In what’s becoming a monthly write-up of Arctic sea ice conditions, here is May 2009’s State of the Arctic.
April was kind to Arctic sea ice – very little areal extent was lost during April, as I covered in my last post on the subject, contrary to recent or climatological standards. Monthly variation doesn’t have to follow climatology, of course, as May’s sea ice conditions continued to demonstrate. Also contrary to recent or climatological standards, Arctic sea ice areal extent decreased at a faster rate. Conditions are now closer to the record-low year of 2007, at this point in the year, than they are to climatology, a reversal of April conditions. However, conditions in April were closer to climatology than conditions now are to the 2007 season. One important factor in May’s areal extent decrease is the low ice volume. Due to multiple years in a row of declining sea ice in the midst of warming ocean temperatures, there is less ice this season that can withstand another melt season than in previous years. Indeed, this phenomenon is expected to create summer-time ice-free conditions in the near future.
To update my last post, here are the corresponding graphs showing the state of the arctic ice sheet as of yesterday, starting with a graphical look at ice extent:
The questions I asked at the end of my last post still apply: now that La Nina conditions have transitioned to a neutral state, how will atmospheric and oceanic currents affect the remaining ice extent? What happens when the next El Nino begins and matures? What kind of weather patterns will exist over the Arctic this summer and fall? These all have direct implications on the final ice extent value for 2009. Case in point: the rapid drop-off in extent seen in the 2007 season during June. Will we see something similar this year? Are we already starting to?