Image of the month News
27.03.2019 10:25 Age: 5 yrs
[SSALTO/DUACS] Jason-3 back in the NRT system as the reference mission
Category: Operational news
A few weeks ago, the Jason-3 acquisition was stopped due to a safe-hold mode (SHM) event. The event itself was processed swiftly by the operations teams, and the ongoing Cal/Val investigations now report nominal quality metrics and no significant impact beyond the short interruption itself. Because Jason-3 is the so-called reference altimeter in the multi-mission system DUACS (CMEMS Sea-Level TAC), the temporary unavailability called for an emergency procedure in the NRT system. The procedure uses a temporary anchor altimeter (here: Sentinel-3A) to stabilize the NRT system until the reference altimeter is back in operations. Because the anchor is not a reference altimeter, the system slowly drifts away from what would have been produced with the reference altimeter (particularly in NRT). Now that Jason-3 has collected enough measurements after the SHM event, the drift was estimated. As expected it is small thanks to the good quality of Sentinel-3A, but not zero. The procedure to seamlessly (no offset) reduce the drift to zero and to switch back to Jason-3 as the reference altimeter will be executed over this week where the system will be in a nominal status (no bias in the system). All efforts are made to make this transition invisible to the CMEMS & DUACS end-users. Please feel free to report any suspicious finding you might have during this period.
A few weeks ago, the Jason-3 acquisition was stopped due to a safe-hold mode (SHM) event. The event itself was processed swiftly by the operations teams, and the ongoing Cal/Val investigations now report nominal quality metrics and no significant impact beyond the short interruption itself. Because Jason-3 is the so-called reference altimeter in the multi-mission system DUACS (CMEMS Sea-Level TAC), the temporary unavailability called for an emergency procedure in the NRT system. The procedure uses a temporary anchor altimeter (here: Sentinel-3A) to stabilize the NRT system until the reference altimeter is back in operations. Because the anchor is not a reference altimeter, the system slowly drifts away from what would have been produced with the reference altimeter (particularly in NRT). Now that Jason-3 has collected enough measurements after the SHM event, the drift was estimated. As expected it is small thanks to the good quality of Sentinel-3A, but not zero. The procedure to seamlessly (no offset) reduce the drift to zero and to switch back to Jason-3 as the reference altimeter will be executed over this week where the system will be in a nominal status (no bias in the system). All efforts are made to make this transition invisible to the CMEMS & DUACS end-users. Please feel free to report any suspicious finding you might have during this period.
