Comparison and correction of IDW based wind speed interpolation methods in urbanized Shenzhen.

Based on the 2-min average wind speed observations at 100 automatic weather stations in Shenzhen from January 2008 to December 2018, this study tries to explore the ways to improve wind interpolation quality over the Shenzhen region. Three IDW based methods, i.e., traditional inverse distance weight (IDW), modified inverse distance weight (MIDW), and gradient inverse distance weight (GIDW) are used to interpolate the near surface wind field in Shenzhen. In addition, the gradient boosted regression trees (GBRT) model is used to correct the wind interpolation results based on the three IDW based methods. The results show that among the three methods, GIDW has better interpolation effects than the other two in the case of stratified sampling. The MSE and R² for the GIDW's in different months are in the range of 1.096–1.605 m/s and 0.340–0.419, respectively. However, in the case of leave-one-group-out cross-validation, GIDW has no advantage over the other two methods. For the stratified sampling, GBRT effectively corrects the interpolated results by the three IDW based methods. MSE decreases to the range of 0.778–0.923 m/s, and R² increases to the range of 0.530–0.671. In the non-station area, the correction effect of GBRT is still robust, even though the elevation frequency distribution of the non-station area is different from that of the stations' area. The correction performance of GBRT mainly comes from its consideration of the nonlinear relationship between wind speed and the elevation, and the combination of historical and current observation data. [ABSTRACT FROM AUTHOR]