Research On The Variation Of Ice Condition In The Key Areas Of The Northwest Passage

The Arctic Northwest Passage stretches from Beaufort sea at the north of Alaska in America in the west to the Davis Strait and Baffin Bay in the east across the Canadian Arctic archipelago waters and it finally connects the Atlantic and Pacific oceans. As the geographic advantage, the sail in Northwest Passage can save at least one third of the range for the world shipping industry, but this route is always in the frozen state all the year round as it is located in the Arctic, and then it has been unable to be utilized. As the climate is becoming warmer and warmer in recent years, the opening time of the Northwest Passage in summer is also becoming longer gradually. So the use of the Northwest Passage seems to be just a matter of time, and the research about the navigation in the Northwest Passage is also increasingly necessary.In order to grasp the navigable time of the Northwest Passage effectively and conveniently, this article focuses the current sea ice trends, and summarizes the historical average of the sea ice along the waters in the Northwest Passage on the basis of the Admiralty Sailing Directions from British Waterway Bureau. And then eventually come to the key areas of the Northwest Passage that can affect and decide the navigable time, and in this article they are defined as BMM key area, North of Victoria Strait key area and BL key area.Focus on three key areas, this article summarizes and analysis the satellite images of the sea ice in key areas on each of the2003-2011August20, August31and September30,and the satellite images of annual extent of minimum sea ice. Because the extent of the sea ice in each August and September changes most obviously in the last9years, and the change of the sea ice in this9years is very representative by the historical information of the Northwest Passage.In order to ensure the systemic and uniformity of the research, the satellite imagery in this article is all made by the PHAROS group from the University of Bremen, Germany, according to the AMSR-E satellite data. To the above information, this article make horizontal comparison among the date of August20,August20,September30and the date of annual minimum sea ice extent,and make longitudinal comparison among the year from2003to2011,and they show that:There are8years of the last9years when the date of the minimum sea ice extent appears in the first half of September, in accordance with the laws of history, so the most appropriate time for navigation in the Northwest Passage should be the first half of September, at the perspective of sea ice. And from the inter-annual variation, it can be known that the extent of the sea ice is in a generally decreasing trend in the first half of September,2003to2011.So it can be drawn that the navigable time of the Northwest Passage should be the first half of September, and then determine after strict observation.However, according to the report of Arctic marine assessment, the international working group agreed that the Northwest Passage is still not navigable until2020because of the lack of port, critical infrastructure, hydrological data, marine data products and so on. Therefore, the navigable time determined in this article should be combined with the conditions above then it can be applied.