Title
Comparison of Two Simulation Methods of the Temperature Vegetation Dryness Index (TVDI) for Drought Monitoring in Semi-Arid Regions of China.
Abstract
The Temperature Vegetation Dryness Index (TVDI), a drought monitoring index based on an empirical parameterization of the Land Surface Temperature (LST)-Normalized Difference Vegetation Index (NDVI) space, has been widely implemented in a variety of ecosystems worldwide because it does not depend on ancillary data. However, the simulation of dry/wet edges in the TVDI model can be problematic because remote sensing images do not have sufficient pixels to identify the wetness and dryness extremes of different vegetation coverages. In this study, an improvement in dry/wet edge simulation was proposed, and a comparison of the original TVDI and the modified Temperature Vegetation Dryness Index (TVDIm) was performed for drought monitoring in Ningxia Province, which is a typical semi-arid region in China. First, the difference between the land surface temperatures in day and night (Delta LST) was used as an alternative to LST when building the TVDIm model. In addition, the wet edges were improved by removing outliers using a statistical method, and the dry edges were optimized by removing the "tail down" points in the NDVI range of 0.0-0.1. Here, the modeling process of TVDIm in 2005, one of recent extreme drought year is illustrated. The results show that both the TVDI and TVDIm can be used to monitor the temporal and spatial variations of drought, and the onset, duration, extent, and severity of drought can be reflected by TVDI and TVDIm maps. However, the magnitude of TVDI is higher than that of TVDIm, which could cause the TVDI-simulated drought condition to be elevated in normal years and underestimated in dry years. The TVDIm has higher coefficients of correlation with in situ meteorological drought index and agricultural drought statistical data than does the original TVDI, and it exhibits better performance in drought monitoring compared to that of the original TVDI in semi-arid regions of China.
Year
DOI
Venue
2017
10.3390/rs9020177
REMOTE SENSING
Keywords
Field
DocType
drought monitoring,temperature vegetation dryness index,dry/wet edges simulation,Moderate Resolution Imaging Spectroradiometer,semi-arid regions
Land surface temperature,Moderate-resolution imaging spectroradiometer,Vegetation,Ancillary data,Arid,Vegetation Index,Remote sensing,Normalized Difference Vegetation Index,Geology,Dryness
Journal
Volume
Issue
Citations 
9
2
1
PageRank 
References 
Authors
0.43
6
9
Name
Order
Citations
PageRank
Lingtong Du110.43
Naiping Song210.77
Ke Liu32016.97
Jing Hou421.15
Yue Hu5138.18
Yuguo Zhu610.43
Xinyun Wang710.43
Lei Wang8401111.60
Yige Guo910.43