• atmospheric water balance;
  • interannual variability;
  • Indian Ocean Dipole


In this study we have investigated atmospheric water balance over South Peninsular India and Sri Lanka during the months October to December (OND) using computed moisture convergence (C) and residual evaporation (E) from National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data and Global Precipitation and Climatology Project (GPCP) precipitation data. The interannual signatures of OND precipitation, moisture convergence and evaporation over the South Peninsular India and Sri Lanka have been captured. The spatial and temporal characteristics of the hydrological cycle and the contribution of evaporation (E) and convergence (C) to precipitation (P) are discussed in detail. Over the South Peninsular India and Sri Lanka, evaporation (E) dominates during the entire monsoon months (OND). However, the interannual variability of precipitation over the domain is not necessarily influenced by the same criteria which influences the mean seasonal precipitation. The moisture from the Indian Ocean (IO) sector also modulates the precipitation over this region on a year-to-year basis. It has been noted that the positive northeast monsoon rainfall (NEMR) is associated with El Nino coupled with IO dipole, but negative NEMR is weakly associated only with La Nina over South Peninsular India and Sri Lanka. There also exists a significant land-atmospheric interaction over the region in modulating the hydrological cycle on a year-to-year basis. Copyright © 2008 Royal Meteorological Society