Precipitation Climatology over the Gandaki River Basin in Nepal

1Jeeban Panthi, 1Piyush Dahal, 2Ramchandra Karki 1The Small Earth Nepal, 2Dept of Hydrology and Meteorology

Data used

Source Format Duration

DHM ground observation

Point 1981-2012

APHRODITE (interpolated)

Grid (0.05°) Grid (0.25°)

1961-2004 1961-2007

Precipitation stations from different agro-ecological zones of the basin

Agro-ecological

Zones

Station

Index

Latitude Longitude Elevation Location District

Trans-Himalaya

(>2500m)

610 29.05 83.88 3465 Ghami Mustang

816 28.55 84.23 2680 Chame Manang

Mountain

(>2500m)

806 28.4 84.37 3650 Larke

Samdo

Gorkha

616 28.36 83.13 2530 Gurja

Khani

Myagdi

Hill

(500m-2500m)

814 28.18 83.48 1740 Lumle Kaski

1057 28.01 85.07 1240 Pansayak

hola

Nuwakot

808 27.93 84.42 965 Bandipur Tanahun

Lowland (Terai)

(<500m)

903 27.35 84.32 270 Jhawani Chitwan

920 27.55 84.82 274 Manahar

i

Makwanpur

Precipitation stations from different agro-ecological zones of the basin

APHRODITE Validation (0.05°)

R² = 0.9221

0

50

100

150

200

250

0 100 200 300

R² = 0.9625

0

500

1000

1500

2000

2500

0 1000 2000 3000

R² = 0.9853

0

300

600

900

1200

1500

0 300 600 900 1200 1500

R² = 0.8276

0.0

200.0

400.0

600.0

800.0

1000.0

0.0 200.0 400.0 600.0 800.0 1000.0

Trans-Himalaya Mountain

Hill Terai

APHRODITE Validation (0.25°)

R² = 0.6913

0

50

100

150

200

250

0 100 200 300

R² = 0.9743

0

500

1000

1500

2000

2500

0.0 1000.0 2000.0 3000.0

R² = 0.9321

0.0

300.0

600.0

900.0

1200.0

1500.0

0.0 500.0 1000.0 1500.0

R² = 0.8882

0.0

200.0

400.0

600.0

800.0

1000.0

0 200 400 600 800 1000

Trans-Himalaya Mountain

Hill Terai

Monthly variation of precipitation

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

900.0

1000.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mo

nth

ly p

reci

pit

atio

n (

mm

)

Terai Hill Mountain Trans-Himalaya

Precipitation distribution - spatial

Annual Monsoon

Post monsoon Winter Pre-monsoon

Annual Change in Precipitation (mm)

Agro-ecological

zone Winter

Pre-

monsoon Monsoon Post-monsoon Annual

Trans-Himalaya -0.619 -1.022 1.898 -0.927* -1.654

Mountain -4.717*** -4.675** 2.586 -0.713 -6.293

Hill -0.425+ -0.218 3.233 -0.128 2.745

Terai -0.580 0.908 0.168 -0.435 -0.362

Average basin -1.458** -1.987* 0.419 -0.619 -4.267

Significant at: *** -> 0.001, ** -> 0.01, * -> 0.05, + -> 0.1

Methodology: Sen’s slope and MK test

Precipitation Anomaly

Trend of Rainy Days

y = -0.133x + 281.16

y = 0.3473x - 587.4

y = 0.0645x - 23.471

y = -0.202x + 462.17

0

20

40

60

80

100

120

140

1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011

Nu

mb

er

of

rain

y d

ays

Number of Rainy Days around GRB (>2.5mm in a day)

Trans Himalaya Mountain Hill Terai

Monsoon timing

y = -0.0864x + 41975

y = 0.3461x + 41218

y = 0.4325x - 756.97

50

60

70

80

90

100

110

120

130

140

150

21-May

10-Jun

30-Jun

20-Jul

09-Aug

29-Aug

18-Sep

08-Oct

28-Oct

1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010

Mo

nso

on

du

rati

on

(D

ays)

Monsoon onset Monsoon withdrawl Monsoon duration

Livelihood vulnerability assessment

0.00

0.10

0.20

0.30

0.40

0.50

Socio-demogaphicprofile

Livelihood strategies

Social network

Health

Food

Water

Natural disaster

Climate variability

Dhading Syangja Kapilvastu

Conclusion

• Dry seasons and regions are getting dryer

• Precipitation is decreasing in recent decades

• Rainy days are decreasing

• Monsoon withdrawal is getting delayed

Landuse and livestock distribution

Landuse in the Gandaki river basin (GRB)

Livestock distribution in the GRB

Thank you