A spatio-temporal analysis of aridity levels in South Sulawesi using the Thornthwaite method

This study a spatio-temporal investigation and analysis of the level of aridity for the whole of the South Sulawesi Province, Indonesia for the 10 years period (1999 – 2008). Temperature, precipitation and evapotranspiration data for the 66 meteorological stations throughout the South Sulawesi were analysed by using the water balance technique based on which the aridity index as proposed by Thornthwaite-Mather was then calculated. The calculatedvalues of the aridity indices were then spatially plotted by using the technique of Poligon Thiessen. The results showed that the level of aridity in the SouthSulawesi Province can be classified into three levels i.e., the low level of aridity index ( 16.7%) which was calculated for the districts of Gowa dan Bone in the south, North Luwu ans South Luwu in the north , and Pinrang and Enrekang in the middle region. The high index of aridity ( 33.3%) was calculated for the district of Palopo in the north, Sidrap and Wajo in the middle, and Makassar, Takalar, Jeneponto, Bulukumba and Selayar in the south. Other districts had shown a medium level of aridity index(16.7 – 33.3%). In general, the main factor of the aridity phenomenon in the South Sulawesi Province was the lack of rainfall and the prevalence of high temperatures for a longer period which in turn produced high rates of evapotranspiration. It was observed that in these conditions all agricultural areas which were solely dependent on natural rainfall failed toproduce harvests.