NAME =  Masafumi Hirose  
ORGANIZATION =  Earth Observation Researchand application Center, Japan Aerospace Exploration Agency  
ADDRESS =  Office Tower 22F, Harumi Island Triton Square, 1-8-10, Harumi, Chuo-ku, Tokyo 104-6023 JAPAN  
COUNTRY =  JAPAN  
PHONE =  +81-3-6221-9158  
FAX =  +81-3-6221-9192  
E-MAIL =  hirose@eorc.jaxa.jp  
POSTER_ONLY =  no  
THEME =  T8  
DATE =  06-Aug-04-14:50:39  
ABSID = T8MH06Aug04145039 
TITLE = Spatial and diurnal variation of precipitation systems over Asia 
AUTHOR_1 = M. Hirose 
INSTITUTION_1 = Earth Observation Research and application Center, Japan Aerospace Exploration Agency 
PRESENTER = AUTHOR_1 
AUTHOR_2 = K. Nakamura 
INSTITUTION_2 = Hydrospheric Atmospheric Research Center, Nagoya University 
ABSTRACT =   

The spatial and diurnal variation of rainfall over Asia was 
investigated using the Tropical Rainfall Measuring 
Mission/Precipitation Radar (TRMM PR) data for four seasons
during 1998-2003. As the sampling errors were reduced for each
month, the fine-spatial distribution of rainfall amount and
scale-based precipitation systems became detectable.
The regional variation of the prevailing 
precipitation systems, having close relationship to the maximum 
hourly rainfall, was shown by examining the fine-spatial 
distribution of rainfall amount and scale-based precipitation 
systems. 

The number of the precipitation systems was highest in summer
over Asia affected by monsoon. Cumulus-scale systems occurred 
most frequently around early afternoon over most of land. On 
the south-facing slopes of the Himalayas, the daytime genesis 
of the small systems was outstanding. Over the Tibetan Plateau, 
the occurrence of the small systems was larger than other regions
such as inland India. On the other hand, meso-scale or synoptic-scale 
systems showed significant regional variation in the diurnal cycle. 
Their maximum occurrence appeared in the evening over near-flat 
landmasses. The wide-spread systems with severe rain pixels 
developed over the foothill of the Himalayas at late 
night-early morning. The systems were well separated from the 
daytime-convection. 
Over ocean, in addition to the morning signature, spatially 
inhomogeneous and systematic characteristics were shown over 
the offshore region, for example, around the Maritime Continent.

The large precipitation systems characterized the total number of 
rain pixels and total rainfall amount significantly. Time of the 
maximum rainfall for all systems corresponded with one for the 
large systems within 3 hours over most (86 %) of the region 
which made up of a majority of the large systems.