Part 2: ORNL DAAC MODIS Processing
After finding that the Oak Ridge National Laboratory hosted a site for intermediate processing of MODIS data (ORNL DAAC MODIS Land Products Subsets), the attempt to handle raw processing was abandoned. Instead, their MODIS Subsetting and Visualization Tool for North America (Collection 4) was used to obtain custom selections of surface albedo.
Step One: Homogenous Forest Site Selection and Validation
A set of 21 sites that appeared to contain relatively homogenous forest cover were selected for analysis with Google Earth (Google Earth .kmz file in downloads). Several land cover data sets were used to validate these sites: 200m LANDSAT, 1 km AVHRR, 2001 NLCD, and the 1 km MODIS land cover product MOD12Q1 (included with the ORNL temporal albedo data for each site). All of these sets along with the coordinates of each site were loaded into ArcGIS and the local homogeneity of forest cover was examined. There was not much agreement between the data sets even though all of them have been scientifically verified to some degree, so it was decided to use the 1 km MODIS Land Cover Product since it used the most spectral bands for analysis and was the most recent.
Step Two: Data ordering and importation
Data was ordered and processed through ORNL DAAC. Since the processed data was not formatted into a easily importable format, a MATLAB m-file was written that imports the data, filters only pixels of a chosen land cover type, and compiles the temporal timeline for the selected pixels, and calculate simple statistical data on an annual basis (mean, median, range, range (95th-5th), range of mean, range of median). In the m-file, variables are imported from the MATLAB workspace into the local workspace of the function, processed, and exported into a workspace file (.mat extension), a .fig file of the composite graph, and a jpeg of the graph for easy transfer and access).
Step Three: Data compilation
The data taken from the MATLAB workspace files were compiled into excel spreadsheets and graphed based on whether the forest land cover was deciduous or evergreen. Results are outlined followed by a discussion of their significance.