September Sea Ice Outlook: July Report

Release Date: 
16 July 2009

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The outlook for arctic sea ice for September 2009, based on June data, indicates a continuation of low pan-arctic sea ice extent and no indication that a return to historical levels will occur.

The July Sea Ice Outlook Report is based on a synthesis of 16 individual pan-arctic estimates (plus nine regional contributions) utilizing a range of methods.

Figure 1.Figure 1. Distribution of individual outlook values for September 2009 sea ice extent based on June data.

The range of individual outlook values this month is from 4.0 to 5.2 million square kilometers, with most of the estimates in a narrow range of 4.4 to 5.2 million square kilometers. The two lowest estimates, 4.0 and 4.2 million square kilometers, would represent a new record minimum. All estimates are well below the 1979–2007 September climatological mean value of 6.7 million square kilometers. The uncertainty / error values, from those groups that provided them, are about 0.4 million square kilometers, thus many of the values essentially overlap.

Although the majority of the responses indicate either persistent conditions or a slight increase over the 2008 sea ice extent, there appears to be about a 20% chance of reaching a new minimum in 2009. The September 2009 extent, as we track it for the rest of the summer, will depend on several factors, including the dynamics of the relatively high levels of thin, first year ice; temperature and wind conditions; and sea level pressure.