Bikeko Samuel Shibeshi, Venkatesham Dr E
Department of Geography, Central University of Tamil Nadu, School of Earth Sciences, Thiruvarur, Tamil Nadu, India.
PLoS One. 2024 Dec 31;19(12):e0311961. doi: 10.1371/journal.pone.0311961. eCollection 2024.
Land use and land cover (LULC) changes are crucial in influencing regional climate patterns and environmental dynamics. However, the long-term impacts of these changes on climate variability in the Bilate River Basin remain poorly understood. This study examines the spatiotemporal changes in LULC and their influence on climate variability in the Bilate River Basin, Ethiopia, over the period from 1994 to 2024. Utilizing multispectral satellite imagery from Landsat 5, 7, and 8, along with meteorological data from five stations, LULC was classified using the Random Forest algorithm on the Google Earth Engine platform. Climate variability and trends were assessed using the Mann-Kendall trend test, the Standardized Precipitation Index (SPI), and the Standardized Temperature Index (STI). The results reveal a consistent decline in forest cover, with a rapid annual loss of 4,681.2 hectares between 2014 and 2024. Concurrently, agricultural land expanded at an annual rate of approximately 1,141 hectares, while urban areas grew by 24.3 hectares annually in recent years. These LULC changes have contributed to significant climate variability in the region. The upper catchment experienced notable declines in rainfall and warming across all seasons. In the middle catchment, spring rainfall increased, accompanied by moderate summer warming. The lower catchment saw significant increases in spring and autumn rainfall, with no notable temperature trends. These findings highlight the critical impact of LULC changes on the region's climate and emphasize the need for sustainable land management and conservation practices to address deforestation, urbanization, and agricultural expansion.
土地利用和土地覆盖（LULC）变化在影响区域气候模式和环境动态方面至关重要。然而，这些变化对比拉特河流域气候变率的长期影响仍知之甚少。本研究考察了1994年至2024年期间埃塞俄比亚比拉特河流域LULC的时空变化及其对气候变率的影响。利用陆地卫星5号、7号和8号的多光谱卫星图像以及五个站点的气象数据，在谷歌地球引擎平台上使用随机森林算法对LULC进行了分类。使用曼-肯德尔趋势检验、标准化降水指数（SPI）和标准化温度指数（STI）评估了气候变率和趋势。结果显示森林覆盖持续减少，2014年至2024年间每年快速减少4681.2公顷。与此同时，农业用地以每年约1141公顷的速度扩张，而近年来城市地区每年增长24.3公顷。这些LULC变化导致了该地区显著的气候变率。上游集水区在所有季节降雨量和气温均显著下降。中游集水区春季降雨量增加，夏季气温适度上升。下游集水区春季和秋季降雨量显著增加，气温无明显趋势。这些发现突出了LULC变化对该地区气候的关键影响，并强调需要采取可持续的土地管理和保护措施来应对森林砍伐、城市化和农业扩张问题。
