- 19 Dec 2008
Inter-Calibration of Low-Earth-Orbit Satellite Instruments Using the SNO Method
There is a need to inter-calibrate polar orbiting radiometers across satellites to achieve the consistency and traceability required for long term climate studies from the more than 25 years of operational satellite data. In addition, the calibration of current operational radiometers should be linked to those of the next generation meteorological satellites. At GSICS, inter-satellite calibration of cross-track scanning polar-orbiting radiometers is accomplished using Simultaneous Nadir Overpass (SNO) observations. At a SNO event, radiometers from a pair of satellites view the same place at nearly the same time at nadir, thus eliminating uncertainties associated with the atmospheric path, view geometry, and time differences. As a result, uncertainties in the inter-satellite calibration are greatly reduced. This method is useful for the on-orbit verification of instrument performance for newly launched radiometers, calibration transfer from instruments on one satellite to those on another, as well as retrospective analyses of historical data in constructing time series for climate studies. The SNOs typically occur in the Arctic and Antarctic regions (70N to 80N and 70S to 80S) for sun synchronous polar-orbiting satellites. In addition to the intersatellite calibration of radiometers, the long-term time series of intersatellite radiance biases at the SNOs may also be very useful for the study of polar climate.
Documentation for LEO-LEO Intercalibration Using the SNO Method
Algorithm Theoretical Basis Document (ATBD): LeoLeoIntercalSnoAtbd
Implementation, Operations, and Distribution (IOD) Plan: LeoLeoIntercalSnoIod
Data Quality Assurance (QA) Plan: LeoLeoIntercalSnoQa