Analyzing Precipitation Using Concentration Indices for North Gujarat Agro Climatic Zone, India

摘要

The climate of India defies easy generalisation, comprising a wide range of weather conditions across a large geographic extent and varied topography. India's unique geography and geology strongly influence its climate; this is particularly true of the Himalayas in the north and the Thar Desert in the northwest. As in much of the tropics, monsoonal and other weather conditions in India are unstable: major droughts, floods, cyclones and other natural disasters are sporadic, but have killed or displaced millions. India's long-term climatic stability is further threatened by global warming. Climatic diversity in India makes the analysis of these issues complex. Gujarat is divided into eight agroclimatic zones. For the present study north Gujarat agroclimatic zone is considered. The major objectives of present study are to investigate the climate characteristics in the area. For the present study daily precipitation data from 167 raingauge stations for 48 years (1961-2008). The present study methodologically attempts to determine the structure of the accumulated precipitation amounts contributed by the accumulated number of precipitation days using concentration index, COIN, to represent the distribution and intensity of the precipitation. The COIN values are ranging from 0.54 to 0.66 with an average value of 0.60. It can be concluded that a concentration index, defined on the basis of the exponential curves, enables the evaluation of contrast or concentration of the different daily amounts of the precipitation by regionalizing the study area into lower and higher variability.