Sarah Worden, A. Anthony Bloom, John Worden, Paul Levine, Mingjie Shi, Rong Fu
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引用次数: 0
摘要
刚果盆地的植被和降雨量存在巨大的时空梯度。然而,其水分平衡(蒸散量减去降水量,或 ET - P)通常是在流域尺度上测量的,主要受限于河流排水数据、陆地储水测量的空间分辨率以及对蒸散量的限制。我们利用对水汽同位素组成的观测,量化了 2003 年至 2018 年刚果盆地地表水净通量的时空变化。利用卫星重力和刚果河总排水量测量数据对这些数据进行流域尺度校准,然后用于估算刚果盆地四个象限的时变蒸散发--P,首次为该地区提供了此类估算数据。我们发现,同位素和基于重力/河流排水量估算的蒸散发的多年记录、季节性和年际变化是一致的。此外,我们利用基于降水和重力的估算值以及基于水蒸气同位素的蒸散发-磷估算值,计算出刚果盆地的时空平均蒸散发和河流净排水量。这些象限尺度的水汽通量估算结果表明:(a)刚果盆地的水汽循环量很大(时间和空间平均蒸散发/P >70%),与模型和基于可见光的蒸散发估算结果一致;(b)刚果西部的河流净流出量最大,因为那里河流较多,流速较高。我们的研究结果证实,相对于其他水源,蒸散发在调节刚果水循环方面具有重要作用。
Congo Basin Water Balance and Terrestrial Fluxes Inferred From Satellite Observations of the Isotopic Composition of Water Vapor
Large spatio-temporal gradients in the Congo basin vegetation and rainfall are observed. However, its water-balance (evapotranspiration minus precipitation, or ET − P) is typically measured at basin-scales, limited primarily by river-discharge data, spatial resolution of terrestrial water storage measurements, and poorly constrained ET. We use observations of the isotopic composition of water vapor to quantify the spatio-temporal variability of net surface water fluxes across the Congo Basin between 2003 and 2018. These data are calibrated at basin scale using satellite gravity and total Congo river discharge measurements and then used to estimate time-varying ET − P over four quadrants representing the Congo Basin, providing first estimates of this kind for the region. We find that the multi-year record, seasonality, and interannual variability of ET − P from both the isotopes and the gravity/river discharge based estimates are consistent. Additionally, we use precipitation and gravity-based estimates with our water vapor isotope-based ET − P to calculate time and space averaged ET and net river discharge within the Congo Basin. These quadrant-scale moisture flux estimates indicate (a) substantial recycling of moisture in the Congo Basin (temporally and spatially averaged ET/P > 70%), consistent with models and visible light-based ET estimates, and (b) net river outflow is largest in the Western Congo where there are more rivers and higher flow rates. Our results confirm the importance of ET in modulating the Congo water cycle relative to other water sources.
期刊介绍:
Water Resources Research (WRR) is an interdisciplinary journal that focuses on hydrology and water resources. It publishes original research in the natural and social sciences of water. It emphasizes the role of water in the Earth system, including physical, chemical, biological, and ecological processes in water resources research and management, including social, policy, and public health implications. It encompasses observational, experimental, theoretical, analytical, numerical, and data-driven approaches that advance the science of water and its management. Submissions are evaluated for their novelty, accuracy, significance, and broader implications of the findings.