辉发河流域坡面与流域尺度融雪侵蚀研究

发布时间：2018-06-21 15:56

本文选题：融雪侵蚀 + 辉发河流域　；参考：《沈阳农业大学》2017年硕士论文

【摘要】：为研究坡面与流域尺度融雪侵蚀特征,选取吉林省吉兴小流域内坡耕地,对积雪属性、土壤因子、径流泥沙进行原位观测,通过分析融雪过程中径流量及含沙量的变化,雪水当量、土壤解冻深度等指标对融雪侵蚀的影响,探讨坡面尺度融雪侵蚀过程及变化规律。同时选取五道沟水文站对流域尺度融雪期水文及侵蚀特征进行分析,通过两个尺度的对比分析,初步探究不同尺度下融雪侵蚀过程特征及联系。研究结果可为多尺度融雪侵蚀机理提供一定的科学理论支持,为融雪侵蚀的预报与防治奠定基础。本研究得出以下主要结论:(1)坡面上积雪属性的时空变化具有规律性。时间上积雪深度的均方根差先增加后减少,积雪密度均方根差呈先增大后减小的趋势,液态含水量的变化复杂且不稳定,融雪过程中总体呈现为随着积雪的深度减少,液态含水量增加,密度逐渐降低。空间上积雪多集中分布在试验场的西南部,积雪密度沿南北方向初始呈递增末期递减,东西方向呈递减趋势,液态含水量在南北方向变化趋势不明显,东西方向呈递减的趋势。地形因子对于积雪属性参数的影响程度由大到小依次为积雪深度、液态含水量、积雪密度。正积温和积雪密度、液态含水量的变化趋势近似,均是先增加后减少再增加的趋势。(2)坡面融雪侵蚀过程历时6天较为集中,初期融雪产流,径流量占总径流量的59.15%;中期积雪融化稳定,土壤表层开始解冻,径流减少含沙量增加,侵蚀量达到最大占总侵蚀量的41.74%;末期融雪产流停止,土壤解冻深度增加,含沙量达到最大为8.00kg/m3。侵蚀特征表现为融雪初期主要产流,中期与末期侵蚀产沙,径流量与含沙量变化趋势相似均为先增加后减少。融雪径流泥沙滞后关系的复杂性受径流泥沙峰值出现频次的影响,当频次一致时,径流—泥沙呈"8"字循环滞后关系;当频次有差异时,径流—泥沙呈复式循滞后关系。融雪径流泥沙之间的滞后关系说明坡耕地融雪侵蚀明显受垄作区域与集水洼地的地形变化影响。径流的来源依次为积雪融化、垄沟内冰层融化和土壤液态水,同时洼地两侧坡面侵蚀过程亦不同步。(3)坡面融雪侵蚀过程中,融雪径流及表层土壤解冻深度是影响融雪侵蚀的主要因素,雪水当量在融雪过程中呈先减少后增加的趋势。积雪由坡上部位向坡下融化,雪水当量的空间异质性变化使融雪径流来源随之发生改变。本研究中16日融雪径流径流来自于坡上、坡下部位;17日径流来自于坡上、坡中、坡下部位;18日、19日融雪径流来自于坡中、坡下部位。土壤解冻深在坡面上空间异质性较均一。随着积雪消融,土壤解冻深度变化较为复杂并且受融雪水分迁移的影响,解冻深度在坡中部位变化最为剧烈,坡上、坡下次之,且与泥沙含量呈正相关。(4)流域尺度上,融雪期年平均径流量与含沙量年际变化相对年径流量波动更加剧烈,但离散程度相对年径流量集中,多年平均融雪径流约为径流的14.18%,多年融雪期含沙量占含沙量的18.68%。在少水少沙年、平水平沙年、多水多沙年,融雪径流所占全年比例分别为22.67%、7.23%、23.08%。梅河口站2015年相当于五道沟站的平沙平水年,其融雪侵蚀过程与1971年近似。(5)对比坡面尺度与流域尺度融雪侵蚀过程,坡面融雪侵蚀过程相对流域持续时间较长,发生时间相近,且坡面的融雪径流深与侵蚀模数相对五道沟站较小。根据泥沙含量的滞后关系,融雪侵蚀在泥沙来源的变化方面,坡面与流域过程相似。
[Abstract]:In order to study the snowmelt erosion characteristics of slope and river basin scale, the insitu observation of snow attribute, soil factor and runoff and sediment in Jilin Jixing small watershed was selected, and the effects of the changes of runoff and sediment concentration, snow water equivalent and the depth of soil thawing on snow melting were analyzed, and the snow melting of slope surface was discussed. At the same time, the hydrological and erosion characteristics of the five ditu hydrological stations were analyzed, and the characteristics and relations of snow melting erosion process under different scales were preliminarily explored through the comparison and analysis of two scales. The results could provide some scientific theoretical support for the mechanism of multi-scale snow melting and snow melting. The main conclusions are as follows: (1) the spatial and temporal variation of snow property on the slope is regular. The root mean square difference of the snow depth increases first and then decreases, the mean square root difference of snow density increases first and then decreases, the change of liquid water content is complex and unstable, and the total snow melting process is general. As the depth of snow decreased, the liquid water content increased and the density gradually decreased. The snow density in the space was concentrated in the southwest of the test field. The snow density decreased in the beginning of the north and the south, the East and west direction decreased, the trend of liquid water content was not obvious in the north and the south, and the direction of the East and the West decreased. The influence degree of terrain factors on snow attribute parameters from large to small is snow depth, liquid water content, snow density, positive accumulated temperature and snow density, and the trend of the change of liquid water content is similar. (2) the