Study on the precipitation characteristics around the Himalayas using TRMM PR data
B. C. Bhatt (1), K. Nakamura (1)
(1) Hydrospheric Atmospheric Research Center, Nagoya University
Despite vastly increased interests in orographic precipitation, there is a co
nspicuous lack of observations on weather system (e.g., precipitation system) ar
ound the Himalayas. The use of Precipitation Radar (PR) onboard the Tropical Rai
nfall Measuring Mission (TRMM) satellite enables more direct precipitation estim
ates from space with homogenous coverage over this landscape. Moreover, the orbi
tal characteristics of TRMM allows to investigate the diurnal cycle of precipita
tion. A study presented here describes the climatological features of the diurna
l cycle of precipitation by utilizing fine resolution (0.05 deg. x 0.05 deg. gri
dded, hourly), near-surface rainfall data by PR around the Himalayas. In additio
n, the GEWEX Asian Monsoon Experiment (GAME) Reanalysis data are utilized to und
erstand atmospheric system. The central purpose of this study is to quantify pre
cipitation characteristics and associated mechanism. The analysis of precipitati
on characteristics presented here, is based on two rain rate thresholds. a) ligh
t rain rate (<=5 mm/hr), and b) moderate to heavy rain rate (> 5mm/hr). The mode
rate to heavy rain exhibits a relatively stronger diurnal cycle of precipitation
over the south-facing slopes of the Himalayas. There appears stronger diurnal c
ycle of precipitation with afternoon maximum during pre-monsoon (MAM) over the s
outh-facing slopes of the Himalayas. During the summer monsoon (JJA), precipitat
ion broadening and movement are noticed during midnight-early morning over the s
outh-facing slopes of the Himalayas. The climatological diagnostic studies from
GAME Reanalysis suggest a robust atmospheric system and provides an impression t
hat the diurnal variations in the atmospheric state is important in driving the
diurnal cycle of precipitation over the south-facing slopes of the Himalayas.
Submittal Information
Name :
Date :
Bhuwan Chandra Bhatt
28-Jul-04-17:22:19
Organization :
Theme :
Hydrospheric Atmospheric Research Center,Nagoya University