Research Of The Hai River Basin Land Surface Changes Based On Remote Sensing

In nearly2000years, Hai river basin has the biggest change in underlying surface among seven main rivers in our country. The change of watershed underlying surface conditions, resulting in river basin rainfall infiltration, evaporation and runoff process changes, it has affected the basin water resources spacetime distribution pattern, thus affecting the regional water resources evaluation. Based on the watershed underlying surface infiltration of Hai river basin study is the premise and foundation to further study the changes of its evaporation and runoff process. The traditional watershed underlying surface analysis is using the ground sample survey method, the spatial resolution is limited, and it is difficult to fully describe the pad surface heterogeneity and update the data. High spatial resolution of remote sensing technology-. rich and dynamic of vegetation coverage and impervious surface of the water ecological hydrology information, to provide possible for comprehensive research on river basin scale underlying surface monitoring, and thus become the most effective means in comprehensive analysis of underlying surface.This paper using satellite remote sensing information with the advantages of the macro, dynamic and objective, extracted the comprehensive factors of hydrological underlying surface remote sensing information, analysis the elements of underlying surface changes; Comprehensive utilization of soil data, terrain data and surface coverage data, to build the model of watershed comprehensive hydrological underlying surface which based on remote sensing, in order to estimate the soil saturated hydraulic conductivity and analyze the Hai river basin soil saturated hydraulic conductivity. The main research contents and results are as follows:(1)The analysis of Hai river basin hydrological underlying surface factorsThe biggest area of grade level for the slope in Hai river basin was shelving, followed by the steep slope and the slight slope; The smallest area of grade level was plains, followed by the vertical wall. Among all the direction of the slope in Hai river basin, the biggest area was the east, followed by the southeast and the south.From1980to2010, the total area of cultivated land, grassland and other land were decreased by24700km2,4800km2and900km2, and annual rate were0.52%,0.39%and0.52%respectively; The area of forest land, water area and construction land were increased by13500km respectively13500km2and14200km2, rate was0.49%,1.56%and2.97%respectively.From1980to1990, the entire basin was given priority to medium vegetation coverage distribution. In1980,1990, the vegetation coverage was31%～70%of the area, respectively,35.9%and40.5%of the total area of river basin. Between2000and2010, high vegetation coverage area gradually dominant, In2000,2010, coverage was71%～100%of the area, respectively,46.5%and45.0%of the total area of river basin.From1980to2010, Hai river basin in different levels of opaque surface area was obviously rising trend, Opaque surface area of the basin area, the proportion of the increased from0.43%in1980to0.91%in1990, and the proportion was1.08%in2000, increased to2.88%in2010.(2)Building integrated hydrological underlying surface modelReference existing research results, and analysis the data of soil (gravel, sand, bulk density), the terrain data (slope, slope direction), the surface coverage data (vegetation coverage, impervious surface coverage) effects on soil saturated hydraulic conductivity. Building relationship equation for data conversion and standardized treatment, through the factor analysis method to build integrated hydrological underlying surface model, to estimate the soil saturated hydraulic conductivity. Hydrological underlying surface model has higher accuracy.(3)To estimate the soil saturated hydraulic conductivity and analyze the change of the soil saturated hydraulic conductivity in Hai river basin.According to comprehensive hydrological underlying surface model estimates1980,1990,1990and2010soil saturated hydraulic conductivity, the northern piedmont plains and mountainous soil saturated hydraulic conductivity was high, other area soil saturated hydraulic conductivity was relatively low.This paper builds the comprehensive model of hydrological underlying surface, due to the introduction of remote sensing data such as the slope and slope direction、vegetation coverage、 impervious surface, not only improves the spatial resolution of soil saturated hydraulic conductivity, but also reflects the spatial characteristics of soil saturated hydraulic conductivity. The model by updating the remote sensing data can quickly update the data in the soil saturated hydraulic conductivity, which can timely reflect the soil saturated hydraulic conductivity of the time change. The integrated hydrological underlying surface model is of high precision by the empirical analysis and evaluation. Using remote sensing data to construct comprehensive hydrological underlying surface model to estimate the soil saturated hydraulic conductivity, with advantages of fast data easy to obtain, update, higher resolution; The Model parameters are based on the data principle and determined by factor analysis method, thus have more extensive applicability.