Drought indices are widely used for drought quantification. The objective of this study is to introduce a hybrid drought index, the Precipitation Evapotranspiration Difference Condition Index (PEDCI), and to compare its performance in Oklahoma to existing drought indices. The PEDCI is based on a simple water balance model, which accounts for the difference between water supply (precipitation) and water demand (potential evapotranspiration). While it is similar in this respect to the Standardized Precipitation and Evapotranspiration Index (SPEI) and the Palmer Drought Severity Index, it uses a different method to normalize the index in time and space which was inspired by Vegetation Condition Index. The performance of the PEDCI is evaluated [...]
