摘要
Climatic characteristics of convective and stratiform precipitation over the Tropical and Subtropical areas are investigated based on the measurements of Tropical Rainfall Measuring Mission's(TRMM) Precipitation Radar(PR) from 1998 to 2007.Results indicate that convective precipitation are distributed mainly over the Intertropical Convergence Zone(ITCZ),the South Pacific Convergence Zone(SPCZ),the Asian Monsoon Region,regions between the South America and the Mid-America,and the Tropical Africa where the frequencies lie between 1% and 2%.But in four seasons,total area fractions of convective precipitation frequencies less than 1% all exceed 85%.The frequencies of stratiform precipitation are much higher than those of convective precipitation,and total area fractions of stratiform precipitation frequencies >1% are over 55% during four seasons.However,frequencies of the two rain types show not only remarkable regionality,but also distinct seasonal variations.Conditional rain rates of convective precipitation range from 6 to 14 mm/h whereas those of stratiform precipitation are smaller than 4 mm/h.Meanwhile,rain tops of convective precipitation are higher than those of stratiform precipitation.The mean profiles of the two rain types show significant latitudinal dependency.And the seasonal variations of precipitation profiles are displayed mainly in the variations of rain tops.The frequencies and conditional rain rates of both rain types over ocean are higher than those over land,but rain tops are just the opposite.Moreover,the seasonal variations of both rain types over ocean are weaker than those over land because of the different stable states of underlying surfaces.
Climatic characteristics of convective and stratiform precipitation over the Tropical and Subtropical areas are investigated based on the measurements of Tropical Rainfall Measuring Mission＇s （TRMM） Precipitation Radar （PR） from 1998 to 2007. Results indicate that convective precipitation are distributed mainly over the Intertropical Convergence Zone （ITCZ）, the South Pacific Convergence Zone （SPCZ）, the Asian Monsoon Region, regions between the South America and the Mid-America, and the Tropical Africa where the frequencies lie between 1% and 2%. But in four seasons, total area fractions of convective pre- cipitation frequencies less than 1% all exceed 85%. The frequencies of stratiform precipitation are much higher than those of convective precipitation, and total area fractions of stratiform precipitation frequencies 〉1% are over 55% during four seasons. However, frequencies of the two rain types show not only remarkable regionality, but also distinct seasonal variations. Condi- tional rain rates of convective precipitation range from 6 to 14 mm/h whereas those of stratiform precipitation are smaller than 4 mm/h. Meanwhile, rain tops of convective precipitation are higher than those of stratiform precipitation. The mean profiles of the two rain types show significant latitudinal dependency. And the seasonal variations of precipitation profiles are dis- played mainly in the variations of rain tops. The frequencies and conditional rain rates of both rain types over ocean are higher than those over land, but rain tops are just the opposite. Moreover, the seasonal variations of both rain types over ocean are weaker than those over land because of the different stable states of underlying surfaces.
基金
supported by Major State Basic Research Development Program(Grant No.2010CB428601)
Knowledge Innovation Project of Chinese Academy of Sciences(Grant Nos.KZCX2-YW-Q11-04 and KJCX2-YW-N25)
Special Funds for Public Welfare of China(Grant Nos.GYHY200906002,GYHY200706032)
Science and Technology Special Basic Research of the Ministry of Science and Technology(Grant No.2007FY110700)
Key Program of the National Natural Science Foundation of China(Grant No.40730950)
National Distinguish Young Scientists Foundation(Grant No.40805008)
