AWS, 雨量計の設置場所
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Transcript AWS, 雨量計の設置場所
P177
バングラデシュにおける
プレモンスーン期およびモンスーン期の
降水の特徴
寺尾
村田
林
徹(大阪学院大学情報学部)
文絵(地球環境学研究所)
泰一(京都大学防災研究所)
Introduction
Bangladesh is one of the
heaviest rainfall areas.
Meso-scale characteristics
Diurnal variations. Midnightearly morning peak is found
in northeastern part of the
country (Ohsawa et al.
2001). Mechanism unknown.
Pre-monsoon meso-scale
disturbances.
Observation plan
Instruments with higher
temporal resolutions.
AWS and raingauges
AWS at Dhaka
Automatic raingauges: 6
Almost one year obs.
Some results is shown today.
Pre-monsoon rainfall
-> A
Diurnal variations
-> B
AWS obs. case study.
-> C
Locations of AWS and raingauges
AWS
Dhaka(ICDDR,B)
Data are browsable
from everywhere in
the world through
the network.
Raingauges
6-locations:□
0.5mm tipping
buckets
Raingauges are
installed in BMD
observatories
Dinajpur
Mymensingh
Rajshahi
INDIA
(Meghalaya)
Sylhet
INDIA
Dhaka
(Tripura)
INDIA
(West Bengal)
Chittagong
BAY OF
BENGAL
Obs. time table of AWS and RGs.
AWS
Dhaka
2004/03/03
2005/07/18
RGs
Chittagong
Dhaka
Dinajpur
Mymensingh
Rajshahi
Sylhet
2004/07/29
2004/08/24
2004/08/01
2004/08/11
2004/08/05
2005/02/28
2005/03/04
2005/03/01
2005/03/03
2005/03/01
2005/07/22
2005/07/18
2005/07/14
2005/07/17
2005/07/15
2005/07/20
30 Jun.- no data
Seasonal march in Bangladesh
Max. temp
Sunshine
1980-1999/Dhaka
Rain inc.: Apr->May
Sunshine dec.:May->Jun.
Pre-monsoon rainfall
begins in May
Rainfall
Def. of pre- and mature monsoon
Pre-monsoon
Jan.->May
Dinajpur
Mature monsoon
Jul.->Dec.
Sylhet
Pre-monsoon rain.
Northeast>West
Mymensingh
Rajshahi
Dhaka
Chittagong
A
Pre-monsoon and mature monsoon [1]
Rainfall intensity
Hourly rainfall
Complicated.
Pre-monsoon and mature monsoon [1]
Rainfall intensity
10-min rainfall
Short intense
downpower
Pre>mature
monsoon.
>5mm/10mi
nexceeds
50% of total
rain.
Intense
Intense
Intense
Pre-monsoon and mature monsoon [1]
Rainfall intensity
1-min rainfall
Almost same
results as 10min rainfall.
Intense
Intense
Intense
Pre-monsoon and mature monsoon [1]
Rainfall intensity
Summary
Intense rain in
pre-monsoon
>5mm/10min
exceeds 50%
of total rain
>1mm/min
exceeds 50%
of total rain
Dinajpur
Mymensingh
Rajshahi
INDIA
(Meghalaya)
Sylhet
INDIA
Dhaka
(Tripura)
INDIA
(West Bengal)
Chittagong
BAY OF
BENGAL
B
Pre-monsoon and mature monsoon [2]
Diurnal variations
Premonsoon
diurnal var.
Evident
peak
Somewhat
differs from
mature
monsoon.
UTC(BST-6h)
Pre-monsoon and mature monsoon [2]
Diurnal variations
Summary I
Diurnal variations
in pre-monsoon
Central part:
afternoon peak.
Northern part:
Midnight-early
morning peak.
Steep peak is
founr mainly in
western part.
Pre-monsoon
Dinajpur
Mymensingh
Rajshahi
INDIA
(Meghalaya)
Sylhet
INDIA
Dhaka
(Tripura)
INDIA
(West Bengal)
Chittagong
BAY OF
BENGAL
Pre-monsoon and mature monsoon [2]
Diurnal variations
Summary II
mature monsoon
Diurnal variations
in mature
monsoon
Mymensingh is
also in afternoon
peak area.
Dinajpur
Mymensingh
Rajshahi
INDIA
(Meghalaya)
Sylhet
INDIA
Dhaka
(Tripura)
INDIA
(West Bengal)
Chittagong
BAY OF
BENGAL
C
Case study of pre-monsoon storm.
AWS
まとめ
バングラデシュ各地にAWSと
雨量計を設置した
AWS×1(2004年3月~)
雨量計×6(2004年8月~)
プレモンスーン期とモンスーン
期の違いを重視して解析した
プレモンスーン期はモンスーン
期に比べて短時間強雨が多い
プレモンスーン期にも降水の
日変化が見られる
データを増や
して確認する
必要がある
Chittagongは例外
5mm/10min, 1mm/min の強
雨が降水量の50%を超える
Mymensinghも夜間ピーク
明確なピークが見られる
AWSや雨量計を用いてメソ擾
乱を観測することができた
構造の解明に有効