And variations in the thickness and extent of sea ice cloaking the Arctic Ocean are driven by yet another set of complicating factors, ranging from long - term shifts
in atmospheric pressure patterns to events as close - focus as the potent Arctic superstorm I reported on earlier this month.
The degree to which Arctic air penetrates into middle latitudes is related to the Arctic Oscillation (AO) index, which is defined by
surface atmospheric pressure patterns and is plotted in Figure 6.
According to Gerry Bell, Ph.D., NOAA's lead seasonal hurricane forecaster, the major climate factors expected to influence this year's activity are the ongoing multi-decadal signal, which produces wind and
atmospheric pressure patterns favorable for hurricane formation, along with ongoing warmer - than - normal sea surface temperatures.
Understanding
the atmospheric pressure patterns, moreover, is essential to interpret results from NASA's Gravity Recovery and Climate Experiment (GRACE).
Were
the atmospheric pressure patterns that caused extreme dry and extreme wet periods happening more frequently?
The North Atlantic Oscillation is
an atmospheric pressure pattern over the North Atlantic that can vary from one week to the next.