川西北高寒区冻融交替作用后土壤水热运移模拟研究  

Simulation Study on Movement Mechanisms of Water and Heat After Freeze-Thaw Cycles in Northwest Sichuan Plateau Based on Hydrus Model

作　　者：宋洁 李晓宁 赵丽[1] 樊敏[1] SONG Jie;LI Xiaoning;ZHAO Li;FAN Min(School of Environment Resources,Southwest University of Science and Technology,Mianyang 621010,China;Handan Hanlin Environmental Assessment Co.,Ltd.,Handan 056000,China)

机构地区：[1]西南科技大学环境与资源学院,四川绵阳621010 [2]河北邯郸市瀚林环境评估有限公司,河北邯郸056000

出　　处：《水土保持研究》2023年第1期274-281,共8页Research of Soil and Water Conservation

基　　金：国家科技支撑计划“川西北藏区农牧废弃物综合利用及沙化土壤改良技术研究与示范”(2015BAC05B05)。

摘　　要：川西北高寒区在黄河和长江上游的水源涵养与补给、生态平衡中发挥着重要作用,该区土壤长期受到昼夜及季节性冻融作用影响,但土壤水分和热量在受到冻融交替作用后的变化规律,及其在草地退化及沙化过程中的作用还不明确。通过野外采集土样进行室内土柱模拟水热运移实验,利用有限元软件HYDRUS建立了一维土柱模型,开展基于冻融循环作用后的非饱和沙化草地和天然草地土壤水热迁移过程的数值计算研究,揭示不同冻融界面条件下沙化草地和天然草地土壤的水热分布特征、空间运移特性。结果表明:HYDRUS软件模拟沙化草地和天然草地土壤体积含水率的模拟结果R2>0.98,其平均值分别为0.997,0.996,模拟效果较理想;在土壤温度特性方面,模拟结果R2>0.98,平均值0.999,HYDRUS软件较好地模拟了川西北高寒区冻融交替作用后天然草地和沙化草地土壤温度和体积含水量的变化特征。通过模拟预测发现,反复冻融作用后,天然草地和沙化草地土壤体积含水率随时间变化均呈现上下波动的趋势,天然草地各土层体积含水率总体均高于沙化草地含水率;土壤温度模拟值呈现先波动上升后波动下降的趋势,且均呈现随着剖面加深,土壤温度逐渐降低的趋势,沙化草地土壤各层最高温度平均低于天然草地各层土壤温度。率定后的土壤水热运移数学模型能够较好地反映出川西北高寒区冻融交替作用后土壤水热的动态变化规律。将率定后的参数及当地的气象资料输入模型,可有效预测该地区冻融交替作用后的土壤水热运移规律。研究结果为该地区土壤沙化治理与预防,维护生态平衡提供科学依据和理论支持。The alpine region of northwest Sichuan plays an important role in water conservation and ecological balance of recharge in the upper reaches of the Yellow River and the Yangtze River.The soil in this region has been affected by day-night and seasonal freezing-thawing effects for a long time.However,the change rules of soil moisture and heat after freezing-thawing alternation and its roles in the process of grassland degradation and desertification are still unclear.The soil samples collected in the field were used for experiment of soil column to simulate the water and heat transport in the laboratory,and the finite element software HYDRUS was used to establish a one-dimensional soil column model to carry out the numerical calculation of the soil water and heat transport process of unsaturated desertification grassland and natural grassland after the freeze-thaw cycle.This study revealed the characteristics of water and heat distribution and spatial transport in soil of desertified grassland and natural grassland under different freeze-thaw interface conditions.The simulated results of soil volume moisture content of sandy grassland and natural grassland fit well with the monitored vales,and the determination coefficients(R~2)were great than 0.98 with the mean values of 0.997 and 0.996,respectively.The simulation effects were reliable.In terms of soil temperature characteristics,the determination coefficients(R~2)were greater than 0.98 with the mean value of 0.999.The software of HYDRUS could simulate the change characteristics of soil temperature and volumetric water content of natural grassland and sandy grassland after freeze-thaw cycle in the alpine region of northwest Sichuan.Through simulation and prediction,it was found that the soil volumetric water contents of natural grassland and sandy grassland fluctuated up and down with time,and the volumetric water content of each soil layer of natural grassland was generally higher than that of sandy grassland after freeze-thaw cycle.The simulated value of soil te

关 键 词：HYDRUS模型 冻融作用 沙化土壤 水热运移 川西北高寒区 

分 类 号：X24[环境科学与工程—环境科学]