This paper presents a new drought assessment method by spatially and temporally integrating temperature
vegetation dryness index (TVDI) with regional water stress index (RWSI) based on a synergistic
approach. With the aid of LANDSAT TM/ETM data, we were able to retrieve the land-use and land-cover
(LULC), vegetation indices (VIs), and land surface temperature (LST), leading to the derivation of three
types of modified TVDI, including TVDI SAVI, TVDI ANDVI and TVDI MSAVI, for drought assessment in
a fast growing coastal area, Northern China. The categorical classification of four drought impact levels
associated with the RWSI values enables us to refine the spatiotemporal relationship between the LST
and the VIs. Holistic drought impact assessment between 1987 and 2000 was carried out by linking RWSI
with TVDIs group wise. Research findings indicate that: (1) LST and VIs were negatively correlated in
most cases of low, medium, and high vegetation cover except the case of high density vegetation cover
in 2000 due to the effect of urban heat island (UHI) effect; (2) the shortage of water in 1987 was more
salient than that that in 2000 based on all indices of TVDI and RWSI; and (3) TVDIs are more suitable for
monitoring mild drought, normal and wet conditions when RWSI is smaller than 0.752; but they are not
suitable for monitoring moderate and severe drought conditions.
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