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03/08/2020
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Ice performs a vital position in preserving Earth’s local weather cool, however our quickly warming world is taking its toll and ice is generally decline. For greater than 10 years, ESA’s CryoSat has been returning vital info on how the peak of our fragile ice fields is altering. Nevertheless, to acquire even higher perception, ESA has spent the final two weeks nudging CryoSat into a better orbit to synchronise it with NASA’s ICESat-2 in order that scientists can profit from simultaneous measurements from totally different house sensors.
CryoSat carries a radar altimeter and NASA’s ICESat-2 carries a laser. Both devices measure the peak of ice by emitting a sign and timing how lengthy it takes the sign to bounce off the ice floor and return to the satellite tv for pc. Knowing the peak of the ice permits scientists to calculate its thickness.However, snow can construct up on prime of the ice and might disguise the ice’s true thickness.While CryoSat’s radar penetrates by way of the snow layer and displays carefully off the ice under, ICESat-2’s laser displays off the highest of the snow layer. Blending simultaneous satellite tv for pc laser and radar readings implies that snow depth might be measured straight from house for the primary time.Knowing the depth of the overlying snow will enhance the accuracy of sea-ice thickness measurements and enhance our data of how snow and ice surfaces, with totally different bodily properties, scatter again the sign from the devices.
ESA’s CryoSat mission supervisor, Tommaso Parrinello, says, “The idea of having CryoSat’s orbit align with that of NASA’s ICESat-2 goes back some years now. It has taken a lot of planning and is a significant undertaking, something we haven’t done before.“Aligning CryoSat with ICESat-2 is like having one satellite with two instruments.”ICESat-2 orbits at an altitude of round 500 km and CryoSat used to orbit an altitude of round 720 km.Two weeks in the past, flight operators at ESA’s spacecraft operation centre in Germany started gently firing CryoSat’s thrusters to elevate its orbit by nearly 1 km to carry it into synch with ICESat-2.
ESA’s ice mission
Ignacio Clerigo, ESA’s CryoSat spacecraft operations supervisor, defined, “CryoSat orbit was much higher and slower than ICESat-2, so we couldn’t align them by having them orbit in tandem. Instead, we raised CryoSat by 900 m through a series of 15 precisely timed thruster burns. The two satellites will now overlap every 19th orbit of CryoSat and 20th orbit of ICESat-2.”Since sea ice floats within the ocean, currents and wind transfer it round. Under regular circumstances, the 2 satellites would take measurements over the identical location quite a few hours aside, so it may very well be totally different ice beneath their regular orbital paths.Dr Parrinello continued, “By raising CryoSat’s orbit we find this sweet spot where every 1.5 days the two satellites will pass over areas of the polar regions around the same time. These few minutes of almost coincident measurements will be key for studying sea ice. CryoSat will remain in this orbit now until the mission is over.”Josef Aschbacher, ESA’s Director of Earth Observation Programmes, remarked, “Having both agency’s satellites aligned in orbit is a wonderful example of our organisations working together to bring greater benefits to science. These coincident measurements are going to be very important for scientists studying our changing world.”
ICESat-2
Sea ice performs an vital position within the world local weather. For instance, it helps preserve Earth’s vitality steadiness whereas serving to maintain polar areas cool by reflecting incident daylight again into house. It additionally retains the air cool by forming an insulating barrier between the chilly air above and the hotter ocean water under.This new info might assist enhance local weather fashions, notably for Antarctica. The fashions scientists presently use to gauge snow depth when calculating sea ice work moderately properly for the Arctic, however much less so for the Antarctic.It might additionally assist sort out the tough job of measuring sea ice in summer season. In hotter climate, ponds of meltwater on the ice swamp the sign from CryoSat, however ICESat-2 has the precision to detect these ponds and differentiate between them and the breaks between floes of ice.
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