Contents page

1. Major results 1

2. First draft of a user concept 1

Attachment 1: List of participiants 5

Attachment 2: Workshop-Agenda 6

1. Major results

During the workshop, participants expressed their interests in different aspects of the mission. These are listed below in the user concept. Apart from this, the workshop revealed some problems in using CryoSat data, which were mainly due to missing information. Although this is probably due to the early state of the mission and the tight schedules in mission preparations, the major open questions are listed below as a reference for the CryoSat SAG:

ï Currently, users are largely lacking information: SAG should define a number of key documents with respect to technical information, orbit information, data product information, data distribution information.

ï Who defines level 2 products?

ï Level 2: what is the error budget, is it available to the user?

ï Geocoding: orbit or footprint oriented?

ï There is large interest in obtaining information about surface properties. What kind of information will be available?

ï Experience with other radar altimeter data shows that corrections applied to the data have to be documented very carefully and detailed.

ï What are the relevant regional scales for validation campaigns?

ï It would be most welcome to have repeated overflights at certain locations on the Antarctic peninsula, to make use of the SIRAL advantages on some of the most rapidly changing glaciers and ice sheets. Could certain orbit phases be planned for this, e.g. during validation orbits?
 
 

2. First draft of a user concept

Due to the major goals of CryoSat, observations of both land ice and sea ice, CryoSat users have a wide range of different approaches to use CryoSat data. There are many different applications of the data, employing different data product levels. Although only preliminarily defined by ESA or the SAG, data products are reviewed in Figure 1. The following paragraphs will always refer to that Figure.

Table 1, designed as a German user concept of CryoSat data, is structured according to these different user groups and levels.

In the table, first land and sea ice applications are differentiated. Although the ultimate question to be answered with CryoSat data, the observation of changes in the mass budgets of ice shields and the sea ice cover is the same for both ice types, the temporal and spatial scales as well as the means of interpretation of results are quite different. This has to be taken into account by a user concept.

Second, CryoSat data are used at different levels for different applications. Broad interest exists in Germany with respect to validation activities. As can be seen from Figure 1, those groups are interested in a variety of data levels, ranging from almost raw data to the final level 2-3 products. In general remote sensing applications, CryoSat data will be used as complementary information for integrated studies involving other satellite data like from ENVISAT, RADARSAT, ASTER, Quickscat, Jason or DMSP. Like with validation activities, using additional other remote sensing data will also enable the development of new algorithms to extract other geophysical data from CryoSat than primarily surface height. In the case of sea ice, this might e.g. be ice concentration or surface roughness. The development of these algorithms corresponds to level 1 to 2 processing. Another user group is interested in looking at confined regions to perform process studies, like the temporal evolution of the sea ice thickness distribution in a certain region, or mass changes of certain glaciers. These groups will only employ level 2 or 3 data. Finally, there is a group of real "end-users" who are applying or exploring the complete, gridded data set (level 3&4). These groups consist mainly of modelers, who will use the derived fields as boundary conditions for their models, e.g. Digital Elevation Models (DEMs), to validate their model results, or to assimilate gridded data into the models. This group will be accompanied by scientists who will look at the statistical behaviour of the derived elevations and thicknesses, to finally assess where and whether the polar ice masses are growing or shrinking.
 

Apparently, in Germany there is no interest to work on the more electrical-engineering side, like in the development of retrackers, or in data processing from level 0 to level 1b data.

A major expectation is the better accuracy of CryoSat data in general compared to older RA data. Furthermore, it is hoped that CryoSat will extend the data base into formerly unmeasureable regions with rough or steep topography which could not be mapped by old-style RAs. A major improvement of RA related activities is of course the extension of the orbit coverage up to 88°N and S.

The table is structured for temporal sequence of activities. First, validation will be performed before the accuracy of the data can be judged and the can be made available to others. Then, the data can already be used for remote sensing and process studies. Finally, after gridding and data collection over longer periods, the derived fields can be used for modeling and statistical exploitation.

