Improved Spatial Collocation And Parallax Correction Approaches For Intercalibration Among Different Sensors In Thermal Infrared Band Under The Framework Of Gsics

Under the framework of GSICS, two modifications, improved spatial collocation with variable weighting (VW) and parallax correction (PC) approaches to enhance the calibration accuracy validation (CAV) performance are proposed. Distinguished from the uniform weighting method recommended by GSICS, the proposed VW one establishes a novel way of overlapping identification and overlapping area computation which is widely suitable for measurements from both same and different platforms. Simulations indicate that the uncertainty of VW method behaves better for the collocated targets far away from satellite's nadir with a certain geolocation error, and is superior to 0.6 K for most overlapping situations when geolocation error is less than 0.5 pixels. Besides of the uncertainty improvement, PC approach has the capability to reduce the bias of CAV by around 0.2-0.3 K. The proposed VW and PC methods are recommended for GSICS utilization and will further benefit to a more comprehensive community.