Determinations of the Warm Edge and Cold Edge of the Vegetation Temperature Condition Index's Drought Monitoring Approach

摘要

The methods for determining the warm edge and cold edge of Vegetation Temperature Condition Index (VTCI) drought monitoring approach are developed by using multi-years' remotely sensed data in a study area located in the Guanzhong Plain, Shaanxi Province, PR China. The AVHRR remotely sensed data acquired at daytime in the first ten days of May from 1999 to 2003 are selected. Several methods are used to determine the warm edge and cold edge of VTCI based on scatter plots of different value composited products of LST and NDVI. Ground-measured precipitation data from the study area are used to validate the edge determination methods. A linear correlation analysis is applied to study the correlation between VTCI and precipitation. The results show the warm edge can be determined by using multi-years' maximum value composited LST and NDVI products at a given period. While, the cold edge is determined by the maximum-minimum value composited approach.