【作者】 王坤；

【导师】 姜琦刚；

【作者基本信息】 吉林大学 ， 地学信息工程， 2009， 博士

【摘要】 青藏高原多年冻土是世界上中低纬度海拔最高,面积最大的多年冻土区。由于地域广阔,实测资料比较少,这就使依靠台站观测资料的传统制图方法受到很大限制,因此建立冻土空间模型非常必要。本文基于GIS技术,以遥感数据为主要数据源,结合青藏高原冻土分布特征,构建了两个经验统计模型:基于RS/GIS的地温反演模型和多变量综合分析模型。模型中充分考虑了与青藏高原冻土分布有关的高程、地表温度、植被和土壤水分等环境因素,并选取青藏公路沿线范围作为试验区,利用所建立的模型模拟其冻土分布现状,在模拟结果能很好的反应公路沿线冻土分布的情况下,将其推广到青藏高原全区,模拟了青藏高原的冻土分布。同时,利用高分辨率的ASTER数据在青藏高原局部地区实现了高精度建模。更多还原

【Abstract】 As an important part of cryosphere,frozen soil covers a large area of global land surface.And permafrost covers about 24%of the northern hemisphere.For its wide distribution and unique thermal characteristics of water,frozen soil is a very important factor of land surface process.Permafrost mainly distributed in Qinghai-Tibet Plateau,Pamirs Plateau, Daxinganling and the top of some eastern mountains in China.And the permafrost mainly in Qinghai-Tibet Plateau at high altitude is the world’s highest elevation and largest area of permafrost regions in the lower latitude.A clear understanding of the the laws of permafrost distribution in Qinghai-Tibet Plateau,which is not only conducive to better plan and resolve the actual engineering problems of permafrost regions,but also it will have a far-reaching significance for the study of permafrost changes,the regulation and contribution to regional water resources in Qinghai-Tibet under climate warming.For the vast area,the measured data of frozen soil is relatively few in Qinghai-Tibet Plateau.In the western,the stations and data is not available,which makes restrict to the traditional method rely on observational data.The existence of frozen soil is bound to their surrounding environment for its wide range and unique thermal characteristics of water,and reflects on the ground information.However we can rapidly obtained a large area and multi-temporal ground information related to permafrost using RS,which makes it possible to study permafrost from the view of RS.Based on GIS technology,using RS data as the main data sources and combined with the feature of permafrost distribution in Qinghai-Tibet Plateau,we build two models:Retrieval Model of Ground Temperature based on RS/GIS and Multi-variable Comprehensive Analysis Model.The Retrieval Model of Ground Temperature based on RS/GIS is on the foundation of MAGT,which is the key division indicator of permafrost in Qinghai-Tibet Plateau.Through the relations established between MAGT and RS information to obtain the MAGT indirectly,and achieved the purpose of permafrost division.While Multi-variable Comprehensive Analysis Model depends entirely on the ground data related to the permafrost distribution to instruct the occurrence of permafrost.Considering the permafrost map used to verify the simulation results,which is based on the measured ground temperature along the Qinghai-Tibet road,so the status of permafrost distribution in the permafrost map should be more reliable along the Qinghai-Tibet road.Therefore we choose the scope along Qinghai-Tibet road as a test area to simulate the status of permafrost distribution using the established model, compared and analyzed the simulation results with the part of permafrost map along the Qinghai-Tibet road.On the premise of simulation results in a very good response to the permafrost distribution,extended the model to the Qinghai-Tibet Plateau.In order to study the merits and demerits of various models,and evaluate the simulation results,we selected the Elevation Model and Frost Number Model to simulate the permafrost distribution along the Qinghai-Tibet road.Compared and analyzed the results with the simulation results of the two models created in this article.Obtained the following conclusion:1.The frozen soil is divided based on the Retrieval Model of Ground Temperature based on RS/GIS,through setting up the relationship between MAGT and remote sensing variables,indirectly obtaining MAGT.The model precision depends on the quantity of the ground temperature observation points and distribution situation.The quality of regression equation is not ideal,because the ground temperature observation points used to set up model are small distribution in island permafrost zone.There are a certain differences between the simulation results in south island permafrost zone and the frozen soil distribution image.The simulation precision will be improved by increasing the ground temperature observation points’ quantity in the island permafrost zone.If the quantity of the ground temperature observation points is enough,this method is still a feasible one which used to obtain the permafrost distribution.2.Multi-variable Comprehensive Analysis Model uses the statistical relationship of surface in permafrost zone variables to indirectly infer the existence of permafrost. The sample points are representative.Because they were picked up along the road, and there were some points distributed on the island permafrost zone.Contrasted with DEM Model,Frost Number Model,Multi-variable Comprehensive Analysis Model shows the frozen soil distribution along the Qinghai-Tibet highway well.Using this model,the relative error of simulation area is less,the firing between the result and frozen soil distribution is best.3.The Multi-variable Comprehensive Analysis Model is used in the whole Qinghai-Tibet Plateau in order to simulate the distribution of frozen soil.The simulation result basically shows the frozen soil distribution principle.The area of permafrost is 136.33 million square kilometers,and that is 52.7 percentage of the whole Qinghai-Tibetan Pateau area.4.In the process of setting up the ground temperature model based on RS and GIS, the stability and prediction ability of model improved obviously,segmented considering the equivalent latitude.The determination coefficient R~2 is improved from 0.598 to 0.617 and 0.826.It shows that slope and aspect have important effect on the frozen soil distribution in Qinghai-Tibeta Plateau.5.In the process of calculating the frost-number model,considering the hardly obtaining of ground temperature by traditional method,affected by the interpolation precision,the precision of simulation result is influenced.Improving the model by trying to use ground temperature,the simulation result is not very well.Therefore,the attempt of introducing the ground temperature retrieval from RS in Fost Number Model is not successful.6.High resolution ASTER data are used in frozen soil simulation in partial area along the road.The result shows that,the precision of simulation result is improved. Especially,in the island permafrost zone,contrasted with the MODIS data simulation result,ASTER data simulation result has the better fitting with frozen soil distribution image.Compared with previous studies,special features of this paper are as follows:1.Based on GIS,and taken the remote sensing data as the main data source,we established the permafrost model suitable for Qinghai-Tibet Plateau,and simulated the distribution of permafrost in Qinghai-Tibet Plateau,which realized the application of remote sensing technology in the study of permafrost distribution in Qinghai-Tihet Plateau.2.Extracted the environment information related to permafrost distribution,such as elevation,land surface temperature,vegetation,soil moisture and so on,which make up for the lack of permafrost data in Qinghai-Tibet Plateau.Compared with the previous studies that only considered a single factor of elevation or air temperature, the model established in this paper is more reasonable.3.Unfrozen regions reflected in the simulation results for the first time,and the simulation results are better fit to the actual distribution of permafrost.Mapping permafrost based on remote sensing technologies is a meaningful work.It is a meaningful attempt to study the simulation of permafrost distribution from the view of RS.更多还原