The Long Thaw

Multi-year Arctic Sea Ice with Graph Overlay || The most visible change in the Arctic region in recent years has been the rapid decline of the perennial ice cover. The perennial ice is the portion of the sea ice floating on the surface of the ocean that survives the summer. This ice that spans multiple years represents the thickest component of the sea ice cover.This visualization shows the perennial Arctic sea ice from 1980 to 2012. This is not the sea ice minimum, which occurs in September each year. This measures the perennial sea ice that survives the summer and thus exists for longer than a one-year time span. The measurement for this sea ice was taken during the months of November, December and January each year. The date assigned to the data point is the year of the last measurement (January). The grey disk at the North Pole indicates the region where no satellite data is collected. A graph overlay shows the area data points are highlighted on the graph. || Multi-year Arctic Sea Ice with Date Overlay || Multi-year Sea Ice (without Graph or Date Overlay) || This image shows the multiyear sea ice in 2012. The grey disk at the North Pole indicates the region where no satellite data was collected. || This image shows the multiyear sea ice in 1980. The grey disk at the North Pole indicates the region where no satellite data was collected. || The graph overlay with transparency || The date overlay with transparency

An image of multi-year sea ice (brighter white) shown over the average sea ice (light blue) during the three winter months ending in January 2012. This image has a transparent background. || The most visible change in the Arctic region in recent years has been the rapid decline of the perennial ice cover. The perennial ice is the portion of the sea ice floating on the surface of the ocean that survives the summer. This ice that spans multiple years represents the thickest component of the sea ice cover.These still images show a comparison of the perennial Arctic sea ice and the first-year sea ice in 1980, 2008 and 2012. The bright white central mass shows the perennial sea ice while the larger light blue area shows the full extent of the winter sea ice including the average annual sea ice during the months of November, December and January. || An image of multi-year sea ice (brighter white) shown over the average sea ice (light blue) during the three winter months ending in January 1980. This image has a transparent background. || An image of multi-year sea ice (brighter white) shown over the average sea ice (light blue) during the three winter months ending in January 2008. This image has a transparent background.