Retrieval of leaf area index in alpine wetlands using a two-layer canopy reflectance model

摘要: Abstract In this paper, we focused on the retrieval of LAI in an alpine wetland located western part China late August and early July 2011. A two-layer canopy reflectance model (ACRM) was used to establish relationships between near-infrared (NIR) red (RED) wavebands. The data were derived from Landsat TM L1T product Terra Aqua MODIS 16-day 8-day composite products (MOD/MYD09) at 250 m resolution. Due lack information about some major input parameters for ACRM, which are sensitive outputs NIR RED wavebands, inverse problem ill-posed. To overcome problem, a method increasing sensitivity while reducing influence other free based study parameters’ ACRM region's features studied. area interest divided into two parts using approximately statistic normalized difference vegetation index (NDVI) value around 0.5. One sparse (0.1  ρ nir –LAI established look-up table algorithm parts. Furthermore, regularization technique fast pixel-wise introduced reduce elements LUT sets maintaining relatively high accuracy. results very promising compared field measured values that correlation ( R 2 ) retrieved reached 0.95, root-mean-square deviation (RMSD) 0.33 August, 2011, 0.82 RMSD 0.25