BOBMEX: The Bay of Bengal Monsoon Experiment

Bhat, G. S.; Gadgil, Sulochana; Kumar, P. V. Hareesh; Kalsi, S. R.; Madhusoodanan, P.; Murty, V. S. N.; Rao, C. V.; Babu, V. Ramesh; Rao, L.V.G.; Rao, R. R.; Ravichandran, M.; Reddy, K. Gopala; Rao, P. S.; Sengupta, Debasis; Sikka, D. R.; Swain, J.; Vinayachandran, P. N.

doi:10.1175/1520-0477(2001)082<2217:btbobm>2.3.co;2

Cited by 207 publications

(172 citation statements)

References 35 publications

Supporting

Mentioning

157

Contrasting

Order By: Relevance

“…Over the Bay of Bengal and the north and northeast India, Class I clouds dominate other cloud types, thus indicating that the overshooting convection over these areas is very likely possible. The Bay of Bengal is, in fact, considered as an important region where convection is often very deep and intense during monsoon (Bhat et al, 2001;Zuidema, 2003).…”

Section: Spatio-temporal Distribution Of Hoicsmentioning

confidence: 99%

A daytime climatological distribution of high opaque ice cloud classes over the Indian summer monsoon region observed from 25-year AVHRR data

Devasthale

Graßl

2009

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract.A daytime climatological spatio-temporal distribution of high opaque ice cloud (HOIC) classes over the Indian subcontinent (0-40 • N, 60 • E-100 • E) is presented using 25-year data from the Advanced Very High Resolution Radiometers (AVHRRs) for the summer monsoon months. The HOICs are important for regional radiative balance, precipitation and troposphere-stratosphere exchange. In this study, HOICs are sub-divided into three classes based on their cloud top brightness temperatures (BT ). Class I represents very deep convection (BT <220 K). Class II represents deep convection (220 K<=BT <233 K) and Class III background convection (233 K<=BT <253 K). Apart from presenting finest spatial resolution (0.1×0.1 degrees) and long-term climatology of such cloud classes from AVHRRs to date, this study for the first time illustrates on (1) how these three cloud classes are climatologically distributed during monsoon months, and (2) how their distribution changes during active and break monsoon conditions. It is also investigated that how many deep convective clouds reach the tropopause layer during individual monsoon months. It is seen that Class I and Class II clouds dominate the Indian subcontinent during monsoon. The movement of monsoon over continent is very well reflected in these cloud classes. During monsoon breaks strong suppression of convective activity is observed over the Arabian Sea and the western coast of India. On the other hand, the presence of such convective activity is crucial for active monsoon conditions and all-IndiaCorrespondence to: A. Devasthale (abhay.devasthale@smhi.se) rainfall. It is found that a significant fraction of HOICs (3-5%) reach the tropopause layer over the Bay of Bengal during June and over the north and northeast India during July and August. Many cases are observed when clouds penetrate the tropopause layer and reach the lower stratosphere. Such cases mostly occur during June compared to the other months.

show abstract

Section: Spatio-temporal Distribution Of Hoicsmentioning

confidence: 99%

A daytime climatological distribution of high opaque ice cloud classes over the Indian summer monsoon region observed from 25-year AVHRR data

Devasthale

Graßl

2009

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…(c) Same as (b), but for rainfall and divergence (Unit: 10 À6 s À1 ). Shaded areas: >4 mm day À1 (IIOE) in the mid-1960s and in 1975-1976, the FGGE Monsoon Experiments in 1978-1979 (MONEX) (Krishnamurti 1985), the Coupled Ocean-Atmosphere Response Experiment in 1992-1993 (TOGA-COARE) (Webster and Lukas 1992), the GEWEX Asian Monsoon Experiment (GAME) in 1996-2000 (GAME ISP, 1998), the South China Sea Monsoon Experiment (SCSMEX) in 1996-2000 (Lau et al 2000;Ding and Liu 2001;Johnson et al 2004), the Bay of Bengal Monsoon Experiment (BO-MEX) in 1999 (Bhat et al 2001) and the Joint Air-Sea Monsoon Interactive Experiment (JAS-MINE) in 1999 and the Arabian Sea Monsoon Experiment (ARMEX) in 2002 (Webster et al 2002). At the same time, a number of books, monographs and review papers written in English summarizing the major scientific achievements of the Asian monsoon in different periods have been published, including Monsoon Meteorology (Ramage 1971), Southwest Monsoon (Rao 1976), Monsoons (Fein and Stephens 1987), Monsoon Meteorology (Chang and Krishnamurti 1987), Monsoon over China (Ding 1994), The East Asian Monsoon (Chang 2004), The Global Monsoon System (Chang et al 2005) and The Asian Monsoon .…”

