This morning I met up with Christian, Bruce, and Chris at Edmonton's International Airport. Taking off just after sunrise, we had a nice long delay in Yellowknife as our plane had some sort of malfunction, so a 30 minute stop over became a few hours delay. Off to a good start.
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| Take off from Edmonton at sunrise. |
We are heading to Sachs Harbour on Friday and from there we head out onto the sea ice in the Beaufort Sea. We will be staying at a field camp of the U.S. Office of Naval Research (ONR) conducting measurements for the ESA/NASA CryoSat-2 Validation Experiment 2014 (CryoVEx 2014). Our work also aids the main project happening at the ONR camp, a scientific program called the Marginal Ice Zone experiment. That experiment will be putting out many buoys on the ice, sensors below the ice and later this year will deploy autonomous underwater vehicles.
We will be doing snow and ice measurements to characterize the conditions in the region and to provide validation data for airborne and satellite surveys from NASA, ESA and York University.
NASA, ESA and York University will fly aircraft over our on-ice measurements. Those airborne measurements will then be used to compare to the satellite data. This is an effort to try to scale up from small, localized but highly accurate in-situ measurements to large scale regional observations in order to better understand the snow and ice conditions and their changes.
In 2010 ESA launched a satellite radar altimeter called CryoSat-2 to improve our knowledge of the changes in sea ice and land ice thickness. The satellite measures the distance between itself and the surface using radar waves by measuring the time it takes for the signal to get to the ground and back to the satellite, much like a police radar gun measures how fast your car is going. For sea ice, we then take the difference of the height of the sea ice surface and height readings from open water between the ice floes to get the freeboard, or the height of the ice above the water. Knowing the density of the ice, the snow and water, and knowing the depth of snow we can then calculate ice thickness.
The idea is that the radar from CryoSat-2 penetrates through any snow on the ice and reflects from the ice surface. However, this is still not 100% clear and so we are trying to figure out if this is the case or not, and if not: where, when, and why that might be. This will make any estimates of freeboard and thickness, and changes in those two variables more certain as we will then be able to quantify the error or uncertainty in the estimates.
NASA is flying an airborne sensor suite for a campaign called IceBridge. The campaign bridges two satellite missions (ICESat-1 and ICESat-2) using airborne campaigns after ICESat-1 died in 2009; ICESat-2 is not scheduled to launch for a couple years yet. ICESat-1 was a laser altimeter so instead of using a radar signal it used a laser to measure the distance to the surface, much like the police sometimes use a laser gun instead of the radar gun to check if you are speeding.
NASA is also flying radar sensors that measure the thickness of the glaciers and also a snow radar that measures snow depth, even on sea ice. The data we provide will help to calibrate and validate that snow radar, and their laser data and then allow us to use the NASA data in comparison to CryoSat-2.
Finally, York University is flying our airborne electromagnetic induction device, the so-called EM Bird. This sensor measures snow+ice thickness, or total thickness. It has been proven to be very accurate in most cases, and thus provides validation data for the other airborne and satellite data.
All of these planes will be flying over our on-ice site where we will do thousands of snow depth measurements, measure snow density, ice thickness, ice and snow surface roughness, and take 3D laser scanner measurements of the snow surface roughness. We will put out buoys and markers for the planes to use to sea our measurements and will deploy radar corner reflectors that strongly reflect radar waves back to the sensor that emitted them providing another reference point both on the on-ice and their height above the snow and ice.
I will try to blog more about this over the coming period, but I know my access to internet is limited. If I have some time tomorrow I will try to pre-write a few blogs. Otherwise, I will be posting on Twitter using the username @SIBeckers and with the hashtag #CryoVEx2014. There is also a lot of information already out there on both NASA Operation IceBridge, and ESA's CryoSat-2. This project is a nice collaboration between two big space agencies, and a handful of research institutes and universities.
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