Ocean–atmosphere coupling over monsoon regions

Gadgil, Sulochana; Joseph, P. V.; Joshi, N. V.

doi:10.1038/312141a0

Cited by 402 publications

(249 citation statements)

References 12 publications

Supporting

Mentioning

237

Contrasting

Unclassified

Order By: Relevance

“…4b). This may be attributed to the fact that the tropical Indian Ocean is a highly convective region during the northern summer, as the mean SSTs are above the minimum convective threshold (26°C) and the southwesterly monsoon winds are conducive for enhanced moisture convergence 32 . Further warming of the Indian Ocean enhances the convection 23 , transferring surplus heat to the upper troposphere [33][34][35] .…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

et al. 2015

View full text Add to dashboard Cite

There are large uncertainties looming over the status and fate of the South Asian summer monsoon, with several studies debating whether the monsoon is weakening or strengthening in a changing climate. Our analysis using multiple observed datasets demonstrates a significant weakening trend in summer rainfall during 1901-2012 over the central-east and northern regions of India, along the Ganges-Brahmaputra-Meghna basins and the Himalayan foothills, where agriculture is still largely rain-fed. Earlier studies have suggested an increase in moisture availability and land-sea thermal gradient in the tropics due to anthropogenic warming, favouring an increase in tropical rainfall. Here we show that the land-sea thermal gradient over South Asia has been decreasing, due to rapid warming in the Indian Ocean and a relatively subdued warming over the subcontinent. Using long-term observations and coupled model experiments, we provide compelling evidence that the enhanced Indian Ocean warming potentially weakens the land-sea thermal contrast, dampens the summer monsoon Hadley circulation, and thereby reduces the rainfall over parts of South Asia.

show abstract

Section: Resultsmentioning

confidence: 99%

“…The Indian Ocean and monsoon exhibit a coupled relationship 32,42,43 , and it is also possible that a feedback from a weak monsoon accelerates the warming in the Indian Ocean 22 . Some studies have suggested a role for anthropogenic aerosols in weakening the monsoon circulation during the recent decades 40,[44][45][46][47][48] .…”

Section: Discussionmentioning

confidence: 99%

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Their study showed that SSTs are highest over BoB in May-June and lowest in December. Gadgil et al (1984); Graham and Barnett (1987); Fu et al, (1994), showed that convection over oceans primarily depends upon the SSTs. Thus the higher magnitude of FD over BoB compared with that over AS may be attributed to increase convection resulting due to higher SSTs.…”

Section: Temporal Variation Of Lightning Flash Density Over Land and mentioning

confidence: 99%

Land‐ocean contrasts in lightning activity over the Indian region

Kandalgaonkar

Kulkarni

Tinmaker

et al. 2009

Intl Journal of Climatology

View full text Add to dashboard Cite

Land-ocean contrasts in the lightning activity over Indian land and two surrounding oceanic regions viz. Arabian Sea and Bay of Bengal have been studied. Satellite-based lightning flash data for 5-year (1998-2002) period have been used. The study revealed that lightning activity over Bay of Bengal was three times higher than that over Arabian Sea and 9.3 times lower than that over land. The bimodal distribution is seen over Arabian Sea (peaks in April and November), and land (peaks in May and September). A unimodal distribution is observed over Bay of Bengal with peak in May. The maximum activity over Bay of Bengal occurs more at northern latitudes (28-30°N) compared with Arabian Sea (12-14°N). The land-ocean contrast is dominated by monsoon season. Comparison of lightning activity in the El Nino (2002) and La Nina year (1998)(1999)(2000)(2001) shows that the lightning activity is increased by nearly 18% over the land region and it maybe attributed to in the increase in surface air temperature during the warm phase of El Nino, land sea breeze circulations and difference in the continental and the oceanic convection.

show abstract

“…In fact, the atmospheric field corresponding to SST greater than 28°C during this period displays the lower OLR anomalies and vigorous convergence of surface winds that are shown in the paper by T. Toyoda et al (Possible roles of seasonal variation in the enhanced coupled waves associated with anomalous El Niño development, submitted to Deep Sea Research, Part I, 2008), both of which are indicative of enhanced convective activity. Thus, our representation of the magnitude and influence of air-sea interactions is likely to be inaccurate if it is based on anomalous SST data alone [Gadgil et al, 1984].…”

Section: El Niñ O and Southern Oscillationmentioning

confidence: 99%

Development of a four‐dimensional variational coupled data assimilation system for enhanced analysis and prediction of seasonal to interannual climate variations

et al. 2008

View full text Add to dashboard Cite

[1] A four-dimensional variational (4D-VAR) data assimilation system using a coupled ocean-atmosphere global model has been successfully developed with the aim of better defining the dynamical states of the global climate on seasonal to interannual scales. The application of this system to state estimations of climate processes during the 1996-1998 period shows, in particular, that the representations of structures associated with several key events in the tropical Pacific and Indian Ocean sector (such as the El Niño, the Indian Ocean dipole, and the Asian summer monsoon) are significantly improved. This fact suggests that our 4D-VAR coupled data assimilation (CDA) approach has the potential to correct the initial location of the model climate attractor on the basis of observational data. In addition, the coupling parameters that control the air-sea exchange fluxes of mass, momentum, and heat become well adjusted. Such an initialization using the 4D-VAR CDA approach allows us to make a roughly 1.5-year lead time prediction of the 1997-1998 El Niño event. These results demonstrate that our 4D-VAR CDA system has the ability to enhance forecast potential for seasonal to interannual phenomena.

show abstract

Ocean–atmosphere coupling over monsoon regions

Cited by 402 publications

References 12 publications

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient

Land‐ocean contrasts in lightning activity over the Indian region

Development of a four‐dimensional variational coupled data assimilation system for enhanced analysis and prediction of seasonal to interannual climate variations

Contact Info

Product

Resources

About