Spatio‐temporal variability in the stratiform/convective rainfall contribution to the summer monsoon rainfall in India

Abstract

Spatio‐temporal variability of contributions of stratiform and convective rainfall to Indian monsoon (June–September) rainfall have been investigated using hourly rainfall data of well distributed 126 stations in India for the period 1969–2015. The criteria used for identifying stratiform rainfall are hourly rainfall ≤5 mm and spatial homogeneity. The study showed that Indian monsoon rainfall exhibits two distinctive features, viz. stratiform component dominating over peninsular (southern) India and convective component dominating over northern India. The diurnal variation shows domination of convective activity in the afternoon hours over the northern parts of India. Intra‐seasonal variability in the stratiform rainfall is the lowest over the West Coast stations through‐out the season. While it shows low values during the onset (June) and withdrawal (September) phases of monsoon and higher values during July–August in Peninsular India. Inter‐annual variations in the convective rainfall are larger than that of stratiform rainfall all over the country. Trend analysis indicates that both stratiform and convective rainfall are decreasing over the central parts of the country and increasing significantly along West Coast and western parts of the country. During excess monsoon year, convective rainfall activity is more than in deficit monsoon year, in Central India. The results brought out in the study will be useful as a proxy for understanding the spatial and temporal variability of the latent heating fields over India in the monsoon season and validation of model simulations of clouds and rainfall types.

Hydraulic jump: The cause of heavy rainfall on the immediate lee side of the Western Ghats in the Maharashtra state of India

“…The heating associated with rainfall produces convective and stratiform bores from the centre of the heating. The large contribution of stratiform rainfall in distant lee side (DLS) of WG found by Deshpande and Kulkarni (2021) may have contributions from the convection over ILS of WG due to HJ. More modelling studies are required to associate the stratiform rainfall over DLS region and convection over the immediate lee side (ILS) of WG due to HJ.…”

“…Tropical rainfall is classified mainly into (a) convective and (b) stratiform. Microphysically, convective rainfall is characterized by strong cloud updrafts, high rain rates, and small area coverages, while stratiform rainfall are characterized by small cloud vertical velocities, low rainfall rates and widespread area coverages (Deshpande and Kulkarni, 2021; Morwal et al, 2016; 2017; Rickenbach and Rutledge, 1998). The cloud top heights are not very high.…”

“…Zhang and Smith (2018) showed that MCS develops on the crest and leeward sides of WG. Deshpande and Kulkarni (2021) showed that stratiform rainfall contributes about 78% to the total rainfall on the lee side of the WG. The above radar pictures of MAX(Z) indicate the existence of MCS on the leeward side and embedded deep convection in ILS region.…”

Changes in convective and stratiform precipitation over the Tibetan Plateau projected by global and regional climate models

“…Based on the classified the 6-hourly precipitation dataset, Rulfov a and Kyselý (2013) found the convective precipitation and shows stronger positive trends compared with the stratiform precipitation over the Czech Republic in recent decades. Deshpande and Kulkarni (2021) have reported that both convective and stratiform precipitation exhibit decreasing trend in the central India and increasing trend significantly in the western India.…”