Variations of Energy Fluxes with ENSO, IOD and ISV of Indian Summer Monsoon Rainfall over the Indian Monsoon Region

Variations of energy fluxes with ENSO, IOD, and Intra-Seasonal Variability of Indian Summer Monsoon Rainfall (ISMR) over the Indian monsoon region are examined using ECMWF Era Interim reanalysis over a period of 1979-2013. The composite anomalies of radiative fluxes, viz. shortwave and longwave, latent, and sensible heat as well as precipitation and winds are analyzed for the years associated with El Nin & tilde;o, La Nin & tilde;a, positive and negative IOD phases, active, and break phases of ISMR with respect to the normal years. It is observed that, the lesser (more) precipitation over the region in the El Nin & tilde;o (La Nin & tilde;a) years is accompanied with enhanced (reduced) top of the atmosphere absorbed solar radiation and outgoing long wave radiation, as well as more (less) surface absorbed solar radiation, and surface sensible heat flux. During the positive IOD phase, enhanced convective activity and precipitation rainfall over the western Equatorial Indian Ocean, Arabian Sea, and west coast of India, with reduced rainfall over the eastern equatorial Indian ocean is accompanied with enhanced shortwave and long wave radiative fluxes over most parts of the Indian subcontinent. The conditions during the negative IOD phases are largely the opposite.

Automated summary

This study examines the variations of energy fluxes in the Indian monsoon region with ENSO, IOD, and Indian Summer Monsoon Rainfall (ISMR) from 1979 to 2013. The research shows that the precipitation in El Niño and La Niña years is inversely related to radiative and sensible heat fluxes. Furthermore, during the positive IOD phase, enhanced convective activity and precipitation over certain areas are accompanied by increased shortwave and longwave radiative fluxes, while the conditions are largely opposite during the negative IOD phases.