摘要
活动层作为多年冻土与大气系统之间能量和水分交换通道,其内部的水热状况是控制水循环和地表能量平衡的主要因素,并直接影响着寒区生态环境、水文过程以及多年冻土的稳定性。利用一维水热耦合模型CoupModel,对青藏高原风火山试验点活动层土壤剖面温湿度进行了模拟。模拟效率参数表明模拟结果很好地反映了研究区多年冻土活动层水热状况。基于已验证的模型,设置多种不同气候变化情形,来分析活动层内部水热状况对全球气候变化的响应。研究结果表明:(1)土壤温度与气温呈正相关关系,气温每升高1℃活动层平均增温约0.78℃,但随着土壤深度增加,增温幅度逐渐减小;(2)升温导致活动层土壤冻结和融化过程发生变化,且对融化过程的影响明显大于冻结过程;(3)活动层各深度土壤含水量随气温升高而增大,且增大幅度随土壤深度增加而不断增大;(4)在完全融化期,降水量增加降低了浅层土壤温度,升高了深层土壤温度,而完全冻结期土壤温度均随降水量增加而升高;(5)降水量增加导致活动层含水量增加,其中完全融化期土壤含水量变化最明显。因此,气候暖湿化将对青藏高原多年冻土区活动层土壤温湿度及冻融循环过程产生较大影响,可能不利于冻土发育。
As the energy-water exchange channel between permafrost-atmosphere system,the thermal-moisture conditions of the active layer are the main factors that control the hydrological cycle and surface energy balance,and directly affect the ecological environment,hydrological processes and stability of the permafrost in cold regions. The temperature and moisture contents within the active layer at Fenghuoshan station were simulated by one-dimensional water-heat coupling model CoupModel. The simulation efficiency parameters showed that the simulation results well reflected the thermal-moisture conditions of the active layer of permafrost in the study area. Based on the verified model,a variety of different climate change scenarios were set to analyze the response of the thermal-moisture conditions in the active layer to global climate change. Results showed that:(1)There was a positive correlation between soil temperature and air temperature,and the average temperature of active layer increased by about 0. 78 ℃ for every 1 ℃ increment of air temperature,but the increment of soil temperature decreased as the soil depth increased;(2)The rising air temperature caused changes in the process of freezing and thawing of the active layer,and the impact by the latter is significantly greater than the former;(3)As the temperature rises,the soil water content at each depth of the active layer increased,and the increment increased with the increase of soil depth;(4)During the complete melted period,the increase in precipitation reduced the temperature of the shallow soil,but increased the temperature of the deep soil,while the temperature of each soil layer during the complete frozen period increased with the increase in precipitation;(5)The increase in precipitation caused an increase in the water content of the active layer,with the most obvious change in soil water content during the complete melted period. Therefore,climate warming and wetting will have a greater impact on the soil temperature and moisture of the active layer and the freezing-thawing cycles process in the permafrost regions of the Qinghai-Xizang Plateau,which may not be conducive to the development of frozen soil.
作者
徐洪亮
常娟
郭林茂
孙文军
XU Hongliang;CHANG Juan;GUO Linmao;SUN Wenjun(College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,Gansu,China)
出处
《高原气象》
CSCD
北大核心
2021年第2期229-243,共15页
Plateau Meteorology
基金
国家自然科学基金项目(41671015)。