Evaluation of the GLC2000 and NALC2005 land cover products for LAI retrieval over Canada

Abstract

Land cover information is an important input parameter for retrieving key land surface biophysical parameters, such as leaf area index (LAI), often parameterized with geometrical-optical properties distinctive among land cover types. This paper presents a comparative assessment and evaluation of the 1 km Global Land Cover (GLC2000) and the 250 m North American Land Cover (NALC2005) over Canada. We used a 30 m Circa 2000 Land Cover from agricultural regions of Canada as a reference dataset. The comparative assessment and evaluation were made at six generalized class levels that were categorized based on relevance for parameterizations of key land surface biophysical parameter retrieval algorithms. The overall per-pixel agreement between the GLC2000 and the NALC2005 was 63.4%. The overall accuracies using the Circa 2000 reference data were 62.3% and 65.5% for the GLC2000 and NALC2005 datasets, respectively. Based on the improved version 2 University of Toronto LAI algorithm, up to a 42% difference in LAI estimation was noted over Canada due to differences in the two regional land cover datasets. This study assessed the performance of the newly produced NALC2005 product and presents, for the first time, the often overlooked land cover characterization impact on large scale LAI estimation.