Asymmetry of Cloud Vertical Structures and Associated Radiative Effects in Typhoon over the Northwest Pacific Based on CloudSat Tropical Cyclone Dataset

Abstract

The clouds’ macro-, microphysical vertical structures and radiative effects in 4 shear-relative quadrants of typhoon over the northwest Pacific during development, maturity and extinction stages are studied based on CloudSat Tropical Cyclone dataset and China Meteorological Administration tropical cyclone dataset from 2nd June 2006 to 31th December 2015. The typhoon cloud is in an asymmetric “mushroom” shape, with the downshear quadrants (in particular of the downshear left quadrant (DL)) have denser clouds than the upshear quadrants. Cloud ice water content mainly distributes near typhoon center with wide vertical range (6–17 km). A large number of ice particles with small sizes are gathering in high levels, while small amount of ice particles with large sizes are gathering in low levels. As typhoon matures, the number concentration and size of cloud ice particles in inner ring increases, especially in the DL quadrant; while in the upshear left (UL) quadrant, a larger amount of ice particles with bigger sizes are transport to high levels (above 16 km) by deeper convection near storm center. The shortwave (longwave) cloud radiative effects (CRE) is mainly heating (cooling) upper layer atmosphere between 10 km and 17 km (between 14 km and 17 km), and the net CRE on atmosphere is heating almost at any levels in typhoon. The strongest heating of shortwave CRE and net CRE, as well as the strongest cooling of longwave CRE are in the DL quadrant at development stage and in the UL quadrant at maturity stage in inner core of storms. The existences of typhoon clouds mainly decrease solar radiation penetrating to the earth surface and increase longwave radiation absorbed by the whole atmosphere in typhoon’s inner core, and they are generally stronger in downshear (especially in DL) quadrants, except the maturity stage when the UL quadrant performs the strongest shortwave CRE on the surface and longwave CRE on the atmosphere in typhoon’s inner core.