利用中国698个气象站点1971-2000年的地面气候资料,采用三种不同方法预测中国0cm、20cm和40cm深度年均土壤温度的空间分布,其中普通克里格和泛克里格法直接以年均土壤温度数据为源数据、回归克里格法以中国年均气温数据和中国DEM数据为源数据进行预测。预测结果的准确性通过平均绝对误差(MAE)和均方根误差(RMSE)值来评价。结果表明回归克里格法预测的MAE值和RMSE值均为最小,说明其预测结果的准确性最好、预测的极端误差也最小;其次为泛克里格法;普通克里格法预测的效果最差。回归克里格法预测结果由于采用了中国DEM数据进行修正,在空间特征表达方面能够更好地表达复杂地形地区的局部变异,其平滑效应明显小于泛克里格法和普通克里格法的预测结果。
Soil temperature influences many biological and geochemical processes in soil.With the growing interest in the fields of environmental sciences,soil science and global change studies,the spatial data of soil temperature in raster form at a national scale are needed.However,there are only discrete data of soil temperatures in China,which are extracted from meteorological stations.These discrete data of soil temperatures cannot meet the needs now.Thus,it is really meaningful to derive spatially continuous data of soil temperature from discrete data using spatial interpolation methods. Based on the meteorological data from 698 stations in China in the period from 1971 to 2000 and the digital elevation models of China,this paper attempted to predict the spatial patterns of mean annual soil temperatures in China using three different methods.The data of mean annual soil temperatures from meteorological stations were used directly by ordinary kriging and universal kriging methods in the estimation.And the data of mean annual air temperatures and the DEM data of China were used by regression kriging method to predict the spatial patterns of mean annual soil temperatures in China.Prediction was validated using mean absolute error and root mean square error.The results from exploratory analysis on the original soil and air temperature data in China revealed that the two datasets were approximated by the normal distribution,which suggested that the two datasets could be analyzed by geostatistical methods.These three geostatistial methods were compared in the precision and bias of the estimations.The values of mean absolute error and root mean square error produced by regression kriging method were the lowest,which were 1.17-1.25℃ and 1.46-1.58℃,followed by universal kriging method and ordinary kriging method.It indicated that regression kriging method yielded more accurate results than the other two methods.The prediction by regression kriging had less smoothing effect and more details of depicting the local variation