Location dependent variability of monsoon rainfall in a tropical region

Abstract

An analysis of rainfall variability in Dakshina Kannada District, Karnataka State, was made using historical monthly rainfall data of 31 raingauge stations. For the 25 year period considered, annual and monsoon rainfall totals of individual stations did not deviate much from their mean values, but considerable spatial variations were observed. Analysis of the dependence of spatial variability on station elevation indicated that this factor alone could explain only 55% of the observed variations in annual rainfall. Considering other location dependent parameters, stepwise regression analysis was used to establish relationships between these and rainfall related variables. The regression models so developed were subjected to a validation test and found to comply fairly well. The applicability of the proposed models has been demonstrated by generating an isohyetal map of annual rainfall for the District, using topographical inputs. This map compared fairly well with the isohyetal map drawn using rainfall data. 1997 Taylor & Francis Group, LLC.