Extended Abstract (120K)12A.2
Evaluation of microwave imagery in the life cycle of tropical cyclones
Roger T. Edson, Anteon Corp., Univ. of Guam, Tamuning, Guam; and M. A. Lander
This paper examines the life cycle of tropical cyclones (TCs) as depicted in satellite-based microwave imagery. Comparisons and links are provided to the existing Dvorak intensification technique. TRMM and SSM/I imagery are examined over the past 4 tropical cyclone seasons in both the 85 GHz and 37 GHz frequencies. Five stages in a TC life cycle are identified and described. These include a genesis stage where low-level moistening and some cyclonic organization are seen in the weaker rain bands. An early intensification stage is then shown to include deeper convective banding, similar to patterns given in the Dvorak technique. This stage also includes the possible existence of a pre-eyewall feature which does not exist in the current intensification technique. Once intensification is established, changes in the character of deep convective rain processes are viewed with respect to signs of rapid intensification, eyewall cycle, and peaking tendency. During the initial weakening stage, comparisons are made between the differences in organization and vigor of the deep convection versus the lower rain bands, especially as seen in the 37GHz imagery and the low-level enhanced 85GHz imagery. The dissipation stage shows the TCs interaction with its environment and provides a guideline to the degree that higher boundary layer winds make it down to the surface. Each stage of development is compared and evaluated with respect to the corresponding Dvorak procedure and available aircraft data.
Session 12A, Tropical Cyclone Observations and Structure I (Parallel with Sessions 12B, 12C, and 12D)
Thursday, 2 May 2002, 8:30 AM-10:30 AM
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