The extent of multiyear ice within the Arctic Ocean is distinctly greater than it was at the beginning of last winter. During the summer of 2013, a larger fraction of first-year ice survived compared to recent years. This ice has now become second-year ice. Additionally, the predominant recirculation of the multiyear ice pack within the Beaufort Gyre this winter and a reduced transport of multiyear ice through Fram Strait maintained the multiyear ice extent throughout the winter. In the picture below, Advanced Scatterometer (ASCAT) imagery reveals the distribution of multiyear ice compared to first year ice for March 28, 2013 (yellow line) and March 2, 2014 (blue line). The ASCAT sensor measures the radar–frequency reflection brightness of the sea ice at a few kilometers resolution. Sea ice radar reflectivity is sensitive to the roughness of the ice and the presence of saltwater droplets within newer ice (and, later in the season, the presence of surface melt). Thus older and more deformed multiyear ice appears white or light grey (more reflection), whereas younger, first-year ice looks dark grey and/or black.
Credit: Advanced Scatterometer imagery courtesy NOAA NESDIS, analysis courtesy T. Wohlleben, Canadian Ice Service Satellite data on ice age reveal that
multi-year ice within the Arctic basin increased from 2.25 to 3.17 million square kilometers (869,000 to 1,220,000 square miles) between the end of February in 2013 and 2014. This winter the multi-year ice makes up 43% of the icepack compared to only 30% in 2013. While this is a large increase, and may portend a more extensive September ice cover this year compared to last year, the fraction of the Arctic Ocean consisting of multi-year ice remains less than that at the beginning of the 2007 melt season (46%) when a large amount of the multi-year ice melted. The percentage of the Arctic Ocean consisting of ice at least five years or older remains at only 7%, half of what it was in February 2007. Moreover, a large area of the multi-year ice has drifted to the southern Beaufort Sea and East Siberian Sea (north of Alaska and the Lena River delta), where warm conditions are likely to exist later in the year.
Credit: NSIDC, Courtesy M. Tschudi, University of Colorado
So why does any of this matter?? Well, it doesn’t to our everyday lives; however, it may eventually show that global temperatures are actually cooling slightly from where they peaked just a few years ago.
What that actually means and where things go from here are still unknown, but it may be a good sign the ice is reforming in the Arctic.
The information in this article is courtesy of nsidc.org