Role of Satellite based precipitation informationin the mountainous region
Madan L. ShresthaNepal Academy of Science and Technology
The 7th Global Precipitation Measurement International Planning Workshop
Bellesalle Kudan, Tokyo, Japan5-7 December
Major Weather Systems
• Northern limit Of the Tropics. • Southern lap of the Himalayas
• Mountainous country
• Topographically complex
• Affected by monsoon In summer and western disturbances in winter
26º 22' N - 30º 27' N Lat. 80º 4'E - 88º 12'E Long.
0 200 400100 Kilometers
India
China
IranPakistan
Myanmar
Thailand
Afghanistan
Laos
Nepal
Cambodia
Bangladesh
Oman
Bhutan
Sri Lanka
Turkmenistan
Malaysia
0 130 26065 Kilometers
Summer Monsoon
Western disturbances
Physiography
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Meteorological Station Network
GOVERNMENT OF NEPAL
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Ministry of Environment, Science & Technology
Department of Hydrology & Meteorology
Physiographic Regions
High Himalaya
High Mountain
Middle Mountain
Siwalik
Terai
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Ministry of Environment, Science & Technology
Department of Hydrology & Meteorology
Physiographic Regions
High Himalaya
High Mountain
Middle Mountain
Siwalik
Terai
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Ministry of Environment, Science & Technology
Department of Hydrology & Meteorology
Physiographic Regions
High Himalaya
High Mountain
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") Precipitation (177)
Ministry of Environment, Science & Technology
Department of Hydrology & Meteorology
Physiographic Regions
High Himalaya
High Mountain
Middle Mountain
Siwalik
Terai
The Diversity
TRANS HIMALAYAHIGH HIMALAYA
MIDLANDS TERAI
Meteorological Stations in Nepal
• Rainfall Station 337• Climate Station 67• Agrometeorological Station 22• Synoptic Station 9• Aerosynoptic Station 6
Total 442
Automatic Weather Station 18
High rainfall pocket areas- Middle mountains
Extreme rainfall areas Churia and Terai regions
Rainfall distribution
80 81 82 83 84 85 86 87 88
27
28
29
30
Monsoon rainfall (mm)
0 500 1000 1500 2000 2500 3000 3500 4000
80 81 82 83 84 85 86 87 88
Longitude (°E)
27
28
29
30
Lat
itu
de
(°N
)
25 50 100 150 200 250 300 350 400 450 500
Highest 24-hr Precipitation [mm]
80 81 82 83 84 85 86 87 88
Longitude (°E)
27
28
29
30
Lat
itu
de
(°N
)
0 5 15 20 30 60
Aridity Index (De Martonne)
Very dry Dry Sem iarid Subhum id H um id Veryhum id
0
100
200
300
400
500
600
Jan
Feb Mar
Apr
May Jun
Jul
Aug
Sep Oct
Nov
Dec
Month
P, P
ET
(m
m)
PETcorr Rainfall (P)
ANNAPURNA
PET > PTherefore these regions have a continual water deficit.
P > PETTherefore these regions have water excess throughout the year.
0
20
40
60
80
100
120
Jan
Feb Mar
Apr
May Jun
Jul
Aug
Sep Oct
Nov
Dec
Month
P, P
ET (
mm
)
PETcorr Rainfall (P)
Jomsom
Number of rainy days y = -0.0576x + 103.76
R2 = 0.0072
70
75
80
85
90
95
100
105
110
115
120
19
71
19
73
19
75
19
77
19
79
19
81
19
83
19
85
19
87
19
89
19
91
19
93
19
95
19
97
19
99
20
01
20
03
Year
Da
ys
Number of days with rain >= 100 mm
19771992, 35
1987, 106 19981975
1982
y = 0.5997x + 61.417
R2 = 0.0984
0
20
40
60
80
100
120
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
Year
Day
s
Extreme rainfall events
On 10 July 2007 heavy rain in the village of Khunde in Everest region produced a devastating
mud slide
27.75N,86.75E
27.5-28N86.5-87E
27-28N86.5-87.5E
27-29N86-88E
[mm
/h]
[mm
/h]
[mm
/h]
[mm
/h]
Precipitation in Khumbu regionJuly 1-31, 2007TRMM-3B42 data
(Yasunari, 2007 in prep.)
July 10-11Heavy rainfall
Tim
e of
day
[UT
C]
Day of year
Day – Time cross section of rainfall (3B42) at 27.75N, 86.75E inJuly in 2007
Heavy rainfallAnd flood
July 10
[mm/h]
Rainfall distribution2007 JUL9-13 at 6hourly
TRMM 3B42
Contour ・・・ topograghy
1000m,2500m,5000,
[LT = UTC + 6]
Heavy rain
↓この豪雨の前後を時空間的に細かく見ると ↓↓
Use of such satellite precipitation data
Remotely sensed precipitation data (ex. TRMM) is invaluable.
Validation of these data can be made with available in situ data.
Enhance the research capability and help to monitor the precipitation, both in the temporal as well as the spatial manner in a remote area, otherwise not possible.
Understand the interaction of monsoon circulation with the orography.
Constraint and Challenges
• Installation of stations in high mountains is difficult and demand more time and resources.
• Accessibility of TRMM data?• Any other such precipitation data available?• Need of the training on such available data sets• Resolution of the data• Downscaling of the data to apply in a complex
topography like the Himalayas.