1. Variability of climate extremes in Nepal
Ram Prasad Awasthi 1,2
Meteorologist
2Ministry of Population and Environment
Nepal
Jeffrey S. Owen1
1 Global campus
Hankuk University of Foreign studies
Asian Conference on Meteorology
(ACM 2017)
Busan, South Korea
24th October, 2017
Mount Everest:
Top of the World

2. Outline Nepal- Geography Introduction Study Area, Data and Methodology
Results and Discussion
Conclusions

3. Nepal- Geography Four Seasons
Pre- monsoon ( March-May )- Local weather phenomena,
hot, thunderstorms, hailstorms, windstorms
Monsoon ( June – Sept.)- Warm and wet
(80% of annual rainfall)
Post-monsoon ( Oct.- Nov.) - Mild weather
Winter ( Dec.- Feb.)- Cold and dry
26º 22' N - 30º 27' N Lat.
80º 4'E - 88º 12'E Long.
200
400
100
Kilometers
India
China
Iran
Pakistan
Myanmar
Thailand
Afghanistan
Laos
Nepal
Cambodia
Bangladesh
Oman
Bhutan
Sri Lanka
Turkmenistan
Malaysia
130
260 65
Physiographic divisions:- 5
Terai (Plains, subtropical climate),
Siwalik (valley, hills, subtropical),
Mid-mountain(warm temperate),
High-mountain (cold temperate/sub-alpine)
High-Himalaya (alpine/tundra)
Distance:- NS-200, EW-800 km
Elevation: m

4. Introduction
Focus of Study : Extreme Climatic Events Importance: provide details on climate variability and risks with respect to extreme climatic events for individual geographical regions of Nepal Application: provide information on national trends in climate including data on extreme weather events occurring at different time scales. The specific objectives of the study are: I ) Analyze historical trends in daily temperature and rainfall amount. II) Characterize extreme events with respect to ongoing climate change. Rationale: There is still a lack of quantitative studies on climate change and extreme weather events in Nepal. This study will provide basic information and quantitative results to detect climate change by using the occurrence of extreme events .

5. Climate induced disasters in Nepal
85% of natural disasters are related to extreme meteorological events and results in 62% and 80% of economic and human loss and damage annually

6. Data: Temperature, Precipitation Data Period: 1970-2015 Tool: RclimDex
Study Area-Nepal
Location of meteorological stations
Number of stations: 90
Data: Temperature, Precipitation
Data Period:
Tool: RclimDex
Stations are operating by the
Department of Hydrology and Meteorology,
Government of Nepal

7. Climate extreme indices
Developed and recommended by the ETCCDMI / WMO /CCl/CLIVAR were considered
SU35
Summer days
CSDI
Cold spell duration indicator
TR25
Tropical nights
DTR
Diurnal temperature range
TXx
Max Tmax
RX1day
Max 1-day precipitation amount
TNx
Max Tmin
Rx5day
Max 5-day precipitation amount
TXn
Min Tmax
SDII
Simple daily intensity index
TNn
Min Tmin
R10
Number of heavy precipitation days
TN10p
Cool nights
R20
Number of very heavy precipitation days
TX10p
Cool days
Rnn
Number of days above nn mm
TX90p
Warm days
CDD
Consecutive dry days
WSDI
Warm spell duration indicator
CWD
Consecutive wet days
TN90p
Warm nights
R95p
Very wet days
R99p
Extremely wet days
PRCPTOT
Annual total wet-day precipitation

8. User defined daily threshold value for calculation climate indices
Physiographic regions/ Parameter
Terai
Siwalik
Mid-Mountain
High-Mountain
High-Himalaya
Upper maximum temperature
35oC
35 oC
30 oC
25 oC
10 oC
Lower maximum temperature
10 oC
5 oC
-10 oC
Upper minimum temperature
20 oC
15 oC
Lower minimum
temperature
3 oC
0 oC
-2 oC
-20 oC
Precipitation
200 mm 
200 mm
150 mm
50 mm
30 mm

9. Results & Discussion

10. Mean Temperature is increasing in all regions and seasons
Annual total precipitation does not have a significant trend but is increasing in low elevated areas

11. Climate extreme indices trend

12. Rapid increase in tropical nights and summer days
Mean temperature is increasing in all seasons but minimum temperature is decreasing during monsoon season
Cold spell duration has almost no change but increase in some parts of Terai/Siwalik/Mid-Mountain
Warm spell duration are increasing
High intensity precipitation amount and frequency are increasing in all seasons except for post-monsoon season
Lengthening of dry spell in all seasons
More than 70% stations show significant trends for temperature indices
Only around 20% of stations show significant trends for precipitation indices

15. Cool days and night are decreasing in almost all regions by 5 days and 6 night/decade respectively
Cold days are increasing in some parts of western and central Terai and adjoining parts due to consistent fog conditions during winter

16. Wet days are increasing in high land and some low lying isolated parts
Mostly decreasing in Mid-Mountain regions, which creates problems for rain fed agriculture
Consecutive dry days are increasing in almost all regions
except some Far-western Mountain and Terai regions

17. Climate extreme indices trends by physiographic regions

18. Cold days are increasing in the Terai and High Himalayan regions during winter and summer.
Maximum temperature and minimum temperature are decreasing in the Terai and High-Himalaya during winter and summer.
Extreme temperatures increased more in the Mountain and Himalayan regions than the other regions. While mean maximum temperature is increasing in all regions and seasons but the mean minimum temperature has slightly decreasing trend especially in High-Mountain and Himalayan regions.
The diurnal temperature range is increasing in all regions and seasons except in Terai regions.
High intensity precipitation is increasing in Mid-Mountain, Siwalik and Terai regions, while decreasing in High-Mountain and Himalayan regions. 10mm, 50mm and 100mm rainfall days are increasing annually.

19. Conclusions
We found increasing trends in warm spell duration and warm day temperature during the summer season. Summer favors heat wave conditions in the Terai and Siwalik regions. Similarly, increase in cold spell duration and decrease in coldest day/night temperature resulting prolonged cold waves in Terai and southern parts of Siwalik.
Mountain regions are experiencing much colder night time temperatures.
Himalayan region is getting warmer in all seasons
High intensity precipitation events are occurring more frequently through Mid-Mountain down to the Terai region.
Dry spells and wet spells are becoming clearest indicators for abnormal climate conditions in Nepal.
In summary, our results provide strong evidence for climate change in all regions of Nepal.

20. Acknowledgement
We Greatly appreciate the KOICA-HUFS Masters’ Degree Program in Atmospheric Environment for continuous support !

21. THANK YOU !
NAMASTE