Due to a recalibration on the Jason-1 Microwave Radiometer, Jason-1 GDR production for cycle 284 onwards will be delayed.

A calibration shift in the Jason-1 Microwave Radiometer (JMR) has been detected after recovery from the last Jason-1 safehold event, during repeat cycle 284 (began on September 16, 2009). Preliminary analysis shows that the JMR wet path delays on the already released Jason-1 IGDR data products from cycles 284 onwards are erroneously wetter by ~8 mm. The preferred approach is to recalibrate the JMR and apply the necessary calibration corrections to the Jason-1 GDR products from cycle 284 onwards. Data from after the next attitude regime change on December 7, from sine-yaw to yaw-fixed, is required to better quantify the calibration corrections. As a result, Jason-1 GDR production for cycle 284 onwards will be delayed until January 2010. These GDR products will contain recalibrated JMR data. IGDR and OSDR production for Jason-1 will continue uninterrupted.