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Evaluating satellite-based precipitation products in monitoring drought events in southwest China

Yan, Guixia, Liu, Yi, Chen, Xi
International journal of remote sensing 2018 v.39 no.10 pp. 3186-3214
drought, gauges, monitoring, rain, remote sensing, satellites, summer, China
Southwest China (SWC) is one of the areas that has most frequently been affected by a variety of drought events in recent years. Satellite-based precipitation products with high spatial resolution, having greatly improved their accuracy and applicability, are expected to offer an alternative to improve drought monitoring. The purpose of this article is to evaluate the reliability of the Tropical Rainfall Measuring Mission (TRMM) V7 3B43 products using the observed monthly precipitation data obtained from 118 meteorological stations from 1998 to 2013 and to monitor the temporal and spatial variations of drought conditions using the Standardized Precipitation Index (SPI), which is derived by a non-parametric approach. The results showed that the TRMM 3B43 products performed well in terms of monthly precipitation, although they slightly overestimated the total precipitation amount, mainly in summer. They matched the observed data well, yielding high correlations and low biases in most parts of SWC. For drought assessment, the SPI based on monthly TRMM 3B43 data oscillated around zero and showed a consistent inter-annual variability compared with gauges. Moreover, the TRMM 3B43 showed similar temporal drought behaviour by capturing most of the drought events at various timescales, and both of them described similar spatial patterns of drought. The TRMM products precisely described the occurrence and development process of the 2009/2010 drought and revealed that compared to the 2009/2010 drought the 2011 drought was more severe and affected a larger area. In general, using the TRMM 3B43 product is suitable and credible for drought monitoring over SWC.