Land cover dependence in the detection of contaminated pixels in satelliteoptical data

Citation
J. Cihlar et al., Land cover dependence in the detection of contaminated pixels in satelliteoptical data, IEEE GEOSCI, 39(5), 2001, pp. 1084-1094
Citations number
15
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
ISSN journal
01962892 → ACNP
Volume
39
Issue
5
Year of publication
2001
Pages
1084 - 1094
Database
ISI
SICI code
0196-2892(200105)39:5<1084:LCDITD>2.0.ZU;2-4
Abstract
The detection of partially contaminated pixels over land is necessary for q uantitative applications of satellite optical measurements to estimate surf ace biophysical parameters such as leaf area index or vegetation compositio n. Threshold-based algorithms suffer from the heterogeneity of land cover a nd the seasonal variability of the radiation reflected and emitted by the l and surface. As an alternative, a method based on a Fourier series approxim ation to the seasonal trajectory of the normalized difference vegetation in dex (NDVI) had been previously developed [2]. In this paper, we introduce m odifications to the basic algorithm to more closely represent NDVI seasonal trends for different land cover types, as well as a simplified way to dete rmine the time- and pixel-specific contamination thresholds. Based on the t ests with 1993-1996 advanced very high resolution radiometer (AVHRR) data o ver Canada, the modified procedure effectively detects contaminated pixels for boreal ecosystems after the growing season of interest, The modificatio ns also improved its performance while the growing season is in progress; i n this case, at least one complete previous growing season coverage is requ ired to provide the temporal series needed to establish the thresholds. The modified procedure also yields a contamination parameter that may be used to estimate the most likely value for NDVI or other variables for each pixe l. It is concluded that the procedure would perform effectively in other ar eas, provided that the NDVI temporal trajectories of the cover types of int erest can be represented by a mathematical model.