云南省Ångström-prescott辐射模型的参数化研究

    Parameterization of Ångström-prescott radiation model in Yunnan province

    • 摘要: 现行的太阳辐射通常采用常规数据进行估算。其中,基于日照的Ångström-prescott公式的估算精度最高、应用最广。但模型应用的关键是如何获得适宜的模型参数。该文采用FAO和Liu等推荐的6种参数化方法,在云南省3个站点应用Ångström-prescott公式计算太阳辐射值,并与实测值进行比较。结果表明,Liu等的2种方法太阳辐射值的估算效果最好,精度与校正参数相当。二者在昆明和丽江的平均偏差(MBE)、均方根误差(RMSE)及相对均方根误差(PRMSE)分别在-0.28~0.50、2.09~2.39 MJ/(m2·d)及12.4%~15.8%之间。相比之下,FAO推荐值在这两地点预测的MBE、RMSE及PRMSE分别为-0.43~0.84、2.61~5.37 MJ/(m2·d)及17.2%~31.7%,估算精度远低于前两种参数化方法。鉴于目前国内直接使用FAO推荐值的做法还相当普遍,该文结果有助于加深人们对Ångström-prescott模型参数选择的重要性的认识,进而实际应用中更多地使用校正值或估算值。

       

      Abstract: Solar radiation is often needed to be estimated by ordinary data in the current applications now, in which the sunshine-based Ångström-prescott formula is widely used with highest accuracy. However, the key of its application is to obtain the appropriate local parameters. In this paper, six parameterization methods, one from FAO and the other five from Liu et al., were evaluated using data from three sites in Yunnan province. The results showed that two methods of Liu et al. performed best, and their estimation accuracy was similar to the calibrated ones. In Kunming and Lijiang, the mean bias error (MBE), the root mean square error (RMSE) and the relative root mean square error (PRMSE) was -0.28-0.50 MJ/(m2·d), 2.09-2.39 MJ/(m2·d) and 12.4%-15.8%, respectively. In contrast, the MBE, RMSE and PRMSE obtained by the FAO scheme at these two sites were -0.43-0.84 MJ/(m2·d), 2.61-5.37 MJ/(m2·d) and 17.2%-31.7%, which showed a much lower accuracy than two methods of Liu et al. Considering the fact that it is still a common practice to directly use the FAO method, this research contributed to understand the importance of parameter choice for the Ångström-prescott model and suggested the calibrated or parameterized parameter can be used as much as possible in practice.

       

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