利用不同插值方法对青藏高原降水稳定同位素空间分布分析

利用稳定同位素大气环流模型模拟结果, 借鉴数据同化的思想, 运用Cressman插值法和最优插值法两种空间插值方法对青藏高原多年平均降水δ¹⁸O模拟结果进行客观订正, 并运用交叉验证方法检验空间插值的效果. 结果表明: 最优插值法订正的结果稍优于Cressman插值法; 对比订正结果与运用经验回归模型BW模拟结果表明, 最优插值所建立的降水稳定同位素的空间分布结果要优于BW模型模拟结果, 而Cressman插值方法订正的降水稳定同位素的空间分布结果与BW模型模拟的结果相当. 两种空间插值所得结果经过高程订正后, 对青藏高原南部的预测结果得到了明显改善.

Spatial distribution of stable isotope in precipitation upon the Tibetan Plateau analyzed with various interpolation methods

The stable isotope (δ¹⁸O) on the Tibetan Plateau was interpolated by Cressman interpolation method and by optimum interpolation method after altitude correction. It is found that the performance of the optimum interpretation method is better than that of the Cressman interpretation method. Comprised with the results of regression model (BW model), the spatial distribution of δ¹⁸O interpolated by optimum interpretation method is also better. In the meanwhile, the δ¹⁸O spatial distribution on the southern Tibetan Plateau has been obviously improved through an altitude correction. However, the δ¹⁸O spatial distribution on the northern Tibetan Plateau has not been better after altitude correction.