摘要:积雪作为一种特殊的覆被，直接影响着土壤温度、土壤水分分布及其冻结深度、冻结速率等，影响当地的生态水文过程。利用2017年11月1日至2018年3月31日天山北坡伊犁阿热都拜流域的土壤含水率资料，划分土壤不同冻融阶段，结合积雪不同阶段，进而分析积雪消融对季节性冻土温湿度的影响。结果表明：在整个土壤冻融期间，土壤温湿度的变化取决于积雪深度、大气温度和雪面温度的高低，且与其稳定性有关。土壤冻结阶段，土壤温湿度持续下降，表层土壤温湿度受气温影响较大，且波动明显，而深层土壤的温湿度变化平缓；土壤完全冻结时，有稳定积雪覆盖，由于积雪的高反射性、低导热性，影响着地气之间的热量传递，因此土壤的温湿度变化较为平稳，积雪有一定的保温作用；冻土消融阶段，气温回升，积雪消融，地表出露，各层土壤温度随气温变化而变化，且越靠近地表，土壤温度越高，变幅越大，与冻结期完全相反。由于融雪水的下渗，土壤湿度快速增加。进一步分析积雪与土壤温湿度的相关性得出，积雪对土壤温湿度的影响分不同时期，对土壤温度的影响主要在积雪覆盖时，对土壤湿度的影响主要是在积雪消融时期，这对于研究该地生态水文循环及后续融雪性洪水的模拟与预报具有一定的参考价值。



Abstract:As a special cover, snow cover directly affects soil temperature, soil moisture distribution, freezing depth and freezing rate, and affects the local eco-hydrological processes. The existence of snow can affect the frozen soil, the interaction of surface-atmosphere, and change the energy exchange and temperature transfer between the soil and the atmosphere. The freezing-thawing process of soil has an important impact on soil water content. It is of great significance for the effective utilization of frozen soil resources, the guidance of irrigation water, the study of soil evaporation, groundwater recharge and local eco-hydrological cycle. In this paper, meteorological data, soil temperature and moisture data and snow cover data were used to analyze the characteristics of seasonal frozen soil temperature and moisture changes in the study area. Based on the data of soil water content from November 1, 2017 to March 31, 2018 in the Alatobe Basin, Ili, on the northern slope of Tianshan Mountains, the different freezing-thawing stages of soil were divided, and the effects of snow melting on the temperature and moisture of seasonal frozen soil were analyzed. The results show that snow melting has a great influence on the temperature and moisture of seasonal frozen soil. The soil was frozen beginning in November in Alatobe Basin, and the soil freezing time lagged with the increase of soil depth. The soil freezing process is one-way, starting from the surface, while the melting process is two-way, starting from both the surface and the bottom. During the whole freezing-thawing period, the change of soil temperature and moisture depends on the depth of snow cover, atmospheric temperature and snow surface temperature. And it mainly affects the surface soil temperature. The deeper the soil depth is, the more slightly the change of soil temperature and moisture is. During the soil freezing stage, the soil temperature and moisture continued to decline, the surface soil temperature and moisture were greatly affected by temperature, and the fluctuation was obvious, while the deep soil temperature and moisture changed slightly. When the soil was completely frozen, there was stable snow cover. Because the high reflectivity and low thermal conductivity of snow affected the heat transfer of surface-atmosphere, the change of soil temperature and moisture was relatively stable, and the snow cover had a certain degree. During the thawing stage, the temperature rises, the snow melts and the surface exposes. The soil temperature varies with the change of temperature. The closer to the surface, the higher the soil temperature, the larger the change range, which is completely contrary to the freezing period. Soil moisture increases rapidly due to the infiltration of snowmelt water. Further analysis of the correlation between snow cover and soil temperature and moisture shows that the influence of snow cover on soil temperature and moisture can be divided into different periods. The influence on soil temperature is mainly in snow cover, and the influence on soil moisture is mainly in snow melting period, which has a certain reference value for the study of the eco-hydrology cycle and the simulation and prediction of subsequent snowmelt flood in this area.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201901040044