Coupling numerical simulation with remotely sensed information for the study of frozen soil dynamics

• 作者: HuiRan Gao WanChang Zhang
• 来源期刊: 寒旱区科学（英文版）
• 年，卷（期）: 2020,（6）
• 所属期刊栏目: Articles
• 页码范围: 404-417
• 页数: 14页
• 语种: 英文

摘要

The acquisition of spatial-temporal information of frozen soil is fundamental for the study of frozen soil dynamics and its feedback to climate change in cold regions. With advancement of remote sensing and better understanding of frozen soil dynamics, discrimination of freeze and thaw status of surface soil based on passive microwave remote sensing and numeri-cal simulation of frozen soil processes under water and heat transfer principles provides valuable means for regional and global frozen soil dynamic monitoring and systematic spatial-temporal responses to global change. However, as an impor-tant data source of frozen soil processes, remotely sensed information has not yet been fully utilized in the numerical simu-lation of frozen soil processes. Although great progress has been made in remote sensing and frozen soil physics, yet few frozen soil research has been done on the application of remotely sensed information in association with the numerical model for frozen soil process studies. In the present study, a distributed numerical model for frozen soil dynamic studies based on coupled water-heat transferring theory in association with remotely sensed frozen soil datasets was developed. In order to reduce the uncertainty of the simulation, the remotely sensed frozen soil information was used to monitor and modify relevant parameters in the process of model simulation. The remotely sensed information and numerically simulat-ed spatial-temporal frozen soil processes were validated by in-situ field observations in cold regions near the town of Naqu on the East-Central Tibetan Plateau. The results suggest that the overall accuracy of the algorithm for discriminating freeze and thaw status of surface soil based on passive microwave remote sensing was more than 95％. These results pro-vided an accurate initial freeze and thaw status of surface soil for coupling and calibrating the numerical model of this study. The numerically simulated frozen soil processes demonstrated good performance of the distributed numerical mod-el based on the coupled water-heat transferring theory. The relatively larger uncertainties of the numerical model were found in alternating periods between freezing and thawing of surface soil. The average accuracy increased by about 5％af-ter integrating remotely sensed information on the surface soil. The simulation accuracy was significantly improved, espe-cially in transition periods between freezing and thawing of the surface soil.