Table 1: User concept for CryoSat data
 

Application / Approach	Scientific question	Geographic region of interest	Data products	Institutions
Validation	ï In-situ height surveys in key regions ((D)GPS, aircraft laser altimetry)	King George Island Filchner Ronne Ice Shelf Ekström Ice Shelf Schirmacher Oasis	Level 2	Uni DD, Uni FR, Uni MS, AWI
	ï Dry vs. wet snow conditions and their influence on height retrievals		s0	Uni FB, AWI
	ï In-situ airborne sub-satellite sea-ice thickness and roughness profiling		Level 2, s0	AWI
Remote sensing	ï Dry vs. wet snow conditions and their representation in CryoSat data	Antarctic Peninsula, Antarctic continental rims, Greenland	Level 2 at different seasons	Uni MS, Uni FR, AWI
	ï Deterioration of ice shelves, retreat of glacier fronts, snow zones/facies	Antarctic Peninsula	Level 2, s0	Uni FR
	ï Derivation of snow accumulation and thickness on sea ice from other (e.g. passive microwave) data for improvement of thickness estimates	Arctic Ocean, Southern Ocean	Level 1b & 2	Uni HB
	ï Development of algorithms for the retrieval of ice concentration	Arctic Ocean, Southern Ocean	Level 0-1b, s0	Uni HB, AWI
	ï Development of algorithms for the retrieval of ice surface roughness	Arctic Ocean, Southern Ocean	Level 0-1b, s0	DLR, AWI
Process studies	ï Change of glacier mass budget after major downstream calving	E.g. Drygalski Glacier (Antarctic Peninsula)	Level 2	Uni FR
	ï Change of ice shelf thickness, deduction of bottom melting rates	E.g. Filchner-Ronne Ice Shelf, Twaites Glacier	Level 2	Uni MS, DLR, AWI
	ï Determination of different glacier facies	Greenland	s0	Uni TR
	ï Development of sea-ice thickness distribution under different atmospheric forcing regimes	Arctic Ocean, Southern Ocean	Level 0-2	AWI
Level 3 data generation	ï Application of specially adapted geo-mathematical techniques: kriging, regional kriging, and cokriging		Level 2	Uni TR
Modeling	ï RA data as boundary condition for ice sheet models	Antarctic continent, Antarctic peninsula, Greenland	High resolution DEM, level 3	Uni MS, Uni DA, AWI
	ï Detection of grounding lines from tidal displacements	Antarctica	Level 2	Uni MS, Uni DA, AWI
	ï Assimilation of sea-ice thickness into regional and large scale sea ice models	Arctic Ocean, Southern Ocean	Level 2 & 3	AWI
	ï Validation of model results (spatial and temporal patterns)	Arctic Ocean, Southern Ocean	Level 2 & 3	AWI
Geodesy	ï Derivation of the geoid over ice covered oceans	Arctic Ocean, Southern Ocean	Level 3 & 3	TUM
Statistical exploitation	ï Monitoring of changes in surface height in large regions		Level 2 & 3	Uni MS, AWI
	ï Extension of available mass-balance time series derived from other sources		Level 2 & 3	Uni DD, Uni FR, Uni TR, AWI
	ï Monitoring of changes in sea-ice thickness in large regions		Level 2 & 3	AWI

Institutions:

AWI: Alfred Wegener Institute of Polar and Marine Research, Bremerhaven

Uni DA: Mechanical Institute, Technical University Darmstadt

Uni DD: Geodetical Institute, University of Dresden

DLR: German Aerospace Center, Oberpfaffenhofen

Uni FR: Institute for Physical Geography, University of Freiburg

Uni HB: Institute of Environmental Physics, University of Bremen

Uni MS: Geophysical Institute, University of Münster

Uni TR: Geographical Institute, University of Trier

TUM Geodetical Institute, Technical University of München
 
 

