AbstractSurface water, which is changing constantly, is a crucial component in the global water cycle, as it greatly affects the water flux between the land and the atmosphere through evaporation. However, the influences of changing surface water area on the global water budget have largely been neglected. Here we estimate an extra water flux of 30.38 ± 15.51 km3/year omitted in global evaporation calculation caused by a net increase of global surface water area between periods 1984–1999 and 2000–2015. Our estimate is at a similar magnitude to the recent average annual change in global evapotranspiration assuming a stationary surface water area. It is also comparable to the estimated trends in various components of the hydrological cycle such as precipitation, discharge, groundwater depletion, and glacier melting. Our findings suggest that the omission of surface water area changes may cause considerable biases in global evaporation estimation, so an improved understanding of water area dynamics and its atmospheric coupling is crucial to reduce the uncertainty in the estimation of future global water budgets.

中文翻译：

---

对地表水域变化导致的陆地蒸散发增加的全球评估

摘要不断变化的地表水是全球水循环的重要组成部分，因为它通过蒸发极大地影响陆地和大气之间的水通量。然而，地表水域面积变化对全球水预算的影响在很大程度上被忽视了。这里我们估计额外的水通量为 30.38 ± 15.51 km3/year 在1984-1999年和2000-2015年期间全球地表水面积净增加导致的全球蒸发量计算中被省略。假设地表水域固定，我们的估计与最近全球蒸散量的年平均变化幅度相似。它还可与水文循环各个组成部分（如降水、排放、地下水枯竭和冰川融化）的估计趋势进行比较。我们的研究结果表明，忽略地表水域变化可能会导致全球蒸发量估算出现相当大的偏差，因此更好地了解水域动态及其大气耦合对于减少未来全球水预算估算的不确定性至关重要。