Estimation of radiative effects of deep convective cloud cores using SAPHIR & ScaRaB onboard Megha-Tropiques satellite

Abstract

The instantaneous radiative effects of cores of deep convective clouds (CDCCs) linked to well-organised long-lived convective system over the tropics is estimated for the first time using Megha-Tropiques (MT) during 2012‐–2018. Sondeur Atmosphérique du Profil d'Humidité Intertropicale par Radiométrie (SAPHIR) and Scanner for Radiation Budget (ScaRaB) onboard MT provides collocated and concurrent observations of CDCCs and associated fluxes on top-of-the-atmosphere (TOA), respectively. The vertical extent of CDCCs is estimated using collocated and concurrent CloudSat and SAPHIR observations. The CDCCs have a vertical extent above 10 km and their frequency of occurrence peaks between 13 and 16 km. CDCCs exert significant longwave radiative effect over the tropical Africa, northwest Pacific Ocean and northern Bay of Bengal during June–August with values ranging between 160 Wm⁻² and 180 Wm⁻². Over the convective core regions, the magnitude of day time (08–17 Local time) shortwave radiative effect of CDCCs (SWREC) ranges from −250 Wm⁻² to −650 Wm⁻² with peak values over northern Bay of Bengal and west Pacific Ocean during June to August. The SWREC aligns with both the incoming solar radiation and the occurrence frequency of CDCCs (OFCs), while the diurnal cycle of LWREC follows the OFCs, with a more pronounced variation over land. A diurnal amplitude of 30–40 Wm⁻² is observed in LWREC over the ocean, $\sim$60 Wm⁻² over land. The CDCCs exert a net radiative cooling ranging from −200 Wm⁻² to −550 Wm⁻² during daytime and a net warming during night time that reaches as high as 160 Wm⁻².