Abstracts for the 5th International GAME Conf.
3-5 October 2001
Aichi Trade Center
Nagoya Japan
Relationship between wind and precipitation observed with a UHF radar, GPS rawinsondes and surface meteorological instruments at Kototabang, West Sumatera during September-October 1998
Eddy Kelana (10), Fumie Murata (1), Shin-Ya Ogino (1), Manabu. D. Yamanaka (3), Masatomo Fujiwara (4), Hiroyuki Hashiguchi (5), Shoichiro Fukao (5), Mahally Kudsy (7), Tien Sribimawati (7), Sri Woro B. Harijono (7)
(10) BMG, Indonesia
(1) Kobe Univ., Japan
(3) Kobe Univ. FORSGC, Japan
(4) Hokkaido Univ., Japan
(5) Kyoto Univ., Japan
(7) BPPT, Indonesia
Simultaneous observations with a UHF-band boundary layer radar
(hereafter referred as BLR), GPS rawinsondes and
a tipping-bucket-type rain gauge
were conducted at Kototabang (0.20 deg. S, 100.32 deg. E, 865 m MSL),
which is located on the mountainous region
near Bukittinggi, West Sumatera Province,
during 27 September--7 October 1998 (rainy season).
Low-level (1--3 km) westerly wind stronger than 10 m/s was observed,
and
precipitation tended to occur when the low-level
westerly wind became weak (2--5 October).
Similar relationship was observed for two months
(1 September--31 October 1998) during which only BLR and surface
meteorological instruments were operated at Kototabang.
NCEP/NCAR objective analysis and GMS TBB data
showed that the low-level (850 hPa) wind field and cloud distribution were
both completely different between the Indonesian Archipelago
(the east of Kototabang) and the eastern Indian Ocean including the Bay
of Bengal (the west of Kototabang) during the analysis period.
Two large-scale cloud disturbances existed along
the equator in the western side (80\degr --100\degr E),
but precipitation at Kototabang
did not correspond to these cloud disturbances.
Thus, it is suggested that
the mountain range of Sumatera prevented
the large-scale cloud disturbances
over the Indian Ocean
from having influences on the atmosphere over the Indonesian Archipelago,
and
the precipitation by local-scale cloud systems prevailed at Kototabang.
The diurnally oscillating local circulations are considered as
the major cause of the local-scale cloud systems,
which may be masked when the westerly wind is strong.
This may lead to a mechanism to suppress equatorial disturbances over
the ocean due to local disturbances generated independently by the topography.
Submittal Information
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Graduate School of Science and Technology, Kobe University | |
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1-1 Rokkodai-cho Kobe, Hyogo 657-8501 | |
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murata@shizen.sci.kobe-u.ac.jp | |