Retrieval Of Leaf Area Index Using PROSAIL Model In The Hokkien Triangular Urban Agglomeration,China

Leaf area index(LAI)generally refers to the total projection area of plant leaves on unit land area.Leaf area index represents the density of vegetation leaves,which is the key factor affecting the effective radiation ability of canopy photosynthesis in carbon cycle.The level of LAI has a direct impact on the strength of photosynthesis,which has an important impact on global carbon cycle,vegetation growth and grain production.Therefore,it is of great significance to research the leaf area index inversion for regional ecological balance and safety guarantee.This paper is based on the LOPEX'93 database,ANGERS leaf optical properties database,taking historical data as the basis for localizing the database.Taking care of the characteristics of the ecosystem and Landsat-8 OLI image in the Hokkien triangular urban agglomeration,the canopy RTM is combined with statistical model to retrieval LAI.Based on that,the methods and techniques of model parameter sensitivity and optimal regression modeled are discussed.It provides data support and method support for remote sensing monitoring of ecosystem in the Hokkien triangular urban agglomeration,which helps to promote multi spectral remote sensing retrieval.The main research work is as follows:1.We discuss the basic principle of PROSAIL model,analyze the local sensitivity and global sensitivity of input parameters of PROSAIL model,and compare the results of two sensitivity methods.2.We study the range of input parameters suitable for PROSAIL model in the Hokkien triangular urban agglomeration and establish the Landsat-8 OLI simulation dataset combined with the canopy reflectance of PROSAIL model.3.According to the characteristics of OLI simulated data sets,using multiple vegetation index VIs(Vegetation Indexs)to carry out linear,exponential and logarithmic and exponential function,two polynomial regression modeling and some experimental design,the optimal LAI-VIs regression model was applied to the study area leaf area index retrieval.4.We verify the results of the retrieval and analyze the uncertainty.The optimum spectral range for the retrieval of LAI and other biochemical parameters is discussed.