In this study,the authors propose a model,called the Daily Downward Shortwave Radiation Random Forest Model over Rugged Terrain(DSRMT),to accurately calculate the downward shortwave radiation over a terrain without br...In this study,the authors propose a model,called the Daily Downward Shortwave Radiation Random Forest Model over Rugged Terrain(DSRMT),to accurately calculate the downward shortwave radiation over a terrain without bright surface on clear days at a daily scale(DSRdaily−rugged).It was built by using the random forest method based on the comprehensive samples from CERES4_SYN1deg_Ed4A within 17 typical mountainous regions.DSRMT could directly estimate DSRdaily-rugged from the instantaneous direct and diffuse solar radiation on a flat surface during 10:30–14:30hrs on each day by comparing with the terrain factors from a digital elevation model,broadband albedo from the Global Land Surface Satellite,and ancillary information.The in-situ validation results showed that it generally delivered superior performance in estimating DSRdailyrugged at any time during 10:30–14:30hrs,especially at noon,yielding a validated root mean-squared error(RMSE)of 24.90–29.22 Wm−2 and mean absolute error(MAE)of 19.16–22.94 Wm−2,and the average weighted DSRdaily-rugged were usually more accurate with the RMSE and MAE of 21.63 and 17.14 Wm−2.Overall,DSRMT was found to deliver satisfactory performance because of its high accuracy,robustness,ease of implementation,and efficiency,so it has the strong potential to be widely used in practice.展开更多
基金funded by the National Key Research and Development Program of China[2020YFA0608704]the National Natural Science Foundation of China[grant no 41971291].
文摘In this study,the authors propose a model,called the Daily Downward Shortwave Radiation Random Forest Model over Rugged Terrain(DSRMT),to accurately calculate the downward shortwave radiation over a terrain without bright surface on clear days at a daily scale(DSRdaily−rugged).It was built by using the random forest method based on the comprehensive samples from CERES4_SYN1deg_Ed4A within 17 typical mountainous regions.DSRMT could directly estimate DSRdaily-rugged from the instantaneous direct and diffuse solar radiation on a flat surface during 10:30–14:30hrs on each day by comparing with the terrain factors from a digital elevation model,broadband albedo from the Global Land Surface Satellite,and ancillary information.The in-situ validation results showed that it generally delivered superior performance in estimating DSRdailyrugged at any time during 10:30–14:30hrs,especially at noon,yielding a validated root mean-squared error(RMSE)of 24.90–29.22 Wm−2 and mean absolute error(MAE)of 19.16–22.94 Wm−2,and the average weighted DSRdaily-rugged were usually more accurate with the RMSE and MAE of 21.63 and 17.14 Wm−2.Overall,DSRMT was found to deliver satisfactory performance because of its high accuracy,robustness,ease of implementation,and efficiency,so it has the strong potential to be widely used in practice.
