Mid-Winter 2015-16 North Pole-Region Warming Events

How we know the air temperature at the North Pole:
The National Science Foundation supported North Pole Environmental Observatory (NPEO) regularly deploys surface drifting buoys of the International Arctic Buoy Program (IABP) in the North Pole region. Usually this is done in the spring with aircraft landing on the sea ice. However, in August 2015, the US Coast Guard with additional support from agencies such as the Office of Naval Research and NOAA carried out a ground breaking atmosphere-ice-ocean observation flight to the North Pole. This grew out of our Office of Naval Research-funded Seasonal Ice Zone Reconnaissance Surveys done by Coast Guard Station Kodiak in their C130 aircraft. The North Pole flight included air-dropping an IABP satellite-tracked, drifting, meteorological buoy (AXIB) measuring  atmospheric temperature and pressure. Because it was dropped at the Pole in August, this AXIB, buoy 132472, at 87.5°N, 12°W, is currently our closest to the Pole.

What the NPEO/IABP buoys tell us about the 12/30/2015 warming event:
AXIB 132472’s data along with that of other NPEO-deployed buoys are found at the North Pole Environmental Observatory. As of 12/30/2015 at 1800Z, buoy 132472 was reporting the air temperature as -23.5°C (-10°F) which is pretty normal. However, looking at data from the last two days, courtesy of the Wendy Ermold of the International Arctic Buoy Programme we see that over a couple of days the AXIB reported temperature near the North Pole rose significantly. It was -37°C at 1800Z, 12/28/2015 and reached a maximum of -8.52°C on 12/30/2015 at 0300Z, quite a rapid transition. So in summary, the forecast warming was qualitatively pretty good even though temperatures at the Pole didn’t reach up to the freezing point. In fairness the forecast front was very sharp so if it didn’t get quite as far north, that would explain temperatures at the Pole being significantly cooler than forecast.

1/1/2016 Update on what NPEO/IABP buoys tell us about the 12/30/2015 warming event:
Several bloggers and reporters brought it to our attention that at least one buoy near the North Pole had exceeded 0°C. The Washington Post reported reported that “WMO ID Buoy 6400476 at a latitude of 87.45 degrees North hit a high temperature of 0.7 degrees C…” This was not one of the buoys that NPEO deployed in 2015, but Wendy found this buoy in the IABP database as imei 300234062788470. To get a better idea of how the warming progressed through the Central Arctic Ocean, Wendy has put together a sequence of maps with all the IABP listed buoy positions color coded by temperature.

For reference to earlier reports, the NPEO-deployed AXIB 132472 and WMO 6400476 (300234062788470) are identified by name. One can scroll through hourly maps and see the buoys report the passage of the warming through the North Pole region. At 0300Z on 12/30 AXIB 132472 at about 87.5°N, 44°W reached its maximum temperature of –8.52° C. At 1300Z on 12/30. WMO 6400476 (300234062788470) reached its maximum temperature of +0.7° C at about 87.5°N, 151°E, almost exactly on the opposite side of the Pole from the AXIB. Simple interpolation would suggest that the Pole never rose above freezing, but it is more significant that above-freezing temperatures actually projected farther into the Arctic Ocean than the Pole.

It may be even more significant that the front passed the Pole in East longitudes, on the Russian side of the Pole. The projection of low atmospheric pressure associated with this storm event promotes a high Arctic Oscillation Index and forces a counterclockwise (cyclonic) wind pattern that accelerates the Transpolar Drift of sea ice across the Basin and out Fram Strait. By itself, a few hours of temperatures above freezing will likely not have a big impact on the Arctic Ocean ice pack. But accelerating the export of ice in winter depletes the Arctic Ocean of older thicker ice, leaving the extent of the thinner ice pack more sensitive to summer melt. In this connection, perhaps the most significant NPEO buoy result (see the NPEO 2015 Data Buoy Drift Map tab) is that the NPEO buoys deployed near the North Pole in April are already (on 1/1/2016) south of 76°N in the Greenland Sea. In the early years (~2000-2005) of NPEO it typically took buoys deployed near the Pole one year to reach Fram Strait at 80°N. The roughly factor of two increase in speed shown is partly due to decreases in ice thickness and strength, but it is safe to predict that if cyclonic storm events like this one ending 2015 continue penetrating the eastern Arctic Ocean, they will increase ice export and reduce summer 2016 ice extent.

— Jamie Morison for the NPEO