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Rising mean and extreme near‐surface air temperature across Nepal
Author(s) -
Karki Ramchandra,
ul Hasson Shabeh,
Gerlitz Lars,
Talchabhadel Rocky,
Schickhoff Udo,
Scholten Thomas,
Böhner Jürgen
Publication year - 2019
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.6344
Subject(s) - climatology , geopotential height , environmental science , monsoon , anticyclone , cloud cover , climate change , troposphere , precipitation , snow , global warming , geography , atmospheric sciences , geology , meteorology , oceanography , cloud computing , computer science , operating system
Abstract Owing to unique topographic and ecological diversity, central Himalayan state of Nepal is exposed to adverse impacts of climate change and associated disasters. However, countrywide historical assessment of mean and extreme temperature changes, a prerequisite for devising adequate adaptation strategies, is still lacking. Here, we present a comprehensive picture of mean and extreme temperature trends across Nepal over the 1980–2016 period, based on high‐quality daily temperature observations from 46 stations. Our results suggest that besides winter cooling in southern lowlands, the country features a widespread warming, which is higher for maximum temperature (~0.04°C⋅year −1 ) than for minimum temperature (~0.02°C⋅year −1 ), over the mountainous region than in valleys and lowlands and during the pre‐monsoon season than for the rest of the year. Consistently, we found a higher increasing trend for warm days (13 days⋅decade −1 ) than for warm nights (4 days⋅decade −1 ), whereas the rates of decrease for cold days and cold nights are the same (6 days⋅decade −1 ). Further investigations reveal that pronounced warming in maximum temperature over mountain regions can be attributed to less cloud cover and snowfall in recent decades during non‐monsoon seasons as a result of positive geopotential height anomalies and strengthening of anticyclonic circulations in the mid‐to‐upper troposphere. Similarly, increased stability of lower atmosphere during winter and post‐monsoon seasons caused prolonged and frequent periods of fog over lowlands, resulting in significant winter cooling there.