Hudson Bay is 1,230,000 square kilometres in size and this makes it the second-largest bay in the world (after the Bay of Bengal). The Bay itself is connected with the Atlantic Ocean by Hudson Strait and to the rest of the Arctic Ocean by Foxe Basin and Fury and Hecla Strait. It is a relatively shallow body of water, with an average depth of about 100 metres. The water in Hudson Bay is less saline than the open ocean as it is covered by sea ice for large portions of the year and large amount of freshwater are added to the Bay from river systems.
Freeze-up of Hudson Bay tends to be a lengthy process because of the large expanse of water there is to freeze. The first sea ice formation usually occurs in late October in the coastal inlets in the northwestern section of the Bay. As the weather grows progressively colder, the ice spreads southward along the shore and eastward into the Bay. During the winter, a 5 to 10 kilometre wide belt of fast ice develops along most of the coastline. Beyond the shore-fast ice, Hudson Bay is covered with pack ice which moves in response to the wind (from http://ice-glaces.ec.gc.ca). I’ll post more on this in the fall when the ice is forming on the Bay.
As temperatures rise in May and June, flaw leads in the northwest portion of the bay become persistent. Normal clearing of the pack ice progresses southward from the Chesterfield Inlet - Southampton Island area and westward from the Quebec side of the bay. Associated ice melt is a slow process which accelerates in July with an open water shipping route to Churchill forming by the end of the month. The pack will often separate into a few large patches before melting completely by the middle of August. (from http://ice-glaces.ec.gc.ca)
This year, the sea ice on the Bay is almost gone and it is only the first week of July. As you can see from the chart below from the Canadian Ice Service website (scroll all the way to the end of the page), this is the lowest concentration of sea ice in Hudson Bay in the record presented.
The following images are the weekly regional ice charts generated for Hudson Bay over the last six weeks. These charts demonstrate the decay of the sea ice on Hudson Bay for 2010. (from http://ice-glaces.ec.gc.ca) The Canadian Ice Service website has a great description of the sea ice disintegration process.
The following chart is the daily ice chart for July 5, 2010 for the northern and southern sections of Hudson Bay. (from http://ice-glaces.ec.gc.ca)
Lastly, here is the global picture of Arctic sea ice decay from the National Snow and Ice Data Centre.
No comments:
Post a Comment