Spatio-temporal variability of lightning and convective activity over South/South-East Asia with an emphasis during El Niño and La Niña

The present analysis investigates the spatio-temporal variability of the convective parameters and associated lightning flash rates during the period 1997–2013 including the El Nino and La Nina episode. It reveals that north-western and north-eastern part along the foothills of Himalayas as well as Indo-China peninsular region and South China Sea are much convective prone zones over the South/South-East Asia. The terrain/orography of the Himalayan range, the influence of cross-equatorial low-level jet and large-scale circulation during pre-monsoon and active phase of monsoon, the western Pacific Warm Pool with increased sea surface temperature as well as the solar-heating-originated local instability instigate the convective anomaly to propagate over the north-western and north eastern Indian sub-continent along with the Indo-China peninsula and South China Sea respectively. The land surfaces of the Indian sub-continent and the sea surface of South China Sea possesses significant correlation with lightning flash rates and convective parameters whereas the sea surface surrounding Indian sub-continent do not show such good correlations among them. Although, the occurrence of convective activities during the El Nino (La Nina) gets reduced (increased), the occurrence of lightning flashes gets enhanced (diminished) during this period which may be the direct consequence of warming atmosphere in relation to changing patterns of regional climate.