What is it about?
Drought is a natural disaster which causes global damages and affects people. In this work, a comparative study of different drought indices such as Normalized Difference Vegetation Index (NDVI), Deviation NDVI (DevNDVI), Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) from HJ-1A/1B multispectral data is discussed. These indices have shown potential to detect the drought severity. The objective of this study is to monitor drought in the Potohar region using HJ-1A/1B satellite data, from late November to April during 2009–2014. Additionally, results obtained from satellite data have been verified using ground-based rainfall and crop yield data. The results concluded that the Potohar region faced drought condition in 2010, which is further verified by ground data. Furthermore, NDVI and VCI in this region are found more effective than other drought indices. On the basis of validation of individual drought index with crop yield data, each index is assigned weight accordingly. Moreover, the combination of indices has the ability to detect time periods where drought is affecting the yield production. Regular monitoring and mapping of satellite-based drought indices would play an important role in predicting drought conditions.
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Why is it important?
In most of the instances, the majority of the drought studies concentrated on assessing drought using single source drought index . Each index has its own data type, complexity, strengths, and weakness. Therefore, they provide different results for the same event of interest. A combination of various drought indices from multiple data sources may provide a more comprehensive assessment of drought conditions than the use of a single one. However, the use of synergic methods has been a challenging task due to the lack of systematic methods for combining, implementing and evaluating this phenomenon. For example, remote sensing-based indices are unable to discriminate vegetation stress caused by sources other than drought. Therefore, the combination of various indices may offer a better understanding and better monitoring of drought conditions.
Perspectives
Further research may be explored
Shaikh Abdullah
Research & Development
Writing of this article was a great success for us as we have used the HJ-1A/AB data for the first time specially in monitoring the drought. Moreover, working with a diverse team was also a great experience of share the knowledge and expertise of respective domain. I hope that this effort will lay down a base for further use of HJ-1A/1B and other Chinese satellite data in the field of remote sensing in Pakistan.
Mudassar Umar
University of Karachi
Read the Original
This page is a summary of: Assessment of drought conditions using HJ-1A/1B data: a case study of Potohar region, Pakistan, Geomatics Natural Hazards and Risk, January 2018, Taylor & Francis,
DOI: 10.1080/19475705.2018.1499558.
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