Incidence of droughts in Andhra Pradesh, Tamil Nadu and Mysore

Abstract

Drought spells in Andhra Pradesh, Tamil Nadu and Mysore during the last 60-65 years are studied by computing the monthly Palmer index values. For computing the index, a detailed hydrologic accounting of the area is carried out for a large number of years using data of rainfall, potential evapotranspiration and water-holding capacity of the soil. Several parrameters are obtained from this accounting and the be are used to compute the 'CAFEC' (Climatically Appropriate For Existing Condition) precipitation of each month of the period. Anomaly of actual rainfall with respect to this 'CAFEC' precipitation is obtained for each month and this is used to compute Palmer index of the month.

Several drought spells occurred in these areas during the period studied. The longest drought spell experienced in each area was: (i) Interior My010re North-70 months (August 1922 to May 1928), (ii) Coastal Andhra Pradesh-57 months (July 1904 to March 1909), (iii) Tamil Nadu-41 months (November 1949 to March 1953), (iv) Rayalaseema 36 months (March 1941 to February 1944), (v) Telangana-35 months (May 1911 to March 1914 and July 1918 to May 1921) and (vi) Interior Mysore South-27 months (December 1948 to February 1951).