Tag Archives: Albedo

From NASA’s Vital Signs of the Planet feature, Arctic winter warming events becoming more frequent, longer-lasting, we learn

Arctic winter warming events – winter days where temperatures peak above 14 degrees Fahrenheit (minus 10 degrees Celsius) – are a normal part of the climate over the ice-covered Arctic Ocean. But new research by an international team that includes NASA scientists finds these events are becoming more frequent and lasting longer than they did three decades ago.

and why does this matter?

Storms that bring warm air to the Arctic not only prevent new ice from forming, but can also break up ice cover that is already present, Graham said. He added that the snowfall from storms also insulates current ice from the cold atmosphere that returns to the Arctic after the cyclones, which can further reduce ice growth.

We know that reduced ice changes albedo, creating a feedback loop (see the Arctic Ice and Global Warming post). The NASA article is from the paper Increasing frequency and duration of Arctic winter warming events where the graph here originates (see supporting information pdf). The data is hard to track down but if you email the authors they may provide you the data used to create these graphs, especially if you mention you want to use it for a linear regression project in a class.

The BBC reports: Sea Level Fears as Greenland Darkens. The article discusses a possible feedback loop where as temperatures warm algae growth may flourish, which darkens the surface and changes the albedo to increase melting.

One concern now is that rising temperatures will allow algae to flourish not only on the slopes of the narrow margins of the ice-sheet but also on the flat areas in the far larger interior where melting could happen on a much bigger scale.

We joined the latest phase of research in which scientists set up camp on the ice-sheet to gather accurate measurements of the “albedo” or the amount of solar radiation reflected by the surface.

White snow reflects up to 90% of solar radiation while dark patches of algae will only reflect about 35% or even as little as 1% in the blackest spots.

Other highlights from the article include:

Currently the Greenland ice sheet is adding up to 1mm a year to the rise in the global average level of the oceans.

It is the largest mass of ice in the northern hemisphere covering an area about seven times the size of the United Kingdom and reaching up to 3km (2 miles) in thickness.

This means that the average sea level would rise around the world by about seven metres, more than 20ft, if it all melted.

You can get Greenland Ice Data from NASA’s Vital Signs of the Planet page as noted in a past post.