JMR Noise Diode Stability and Recalibration Methodology after Three Years On-Orbit

Long term drifts and shifts in the Jason Microwave Radiometer (JMR) geophysical retrievals, relative to ground truth, have been attributed to long term changes in the JMR noise diode (ND) brightness, which is used for gain calibration. An optimal estimation based calibration system is developed to find an optimal set of calibration coefficients which minimize the root-mean-square (RMS) difference between the JMR brightness temperatures (T_Bs) and on-Earth references. This calibration system is used to derive a time series of the ND brightness. Changes in the ND brightness, on the order of 1-2%, are observed over the first three years of the mission. Results of the recalibration effort and validation of the retrieved ND time series are presented