CHARACTERIZATION OF THE SPATIAL UNIFORMITY OF THE TUZ GOLU CALIBRATION TEST SITE

Based on absolute radiometric calibration studies conducted in 2008 and 2009 using ground measurements and satellite image data, Tuz Golu, a salt lake in Central Turkey, was internationally acknowledged as an official CEOS cal/val test site. In particular, spatial uniformity and temporal stability are important qualities that are required of calibration test sites, as the homogeneity of the area effects site selection and the usability of test areas. In this study, the question of how to select a calibration test site in the lake that is the most homogenous and minimizes the number of ground sampling measurements is examined. The performance of Getis statistics in site selection is analyzed and it is observed that Getis statistics are not a good choice for uniformity analysis. Based on a power spectrum analysis of images, the error in continuous interpolation of in situ measurements was evaluated. However, further work is necessary to determine the actual error levels.