Operational monitoring of vegetation drought considering the propagation processes between various meteorological drought indices and vegetation indices

Abstract Vegetation drought (VD) is a condition in which vegetation experiences stress due to various meteorological factors. Several meteorological drought indices (MDIs) have been developed and applied to quantify the effects of such drought. However, researches on which meteorological factors to consider when monitoring VD are still limited. While advances in Earth observation technology have significantly improved human vegetation monitoring, the question of which vegetation indices (VIs) are most suitable and reliable for monitoring the spatiotemporal behavior of VD is not yet clearly answered. This study aims to develop a copula-based framework for routine monitoring of VD propagated from meteorological drought (MD) caused by changes in various meteorological factors. For this purpose, we propose the Ecological Drought Index-vegetation (EDI-veg), a VD index that combines various MDIs and VIs. The proposed approach represents an advancement over the traditional use of either MDI or VI alone. The EDI-veg was able to effectively monitor the occurrence, development, and dissipation of VD in the Far East Asia region. In addition, it enabled the identification of the most relevant MDIs and VIs for VD monitoring in specific regions and time periods. Information on vulnerable periods and regions was derived from the probability of VD for each land use pattern and region, estimated from the monitored VD timeseries.