19-Use of 24 hour maximum point rainfall for demarcating homogeneous rainfall zones in India.

Abstract

The highest recorded 24-hour rainfall totals during the period 1875 to 1982 for about 300 stations were plotted and isohyets drawn to delineate the homogeneous zones of heavy rainfall. The isohyetal pattern indicated an unsteady increas( from less than 20 cm in the far west and far north to over 50 cm on or near the coasts. There are a few inland stations where outstanding amounts have been recorded but these are randomly distributed in space and time. Besides., these, there existed a densly gauged areA in the central peninsula lying between Latitudes 8 N to 21'N within which more than 20 cm of rain in 24 hours have never been recorded. The area which will be treated as meteorologically homogeneous with regard to the occurrence of heavy falls includes virtually the entire Indian region excepting the far western extremity, northern area bordered by the Himalayas and the central peninsular region. The correlation coefficient between the highest rainfall and elevation indicated no significant relationship.