SENSITIVITY OF SOME DROUGHT INDICIES IN SOUTH VIETNAM

Abstract

This study aimed to assess the sensitivity and suitability of some drought indices for southern Vietnam (SVN). Three groups of drought indexes were included in the analysis, including one group consisting of only one factor is rainfall, a group of indicators showing the balance between rainfall and evaporation, and the other group showing fluctuations of temperature and amount of rain. The study results show that with the drought index based on rainfall, the Percent of Normal Index (PN) showed the drought condition of the study basin more realistically than other drought Indicators and have a good relationship with the Ocean Niño Index (ONI). For drought indices based on rainfall and evaporation, the Aridity Index (AIu) is an option because it is quite suitable for the drought situation in the study area and also has a good relationship with ONI. For drought index based on temperature and rainfall, Ped shows most clearly the effects of ENSO. However, this indicator is only suitable for analyzing drought situation at discrete times. In addition, it is necessary to adjust the break values on drought classification for PN, AIu and Ped to better suit the climate type of this area.