25-years of ISCCP organized deep convection from tropical weather states and cold clouds from GridSat

Various satellite observations have been used to evaluate tropical deep convective (DC) activity. It has been suggested that the ISSCP tropical “Weather State 1” (WS1) better lends itself to the study of DC activity compared to other DC proxies since it depends on the full range of DC cloud optical properties and does not depend on preimposed cloud property thresholds. The present study tests this hypothesis by evaluating climatological patterns from 25-years of GridSat 11 μm cloud brightness temperatures ≤ 235 K (GS235) and compares this data with WS1 to examine similarities between the two datasets for tropical (15S–15N) land and ocean regions. For the Indian (45–105E), Western Pacific (105–150E), Central Pacific (150–200E), and Eastern Pacific (200–280E) oceans, correlations between WS1 and GS235 normalized monthly frequency anomalies are high at 0.90, 0.92, 0.86, and 0.93. Trends are evaluated to explore the statistical uncertainty of DC activity associated with each dataset particularly in support of the so-called 11th climate monitoring principle. Power spectrum analysis is also performed as it relates to the Madden-Julian Oscillation in the Indo-Pacific region to further explore GS235 and WS1 dynamical influences and the prevalence of extreme MJO events.