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利用2013年10月1日至2014年5月31日黄河源区鄂陵湖流域的土壤温度资料首先划分土壤不同冻融阶段,然后在每个阶段各选取一次降雪过程,分析了降雪对土壤温湿变化的影响。结果表明:在土壤冻结阶段,雪后晴天(有雪覆盖)土壤净输出的热量减少,5 cm和10 cm土壤日最低温度明显升高,20 cm土壤日最低温度升至0℃以上,导致20 cm土壤达到完全冻结的时间延长;在土壤消融阶段,降雪当天土壤净输入的热量减少,5 cm和10 cm土壤日最高温度突降至0℃以下,导致5 cm和10cm土壤达到完全消融的时间增加。在以上两个阶段的降雪过程中,积雪不仅可通过自身的消融增加浅层土壤湿度,还可通过改变浅层土壤温度间接影响浅层土壤湿度,而在土壤完全冻结阶段,积雪对土壤温度虽有影响,但对土壤湿度的直接和间接影响都较小。在整个土壤冻融阶段,与由土壤冻结和消融引起的土壤湿度变化相比,降雪引起的土壤湿度变化较小。
Based on the soil temperature data of Eling Lake Basin in the source region of the Yellow River from October 1, 2013 to May 31, 2014, the soil was first divided into different freeze-thaw phases and then snowfalls were selected at each stage. The effect of snowfall on soil temperature Effect of wet change. The results showed that in the freezing stage of the soil, the net output of heat in the sunny (snow-covered) soil decreased after snowfall, the daily minimum temperature in 5 cm and 10 cm increased significantly, and the daily minimum temperature in 20 cm increased above 0 ° C, resulting in 20 cm soil reaches a complete freezing time. In the soil ablation stage, net input of heat on the day of snowfall decreases and the daily maximum temperature at 5 cm and 10 cm drops suddenly below 0 ° C, resulting in complete ablation time of 5 cm and 10 cm soil increase. During the above two stages of snowfall, snow cover can not only increase the shallow soil moisture by its own ablation, but also indirectly affect the shallow soil moisture by changing the shallow soil temperature. In the completely frozen soil stage, Although temperature has an impact, it has less direct and indirect impacts on soil moisture. During the entire period of soil freezing and thawing, the change of soil moisture caused by snowfall is less than that of soil moisture caused by soil freezing and ablation.