Nansen Center contributes significantly at OceanObs´09

OceanObs'09 Logo: Ocean information for society: sustaining the benefits, realizing the potential 21-25 September 2++9, Venice, ItalyOceanObs'09 Logo: Ocean information for society: sustaining the benefits, realizing the potential 21-25 September 2++9, Venice, ItalyThe OceanObs conference in 1999 played a major role in forming the foundation for the comprehensive ocean observing systems implemented during the last decade facilitating systematic information about the physical environment of the worldwide oceans. The outcome of OceanObs´09 is between other manifested through the global availability of the Argo float system and extensive global efforts in ocean observation systems. This week OceanObs´09 gathers again in Venice to celebrate the last 10 years achievements and to lay the way forward in operational ocean observing systems. The Nansen Center have key roles in three major community white papers and several other presentations at OceanObs´09.

Stein Sandven, Ola M. Johannessen et al presents the Arctic Regional Ocean Observing System (Arctic ROOS) established by a group of 14 institutions from nine European countries working actively with ocean observation and modeling systems in Arctic and sub-Arctic seas. The background for Arctic ROOS is the growing demand for operational monitoring and forecasting services in Arctic and sub-Arctic seas as a consequence of climate change and increasing human activities in these areas. The main components of Arctic ROOS are (1) satellite observations from polar orbiting satellites using active and passive microwave, optical and infrared instruments, (2) numerical modeling including data assimilation, nowcasting, short term forecasting, model comparison and validation, and (3) In situ observation systems based on ship-borne instruments, moored instruments, ice buoys, floats and drifters. Satellite observations of seas ice, wind, waves, oil spills and ocean color parameters have been developed extensively in recent years with support from GMES projects funded by ESA and EU as well as national programmes. More information about ArcticROOS is found at http://arctic-roos.org.

Stein Sandven contributes to community white paper on “Remote sensing of Sea ice”. Sea ice data from satellites represent one of the longest earth observation records from space. The variations in temperature, emissivity and reflectivity of sea ice and the differences compared to the surrounding open ocean make it an ideal application of remote sensing. Several techniques and instruments have been developed and successfully utilized and today it is impossible to imagine operational sea ice monitoring and analysis without satellite data. However, as the use expands and need for knowledge moves forward, remote sensing of sea ice faces new challenges. Accordingly the paper provides an overview of status, recent developments and future challenges to improve sea ice monitoring from satellites.

Hanne Sagen, Ola M. Johannessen and Stein Sandven lead a presentation on “Acoustic technologies for observing the interior of the Arctic Ocean” and contribute to a community white paper on “A Global Ocean Acoustic Observing Network”. The demand for operational monitoring and forecasting systems in Arctic Ocean is growing as a consequence of climate change and increasing human activities in the area, but there is a severe lack of systematic observations of the deep Arctic Ocean. Acoustic tomography provides measurements of acoustic travel times between acoustic sources and receivers. Through inversion techniques, internal ocean temperature can be retrieved at an accuracy of 0.01°C over a 200 km distance. This acoustic observing system can also be used to assess the impact of increasing ambient noise levels on marine mammals. The implementation of multipurpose observing system will build on experience from the previous acoustic tomography experiments in the central Arctic Ocean and the regional acoustic system currently under implementation in the Fram Strait within the EU DAMOCLES and ACOBAR projects.

Johnny A. Johannessen contributes to a plenary presentation on operational ocean modeling, presenting the EC FP7 MyOcean project of the European Marine Core Service - aiming at deploying the first concerted and integrated pan-European capacity for ocean monitoring and forecasting. During years 2009-2011, MyOcean will lead the setting up of this new European service, grown on past investments in research & development, system development and international collaborations. It is indeed in Europe one of the most important legacy of the GODAE initiative. Implementing a European Marine Core Service is one of the top-three priorities of the GMES (Global Monitoring for Environment and Security) program led by the European Commission to enhance the development of new services based on Earth Observation, and organize their long-term sustainability. MyOcean is a direct answer to this priority. The ultimate challenge is to turn our overall approach of operational oceanography to a full service organization driven by user needs, and linked on a sustainable basis with the main stakeholders of operational oceanography in Europe and at the international level.

Johnny A. Johannessen and Laurent Bertino participate in the paper “Ocean Modelling using GOCE geoid products”. With the availability of satellite altimeter data since the mid eighties, both globally andover longer periods of time a huge effort were made in the scientific communities to process those global data sets in joint analyses of geoid and ocean dynamic topography. The quality of the available data was not sufficient to recover the details of the general ocean circulation. However, the very large scales (>5000 km) of the dynamic topography could be recovered and compared with the early oceanographic results obtained from hydrographic data.The basic definition of the ocean dynamic topography is simply the difference between the sea surface height and the geopotential reference surface called the geoid. Hence, the topography is a geometrically surface that describes the shape of the Earth. Simultaneously the dynamic topography may be considered as a reference surface for the ocean circulation at the ocean surface. The purpose of this white paper is to further advance mutual understanding between the geodesy and oceanography communities and to identify issues related to methods for producing a mean dynamic topography from the gravity and altimeter data. It will furthermore identify issues on how the geoid or the mean dynamic topography (MDT) will be used by the oceanography community and how the errors in the MDT can be estimated and used. The purpose is to fill a gap by describing the final uses of satellite gravity data within oceanography, and should inform the geodesy community about the subtleties encountered for ocean circulation studies. Further information about Ocean Obs´09 are found at http://www.oceanobs09.net.