Moisture Regime Associated with Flow Dynamics over Sub-Himalaya during Different Phases of Summer Monsoon

  • L. P. Devkota Central Department of Hydrology and Meteorology Tribhuvan University Kirtipur; Kathmandu


The break and active events of the southwest Indian monsoon over Nepal were determined through the analysis with Hovemoller diagram of the sea level pressure. Structure of Indian summer monsoon, fields of mass transport potential and precipitation minus evaporation were diagnosed for these two cases. Generally the mass transport at lower isentropic surface was from the oceanic heat sink regions of the South Indian Ocean, Tropical East Pacific and South Atlantic towards the continental heat source regions of South and Southeast Asia. The strongest divergent mass transport was associated with the southwest Indian monsoon and was observed over the Arabian Sea. At the upper isentropic layer, the larger domain of the South Asia was occupied by relatively strong positive absolute vorticity during active Indian monsoon than break. The most notable moisture source was observed over the Southwest Arabian Sea. This source was mainly associated with the high evaporation occurring within the Somali jet