Premium
Modulation of monsoon intraseasonal oscillations in the recent warming period
Author(s) -
Sabeerali C. T.,
Rao Suryachandra A,
George Gibies,
Rao D. Nagarjuna,
Mahapatra S.,
Kulkarni A.,
Murtugudde Raghu
Publication year - 2014
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd021261
Subject(s) - climatology , monsoon , environmental science , equator , sea surface temperature , indian ocean , monsoon of south asia , madden–julian oscillation , coupled model intercomparison project , indian subcontinent , zonal and meridional , climate model , atmospheric sciences , climate change , oceanography , geology , latitude , geography , meteorology , ancient history , convection , geodesy , history
The Indian Ocean sea surface temperature (SST) during the boreal summer has shown a significant warming of 0.3°C in the recent decade (2001–2010) compared to a former decade (1979–1988), and it is most pronounced in the central tropical Indian Ocean. By using reanalysis and satellite‐derived data sets, we investigated how the monsoon intraseasonal oscillation (MISO) over the South Asian summer monsoon (ASM) region has been influenced by the recent warming in the Indian Ocean. It is found that the MISO variance has increased over the ASM region in the recent period compared with the earlier decade. It is also noted that the characteristic northward propagation of the MISO has slowed over 2001–2010, resembling more of a standing oscillation near the equator. Mechanisms implicated in the observed MISO changes are explored by conducting several model sensitivity experiments with an atmospheric general circulation model. The model experiments suggest that the mean SST increase over the Indian Ocean, and the associated changes in the air‐sea interaction, the increased mean moisture convergence, and changes in the large‐scale circulation are responsible for the changes in the characteristics of the MISO. The influence of the recent Indian Ocean warming on the MISO characteristics must be understood fully since they determine the seasonal amount of rainfall over the Indian subcontinent. An examination of future projections of the MISO using the MPI‐ESM‐LR model from the Coupled Model Intercomparison Project phase 5 archive also gives consistent result.