Coordinated estimates of 4-day 500 m global land surface energy balance components

文献类型: 外文期刊

第一作者: Wang, Junrui

作者: Wang, Junrui;Tang, Ronglin;Jiang, Yazhen;Huang, Lingxiao;Li, Zhao-Liang;Wang, Junrui;Tang, Ronglin;Jiang, Yazhen;Huang, Lingxiao;Li, Zhao-Liang;Liu, Meng;Li, Zhao-Liang

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关键词: Surface energy balance components; Net radiation; Sensible heat flux; Latent heat flux; Evapotranspiration

期刊名称:REMOTE SENSING OF ENVIRONMENT ( 影响因子:11.4; 五年影响因子:14.3 )

ISSN: 0034-4257

年卷期: 2025 年 326 卷

页码:

收录情况: SCI

摘要: Accurate estimations of global land surface energy balance components [including net radiation (Rn), latent heat flux (LE), soil heat flux (G) and sensible heat flux (H)] are crucial for quantifying the exchange of heat and water between the land surface and atmosphere. In this study, a novel and practical model for Coordinated estimates of 4-day 500 m global land Surface Energy Balance components (CoSEB) was developed, using the multivariate random forest technique and a synthesis of remote sensing and reanalysis datasets, as well as the extensive observations at 336 eddy-covariance sites worldwide. The CoSEB model effectively balances the estimates of Rn, LE, H, and G by learning the physics of energy conservation embedded in these components within the training datasets. Its advantages include 1) the accurate estimation of the four energy components and their ratios [i.e. evaporation fraction, defined as LE/(Rn-G), which reflects the proportion of surface available energy that is allocated to LE instead of H], and 2) the ability to maintain energy balance among the four energy components, i. e. Rn-G-LE-H = 0. With the 10-fold cross-validation at 286 sites, the CoSEB model achieved the root mean square error (RMSE) of 16.42 W/m2, 16.40 W/m2, 16.49 W/m2, 4.79 W/m2 and 0.22, and the coefficient of determination (R2) of 0.92, 0.86, 0.83, 0.55 and 0.59, respectively, for estimating Rn, LE, H, G and evaporative fraction, which were comparable or superior to those estimated by other typical data-driven uncoordinated and coordinated models. In the validation with test datasets at another 50 eddy-covariance sites, the CoSEB model, with the RMSE of 18.23 W/m2, 17.98 W/m2, and 19.17 W/m2, and the R2 of 0.87, 0.72, 0.71 in estimating Rn, LE, and H, respectively, outperformed all six state-of-the-art algorithms/products, i.e. FLUXCOM, BESSV2.0, MOD16A2, PML_V2, ETMonitor and GLASS. Besides, the CoSEB model successfully maintained energy balance, exhibiting an energy imbalance ratio [EIR, defined as 100% x (Rn-G-LE-H)/Rn] of 0, in comparison to other coordinated and uncoordinated models/products presenting the EIRs of as high as 50%. The new model also produced consistent global patterns with the six state-of-the-art products for each of the Rn, LE, and H estimates at 8-day, monthly, and yearly scales. The CoSEB model is promising for operationally generating high-accuracy global balanced land surface energy components and their ratios, which is essential for rationally partitioning surface available energy into H and LE, and for revealing the spatiotemporal variations of the energy components and their attributions and mechanisms at regional and global scales.

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