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Study on the Spectral Characteristics of Salinized Soils with Ground Objects in the Typical Oasis of Arid Area

Author: ZhangFei
Tutor: TaXiFuLaTi·TeYiBai
School: Xinjiang University
Course: Ecology
Keywords: Ugan-Kuqa River Delta Oasis’s salinized soils halophyte field spectrum spectral characteristics
CLC: S156.4
Type: PhD thesis
Year: 2011
Downloads: 124
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Abstract

With the economic development and the population increase, unreasonable land development caused ecological problems such as land degradation, while soil salinization becomes a major problem in arid and semi-arid area. So acquiring accurate soil characteriscs information timely is important for evaluation soil salinization to protect soil from degrading and realizing agriculture sustainable development.The study on spectral characteristics in surface features is an important component of modern remote sensing technology. It is also one of the main signs for discriminating the surface features. The most imponant characteristic of remote sensing is the unities of map and spectmm information, and the spectrum information is an important advantage in hyperspectral technology, whose application process requires ground spectra data and picture spectrum combined together.Therefore, the collection and processing of spectral data is essential, and the quality of spectral directly affects the results of the application.It is a work foundation that study soil salinization, the spectrum characteristics by using remote sensing technology to achieve on regional scale for monitoring and evaluation of soil salinization, and also is to establish the ground data and remote sensing data relationship of the bridge. In this paper, the author takes the delta of Weigan and Kuqa rivers located in the North of Tarim Basin as study area, adopting spectroscopy technology and remote sensing technology method. This thesis indicates some major conclusions as the following:(1) The paper expatiated the COST model method and arithmetic,and how to confirm the parameters.With COST model finishing atmospheric and radiometric correction of TM,retrieve of earth reflection had been carried out. It is show that we can get reflecting rate image after the pretreatment of remote sensing data, TM image by adopting the COST model, and comparatively analyzes the anisochronous spectrum data and it and receives their coefficient correlation value, 0.9249.so we can use reflecting rate image to analyze spectrum data replacing the corresponding surface feature spectrum in the field of Open-air measurement. By construing the difference of the several kinds of typical surface features in this area in terms of the mechanism of the spectrum and spectrum curve, this is theory base and practice foreshadowing further of drawing saline-alkali soil information make kind.(2) Using ASD spectrograph spectral properties of vegetation to measure spectral data in surface features. the spectral data must be removed the equipment itself and the outside world noise conditions.Aimed at this experimental application study, choose appropriate way from existing spectral matching processing technologies such as Binary Encoding, Spectral Angle Mapping, Spectral Absorption Index, Spectral Feature Fitting, Matched Filter and mixed-pixel analysis of the issue. Resembling the hperspectral data to the TM data’s wave band scope, establishes both relation.And then re-sampled data is mapped to the space, we could get the two-dimensional scatter plot and achieve the space to spectral space mapping transformation. The author extracted the spectrum dimension character model from the spectrum curve. And did some analysis to the model, and gave the general application of the model and other application on growth evaluation of vegetation.But also analyzes spectrum curve characteristics under the condition of the different drying and different particle sizes.(3) The article reviews the theory development of spectrum of remote sensing and information drawn and makes deep exposition to spectrum characteristic and surface feature spectrum theory of the remote sensing data. It comparatively analyses the information spectrum data of remote sensing and the measure spectrum for several kinds of typical surface features. We set up the linear model to accomplish the quantitative transformation from edmember scale to pixel scale. This paper also proposes a method which uses TM images with lower spectrum resolutiom to simulate images with higher speemun resolutions.Based on previously obtained data (i.e.spectrum library) and simulations of the radiation transmission process. Our method uses the texture and sorting information of objects which is derived from a TM image with a wider spectral band, and to finally simulate an image with a subsection of spectral band. During the simulation process, unacceptable calculations were avoided. Our results show that our technique is effective.More over, the thesis focused on retrieving soil physical and chemical characteristic parameters (ions, electric conductivity, salinity, moisture content, pH, TDS and compactness data, etc.) from the hyperspectral data.The hyperspectral reflectance data were transformed to several mathematics mathematic transformations, such as reciprocal, logarithm, differential and so on. Using single-correlation analysis, the quantifying regression models between soil reflectance and soil ions, electric conductivity, salinity, pH, TDS and compactness were established.(4) Unified .NET and the SuperMap platform with SQL Server database stored data, used the B/S pattern and the C# language to design and develope the typical surface object spectral information system, and established the typical surface object spectral database according to the characteristics of arid areas oasis. The system implemented the classified storage and the management of typical surface object spectral information and the related attribute data of the study areas; this system also implemented visualized two-way query between the maps and attribute data, the drawings of the surface object spectral response curves and the processing of the derivative spectral data,continuum cure and normalizaed data by the continuum removal and its drawings. In addition, the system initially possessed a simple spectral data mining and analysis capabilities, and this advantage provided an efficient, reliable and convenient data management and application platform for the Ugan-Kuqa River Delta Oasis’s follow-up study in soil salinization. Finally, it’s easy to maintain and convinient to secondary development and practically operate in good condition.To sum up, the result of this research will produce the significant meaning for the research on the saline-alkali soil in the arid area. And in the expansion XinJiang that a large part of it belongs to the arid area, taking the delta oasis of Weigan and Kuqa rivers as study area has realistic meaning to the environment research in arid area.

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CLC: > Agricultural Sciences > Agriculture as the foundation of science > Soil > Soil improvement > Improvement of saline-alkali soil
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