Section: Introductionmentioning

confidence: 99%

The Variability of the Asian Summer Monsoon

Ding

2007

Journal of the Meteorological Society of Japan

239

150

View full text Add to dashboard Cite

The Asian monsoon is the most significant component of the global climate system. During recent two decades, a more and more efforts have been made to study the Asian monsoon. A substantial achievement has been made in basic physical processes, predictability and prediction since the MONEX of [1978][1979]. The major advance in our new understanding of the variability of the Asian summer monsoon has been highlighted in this paper. The present paper is structured with four parts. The first part is the introduction, indicating the new regional division of the Asian monsoon system and significant events of the history of the Asian monsoon research. The second part discusses the annual cycle and seasonal march of the Asian monsoon as the mean state, with a special emphasis on the onset, propagation, active-break cycle and withdrawal of the Asian summer monsoon. The process and mechanism of the earliest onset of the Asian summer monsoon which takes place in the near-equatorial East Indian ocean-central and southern Indochina Peninsula have been well documented. The third part deals with the multiple scale variability of the Asian summer monsoon, including the intraseasonal, interannual and inter-decadal variability. Their dominant modes such as 10-20 day and 30-60 day oscillations for the intraseasonal variability, the Tropospheric Biennial Oscillation (TBO), the Indian Ocean Dippole Mode (IODM) and teleconnection patterns for interannual variability and the 60-year oscillation for the inter-decadal variability, as well as related SST-monsoon relationship and land-monsoon relationship have been discussed in more details. The fourth part is the conclusion, summarizing the major findings and proposing future work.

show abstract

“…Here, we particularly focus on extended monsoon -breaks, which are longer than 2 weeks. It is well recognized that air-sea exchanges on intraseasonal timescales in the tropical Indian Ocean give rise to significant fluctuations of sea surface temperature (SST) and heat fluxes at the ocean-atmosphere interface (Rao, 1987;Krishnamurti et al, 1988;Bhat et al, 2001;Sengupta and Ravichandran, 2001;Veechi and Harrison, 2002). Earlier studies have reported anomalous warming of SST preceding a convection maximum in association with positive shortwave and latent heat flux anomalies into the surface (e.g.…”

Section: Introductionmentioning

confidence: 99%

Cloud‐radiative impacts on the tropical Indian Ocean associated with the evolution of ‘monsoon breaks’

Samala¹,

Krishnan²

2007

Intl Journal of Climatology

View full text Add to dashboard Cite

ABSTRACT:A detailed diagnostic analysis of a suite of observed datasets was carried out with a view to understand the importance of cloud-radiative effects on the evolution of prolonged 'monsoon breaks' over the Indian region. The study particularly focuses on the role of clouds in affecting the sub-seasonal/intra-seasonal variability of sea surface temperature (SST) and atmospheric convection in the equatorial and south-eastern tropical Indian Ocean (SETIO) during monsoonbreak transitions. A characteristic feature of the monsoon-break evolution is the appearance of suppressed convection over the SETIO region nearly 7-10 days prior to the commencement of a break spell over India. It is seen from the present analysis that the lack of cloud cover over the SETIO during the 'pre-break' phase leads to significant warming of the tropical Indian Ocean due to strong solar insolation at the surface. During the 'pre-break' phase, the net cloud-radiative forcing (NETCRF) at the surface is found to be typically around −30 Wm −2 and the mean SST in the SETIO is about 29.3°C. Following the transition to a monsoon-break phase, the cloud amount increases by about 25% over the SETIO region in association with intensified convection. The NETCRF at the surface over the SETIO averaged during the 'break' phase is found to be about −60 Wm −2 (i.e. a change of about −30 Wm −2 from the 'pre-break' phase). Consistent with the above change in the NETCRF, the SST in the SETIO shows a cooling of about 0.7°C, although the mean SSTs during the 'break' phase remain as high as 28.6°C. On the basis of the findings from this study, it is suggested that the SST warming during the 'pre-break' phase plays a key role in maintaining high SST and allows sustained convection to occur over the SETIO during prolonged monsoon breaks.

show abstract

BOBMEX: The Bay of Bengal Monsoon Experiment

Cited by 207 publications

References 35 publications

A daytime climatological distribution of high opaque ice cloud classes over the Indian summer monsoon region observed from 25-year AVHRR data

A daytime climatological distribution of high opaque ice cloud classes over the Indian summer monsoon region observed from 25-year AVHRR data

The Variability of the Asian Summer Monsoon

Cloud‐radiative impacts on the tropical Indian Ocean associated with the evolution of ‘monsoon breaks’

Contact Info

Product

Resources

About