Constructing the machine learning techniques based spatial drought vulnerability index in Karnataka state of India

Abstract

The drought induced vulnerability is owed much to rapid modernization, climate extremes, and over exploitation of natural resources. However, a natural phenomenon, the drought is amplified by anthropogenic activities that in its enormity influences water availability, agricultural productivity, ecosystem, groundwater storage. The Karnataka state of India is frequently affected by the drought that causes huge loss in agricultural sector and other allied sectors. Therefore, it is essential to measure the vulnerability status for the better management of natural resources in the state of Karnataka. No advanced models are being used yet to portray the drought vulnerability status. Different advanced machine learning models are effective in predicting various physical vulnerabilities. The aim of this study was to use sophisticated machine learning models to precisely define relative drought vulnerability. In that endeavour, it used two advanced machine-learning algorithms (MLAs), namely, Bagging and Artificial Neural Network (ANN) which are still not used in this field. Twenty-six meteorological and socio-economical parameters were considered to find the most drought vulnerable areas. The predisposing parameters were classified as resilience (7 parameters), sensitivity (9 parameters), and exposure (10 parameters). The researchers have produced drought vulnerability maps for overall condition, resilience, sensitivity, and exposure. The relative drought vulnerability maps (RDVMs) clearly show that 40.87%–52.03% of areas fall under very high vulnerability, which is situated in the central and eastern parts of the state. The prediction capacity of newly built models was judged with efficiency, root mean square error (RMSE), true skill statistics (TSS), Friedman and Wilcoxon rank test, and area under the curve (AUC) of receiver operating characteristic (ROC). All of them showed satisfactory results - the RMSE value of 0.32 and 0.33, TSS values of 0.82 and 0.81, and AUC values of 86.50% and 84.20% as obtained by ANN and bagging models, respectively. The produced RDVMs demonstrate the urgency of policy interventions to minimize vulnerability in prioritized areas.