Dispatch 13: Radiosondes and Pictures of Ice     Print

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Joey Wenig

October 3, 2014

After a short trip south during the night for some XCTD work, we returned to TU-1 in the early AM today so that the TUMSAT mooring could be recovered, moved to the right water depth, and redeployed. It was nice to see it disappear this time around. With that out of the way, we set a course for TU-2, about a hundred and fifty nautical miles to the northwest. Lying almost due north of Bering Strait over the Chukchi Abyssal Plain, TU-2 will be the westernmost station of our cruise. Interesting bathymetric features along the way: another abyssal plain, aptly named ‘Northwinds’, and the Chukchi Plateau. Up until yesterday, we’ve spent most of our time above the Canada Abyssal Plain, so it’s exciting to encounter some new terrain—even if we can’t see it.

In dispatch 6, I included a photo of Sigrid Salo releasing a weather balloon (technically a ‘radiosonde’) as a C130 aircraft passed by overhead. Sigrid works at NOAA’s Pacific Marine Environmental Laboratory in Seattle, and unlike most of the science crew, she is not here to do oceanography. Sigrid’s balloons are like CTD casts, but for the atmosphere: twice daily, they soar upwards measuring GPS position, temperature, humidity, and pressure as they go, all of which is transmitted back to the ship via VHF. Unlike the CTDs, however, Sigrid does not get these balloons back. After traveling roughly 20 km vertically, and anywhere between 30 and 60 kilometers in a direct line from their original release point, these balloons cease transmitting and are gone forever. Airplanes like the C130 from the photo use data from radiosondes to calibrate their instruments (another U.S. Coastguard flyover is tentatively scheduled for Monday, this time in a P-3 plane). But given how little access there is for this type of research in the Arctic, the data is also valuable because it gives us a background picture of the Arctic atmosphere.