Based on DEM (digital elevation model) data, a distributed model for calculating 30 min solar radiation under actual weather and terrain condition is established. In the model, the domestic and overseas estimating methods of solar radiation are used. The performance of this model is validated  using 30 min total radiation data at 3 sites in  mountainous region of Mafengou river basin of Qilian Mountain region from September  2008 to June  2009. The result shows that the error of DEM can induce the error of calculated  shade, which in turn induced the error of calculated total radiation near sunrise and sunset is big. Using the actual shade data of the 3 validated points, the  performance of model are improved a lot. Over all, the validated results show that R² are all above 0.9, which means the 30 min solar radiation model is applicable over other regions.

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