In order to better predict weather and climate, scientists need more precise data on water exchange between the oceans, the land and the atmosphere as well as on precipitation and evaporation. Up to now, such data have been measured in situ by means of water and soil samples. Now, a new era is dawning: remote sensing from space by satellite through the SMOS mission (Soil Moisture & Ocean Salinity) of the European Space Agency, ESA.
The sea is the primary regulator of our earth's climate. Global ocean circulation transports heat from the equator polewards. For example, the Gulf Stream brings a warmer climate to Europe's mid-latitudes than is found at the same latitudes in North America. Such circulation processes are strongly dependent on the salinity of the sea water. For global atmospheric circulation, the moisture content of the soil also plays an important role, for example with respect to evaporation and precipitation. This information about salinity and soil moisture is used in oceanographic and meteorological models. If the SMOS mission runs successfully over a longer period of time, its results could also serve to improved global climate models.
In addition, global warming accompanied by melting of the polar ice caps leads to decreasing salinity of the sea. This decrease in salinity helps to estimate the rate of ice melting.
The SMOS mission is based on new technology. The underlying principle is the fact that every physical body emits a certain electromagnetic radiation depending on its temperature and electrical properties. Thus, the salinity of the ocean and the moisture of the soil affect their conductivity, and this influence is strongest in the microwave radiation around 1.4 GHz.
The SMOS mission will cost around 210 million Euros and is being funded by the ESA with contributions by the French and Spanish Governments, which were instrumental in the planning and development of SMOS.
The German national project office is at the Institute for Physical Oceanography (IfM) of the University of Hamburg and can be contacted for further information.
A workshop on 9-10 November at the IfM served to bring together oceanographers, geophysicists and geographers, who related how SMOS data will be incorporated into their research work.
The planned start of this ESA mission will be the end of 2007. It will deliver data to the scientific institutes after about six months.
The IfM project office will evaluate the first satellite data and compare them to simultaneously collected data from water and soil samples in order to calibrate the measurement systems. This calibration phase will be supported by numerous European research groups which will collect samples from different positions all over the earth.
Further information on the SMOS satellite as well as results from the workshop can be found under www.smos.zmaw.de.
Contact:
Dr. Steffen Dransfeld
Projektbüroleiter SMOS
Institut für Meereskunde, Universität Hamburg
Zentrum für Meeres- und Klimaforschung (ZMK)
Bundesstrasse 53, D-20146 Hamburg
Tel.: ++49 (0)40/4 28 38-74 69
Fax: ++49 (0)40/4 28 38-74 71
E-Mail: steffen.dransfeld(at)zmaw.de