erosion process of snow melting over 6 days is more concentrated, early snowmelt and runoff The amount accounts for 59.15% of the total runoff, the soil surface begins to thaw, the soil surface begins to thaw, the runoff reduces the sediment content and the erosion amount reaches 41.74% of the total erosion. The end of the snowmelt flow is stopped, the depth of the soil thawing is increased, the maximum sediment content is 8.00kg/m3., which is the main runoff in the early stage of snow melting. The variation trend of runoff and sediment yield is the first increase and then decrease. The complexity of the hysteresis relationship of the snowmelt runoff is affected by the frequency of runoff and sediment peak. When the frequency is consistent, the runoff and sediment is "8" cycle lag relationship; when the frequency is different, the runoff and sediment show the complex hysteresis relationship. The lagging relationship between sediment shows that snow melting erosion in sloping farmland is obviously affected by topographic changes in the ridge area and the pool area. The source of runoff is the melting of snow, the melting of the ice in the ridge and the liquid water in the soil, and the erosion process on the sides of the slope on both sides of the depressions is also not synchronized. (3) the snow melting runoff and the surface soil solution during the snowmelt erosion process of the slope surface. The freezing depth is the main factor affecting the snowmelt erosion, and the snow water equivalent decreases first and then increases in the snow melting process. The snow melt from the slope to the slope, and the spatial heterogeneity of the snow water equivalent changes the source of the snowmelt runoff. In the 16 day of this study, the snowmelt runoff comes from the slope, the lower part of the slope, and the 17 day runoff. On the slope, slope and lower slope, the snowmelt runoff from 18 days and 19 days comes from the slope and below the slope. The soil thawing depth is more homogeneous on the slope. With the melting of snow, the depth changes of the soil thawing are more complex and affected by the migration of snow water, the thawing depth is the most intense in the slope, and the next, slope, slope, and the next. There is a positive correlation with the content of sediment. (4) the annual mean runoff and sediment concentration in the snow melting period are more intense than the annual runoff, but the relative annual runoff concentration is concentrated, and the average snowmelt runoff is about 14.18% of the runoff for many years. The 18.68%. in the years of snow melting during the snowmelt period is in the year of less water and less sand and horizontal sand. The annual ratio of snowmelt runoff accounted for 22.67% and 7.23%, respectively, in the year of 23.08%. in Meihekou Railway Station in 2015, which was similar to 1971. The snowmelt erosion process was similar to that in 1971. (5) the snowmelt erosion process was compared with the slope surface scale and the basin scale, and the snow melting erosion process was relatively long and the time lasted for a long time. According to the lag relation of sediment content, the slope surface is similar to the basin process according to the lag relation of sediment content.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S157.1

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