Stratiform and Convective Precipitation Properties of Tropical Cyclones in the Northwest Pacific

Abstract

AbstractThe properties of stratiform and the convective precipitation of tropical cyclones (TCs) over the northwest Pacific are examined using the Tropical Rainfall Measuring Mission data for 1998–2013. TCs are classified into inner core (IC), inner rainband (IB), and outer rainband (OB) regions, and the results show that TCs are dominated by stratiform precipitation, which accounts for more than 78% of the total raining area. The highest fraction of the stratiform raining area exists in the IB region and increases as the TC intensity increases (from 80% to 93%). Strong convective signatures generally occur in the IC region, less often in the IB region, and least often in the OB region. Stratiform precipitation in the IC region generally has comparable or even stronger ice scattering signatures and higher 20 dBZ radar echo heights than the convective precipitation in the IB and OB regions. Weak convection decreases significantly as the TC intensity increases, which leads to increased convective intensity. Stratiform (convective) precipitation accounts for 61% (39%) of the total TC volumetric rain and 25% (75%) of the total TC lightning flash, respectively. Moreover, stratiform precipitation's contribution to the total TC volumetric rain and lightning flash increases as the TC intensity increases, which indicates that stronger TCs are favorable for maintaining more stratiform precipitation. The stratiform and convective precipitation properties in different TC regions and intensities cooperatively change with the enhanced ascending branch in the IC region and the radial outflow at the upper levels of the secondary circulation.