Data for: Development of a snow kernel to better model the anisotropic reflectance of pure snow in a kernel-driven BRDF model framework
Description
1. About the visulization tool for the RossThick-LiSparseReciprocal-Snow (RTLSRS for short) BRDF model. This is the description for the interface and operation of the # rtlsr_gui.sav application, which can be used to launch runtime IDL applications. Source code will be offerred on request from email: jiaozt@bnu.edu.cn. "Constrain" botton on this application interface inplements the function that does not allow negative model parameters, which are suggested by MODIS BRDF parameter product. 2. Environment：need to install IDL8.2 and above 3. Data format：this tool supports the input format of text file. The specific input format is requested as follows: the first line defines the number of multi-angle observations and the number of bands for the multi-angle input dataset, respectively. From the beginning of the second line, each line defines an observation with each sample representing the viewing and solar geometries (in degree) and the reflectances in different bands. Specifically, from left to right, each sample represents view zenith angle,view azimuth angle,solar zenith angle,view azimuth angle and the reflectance of each band in sequence. 4. The exemplary data A typical POLDER example was obtained in Apr. 2006 from the file "brdf_ndvi02.0216_3046.txt." in POLDER database. This pixel is located on the central North Greenland Ice Sheet (i.e., 52.1W, 78.03N) and was recorded to represent a relatively pure snow and ice IGBP class with a Normalized Difference Vegetation Index (NDVI) value of -0.03. This pixel incorporates more than 1,000 POLDER reflectances and 70 solar angles representing a very good BRDF sampling distribution. The method proposed by Breon (2005) should be utilized to correct the viewing geometry from the original POLDER measurements that offer two correction parameters (DVzC and DVzA), which was used in the paper. However, please note that this input example file including 6-band observations is not corrected for the viewing geometries. Input directory: contains an input example file, e.g., "brdf_ndvi02.0216_3046.txt". Output directory: contains the corresponding output example file, e.g.,"brdf_ndvi02.0216_3046_result.txt". 5. All validation data for the RTLSRS model are open and available to users following the details of the paper.