Contribution of clouds to cold air masses found above tropical cyclones

What is it about?

Tropical cyclones (regionally: hurricanes, typhoons, cyclones) exhibit cold air masses near their tropopause (~17 km above sea level); cold air masses which we affectionately refer to as TLC (tropopause layer cooling). Several mechanisms have been proposed to explain TLC, and this study explores the possible effect of clouds. Specifically, this study explores the radiative impact of clouds, that is, the way clouds interact with electromagnetic radiation such as visible light and infrared light (felt by humans as heat). This is done using space-borne lasers and radars. We find that the way clouds interact with electromagnetic radiation may only produce a small amount of TLC, suggesting that other mechanisms must produce the rest of TLC.

Featured Image

Why is it important?

Upper-level (15--20 km altitude) processes in tropical cyclones have historically been less studied due to a lack of reliable observations, but also to the general ground-up approach of the scientific community. While upper-level processes do not drive tropical cyclones, they may modulate their structure, intensity, and frequency of occurrence. This study aims at improving our understanding of these upper-level processes, specifically, the mechanisms behind an upper-level cooling that may modulate tropical cyclone intensity.