Although considerable effort has been deployed to understand the impact of climate variability and vegetation change on runoff in major basins across Africa, such studies are scarce in the Gulf of Guinea Basin (GGB). This study combines the Budyko framework and elasticity concept along with geospatial data to fill this research gap in 44 nested sub‐basins in the GGB. Annual rainfall from 1982 to 2021 show significant decreasing and increasing trends in the northern and southern parts of the GGB, respectively. Annual potential evapotranspiration (PET) also shows significant increasing trends with higher magnitudes observed in the northern parts of the GGB. Changing trends in climate variables corroborates with shift to arid and wetter conditions in the north and south, respectively. From 2000 to 2020 vegetation cover estimated using enhanced vegetation index (EVI) shows significant increasing trends in all sub‐basins including those experiencing a decline in annual rainfall. Vegetation composition measured using vegetation continuous fields (VCFs) from 2000 to 2020 show an increase in tree canopy cover (TC), a decline in short vegetation cover and marginal changes in bare ground cover (BG). Elasticity coefficients show that a 10% increase in annual rainfall and PET may lead to a 33% increase and 24% decline in runoff, respectively. On the other hand, a 10% increase in EVI may lead to a 4% decline in runoff while a 10% increase in TC, SV and BG may reduce runoff by 4% and increase runoff by 3% and 2%, respectively. Even though changes are marginal, decomposing vegetation into different parameters using EVI and VCFs may lead to different hydrological effects on runoff which is one of the novelties of this study that may be used for implementing nature‐based solutions. The study also demonstrates that freely available geospatial data together with analytical methods are a promising approach for understanding the impact of climate variability and vegetation change on hydrology in data‐scarce regions.

中文翻译：

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气候、植被覆盖和植被组成的变化影响几内亚湾盆地径流的产生

尽管为了了解气候变化和植被变化对非洲主要流域径流的影响已经付出了相当大的努力，但在几内亚湾流域（GGB），此类研究却很少。本研究将 Budyko 框架和弹性概念与地理空间数据相结合，填补了 GGB 44 个嵌套子流域的研究空白。 1982年至2021年，大湾区北部和南部的年降雨量分别呈现显着减少和增加的趋势。年潜在蒸散量 (PET) 也显示出显着的增加趋势，在 GGB 北部观察到的幅度更高。气候变量的变化趋势证实了北部和南部分别向干旱和湿润条件的转变。从 2000 年到 2020 年，使用增强植被指数 (EVI) 估算的植被覆盖度显示，所有子流域（包括年降雨量下降的子流域）均呈显着增加趋势。 2000年至2020年使用植被连续田（VCF）测量的植被组成显示，树冠覆盖率（TC）增加，短植被覆盖率下降，裸地覆盖率（BG）发生边际变化。弹性系数显示，年降雨量和PET增加10%可能分别导致径流增加33%和减少24%。另一方面，EVI增加10%可能导致径流减少4%，而TC、SV和BG增加10%可能分别减少径流4%和增加径流3%和2%。尽管变化很小，但使用 EVI 和 VCF 将植被分解为不同的参数可能会对径流产生不同的水文影响，这是本研究的新颖之处之一，可用于实施基于自然的解决方案。该研究还表明，免费提供的地理空间数据与分析方法是了解气候变化和植被变化对数据稀缺地区水文影响的一种有前途的方法。