Temporal and Spatial Variation of Temperature over Nepal

Abstract

Temperature is one of the most important key indicators of climatic variables. Ithas significant role in socio-economic part of the human civilization. Since, globalwarming and the climate change have been threatening the world seriously; studieshave been carried out on climate change over much of the globe since last fewdecades. This study concerned with the investigation of the temporal and spatialvariation of temperature at various locations in Nepal. In the study, increasing trend in the maximum temperature by 0.08 C/year foundfor the period from 1970 to 2004 and for the minimum temperature, the increasingtrend is found as 0.05 o C/year over the nation. After 1986, the maximum (0.05 C/year)and minimum (0.03 o C/year) temperatures over the nation were also slightly increasing.Almost constant trend in the maximum temperature was found at Terai region ofNepal, however, in the case of minimum temperature the trend was found slightlyincreasing. The greatest increased rate in maximum temperature was observed atHimalayas (0.12 o C/year) and Middle Mountain (0.09 o C/year) region of Nepal,however, in the case of minimum (0.10 o C/year) temperature the greatest trend wasfound at Siwalik. But in the station Jomsom, maximum temperature was observed atcooling rate and minimum temperature was observed at warming rate. According to season-wise distribution it was observed that the maximumtemperature was observed slightly warming rate at monsoon and post-monsoon seasonof Terai region whereas winter and pre-monsoon seasonal trends were found inslightly cooling rate. In the study, the rate of increase in minimum (0.025 C/year)temperature over Terai region was observed about twice to be decreased in maximumtemperature (0.012 o C/year)and also observed slightly increasing trends in maximumtemperature (0.07 o C/year) and minimum (0.10 o C/year) in the Siwalik region. Thetemperature Vs. altitude has also calculated in different region as well as seasons. Thevalues of maximum temperature and minimum temperature were also observed at thedecreasing rate of 5.7 o C per kilometer and 4.8 o C per kilometer respectively. Thehighest decreasing rate was observed to be 6.9 o C per kilometer at pre-monsoonalmaximum temperature and 5.3 o o C per kilometer at monsoonal minimum temperature. Due to lack of sufficient data of Himalayan region, the study could not cover trendof temperature of the whole Himalayan region, therefore, the study only shows thetemperature trends in combined form of both higher mountain and Himalayan region.