了解干旱的时空模式对于规划至关重要,备灾,脆弱性评估,影响评估,和政策制定,以减轻干旱造成的影响。这项研究的目的是使用Menna流域的地理空间技术评估降雨趋势和气象干旱的时空格局。气候危害组有站的红外降水(CHIRPS)降雨,基于站点的观测降雨量是使用的数据集。基于站点的降雨用于确认CHIRPS降雨数据的准确性。Mann-Kendall(MK)检验和Sen的斜率估计器被用来评估趋势并确定变化的程度。为了描述气象干旱的特征,正常百分比(PN),标准化异常指数(SAI),在作物生长季节(2000-2022年)计算了标准化降水指数(SPI)。验证结果证实了观测到的降雨数据与CHIRPS降雨数据之间的高度一致性(R2=0.88)。根据MK测试,年(3.7毫米/年)和贝尔(3.4毫米/年)降雨量呈上升趋势,在p<0.05时显著。但是kiremt季节略有下降(-0.7毫米/年)。PN,SAI,SPI值检测到2002、2004、2009、2011、2014、2015和2019年是该地区的干旱年。在2009年,2014年和2015年,即使只有1.4%,0.2%和0.5%的流域没有干旱,由于降雨量极高。相反,与其他年份相比,2001年,2010年和2016年的降雨量最高。一般来说,该地区可以归类为埃塞俄比亚西北部极易发生气象干旱的地区。在整个研究期间,甚至没有一年没有干旱。在这种程度上,在研究期间,约有86%的人反复遇到极端降雨不足(7-23次)。因此,人口总是被频繁的干旱摧毁。为了应对现有挑战并减轻即将到来的风险,持续监测干旱和实施有效的预警系统对该地区至关重要。
Understanding the spatiotemporal patterns of drought is crucial for planning, disaster preparedness, vulnerability assessment, impact evaluation, and policy formulation to mitigate drought-induced effects. The purpose of this study was to assess rainfall trends and spatiotemporal patterns of meteorological drought using geospatial techniques in Menna watershed. The Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS) rainfall, and station-based observed rainfall were the datasets used. The station-based rainfall was used to confirm the accuracy of CHIRPS rainfall data. The Mann-Kendall (MK) test and Sen\'s slope estimator were utilized to assess trends and ascertain the extent of change. To characterize meteorological droughts, percent of normal (PN), standardized anomaly index (SAI), and standardized precipitation index (SPI) were computed during the crop growing seasons (2000-2022). The validation result confirmed a strong agreement between the observed and CHIRPS rainfall data (R2 = 0.88). Based on the MK test, an increasing trend has been observed in annual (3.7 mm/year) and belg (3.4 mm/year) rainfall, which was significant at p < 0.05. But the kiremt season was slightly decreasing (-0.7 mm/year). The PN, SAI, and SPI values detected that 2002, 2004, 2009, 2011, 2014, 2015, and 2019 were drought years in the area. Even only 1.4, 0.2, and 0.5% of the watershed were free from drought in 2009, 2014, and 2015, respectively, due to extremely high rainfall deficiency. Conversely, 2001, 2010, and 2016 were notable for having the highest amounts of rainfall compared to the other years. Generally, the region could be classified as an area highly susceptible to meteorological drought in northwestern Ethiopia. There was no even a single year free from drought in the entire study period. To that extent, about 86% of it had repeatedly encountered extreme rainfall deficit (7-23 times) during the study period. Thus, the population has always been repeatedly smashed down by the frequent droughts. To tackle existing challenges and mitigate upcoming risks, continual droughts monitoring and implementation of efficient early warning systems are vital for the region.