NAME =  Tomotsugu INOUE  
ORGANIZATION =  University of Tsukuba  
ADDRESS =  Tsukuba, Ibaraki 305-8572  
COUNTRY =  Japan  
PHONE =  +81-29-853-5692  
FAX =  +81-29-853-5692  
E-MAIL =  s0430629@ipe.tsukuba.ac.jp  
POSTER_ONLY =  no  
THEME =  T8  
DATE =  31-Jul-04-16:43:23  
ABSID = T8TI31Jul04164323 
TITLE = Features of Cloud Types over the Bay of Bengal Using Split Window Measurements and TRMM Satellite Data 
AUTHOR_1 = Tomotsugu INOUE 
INSTITUTION_1 = University of Tsukuba 
PRESENTER = AUTHOR_1 
AUTHOR_2 = Hiroaki UEDA 
INSTITUTION_2 = University of Tsukuba 
AUTHOR_3 = Toshiro INOUE 
INSTITUTION_3 = Meteorological Research Institute 
ABSTRACT = 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.