Identification of drought prone areas in Sri Lanka using multi-temporal satellite data

Drought is an insidious hazard of nature with a slower onset and is often misunderstood as a minor weather hazard. Nevertheless, it has become a common and recurring natural disaster in Sri Lanka during recent times affecting the livelihood of rural agricultural sector in particular. This study has attempted to identify spatial patterns of drought prone areas to improve drought preparedness and strengthen appropriate drought management strategies. Drought prone areas for each month were produced and by aggregating them, a resultant composite map was developed showing overall drought prone possibilities across Sri Lanka.The results revealed that drought is a less frequent phenomeon in January in Sri Lanka except in some parts of Western and Southern provinces. Drought conditions at most of the North-eastern parts of the Dry zone areas of Sri Lanka could be seen during May to September with a peak drought during August and September in the Uva and Eastern provinces. Jaffna, Killinochchi and Batticaloa districts can be categorized as severe drought prone districts of the country. Accuracy of the composite map was checked using historical records of Disaster Management Centre, Sri Lanka from 2001-2017 at the DS Division level. The accuracy was 77.01%, Type I Error was 22.09% and Type II Error 0%. The Chi-Square Test showed high accuracy levels (p<0.05) suggesting that the vegetation condition approach is appropriate for drought assessment in Sri Lanka.