TEMPORAL AND SPATIAL ANALYSIS OF RAINFALL IN UTTARANCHAL

Abstract

Rainfall varies geographically and seasonally. It varies from one country to another, from one watershed to another in the same country, and from one point to another some distance away within the same watershed. This variation can be considerable, depending upon the atmospheric and topographic factors as well as their interactions. Elevation, slope aspect and exposure are the main topographic factors affecting rainfall variability. In the present study, monthly and annual rainfall records of 44 stations of Uttaranchal have been analysed. The specific objectives of the study are as follows: (i) analysing rainfall of Uttaranchal in temporal and spatial domain, (ii) developing simple computer based tools for statistical analysis and (iii) preparing rainfall pattern and distribution maps of Uttaranchal. Any conclusion based on the data from grossly inadequate number of stations in a region with high rainfall variability cannot boast of commendable accuracy. The total geographical area of the state is 53,484 sq. km., most of which lies in the mountains. The maximum number of rain gauges in the state maintained by IMD was 44, which currently has been reduced to only 8. As per WMO and IMD guidelines, this number should be around 200 considering a uniform raingauge density of 1 raingauge per 250 km2. In the present study, a statistical package using Visual Basic Applications in Microsoft Excel has been -developed. Using this package data sets have been analysed. Based on the analysis of these data sets, some of the preliminary conclusions are as follows:....