Recently Amplified Interannual Variability of Great Lakes ice cover and
its Connection to Sea Ice over the Bering and Chukchi Seas
Abstract
The interannual variability of the annual maximum ice cover (AMIC) of
the Great Lakes is generally dominated by a dipole pattern over
mid-latitude North America and Western Alaska via a ridge-trough system.
We discovered a significant breakpoint in the winter of 1997/98 after
which AMIC increased its interannual variability and negatively
correlated with sea ice coverage over the Bering and Chukchi Seas in the
preceding Novermber and Decemeber. The first covarying mode of the
500hPa geopotential height and surface air temperature indicated that
the dipole pattern shifted northward to the northern Rocky Mountains
after the breakpoint. Correlati The correlations with AMIC of the other
well-known teleconnection patterns such as the El Niño–Southern
Oscillation on AMIC became insignificant after the brekpoint and were
replaced by that from the Eastern Pacific Oscillaiton, which likely
controlled the interannual variabilities of AMIC and sea ice cover the
Bering and Chukchi Seas.