Due to infrequent rainfall, high temperatures, and degraded land, the Sahel region often suffers from droughts. The Sahel region is considered as one of the world’s driest and extreme environmental conditions. In order to assess spatiotemporal vulnerability of potential drought impacts, we used remote sensing and ground station data to evaluate drought conditions in the Sahel region from 1985 to 2015. The standard precipitation index (SPI), standard precipitation evapotranspiration index (SPEI), vegetation condition index (VCI) anomaly, along with socioeconomic indicators were performed. In addition, Pearson correlation coefficient (PCC) was computed between drought indices and three main crops (sorghum, millet, and maize) in the region to estimate the effects. The analysis showed that temperature increased by 0.78°C from 1985 to 2015, which had a significant impact on crop yield for sorghum, maize, and millet with a statistical significance value of P > 0.05. In the decade spanning 1994 to 2005 alone, the temperature increased by 0.57°C, which resulted in extreme drought in Algeria, Sudan, Chad, Nigeria, and Mauritania. For the effect of drought on crop production, high significance was noted on the SPI and SPEI-3 timescale: sorghum with SPI-3 (r = 0.71) and SPEI-3 (r = 0.65), millet with SPI-3 (r = 0.61) and SPEI-3 (r = 0.72), and maize with SPI-3 (r = 0.81) and SPEI-3 (r = 0.65) during the study period. In the growing season, VCI anomaly had strong correlations with sorghum and millet (r = 0.67 and 0.75, respectively). A significant agreement was also noticed between the combined drought index (CDI) and vulnerability index (VI) in Burkina Faso (r = −0.676; P < 0.00), Mali (r = −0.768; P < 0.00), Mauritania (r = 0.843; P < 0.001), Niger (r = −0.625; P < 0.001), and Nigeria (r = −0.75; P < 0.005). The results show that the above indices are effective in assessing agricultural drought and its impact on crop production in the Sahel, and in identifying areas most affected by drought.

中文翻译：

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1985年至2015年萨赫勒地区国家的时空干旱评估

由于降雨少，温度高和土地退化，萨赫勒地区经常遭受干旱。萨赫勒地区被认为是世界上最干旱和极端的环境条件之一。为了评估潜在干旱影响的时空脆弱性，我们使用遥感和地面站数据来评估萨赫勒地区1985年至2015年的干旱状况。标准降水指数（SPI），标准降水蒸散指数（SPEI），植被状况指数（VCI）异常，以及社会经济指标。此外，计算了该地区干旱指数与三种主要农作物（高粱，小米和玉米）之​​间的皮尔逊相关系数（PCC），以评估其影响。分析表明，从1985年到2015年，温度升高了0.78°C，P＞ 0.05。仅在1994年至2005年的十年间，温度升高了0.57°C，这导致了阿尔及利亚，苏丹，乍得，尼日利亚和毛里塔尼亚的极端干旱。对于干旱对作物生产的影响，在SPI和SPEI-3时间尺度上具有很高的意义：高粱具有SPI-3（r = 0.71）和SPEI-3（r = 0.65），小米具有SPI-3（r =在研究期间，将玉米与SPI-3（r = 0.81）和SPEI-3（r = 0.65 ）和SPEI-3（r = 0.72 ）和SPEI-3（r = 0.72）结合使用。在生长季节，VCI异常与高粱和小米（r分别为0.67和0.75）。在布基纳法索（r = -0.676; P <0.00），马里（r = -0.768; P <0.00），毛里塔尼亚（r = 0.843；P <0.001），尼日尔（r = -0.625；P <0.001）和尼日利亚（r = -0.75；P <0.005）。结果表明，上述指数在评估农业干旱及其对萨赫勒地区农作物生产的影响以及确定受干旱影响最严重的地区方面是有效的。