Extreme Weather Events in Nepal: Trends and Projections

Nicky Shree Shrestha The Small Earth Nepal, Kathmandu University

Piyush Dahal The Small Earth Nepal

The Changing Climate

The Changing Climate

Devastating Natural Disasters

CLIMATOLOGICAL NON-CLIMATOLOGICAL

Distribution of Natural Disasters of Nepal

AVALANCHE COLD WAVE DROUGHT

FAMINE FLOOD FOREST FIRE

FROST HAIL STORM HEAT WAVE

LANDSLIDE RAINS SNOW STORM

STORM STRONG WIND THUNDERSTORM

Distribution of Major Climatological Disasters of Nepal

Looking at the past climate extremes

Looking at the past climate extremes

Looking at the past climate extremes

Looking at the past climate extremes

• Catchment area-32104 km2

• 12 districts (entire) and 7 (partial)

• Altitude-88 to 8148 masl

• Mean annual temperature-3.1 to 30.9OC.

• 16% area is covered by snow and ice and water bodies.

• Around 40% of the is covered by agricultural land.

A Case Study of the Gandaki River Basin, Nepal

• DHM, Government of Nepal.

• Temperature -5 stations

• Precipitation-20 stations

• Data sets from year 1981 to 2012 (above 30 years).

Data Sources

Station

No.

Altitude

(m) SU25 TXx TXn TNn TNx TX10P TX90P TN10P TN90P

601 2744 -0.225 -0.027 0 0.137 0.06 0.106 -0.003 -0.338 0.251

604 2566 0.003 -0.009 0.005 -0.034 -0.007 -0.175 0.321 0.046 -0.142

906 868 0.662 0.016 0.072 0.005 -0.057 -0.406 0.389 -0.031 -0.006

1007 474 0.324 0.020 0.041 0.102 0.03 -0.222 0.169 -0.565 0.393

1038 1085 0.416 -0.034 -0.051 0.012 0.044 -0.153 0.016 -0.381 0.155

Average 0.236 -0.007 0.013 0.044 0.014 -0.170 0.178 -0.254 0.130

No. of Stations with

positive trend 4 2 4 4 3 1 4 1 3

No. of Stations with

negative trend 1 3 1 1 2 4 1 4 2

Station

No.

Altitude

(m) WSDI CSDI DTR

TMAX

Mean

TMIN

Mean TR15 TR20

601 2744 0.184 -0.246 -0.054 -0.004 0.051 0.246 0

604 2566 0.525 -0.524 0.044 0.031 -0.018 -0.065 0

906 868 0.33 0.438 0.051 0.057 0.007 0.496 -0.077

1007 474 0.326 -0.97 -0.037 0.019 0.054 1.899 0

1038 1085 -0.2 -0.463 -0.017 0.015 0.033 0.449 0.994

Average 0.233 -0.353 -0.0026 0.0236 0.0254 0.605 0.1834

No. of Stations with

positive trend 4 1 2 4 4 4 4

No. of Stations with

negative trend 1 4 3 1 1 1 1

Temperature Indices

0

500

1000

1500

2000

2500

3000

-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6

Elev

atio

n (m

)

Percentage of days/year

Cool Nights

Warm Nights

0

500

1000

1500

2000

2500

3000

-0.6 -0.4 -0.2 0 0.2 0.4 0.6

Ele

vati

on

(m)

Percentage of days/year

Cool Days

Warm Days

Trend in cool and warm nights with elevation

Trend in cool and warm days with elevation

Temperature Indices

0

500

1000

1500

2000

2500

3000

-1.5 -1 -0.5 0 0.5 1

Elev

atio

n (m

)

Annual count (days)/year

CSDI

WSDI

0

500

1000

1500

2000

2500

3000

-0.4 -0.2 0 0.2 0.4 0.6 0.8

Ele

vati

on

(m

)

