The CryoSat-2 measurement systemPosted on 04/09/2010 11:42:13 AM PDT by Ernest_at_the_Beach
Europe's satellite mission to measure the Antarctic and Greenland ice sheets, the Earth observation satellite CryoSat-2, was launched at 15:57 CET on a Russian Dnepr launcher from Baikonur in Kazakhstan. The satellite is now in orbit 717 kilometres above Earth. The mission will survey the Antarctic and Greenland ice sheets and sea ice until 2013. Researchers expect to gain a new understanding of the relationships between global warming, the shrinking of the polar ice sheets and changes oceanic and atmospheric circulation from the mission. DLR is contributing towards the funding of the mission on behalf of the German Federal Government. Germany contributes 24 percent of the total funding for the European Space Agency's (ESA) Living Planet programme, of which the CryoSat-2 mission is a part. The total cost of the mission is around 140 million Euro.
The polar ice sheets are of fundamental importance for the global climate, ocean currents and sea levels. Due to the greenhouse effect, more ice is melting at the north and south poles than is being created. The salt concentration of seawater at low latitudes is decreasing. This inhibits the transport of cold, deep-sea water to the Equator as well as the corresponding counter-flow of warm, surface water to the poles. This also weakens the Gulf Stream, which warms the lower latitudes of Europe in comparison to similar latitudes on other continents. With CryoSat-2, scientists will, for the first time, be able to measure changes in the thickness and mass of the polar ice sheets from space, and accurately determine contribution to sea-level change due to the melting of large ice sheets. This will make it possible to create reliable climate forecasts and provide early detection of risks for low-lying areas.
Innovative SIRAL measurement technology used for the first time
The CryoSat-2 measurement systemDistinguishing between sea ice, which is largely underwater, and the water around it, is a challenge for conventional space-based altimeters. These systems direct radar signals vertically down to Earth, and receive the reflections from its surface. By knowing the exact position of the satellite at a particular time and the amount of time it takes the radar to be reflected back up from Earth’s surface, the height of the illuminated area can be calculated. This technology has a measurement uncertainty of about 10 centimetres. However, at the sloped, often rough edges of the ice sheets, the error can grow to more than 100 metres.
This is why CryoSat-2 is equipped with a new measurement system, SIRAL (Synthetic Aperture Interferometric Radar Altimeter). It employs two antennas, arranged transversely, or across the satellite’s flight direction, and connected by a carbon-fibre antenna frame. The system measures the phase difference – that is, the difference between the travel times from the satellite to Earth and back – of the signals received by the two antennas. From this, it is possible to precisely determine the location where the reflection occurred, even when the reflecting surface is sloped.
fyi
It will be interesting how much data will be released if it goes agaisntt he global warming cabal...
The Europeans don’t trust the data gathered by American satellites - American satellite data has a Westerner-filter that is sure to destroy the pristine nature of captured data ...
If you're going to announce your results before conducting the experiment, why conduct the experiment at all? Just pocket the money and fake the data like the CRU at East Angelica does routinely.
Regards,
GtG
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