Tropical Tropopause Layer Cloud Properties from Spaceborne Active Observations

A significant part of clouds in the tropics appears over tropopause due to intense convections and situ condensation activity. These tropical layer (TTL) not only play an important role radiation budget tropics, but also water vapor other chemical material transport from troposphere stratosphere. This study quantifies analyzes properties TTL based on spaceborne active observations, which provide one most reliable sources information cloud vertical distributions. We use four years (2007–2010) observations joint Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) CloudSat consider all cloudy pixels with top height above as clouds. The occurrence frequency during nighttime is found be almost 13% can reach ~50–60% areas frequent convections. annual averages height, temperature, are 16.2 km, −80.7 °C, 16.6 respectively, average exceeds by approximately 500 m. More importantly, presence causes temperature ~3–4 °C colder than all-sky condition. It lifts heights ~160 m lowers ~84 daytime. From a type aspect, ~91% ~4% high altostratus, ~5% them associated (i.e., nimbostratus deep convective clouds). Approximately 30% single-layer clouds, multi-layer dominated those 2–3 separated layers.