Designing of the perpendicular drought index |
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| Authors: | Abduwasit Ghulam Qiming Qin Zhiming Zhan |
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| Institution: | (1) Institute of Remote Sensing and GIS, Peking University, Beijing, 100871, China |
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| Abstract: | In this paper, a simple, effective drought monitoring method is developed using two dimensional spectral space obtained from
reflectance of near-infrared (NIR) and Red wavelengths. First, NIR–Red reflectance space is established using atmospheric
and geometric corrected ETM+ data, which is manifested by a triangle shape and in which different surface targets possess
certain spatial distribution rules. Second, perpendicular drought index (PDI) is developed on the basis of spatial characteristics
of moisture distribution in NIR–Red space, as well as the relationships between PDI and soil moisture is examined. Validation
work includes: comparison of PDI with in-situ drought index obtained from field measured data in the study area which includes
bulk soil moisture content at different soil depths, field moisture capacity and wilting coefficient, etc.; and comparison
of PDI with other recognized drought monitoring methods such as LST/NDVI and vegetation temperature condition index (VTCI).
It is evident from the results that graph of PDI of field measured plots demonstrates very similar trends with ground truth
drought data, LST/NDVI and VTCI. PDI is highly correlated with in-situ drought values calculated from 0 to 20 cm mean soil
moisture with correlation coefficients of R
2 = 0.49 (r = 0.75). This paper concludes that PDI has a potential in remote estimation of drought phenomenon as a simple, effective
drought monitoring index. |
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| Keywords: | NIR– Red spectral space Perpendicular drought index (PDI) Drought monitoring |
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