Annual count (days)/year

SU25

Trend in CSDI and WSDI with elevation

Trend in summer days (SU25) with elevation

Temperature Indices

Station

No. CDD CWD PRCPTOT R10 mm R20 mm R50 mm R95p R99p RX1day RX5day SDII

613 0.931 -0.116 0.504 0.06 -0.031 -0.069 -4.02 1.281 0.503 -0.44 -0.027

614 0.368 0.104 -5.013 -0.056 -0.168 -0.059 -3.595 0.397 0.041 0.041 -0.064

701 1.154 0.033 -15.815 -0.529 -0.329 -0.103 -1.662 3.311 0.808 -0.4 -0.101

704 1.718 -0.13 -0.211 -0.173 -0.014 0.049 4.525 1.467 -0.221 2.554 0.242

725 1.093 -0.047 -5.974 -0.262 -0.113 -0.016 1.121 1.495 0.546 -0.513 0.029

802 0.892 -0.232 -0.177 -0.08 0.087 -0.026 -0.727 -3.61 -0.849 -1.121 0.017

805 1.538 0.114 10.022 -0.086 0.01 0.137 13.435 6.341 1.292 2.189 0.045

807 1.245 -0.071 10.469 0.252 0.181 0.158 9.87 0.504 0.691 2.083 0.215

808 0.628 0.237 -3.71 -0.407 0.017 0.008 0.885 2.623 0.296 0.101 -0.051

810 1.29 0.083 -8.5 -0.1 -0.12 -0.095 -4.873 -2.769 -1.807 -3.241 -0.172

814 0.431 0.802 7.61 -0.038 0.032 0.079 11.601 5.859 -0.469 -1.343 0.112

815 0.941 0.066 -10.275 -0.006 -0.212 -0.14 -1.474 0.558 0.208 1.07 -0.096

824 0.594 -0.284 2.456 -0.079 0.22 0.085 3.365 -1.925 0.106 -0.198 0.074

903 1.373 -0.261 5.449 -0.249 0.025 0.093 10.357 4.743 1.596 2.142 0.069

904 1.749 -0.293 -3.698 -0.296 -0.079 0.063 5.292 1.258 0.292 2.446 0.075

906 0.588 -0.096 5.082 0.015 -0.054 0.076 10.458 4.273 1.203 3.471 0.109

920 1.222 -0.511 -5.821 -0.359 -0.047 0.066 3.191 -0.256 -0.721 -0.211 0.124

1007 2.808 0.351 -14.923 -0.25 -0.275 -0.147 -9.623 -0.855 -0.584 -1.106 -0.151

1038 0.45 -0.037 5.366 0.254 0.137 0.027 0.519 -2.744 -1.1 -0.168 0.017

1054 2.059 -0.821 -13.247 -0.562 -0.009 0.001 2.915 7.208 -0.317 -0.955 -0.014

Average 1.154 -0.056 -2.0203 -0.14755 -0.0371 0.00935 2.578 1.45795 0.0757 0.32005 0.0226

Stations

with

positive

trend 20 8 8 3 8 12 13 14 12 9 12

Stations

with

negative

trend 0 12 12 17 12 8 7 6 8 11 8

Precipitation Indices

Precipitation Indices

0

500

1000

1500

2000

2500

-6 -4 -2 0 2 4 6 8

Elev

atio

n (m

)

Trend (mm/year)

R99p

R99p

0

500

1000

1500

2000

2500

-0.8 -0.6 -0.4 -0.2 0 0.2 0.4

Elev

atio

n (m

)

Trend (mm/year)

R10 mm

R10

Trend in R99P (extremely wet days) with elevation

Trend in R10 (No. of heavy precipitation days) with elevation

Precipitation Indices

0

500

1000

1500

2000

2500

-20 -15 -10 -5 0 5 10 15

Ele

vati

on

(m

)

Trend (mm/year)

PRCPTOT

PRCPTOT

0

500

1000

1500

2000

2500

0 0.5 1 1.5 2 2.5 3

Elev

atio

n (m

)

Trend (mm/year)

CDD

CDD

Trend in CDD with elevation

Trend in PRCPTOT (wet day precipitation) with elevation

Precipitation Indices

Future projection of extremes events

Future (2041-2071) projection of change (%) in Consecutive dry days with baseline 1970-1999

Trend in CDD with elevation

Future projection of extremes events

Future (2041-2071) projection of change (%) in wet days index with baseline 1970-1999

Future projection of extremes events

Future (2041-2071) projection of change (%) in highest one day rainfall with baseline 1970-1999

Trend in CDD with elevation

Future projection of extremes events

Future (2041-2071) projection of change (%) in consecutive wet days with baseline 1970-1999

Conclusion

Warming trend of temperature. No distinct trends of precipitation but the extreme precipitation events are increasing. Consecutive dry days are increasing and are more pronounced in the higher altitude. In future, the wet days index is projected to increase in the lowland Terai but decrease in the higher altitude.

Acknowledgement

This study is a part of research project “Climate Change Adaptation for Livestock Smallholders in Gandaki River Basin Nepal” and is

supported by USAID Feed the Future Innovation Lab for Collaborative Research on Adapting Livestock Systems to

Climate Change.

THANK YOU