The impacts of climate change on meteorological drought in the Central Highlands region of Vietnam

ABSTRACT This study aimed to analyse the characteristics of drought under the impacts of climate change in the Central Highlands of Vietnam. The standardized precipitation indices at 3-, 6-, 9- and 12-month time scales were calculated based on the average monthly precipitation at 11 meteorological stations between 1985–2014. The drought characteristics were analysed based on the modified Mann-Kendall test, Theil-Sen methods and the theory of runs. Analysing the impact of climate change on drought events, four CMIP6 GCM models, namely, CNRM-CM6-1-HR, MRI-ESM2-0, BCC-CSM2-MR and MIROC6, under the SSP2-4.5 and SSP5-8.5 scenarios were used to obtain the average monthly precipitation for the period 2031-2060 to compute the SPI3, SPI6, SPI9 and SPI12. The results indicate that the drought frequency under the SSP5-8.5 scenario ranges from moderate to severe. The BCC-CSM2-MR, CNRM-CM6-1-HR and MIROC6 models showed an increase in drought frequency from 2 to 4% for SPI3 and SPI6 and from 4 to 6% for SPI9 and SPI12. Under the SSP2-4.5 scenario, the frequency of severe droughts also increases by 2-4% compared with that in the 1985-2014 baseline periods for SPI6, SPI9 and SPI12. Consequently, moderate to severe drought episodes are predicted to occur more frequently in the research area.