Characteristics of Overshooting Convections over Asia Observed from TRMM Satellite

Friday, 19 December 2014
Tie Yuan and Xia Li, LZU Lanzhou University, Lanzhou, China
The spatial-temporal distribution and intensity of Overshooting Convections (OCs) over Asian have been investigated by using the multi-sensor data based on the Tropical Rainfall Measuring Mission (TRMM) satellite from 1998 to 2011, and the corresponding meteorological fields also have been analyzed from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data (i.e. ERA-Interim). The results show that OCs Only account for 2.6% of total cold cloud systems (cloud top IR brightness temperature less than 235 K) over Asian, and are mainly distributed to the south of 15°N, and nearly 50% of OCs occur in summer. The number of OCs over the ocean is higher than that over the land almost in every month, and the volumetric precipitation rate and area of OCs over the ocean are also higher than that over the land. It can be seen that OCs is obviously stronger than Non-Overshooting Convections (NOCs), and the OCs over the land are stronger than that over the ocean from lightning frequency, microwave brightness temperature and radar echo top. Strong OCs are mainly concentrated in the south slope of the Himalayas, eastern China and Southeast Asia, where the probability of OCs occurrence is also higher. It can be found that there are similar patterns of spatial distribution between OCs and thermodynamic and humidity parameters. The CAPE and specific humidity in the tropics are higher than that in the subtropics, which provides a favorable environmental condition for OCs occurrence. In summer, the same scenario also can be seen in the south slope of the Himalayas and the eastern-central China.