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›› 2012, Vol. 35 ›› Issue (5): 708-716.

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Sensitivity analysis of response of MODIS derived drought indices to drought in North China

BAI Ligai1,3,YAN Qin2,ZHANG Li3,TAN Zhixiang4   

  1. 1  Department of Construction Engineering, North China Institute of Aerospace Engineering, Langfang  065000,Hebei,China; 2  Key Laboratory of Earth Observing Technology of State Bureau of Surveying and Mapping, Chinese Academy of  Surveying and Mapping, Beijing 100830, China; 3  Key Laboratory of Digital Earth, Center for Earth Observation and Digital Earth, Chinese Academy of  Sciences, Beijing 100094, China; 4  Jiangsu Key Laboratory of Resources and Environmental Information Engineering, China University of Mining and Technology, Xuzhou 221116,Jiangsu,China
  • Received:2011-12-24 Revised:2012-02-21 Online:2012-09-25
  • Contact: ZHANG Li E-mail:lizhang@ceode.ac.cn

Abstract: Drought occurred frequently in recent years in North China. In this study, MOD09A1,8day surface reflectance derived from MODIS(moderateresolution imaging spectroradiometer)images provided by NASA and monthly precipitation data from ground observations obtained by China Meteorological Data Sharing Service System, which were used to study temporal responses of MODISderived drought index to climatic factors in North China. Anomaly Vegetation Index(AVI) was computed from the time series data of NDVI (based on infrared and near infrared bands) and Anomaly Water Index(AWI) was calculated from NDWI (based on near infrared and short infrared wave bands) of MODIS. Given the consequences and pervasiveness of drought, it is important to assess the specialized indices that were used to assess drought sensitivity. The standardized precipitation index (SPI) has several characteristics that are an improvement in previous indices. In this paper, 1-SPI, 2-SPI, 3-SPI, 6-SPI and 12-SPI were calculated. The correlations and lag relationships between AVI from April to October (the growing season) during 2000 to 2009 and the multipletime scale SPI in North China grassland and cropland sites were investigated based on MODIS and climate data. Besides, the relations between AVI and AWI in different periods were also analyzed. According to the sensitivity analysis of the response of AVI and AWI to drought, summer drought from June to September in 2009 in North China were monitored and analyzed by AWI. The results show: (1) the correlations are different between AVI and SPI at different time scales during vegetation growing seasons. For the grassland, the correlations are insignificant between AVI and 1-SPI, but significant between AVI and 3-SPI. However, the correlation is lower between AVI and SPI for cropland than that for grassland. In general, the correlation is higher between AVI and 3-SPI for cropland. (2) Similarly to AVI, AWI shows lag response to SPI, and has better correlation with 3-SPI. The correlation between AWI and 3-SPI is better than that between AVI and 3-SPI during period from June to August when serious drought occurs. Therefore, AWI is more sensitive to drought than AVI in North China. (3) The timeseries drought monitoring maps in North China for 2009 derived from AWI reflects the temporal and spatial dynamics of drought, which are consistent with the relevant meteorological results.

Key words: North China, drought, anomaly vegetation index(AVI), anomaly water index(AWI), standardized precipitation index(SPI)

CLC Number: 

  • TP79