Attachment 1: List of participiants
 

Reinhard	Dietrich	Inst. f. Planetare Geodäsie	Universität Dresden	dietrich@ipg.geo.tu-dresden.de
Mark	Drinkwater	ESTEC Earth Sciences Division		mdrinkwa@estec.esa.nl
Jakob	Flury	GOCE-Projektbüro Deutschland	Inst. f. Astr. und Phys. Geodäsie	flury@bv.tum.de
Oliver	Funke	Inst. f. Umweltphysik	Universität Bremen	ofunke@uni-bremen.de
Hermann	Goßmann	Inst. f. Physische Geographie	Universität Freiburg	hego@ipg.uni-freiburg.de
Ralf	Greve	Institut fuer Mechanik	TU Darmstadt	greve@mechanik.tu-darmstadt.de
Klaus	Grosfeld	Inst. f. Geophysik	Universität Münster	grosfel@uni-muenster.de
Christian	Haas	Alfred-Wegener-Institut		chaas@awi-bremerhaven.de
Ute C.	Herzfeld	FB6 Geowissenschaften	Universität Trier	uch@denali.uni-trier.de
Georg	Heygster	Inst. f. Umweltphysik	Universität Bremen	heygster@physik.uni-bremen.de
Ralf	Krocker	Alfred-Wegener-Institut		rkrocker@awi-bremerhaven.de
Thomas	König	DLR		Thomas.Koenig@dlr.de
Gert	König-Langlo	Alfred-Wegener-Institut		gkoenig@awi-bremerhaven.de
Susanne	Lehner	DLR		susanne.lehner@dlr.de
Peter	Lemke	Alfred-Wegener-Institut		plemke@awi-bremerhaven.de
Wolfgang	Lengert	ESA-ESRIN		wolfgang.lengert@esa.int
Jan	Lieser	Alfred-Wegener-Institut		jlieser@awi-bremerhaven.de
Uwe	Mallow	Astrium GmbH		uwe.mallow@astrium-space.com
Heinrich	Miller	Alfred-Wegener-Institut		hmiller@awi-bremerhaven.de
Hans	Oerter	Alfred-Wegener-Institut		hoerter@awi-bremerhaven.de
Helge	Rebhan	ESTEC Earth Sciences Division		hrebhan@jw.estec.esa.nl
Klaus	Reiniger	DLR		klaus.reiniger@dlr.de
Friedhelm	Rostan	Astrium GmbH		Friedhelm.Rostan@astrium-space.com
Klaus-Peter	Schmidt	DLR		Kp.schmidt@dlr.de
Jens	Schröter	Alfred-Wegener-Institut		jschroeter@awi-bremerhaven.de
Daniel	Steinhage	Alfred-Wegener-Institut		dsteinhage@awi-bremerhaven.de
Ralf	Stosius	FB6 Geowissenschaften	Universität Trier	stosius@uni-trier.de
Klaus	Strübing	BSH Eisdienst		klaus.struebing@m1.hamburg.bsh.d400.de
Bernd	Vennemann	DLR		bernd.vennemann@dlr.de
Martin	Wiehl	Inst. f. Planetare Geodäsie	Universität Dresden	wiehl@ipg.geo.tu-dresden.de
Duncan	Wingham	University College London		djw@mssl.ucl.ac.uk
Klaus	Zahnen	Geographisches Institut	Humboldt-Universität zu Berlin	nikolaus.zahnen@rz.hu-berlin.de

Attachment 2: Agenda
 
 

Montag, 28.05.2001, AWI Gebäude F, Bussestrasse 24
 

13:00 - 13:30	Begrüssung, Aufgaben und Ziele des Projektbüros	C. Haas, AWI  K. Schmidt, DLR
13:30 - 13:50	CryoSat - The first mission of the Earth Observation Envelope Programme	M. Drinkwater, ESA
13:50 - 14:15	Scientific goals of the CryoSat mission	D. Wingham, UCL
14:15 - 15:00	CryoSat Raumsegment und Ablauf der industriellen Aktivitäten	U. Mallow, Astrium
	SIRAL (Synthetic-Aperture Interferometric Radar Altimeter): Aufbau, Funktion und Kalibration	F. Rostan, Astrium
15:00 - 15:20	Kaffeepause
15:20 - 16:30	Status Cal/Val, Processing/Archiving, Level 2, AO's	H. Rebhan, ESA
16:30 - 17:30	Arbeit der SAG (Scientific Advisory Group); Aspekte/Anforderungen von Landeismessungen	H. Miller, AWI
	Cal/Val-Aktivitäten, Aspekte/Anforderungen von Meereismessungen	P. Lemke, AWI
17:30 - 17:45	Das neue hochaufloesende Schwerefeld aus der GOCE-Mission  als Beitrag zur Eisforschung?	J. Flury, GOCE-Projektbuero D
18:30	gemeinsames Abendessen / Buffet

Dienstag, 29.05.2001, AWI Gebäude F, Bussestrasse 24
 

09:00 - 12:30	Erarbeitung der Anforderungen deutscher Nutzer an Datenprodukte.  Beiträge deutscher Institutionen zur Schaffung höherwertiger Datenprodukte.  Möglichkeiten und Interessen deutscher Gruppen zu Cal/Val-Aktivitäten.	alle
12:30 - 13:00	Imbiss