Historical Trends in North
Pole Hydrography since the 1950s
A comparison of profiles
of ocean temperature and salinity at the North Pole shows
the extent of recent Arctic oceanic change.
Values for the 1950s through the 1980s are obtained from mean
fields of the Environmental Working Group
Winter Atlas (EWG,1997). Each
of these values is a decadal mean for those depth levels.
Each sample from the 1990s is an individual cast, either
Conductivity-Temperature-Depth (CTD) or Expendable CTD (XCTD).
Each of these is a snapshot in both time and space, as near to
Pole as the particular expedition could reach, and may not be completely
representative of local geographic or seasonal variation. Profiles
for the years 2000 through 2008 and for 2010 are Seacat CTD casts obtained during
North Pole Environmental Observatory deployment operations, during
April of each year. The 2009 profile was a Seacat CTD-Chemistry cast made by Lamont-Doherty Earth Observatory in May 2009 as part of the Switchyard project. (Click
to view in PDF format)