Abstracts for the 6th International GAME Conf.

3-5 December 2004

Kyoto Japan

Features of Cloud Types over the Bay of Bengal Using Split Window Measurements and TRMM Satellite Data

Tomotsugu INOUE (1), Hiroaki UEDA (1), Toshiro INOUE (3)

The Asian monsoon is characterized the enhanced convection which is composed of diurnal cycle as well as intraseasonal variation, besides the basic seasonal evolution. Although several studies have used Outgoing Logwave Radiation (OLR) and Black Body Temperature (TBB), these data sets are not necessarily represented deep convection area attended latent heating. Therefore, the main objective of the present study is to reveal spatiotemporal structures of cloud properties over the Bay of Bengal in summer derived from split window measurements. In this study, split window data from Advanced Very High Resolution Radiometer (AVHRR) on board NOAA-9 is utilized during the period 1986 to 1993. Optically thin clouds (cirrus type clouds) can be identified by inspection of the image constructed from the brightness temperature difference (BTD) between 11ƒÊm and 12ƒÊm (split window) data. Cloud type classification based on a threshold technique in the TBB-BTD diagram. In boreal summer, optically thick clouds (cumulonimbus type clouds) associated with deep convection appear principally over the eastern Bay of Bengal, while cirrus type clouds including anvil clouds are found over the whole Bay of Bengal. With respect to seasonal evolution, cirrus type clouds observed nearby the tropic abrupt northward expand in the monsoon onset. Its expanded cirrus type clouds reduce gradually after the monsoon season. Although this annual cycle is similar to that of OLR, cumulonimbus type clouds exhibit different variability from OLR. Finally, comparison of cloud type derive from split window measurements and Tropical Rain fall Measuring Mission (TRMM) Precipitation Radar (PR) data is conducted for convective activity area. Very good agreement is obtained for the distribution of cumulonimbus type clouds and large precipitation area over the Bay of Bengal.

Submittal Information

Name : Date :
    Tomotsugu INOUE
    31-Jul-04-16:43:23
Organization : Theme :
    University of Tsukuba
    Theme 8
Address : Presentation :
    Tsukuba, Ibaraki 305-8572
    Poster or oral
Country : Abstract ID :
    Japan
    T8TI31Jul04164323
Phone : Fax :
    +81-29-853-5692
    +81-29-853-5692
E-mail :
    s0430629@ipe.tsukuba.ac.jp