This study assesses the spatial and temporal characteristics (e.g., frequency, intensity, spatial extent) of meteorological drought in Syria. Specifically, drought was characterized using the observed rainfall data from 36 rain gauges spanning the period between 1990 and 2010 and covering the main climatic regions in Syria (i.e., Mediterranean, arid, semiarid and mountainous). Meteorological drought was assessed using the standardized precipitation index (SPI) at 12-month timescale, allowing for detecting the impacts of climate variability on agricultural droughts. The dominant modes of drought were defined using an S-mode of the principal component analysis. To assess the links between meteorological drought evolution and vegetation greening in Syria, the time series of SPI were correlated with the normalized difference vegetation index (NDVI). Time series of NDVI were retrieved from the remotely sensed National Oceanic and Atmospheric Administration Advanced Very High-Resolution Radiometer (NOAA/AVHRR) sensor at a spatial resolution of 25 km for the common period 1990–2010. Trend analysis suggests a statistically significant increase in the frequency and intensity of drought at 12-month timescale. The observed intensification of meteorological drought is mostly associated with the increase in mild and moderate droughts, relative to extremes and very extreme droughts. Results also suggest a statistically significant decrease (p < 0.05) in vegetation greening over Syria during the study period, especially in the eastern parts of the country. Our results demonstrate that the decrease in vegetation cover can directly be linked to the anomalous drought events, with Pearson’ r coefficients generally above 0.6. This dependency was more highlighted during wintertime for the Mediterranean vegetation and in northeastern portions of the country. Overall, the increase in the frequency and intensity of meteorological drought, combined with a series of unrest and political instability, have drastic impacts on the agricultural sector in Syria, with serious implications for crop yield.

这项研究评估了叙利亚气象干旱的时空特征（例如频率，强度，空间范围）。具体而言，干旱是根据1990年至2010年这段时间内从36个雨量仪观测到的降雨数据来表征的，这些数据涵盖了叙利亚的主要气候区（即地中海，干旱，半干旱和山区）。使用标准化降水指数（SPI）在12个月的时间尺度上评估了气象干旱，从而可以检测出气候变化对农业干旱的影响。干旱的主要模式是使用主成分分析的S模式定义的。为了评估叙利亚的气象干旱演变与植被绿化之间的联系，将SPI的时间序列与归一化植被指数（NDVI）相关联。NDVI的时间序列是从遥感的美国国家海洋与大气管理局高级超高分辨率辐射计（NOAA / AVHRR）传感器中获得的，在1990-2010年的共同时期内，其空间分辨率为25 km。趋势分析表明，在12个月的时间范围内，干旱的频率和强度在统计上显着增加。相对于极端干旱和非常极端干旱，观测到的气象干旱加剧主要与轻度和中度干旱的增加有关。结果还显示出统计学上的显着下降（趋势分析表明，在12个月的时间范围内，干旱的频率和强度在统计上显着增加。相对于极端干旱和非常极端干旱，观测到的气象干旱加剧主要与轻度和中度干旱的增加有关。结果还显示出统计学上的显着下降（趋势分析表明，在12个月的时间范围内，干旱的频率和强度在统计上显着增加。相对于极端干旱和非常极端干旱，观测到的气象干旱加剧主要与轻度和中度干旱的增加有关。结果还显示出统计学上的显着下降（p  <0.05）在研究期间叙利亚境内的植被绿化特别是在该国东部地区。我们的结果表明，植被覆盖率的下降与干旱异常事件直接相关，Pearson r系数通常高于0.6。在冬季，地中海植被和该国东北部的这种依赖性更加突出。总体而言，气象干旱的频率和强度增加，加上一系列动荡和政治动荡，对叙利亚的农业部门产生了严重影响，对作物产量产生了严重影响。