The crew of the Arctic Spring expedition have made their way north through the Bering Strait and into the Chukchi Sea. The first image below (from May 17) shows a couple of interesting features in the sea ice. Just south of 69N, in the western part of the image, a lead has developed in the ice. A lead is a large fracture in sea ice that results in a large area of open water. To the northeast of the lead are large patches of drift ice, sea ice that has broken away from the solid ice (called fast ice) and is carried away by a combination of wind and the ocean currents. In the next few weeks we will use these satellite images to observe how the ice floes develop and the Arctic spring turns into summer.

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MODIA-Aqua True Color image for May 17th, 2014.

The next image is from two days later (May 19), when the USCGC Healy and the expedition crew entered the Chukchi Sea. In this image we can observed the the lead seen on May 17 has expanded in size, and a new lead is opening up just to the north of the drift ice (see image below). The Healy is now in the thicker sea ice over the northern Chukchi Sea.

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MODIS-Aqua True Color image from May 19th 2014. The approximate location of the USCGC Healy shown.

The MODIS sensor on the Aqua satellite that we use to make these satellite images also measures the color of the ocean, which we can use to estimate how much chlorophyll is in the water. We can then use the chlorophyll concentration to estimate how much algae is in the water. The image below shows high chlorophyll concentration in the open-water region in the southern Chukchi Sea that was covered with sea ice only a few weeks ago. These are open ocean blooms which typically occur soon after the sea ice retreats in the Arctic. The team on the Healy though are positioning themselves further to the north in thick ice in the hope of measuring blooms that occur beneath the sea ice.

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False Color image of phytoplankton concentration overlaid on True Color image, both from May 19th 2014. The approximate location of the USCGC Healy shown.

About The Author

Peter Gaube
Oceanographer

Oceanographer at the Woods Hole Oceanographic Institution, Peter works with satellite observations and numerical ocean models to study physical/biological interactions in the sea. During the expedition, Peter will be uploading satellite images and writing about the sea ice and phytoplankton.

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