Katerina Anesiadou – Use of altimeters in a coupled ocean-atmosphere data assimilation system
December 3 @ 16:00 - 17:00
CESOC continues the seminar series “My Research” this Winter term 2024/25 with a series of talks given by scientists from University of Bonn, University of Cologne and Research Centre Jülich.
This semester, we are excited to announce that the seminar series will be in a hybrid format and hosted by the different CESOC partners and it will also be streamed online (via zoom). The seminars will take place on Tuesdays on a bi-weekly basis at 16:00 hr.
on Tuesday, 03 Dec. 2024 at 16:00 (CST)
Katerina Anesiadou
a Step-UP fellow at ECMWF and the Institute for Geodesy and Geoinformation, University of Bonn, talking on their work
“Use of altimeters in a coupled ocean-atmosphere data assimilation system”
Location: Room 2.004 (2nd floor) Nussallee 15, 53115, Bonn
It is open to any interested person within the CESOC research disciplines (any Earth system sciences, mathematics or computer science).
Please contact info[@]cesoc.net, if you would like to participate.
Full Schedule is available here!
Abstract:
Altimeter observations are currently used in ocean data assimilation (DA) system as sea level anomalies (SLA). These anomalies are subject to several geophysical corrections, including the atmospheric delay one. The atmospheric delay correction is similar to the ground-based GPS Zenith Total Delay (ZTD) measurements, which are assimilated in atmospheric DA systems and provide column integrated water vapour information.
Recent developments in coupled DA, linking the ocean and atmospheric DA components more closely, suggest the assimilation of quantities coming from instruments that have a multi-earth system component sensitivity. Altimeters are such instruments.
The main idea of this work is to explore the potential of advancing the use of altimeters in a coupled DA system. This is implemented by assimilating a new quantity derived from altimeter range (without atmospheric delay correction) which is sensitive to both the sea surface height above the geoid (SSH) and the atmospheric delay. This quantity, called sea surface to satellite delay (S3D), is equal to ZTD minus SSH and is being assimilated in the atmospheric 4D-Var. To do that, SSH is incorporated and estimated in the atmospheric 4D-Var system as an extended control variable.