Research On The Forest Soil Moisture In The Changbai Mountains Using The Quantitative Remote Sensing Methods

Most of the Changbai Mountains area is the forest ecological system, and also the most important ecological barrier in the northeast China and the northeast Asia. It is one of the best ecological environment in the northeast China. The forest soil is the basis of the ecological forest system of the Changbai Mountains, and the moisture is one of the most important parts in the soil. It has the impact on the heat balance between land and atmospheric, land surface atmospheric circulation and the land surface temperature. At the same time it is one of the most important characteristics to evaluate the soil resource. Many advantages in monitoring the forest soil in the Changbai Mountains are revealed by remote sensing technology, especially using the multi-angle information, hyperspectrum and polarized information to obtain the 3-D characteristics of the soil in 2πspace. It is the important direction to research modern remote sensing technology.In this paper, the author researched and analyzed the forest soil in the Changbai Mountains from both micro-perspective and macro-perspective point. The basis of remote sensing technology is to describe the characteristics of the electromagnetic waves, including the spectral intensity, polarized properties and the features of the object itself. From the microscopic point, the author had full consideration to the forest soil spectral in Changbai Mountains, for example, the light zenith angle, azimuth angle, the effects of wavelength and the polarized information. The math-models were built about the forest soil moisture through the polarized reflection characteristics and the bidirectional reflectance information, while take the combination of the multi-angle information, hyperspectral and the polarized information. That could be the strong support for the development of the quantitative remote sensing. From the macro-perspective, the author used the NDVI and Land Surface Temperature (LST) in the MODIS product data and establishes the TVDI triangle. The triangle has the wet and the dry side and we could get the inversion of the soil moisture in Changbai Mountains. And we could get the analysis on the results with the measured data. The content and conclusions of the thesis work are as follows:(1) The characteristics of the multi-angle hyperspectral polarized information of the forest soil in Changbai Mountains with different moisture conditionsIt is found that the dry forest soil has no significant on the reflectance characteristics of polarization through comparative analysis; when the incidence angle is fixed, the trend of the polarized reflection is decreased with the viewing zenith angle decreased and the wave shape has little change. The polarized reflection characteristics would not change with the different viewing zenith angle. The polarized reflection curves changed with the different soil moisture conditions. When the incidence angle equals to the viewing zenith angle, the polarized reflection is the biggest under the relative azimuth 180°; the curve of polarizer 45°is between the angle of 0°and 90°; the same circumstances of the incidence angle, viewing zenith angle, the relative azimuth angle and the polarized angle, the curves have different spectral under different soil moisture. With the moisture increased, the multi-angle hyperspectral polarized reflection is decreased, while reaches some certain moisture content, the reflection is increased with the moisture increased.(2) Regression models between multi-angle hyperspectral polarized information and the soil moistureAfter a large number of curves of the forest soil in Changbai Mountains, it is found that the multi-angle hyperspectral polarized information has 4 major basic characteristics and the associated with the moisture is the reflection valley near 1450nm and 1940nm. The water absorption spectrums in the polarization peaks have the correlation relationship with the moisture under different polarized states. We could also get the models and the correlation coefficient. The models build aroud 1450nm and 1940nm with the degree of polarization and the moisture could go through the statistical test, and we could also find the statistical rules.(3) Making orthogonal design for the interaction analysisThe author made an orthogonal design of the multi-angle hyperspectral polarized information of the forest soil under different moisture, and also had the interaction analysis. It is found that the polarized angle, viewing zenith angle and the relative azimuth angle could have the effects on the multi-angle hyperspectral polarized reflection, and those effects were showed by the interaction. The results showed that the polarized angle and the soil moisture have an especially significant on the curves, the moisture also has the especially significance, and both of the above two played a primary role. The interaction of the viewing zenith angle and the moisture has significant on the curves and polarized angle has particularly significant. All the other factors have little effect on the multi-angle hyperspectral polarized reflection of the forest soil.(4) Monitoring the soil moisture conditions in Changbai Mountais area by the MODIS product dataThe author analyzed the soil moisture in Changbai Mountains using the NDVI and LST information in MODIS product data. We established the TVDI model by the wet and dry functions and the parameters and inverse the soil moisture conditions from March to November in 2007 in Changbai Mountains area. The significant linear regression equation could be found by TVDI and soil relative moisture and T test, which means the TVDI could reflect the soil moisture conditions in Changbai Mountains area. And the author analyzed the surface vegetation types and TVDI by the MODIS product data from the spatial distribution of the soil moisture condition according to remote sensing information.The innovation of the paper is to analysis the soil moisture conditions under both micro level and the macro level and could obtain the forest soil spectral curves and parameters with different water contents, which breaks the traditional study of expression to use only a single index. At the same time the author used the orthogonal experimental design and interaction analysis. That shows the interaction factors of the multi-angle factor, polarized factor, hyperspectral factor and the moisture factor. The paper reflects the interaction of the factors on the multi-angle hyperspectral polarized characteristics of the forest soil in the Changbai Mountains area, which overcomes the disadvantages of traditional single factor analysis.