TRMM and Rain gauge dataset for Adama,Ethiopia.

Drought – a very critical natural process which greatly affects the agriculture which is the major source for human existence. Various researches, experiments have been done in the past which monitored meteorological droughts using standardized indices of precipitation deficits. They mostly relied on rain gauge-based measurements which has the limitations of spatial coverage, data availability and cost efficiency. The purpose of this paper is the potential to apply the satellite derived rainfall product to monitor meteorological drought. Most common is the Standard Precipitation Index (SPI) for research and operational applications on meteorological and agricultural drought monitoring and early warning. The monthly precipitation data accuracy of TRMM (the Tropical Rainfall Measurement Mission) 3B43, was implemented by comparison with the rainfall data of five ground stations in and around Adama woreda from 1998 to 2015. The substantial correlations between the two sources were found during August, and the decision coefficients (R2) are 0.10, 0.25, 0.065, 0.05 and 0.49 respectively. TRMM rainfall data from 1998 to 2015 were used to calculate 3,6,9 and 12-month Standard Precipitation Index (SPI) pixel by pixel for Adama woreda. This 3,6,9 and 12 month SPI was incorporated to depict spatial patterns of meteorological drought and its severity during typical drought and wet years. Further, time series of SPI were considered to assess the drought risk in Adama woreda. We clinch that the TRMM product can properly monitor meteorological droughts though it has relatively short dataset length (~15 years). Lastly, we suggest an assimilation of rain gauge and satellite-based precipitation data to provide more robust estimates of meteorological drought severity.

干旱——一种极为关键的天然过程，对人类赖以生存的主要资源——农业产生了深远影响。过往的研究与实验中，研究者们采用了基于降水短缺的标准化指标来监测气象干旱。这些研究主要依赖雨量计测量，其局限性在于空间覆盖范围、数据可获得性和成本效益。本文旨在探讨将卫星衍生的降水产品应用于气象干旱监测的潜力。在气象和农业干旱监测与早期预警的研究与实际应用中，最常用的指标是标准降水指数（SPI）。通过对1998年至2015年间阿达玛地区及其周边五个地面站的降雨数据进行对比验证，TRMM（热带降雨测量任务）3B43的月降水量数据精度得到了验证。在8月份，两种数据源之间发现了显著的相关性，决定系数（R²）分别为0.10、0.25、0.065、0.05和0.49。1998年至2015年的TRMM降雨数据被用于计算阿达玛地区的3、6、9和12个月标准降水指数（SPI），像素级进行计算。这一3、6、9和12个月的SPI被纳入分析，用以描绘典型干旱年和湿润年气象干旱的空间分布及其严重程度。此外，SPI的时间序列被用来评估阿达玛地区的干旱风险。我们坚信，尽管TRMM产品所依赖的数据集长度相对较短（约15年），但它能够有效监测气象干旱。最后，我们建议将雨量计和基于卫星的降水数据进行融合，以提供更稳健的气象干旱严重程度估计。