Abstract: Three kinds of interpolation methods including Inverse Distance Weight(IDW),Ordinary Kriging(OK) and Thin Plate Smoothing Spline(TPS) were used to interpolate monthly average air temperature,precipitation and relative humidity at the spatial resolution by 1.0 km×1.0km in 1971-2000 in 92 meteorological stations,which covered the mountainous areas of the Southwest China.The results were verified by the cross validation and the random validation.The results showed that TPS was of the best accuracy of three methods for temperature,precipitation and relative humidity,significantly for air temperature and precipitation.The difference of the accuracy of three interpolation methods for the aestival relative humidity was not significant.However,the interpolation accuracy for the temperature and relative humidity were greatly improved as the number of samples increased,but it was not obviously for the precipitation.

Key words: Mountain climate, Mountain climate, Spatial interpolation, Thin plate smoothing spline(TPS), Agri-meteorology, Southwest China