14A.3 Is tropical cyclone intensity change related to the strength of its convective precipitation features? Using 9 years of TRMM data to find an answer

Thursday, 1 May 2008: 10:45 AM
Palms GF (Wyndham Orlando Resort)
Haiyan Jiang, University of Utah, Salt Lake City, UT; and E. Zipser

Over 100,000 Tropical Cyclone-Related Precipitation Features (TCPFs) are identified from the 9-yr University of Utah TRMM Precipitation Feature (PF) database. For each PF and TCPF observed by TRMM, a large number of statistics describing that event are saved, including a number of proxies for convective intensity. These TCPFs belong to a total of over 700 storms that reached tropical storm status or above during 1998-2006. Six basins are considered: Atlantic (ATL), east-central Pacific (ECPAC), northwest Pacific (NWPAC), north Indian Ocean (NIND), south Indian Ocean (SIND), and South Pacific (SPAC). TRMM-based convective intensity proxies as measured by TRMM PR, TMI, VIRS, and LIS are used to assess the relationship, if any, between intense convection and the intensity change of the tropical cyclone. Several authors hypothesize that vertical hot towers or convective bursts precede rapid intensification of the cyclone; the purpose of this research is to seek evidence for such an effect in the 9-year TRMM database.

To relate tropical cyclone intensity change to the properties of the convection, TCPFs that are related to intensifying or non-intensifying stages are categorized according to the best track maximum wind speed. Feature-based properties that are examined include maximum height of 40 dBZ echo, maximum height of 20 dBZ echo, minimum 85 GHz PCT, minimum 37 GHz PCT, total area of VIRS channel 4 (10.8 micron) TB less than 210 K, flash rate, etc. Statistics, such as cumulative density functions (CDFs), of these properties are compared for intensifying and non-intensifying TCPFs globally and regionally.

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