CryoSat-2 calibration/validation in Antarctica: Quantifying uncertainties utilising different satellite, airborne and ground-based techniques


Contact
Veit.Helm [ at ] awi.de

Abstract

ESA's CryoSat-2 mission with its radar altimeter system SIRAL has been designed in order to determine fluctuations in the mass of the Greenland and Antarctic ice sheets and of sea ice floating in the polar oceans. To fulfill the main goals of the CryoSat-2 mission it is necessary to validate the different CryoSat-2 products against independent measurements. The objective of the CryoSat Validation Experiments (CryoVEx) is to collect and analyse ground-based and airborne measurements in order to get such independent data sets. In Antarctica, blue-ice areas are particularly suited for calibration/validation activities related to airborne/spaceborne radar systems due to the fact that altimetric returns at blue ice are dominated by surface reflection. Such an area exists about 70 km south-east of Schirmacher Oasis, Dronning Maud Land, East Antarctica. Since 1991, surface-height changes and surface velocities along traverses crossing the blue-ice area have been repeatedly observed by the Institut für Planetare Geodäsie of TU Dresden in order to determine long-term variations. For that purpose kinematic GNSS measurements were carried out. Over the last years several Antarctic CryoVEx field campaigns in the blue-ice area were realised whereby the extent of the kinematic GNSS observations was increased substantially. These campaigns provide an excellent continuation of the long-term height observations. Up to 2008 the repeated measurements yielded a surface-height decrease of up to -20cm/a in this area. In contrast to this, the observed rates of the surface-height change between 2008/09 and 2010/11 show a positive trend in the same order of magnitude. In order to classify the anomalous trend change and to continue the long-term observation we carried out an additional CryoVEx campaign during the 2014/15 Antarctic season. We will discuss the final outcome of the latest CryoVEx campaign with respect to former ground-based measurements. We will compare our ground-based results with coordinated airborne measurements carried out by AWI Bremerhaven including a collection of radar (ASIRAS) and laser altimeter data. Finally, comparative investigations of ground-based determined surface heights, airborne data and most recent CryoSat-2 products will be presented.



Item Type
Conference (Talk)
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Primary Division
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
ESA Living Planet Symposium, 09 May 2016 - 13 May 2016, Prague, Czech Republic.
Eprint ID
41443
Cite as
Knöfel, C. , Scheinert, M. , Schröder, L. , Strößenreuther, U. , Helm, V. and Horwath, M. (2016): CryoSat-2 calibration/validation in Antarctica: Quantifying uncertainties utilising different satellite, airborne and ground-based techniques , ESA Living Planet Symposium, Prague, Czech Republic, 9 May 2016 - 13 May 2016 .


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