黑河上游山区典型站的水热过程模拟研究

Noah LSM陆面过程模型在国际上被广泛应用于陆面的水热过程模拟, 但在高寒山区的适用性研究并不充分, 目前还没有在黑河上游高寒山区应用的案例. 利用Noah和黑河上游两个典型站(大冬树山垭口站和阿柔站)2008-2009年的观测数据, 对两站的水热过程进行了模拟. 通过比较模拟结果和实测的地温和液态水含量, 表明Noah能够较真实地反映该地区的水热过程. Noah对观测站的地温模拟较好, 但冬季存在一定偏差; 液态水含量的模拟总体偏低, 表层液态水含量在春季土壤融化期的模拟偏差较大. 以上现象与该地区土壤异质性较大、 春季融化期土壤冻融过程中土壤含冰量判定存在偏差、 冬季降水量观测不准等有关. 此外, 结合模拟结果, 讨论了观测数据的质量问题.

Simulating the Water-Heat Processes on Typical Sites in the Mountainous Areas of the Upper Reaches of the Heihe River

The Noah land surface model (LSM) is widely used to simulate water-heat processes in global or regional land surface studies. However, there are few studies on its applicability in cold alpine area characterized by high elevation and cold climate condition. So far, no study has been conducted using Noah LSM in the upper reaches of the Heihe River, a typical cold alpine area. In this paper, based on the observation from 2008 to 2009, Noah LSM was applied to simulate water-heat processes in two typical sites, e.g., Dadongshu Pass Site and Arou Site, located in the upper reaches of the Heihe River. A comparison between simulated and observed soil temperatures and soil liquid contents shows that Noah LSM is able to describe the actual water and heat processes in such alpine cold regions. Soil temperature is simulated generally well, with a few biases in winter. Simulated soil liquid content is generally lower than observed one. Large biases in soil liquid simulation in the upper layers can be seen obviously in spring, when frozen soil begins to thaw. Abovementioned simulation problems are largely related with the insufficient considerations of Noah LSM in soil profile heterogeneity, resulting in incorrect estimating ice content in spring, as well as with the inaccurate precipitation observation, especially in winter. Apart from the applicability of Noah LSM, observation quality is also discussed in this paper.