Drought has frequently brought huge damage to local agricultural production and ecological environment in China. In order to acquire large-scale land surface water information to assess drought severity quickly and accurately, normalized difference drought index (NDDI) was proposed which based on visible and near infrared band reflectance. In this paper, the spatio-temporal characteristics of drought in southwest China in 2010 was analysed using NDDI, with Yunnan, Guangxi and Guizhou provinces as the study area. Firstly, MODIS images were preprocessed and then normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) were calculated with different bands data retrieved from MODIS reflectance product. Secondly, NDDI was calculated by using NDVI and NDWI. During this process, pixel reliability data acquired from MODIS product was introduced. The main purpose of this data was to eliminate noise such as clouds and ice or snow in NDDI calculation. Next, the correlation between NDDI and ground-based soil moisture was validated, also intercomparison between NDDI and vegetation condition index (VCI) was analysed. The result showed that NDDI was sensitive to ground soil moisture and demonstrated even quicker response to shallow surface drought severity than that of VCI. Finally, the spatio-temporal distribution of drought in southwest China in 2010 was reoccurred with NDDI index, and also land area with different drought severity was derived. The result showed that the period that suffered from most severe drought conditions lasted from January to April in 2010 in Guizhou Province, the maximum drought-stricken area was 132257 km2 and it occupied more than 75% of the total area of Guizhou Province. Meanwhile, the maximum area suffered from "heavy drought" was 88246 km2 and it occupied more than 50% of the total area of Guizhou Province.
BAI Kaixu, LIU Chaoshun, SHI Runhe, GAO Wei
. Analysis of Spatio-temporal Characteristics of Drought in Southwest China in 2010 by Using MODIS-based Normalized Difference Drought Index[J]. Journal of Geo-information Science, 2012
, 14(1)
: 32
-40,48
.
DOI: 10.3724/SP.J.1047.2012.00032
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