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Lanzhou University (2009)

Study On Land Surface Process And Remote Sensing Application Over Semi-arid Region

张杰; Zhang Jie

Titre : Study on Land Surface Process and Remote Sensing Application Over Semi-arid Region

Auteur : 张杰; Zhang Jie

Grade : Doctoral Dissertation 2009

Université : Lanzhou University

Résumé partiel
It is found that biosphere activity and human activity change not only land use and land cover, but also the matter, energy and water exchange. Because of biosphere system considered, land process researches have been developed from physical process to biosphere chemical process. As the main body of land process, biosphere activity and the relations between atmosphere and human activity are needed to resolve so as to evaluate biosphere frangibility and adaptability, all these need to developing a perfect land process model for climate model.Developping a good land processing model relays on developping a perfect parameterizing project. To these days, there are more than 50 land process experiments, all these experiments paying attentions to integrate observation of the interaction between land, vegetation and atmosphere, and analyzing land process character and parameterize relation from stations to wide range by using satellite and numerical model. On the basis of above means, the land process parameterize project is developed for atmospheric numerical model. Due to complex, heterogeneous surface, and sparse vegetation, some land process experiments results have never been used by land process model and satellite retrieval method. Because continuum and real vegetation activity information can be obtained from remote sensing, the perfect land process parameterizing project for improving land process model is important aiming at sparse vegetation.The research do some experiments, by combining experiment over Dingxi station in loess plateau, with remote sensing data, the parameterize researches in heterogeneous are done, and the parameterize model for remote sensing are built. The intention of land process parameterizing is obtaining land energy, water and matter, the energy parameters are net radiance, sensible heat flux, soil heat flux and latent heat flux, water parameter is evaportranspiration, matter parameter is Npp. The prime of these parameterizing is obtaining albedo, surface and air temperature, and aerodynamic resistance and aerodynamic roughness length. According to the parameter idea, paramterizing research is performed, the aerodynamic roughness length is parameterized for the first time.BRDF model is used for geometry revising of albedo retrieval. On the air temperature parameterizing, high vertical resolution and high spectrum resolution data was used for atmospheric profile retrieved so as to obtain surface air temperature for the first time.Except for evapor-transpiration, leaf water potential is parameterized for the first time for evaluating water status.In addition, on the basis of surface temperature retrieval and energy balance and matter balance theory, land energy flux and NPP is retrieved, the parameterizeing projects were used over loess plateau, and some interesting conclusions were drawn.a. Aerodynamic roughness length project over sparse vegetation region is put forward in the research, the project replace the experience relation performed former, and help to realize roughness length over sparse vegetation.

Mots clés : sparse vegetation; land process parameterize project; aerodynamic roughness; aerodynamic resistance; albedo; surface temperature; air temperature; energy balance; C balance; LAI;

Présentation (CNKI)

Page publiée le 21 avril 2013, mise à jour le 20 avril 2018