| 摘 要： |
The change in heat storage (G(c)) is an essential component of a lake ' s energy balance, and its importance for lake evaporation (E-w) has been widely recognized. However, the effect of G(c) on Ew exhibits diversity across time dimensions. The controls on G(c) and the effects of G(c) on Ew estimates at different time scales remain largely unexplored. To address these gaps, we identified the primary controls on G(c) at an eddy covariance site in a large shallow lake (Lake Taihu) and quantified the role of G(c) in estimating Ew on three (hourly, daily, and monthly) time scales based on two energy balance-based E-w models. Our results indicate that the diurnal variation of G(c) is dominated by net radiation and peaks around noon, while the seasonal variation of G(c) is mainly controlled by air temperature and peaks in spring. In contrast, the daily variation of G(c) is subjective to a confluence of factors-net radiation, wind speed, and relative humidity-displaying more stochasticity than that on the other two time scales. We also found that the importance of G(c) for E-w estimates decreases as the time scale extends. Compared to the two models disregarding G(c), considering the effect of G(c) enhances the average Kling-Gupta efficiency (KGE) values of the two models by 1.33, 0.42, and 0.08 on the three time scales, respectively. Overall, this study highlights the importance of time scales in evaluating the effect of G(c) on E-w estimates. |
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