the Se Arabian Sea Warm Pool And Onsetmentioning

confidence: 99%

Intraseasonal Variability of the Summer Monsoon over the North Indian Ocean as Revealed by the BOBMEX and ARMEX Field Programs

Rao

Sikka²

2005

Pure appl. geophys.

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During the summer monsoon season over India a range of intraseasonal modulations of the monsoon rains occur due to genesis of weather disturbances over the Bay of Bengal (BOB) and the east Arabian Sea. The amplitudes of the fluctuations in the surface state of the ocean (sea-surface temperature and salinity) and atmosphere are quite large due to these monsoonal modulations on the intraseasonal scale as shown by the data collected during the field programs under Bay of Bengal Monsoon Experiment (BOBMEX) and Arabian Sea Monsoon Experiments (ARMEX). The focus of BOBMEX was to understand the role of ocean-atmospheric processes in organizing convection over the BOB on intraseasonal scale. ARMEX-I was aimed at understanding the coupled processes in the development of deep convection off the West Coast of India. ARMEX-II was focused on the formation of the mini-warm pool across the southeast Arabian Sea in April-May and its role in the abrupt onset of the monsoon along the Southwest Coast of India and its further progress along the West Coast of India. The paper attempts to integrate the results of the observational studies and brings out an important finding that atmospheric instability is prominently responsible for convective organization whereas the upper ocean parameters regulate the episodes of the intraseasonal oscillations.

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“…Further, in the layer 1000 -850 hPa, C(A Z , A E ) is less than C(A E , K E ). This may be quite likely that the transfer of sensible heat due to air-sea interaction may be responsible for the generation of A E in the boundary layer (SEETARAMAYYA and MASTER, 1984). The generation of A E due to the diabatic process may be taking place in the mid-troposphere.…”

Section: Time Mean Energeticsmentioning

confidence: 99%

A Diagnostic Study of the Cyclonic Storm over the Arabian Sea during June 1994

George

Salvekar

Singh

1999

Pure and Applied Geophysics

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Based on the NCMRWF analysis over the Arabian Sea, a complete energy cycle of the severe cyclonic storm that formed in the beginning of June 1994 in the east central Arabian Sea is carried out, using the in-house developed energy package. Both barotropic and baroclinic energy conversions are responsible for the maintenance of the system, however dominance of one over the other is noticed at different stages of the system at different heights. Dynamical characteristics of synoptic scale monsoon flow surrounding the cyclonic storm are also investigated. By examining the generation and dissipation terms, it is observed that both zonal and eddy components of the synoptic scale flow act as source of energy for the cyclonic storm, both in the predeveloped and developed stages.

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Observed air-sea interface conditions and a monsoon depression during MONEX-79

Cited by 38 publications

References 8 publications

Air–sea interaction and formation of the Asian summer monsoon onset vortex over the Bay of Bengal

Air–sea interaction and formation of the Asian summer monsoon onset vortex over the Bay of Bengal

Intraseasonal Variability of the Summer Monsoon over the North Indian Ocean as Revealed by the BOBMEX and ARMEX Field Programs

A Diagnostic Study of the Cyclonic Storm over the Arabian Sea during June 1994

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