A Study on Spatial and Temporal Distribution of Rainfall in Province Number 3, Nepal
Date
2019
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Hydrology and Meteorology
Abstract
Daily observed precipitation data of 23 stations for the period of 1980-2015 is used in
the study of spatial and temporal distribution of rainfall in Province 3 of Nepal. The
study is basically focused on the study of space time variation and principal
component analysis of rainfall. About 80.6% of annual rainfall is covered by monsoon
rainfall so both spatial and temporal distribution of annual rainfall is proportionate
with monsoon rainfall (JJAS). Highest rainfall pocket area is observed in northeastern
part of Province in the periphery of Gumthang, Sindhupalchok with rainfall of 3828
mm while lowest rainfall is observed in Tamachit, Rasuwa with 720 mm. Temporally
rainfall is high in 1999 with rain 2399.4 mm and low in 1992 with rain 1508 mm. July
is highest rain month and November is lowest. Seasonally, increasing trend of rainfall
is seen in Pre monsoon while decreasing trend is seen in Monsoon, Post monsoon and
winter. On decadal rainfall analysis it is obtained highest rainfall in third decade
(2000-2009) and lowest in last decade (2010-2015). Analysis of rainfall shows
average annual rainfall in lowland is 1883.8 mm and highland is 1959.6 mm. The
correlation coefficient between rainfall in highland and lowland is 0.79.
In most of the La Nina year there is increased rainfall and El Nino year the rainfall is
decreased. So, we can conclude that there is some influence of large scale
atmospheric phenomena like ENSO.
First component (PCA1) of Principal component analysis which covers largest
information of space time variation of rainfall shows that pre monsoon precipitation
pattern is highly concentrated in central part of the Province while monsoon is
concentrated in southern part of the Province. Similarly, Post monsoon precipitation
pattern is concentrated in central part of the Province while winter precipitation
pattern is concentrated over both the central as well as southwestern part of the
Province.
Description
Keywords
Temporal, ENSO, Inverse distance weighting, Principal component analysis