Wet and Dry Spells over Southeast Peninsular India

*Mohana S. Thota*

### **Abstract**

The southeast peninsular India contains, to name a few, several important cities crucial for trade and economic growth of the country, rice bowls, institutes for science and technology, space port, etc. Despite its importance, not many reports exist on rainfall and its variation on different temporal scales over this region during southwest monsoon, partly because the rainfall in this region is relatively less and it forms only a minor part of all India rainfall. Here, an attempt has been made to understand differences in thermal and dynamical characteristics and energetics of the atmosphere between wet and dry spells of the Indian summer monsoon over the southeast India by utilizing various observations and reanalysis products. Observations demonstrate that the difference in the thermal structure between wet and dry spells is significant only in the lower troposphere (< 2-3 km) with mean CAPE values are reaching as much as 1000 Jkg-1during wet spell. Vertical buoyancy profiles indicate the bi-modal distribution during dry spells with peaks in 700 and 500 hPa levels. The observed thermal features are not confined to Gadanki but seen over entire southeast peninsular India. Associated dynamical variations also exhibit obvious differences during wet and dry spell. The diurnal variation of winds exhibits difference in amplitude and phase are remarkably large during dry spell than in wet spell. Synthesis are all the measurements indicates that the thermal and dynamical differences observed in wet and dry spells are pronounced in the boundary layer.

**Keywords:** wet and dry spells, Monsoon, CAPE, Southeast peninsular India
