Abstract:
Characteristics of the storm top altitude including its diurnal variations for the convective and stratiform precipitation and its relationship with surface rain rate in summer Asia are investigated based on measurements of the TRMM Precipitation Radar in the latest ten years from 1998 to 2007. The results indicate that more than 70% of convective storm top ranges from 8 to 12 km and from 5 to 10 km over the Tibetan Plateau and the eastern plain of the mainland, respectively. In other regions, the convective storm top is between 5 and 9 km. Generally, the mean altitude of convective storm top is higher over land than that over ocean. For stratiform precipitation, most of its storm top altitude varies from 5 to 8 km no matter over land or over ocean. Furthermore, the results also show a small percentage of shallow convective precipitation occurring in summer Asia but more than 40% of deep convective precipitation appearing in the eastern plain of the mainland, Southwest China, and the area from the western Indian subcontinent to the eastern Iran Plateau. The statistics shows that the storm top for weak convective precipitation has the mean altitude of about 7-8 km while that for weak stratiform precipitation has mostly the mean altitude less than 7.5 km over both land and ocean. On the other hand, about 90% of the heavy convective precipitation tops over land are higher than 9 km while the most heavy stratiform precipitation tops are less than 8.5 km. Additionally, the mean altitudes of both the convective and stratiform storm top in summer Asia increase with the increment of mean surface rain rate, which fits the approached curve of quadratic function. The analyses also show that the distributions of the diurnal peak for the frequency, intensity and storm top of both convective and stratiform precipitation suggest a consistent variation trend in summer Asia but with quite stronger diurnal fluctuation over land than over ocean.