CAJ | 학술논문

为了研究季节性冻土区土壤水热时空分异特征，揭示冻融过程中的水热相互作用机理及其复杂性。在松嫩平原黑土区，以野外实测试验数据为基础，分别建立裸地、自然降雪、积雪压实和积雪加厚覆盖处理条件下20 cm土层土壤含水率和温度的耦合模型，并通过对比模型的预测效果研究土壤水热变化的复杂程度，采用差异性分析和基于小波变换的分形理论方法定量研究含水率与温度序列的变异波动性和分维指标，进而验证不同覆盖处理条件对于土壤水热空间变异复杂性的影响。结果表明：冻结期，积雪阻碍了环境因素对于土壤水热迁移过程的影响，土壤含水率和温度的耦合效果较好，并且预测值与实测值能够较好的吻合，裸地、自然降雪、积雪压实、积雪加厚处理条件下的相对误差分别为0.42%、0.31%、0.13%和0.06%，随着积雪厚度的增加和密度的增大，含水率和温度的差异性减弱，复杂程度逐渐降低；融化期，积雪覆盖区的融雪水入渗抑制了土壤温度稳定提升，含水率出现骤然升高的现象，自然降雪、积雪压实、积雪加厚条件下的含水率变化分别为14.31%、15.90%和16.91%，土壤温度变化范围分别为?5.9～5.3、?3.6～6.9和?3.1～3.8℃，二者的互作效应减弱，并且随着积雪覆盖量的增加，土壤的水热时空迁移复杂程度逐渐增强。同时，采用基于小波变换的分形理论研究土壤含水率和温度的时间序列复杂性精度较高、结果可靠。该研究对于揭示冻土区土壤水热迁移动态规律，准确预测春播期土壤温度和墒情，合理高效地利用松嫩平原的土壤水资源具有重要的理论价值和现实意义。
위료연구계절성동토구토양수열시공분이특정，게시동융과정중적수열상호작용궤리급기복잡성。재송눈평원흑토구，이야외실측시험수거위기출，분별건립라지、자연강설、적설압실화적설가후복개처리조건하20 cm토층토양함수솔화온도적우합모형，병통과대비모형적예측효과연구토양수열변화적복잡정도，채용차이성분석화기우소파변환적분형이론방법정량연구함수솔여온도서렬적변이파동성화분유지표，진이험증불동복개처리조건대우토양수열공간변이복잡성적영향。결과표명：동결기，적설조애료배경인소대우토양수열천이과정적영향，토양함수솔화온도적우합효과교호，병차예측치여실측치능구교호적문합，라지、자연강설、적설압실、적설가후처리조건하적상대오차분별위0.42%、0.31%、0.13%화0.06%，수착적설후도적증가화밀도적증대，함수솔화온도적차이성감약，복잡정도축점강저；융화기，적설복개구적융설수입삼억제료토양온도은정제승，함수솔출현취연승고적현상，자연강설、적설압실、적설가후조건하적함수솔변화분별위14.31%、15.90%화16.91%，토양온도변화범위분별위?5.9～5.3、?3.6～6.9화?3.1～3.8℃，이자적호작효응감약，병차수착적설복개량적증가，토양적수열시공천이복잡정도축점증강。동시，채용기우소파변환적분형이론연구토양함수솔화온도적시간서렬복잡성정도교고、결과가고。해연구대우게시동토구토양수열천이동태규률，준학예측춘파기토양온도화상정，합리고효지이용송눈평원적토양수자원구유중요적이론개치화현실의의。
Seasonal frozen soils accounts for 54% of Chinese total acreage,mostly distributed in Northeast China where snowing is frequent. Soil moisture under snow cover may interact with temperature, both affecting many processes of biogeochemistry. However, few studies have focused on soil moisture and temperature interaction under snow covers. Therefore, this study investigated the soil moisture and temperature characteristics under seasonal frozen soils in field experiments. The experiment was set up in an experiment field of Northeast Agricultural University, Harbin, China. It was located in south Songnen Plain. During November 8 of 2013-April 28, 2014, four treatments were designed including bare land, natural snow cover land, snow compacted land, and snow thickened land. Each treatment was repeated three times. In bare land, snow was removed by hand. In snow compacted land, snow density was manually increased to 0.256 g/cm3. In the snow thickened land, snow depth was increased but snow density was similar with natural snow cover land. During the experiment, soil temperature was measured by thermometers at 5, 10, 15 and 20 cm soil depth, and soil moisture was measured by time domain reflectometery at same depth. Soil moisture data were divided into two parts: one for model establishment and the other for model validation. Relationship between soil moisture and temperature was described by exponential models. Fractal dimensions were used to evaluate complexity of soil moisture and temperature. The results showed that: 1) The whole experiment duration could be divided into rapid freezing stage, stable freezing stage, and melting stage; On March 1, the freezing depth reached the highest value of 118 cm; 2) Soil moisture and temperature could be well described by exponential models with determination coefficient about 0.9 and relative errors less than 5% for the model establishment and relative error less than 3% for the model validation; 3) The complexity of soil moisture and temperature interaction was simpler during freezing phase than the melting phase since the relative errors of the former were less than that of the latter; The relative errors decreased with increasing snow density and thickness during the freezing phase, but the contrast was observed during the melting phase, indicating the interaction of soil temperature and moisture is greatly affected by freezing-thawing process; 3) During melting stage, soil moisture was 14.31%, 15.9%, and 16.91% for natural snow, snow compacted, and snow thickened treatments, respectively, and soil temperature ranged -5.9-5.3, -3.6-6.9 and -3.1-3.8℃ for natural snow, snow compacted, and snow thickened treatments, respectively, and the interaction between soil moisture and temperature weakened; The complexity of soil temperature and moisture interaction increased with snow cover; and 4) The fractal dimension of soil temperature under different treatments lied between 1.4149-1.6019 during the freezing phase and 1.4621-1.5775 during the melting phase, revealing a downward trend with snow thickness and compactness during the freezing phase but an opposite trend during the melting phase; The fractal dimension of soil moisture ranged from 1.5047 to 1.5973 and from 1.547 to 1.6607 during the freezing and melting phases, respectively, with a similar trend with soil temperature changes among different snow cover treatments. The results are helpful in predicting soil temperature and moisture in sowing stage, and revealing soil moisture and temperature dynamics.