Which way does the wind blow at the north pole?
The North and South Poles are special points on the Earth, because they
are singularities of our coordinate system. All directions from the
North Pole can be called South, because they are directed exactly away
from the North Pole. The directions of North, South, East and West
lose the meaning they have elsewhere on the Earth.
Nonetheless, if you were positioned there, you would not notice any
difference from anywhere else on Earth (except it is quite cold, and
there are very few trees ;)). If, as is quite likely, there is a wind,
it comes from a definite direction, which may be from your front, your
right hand or your left.
So the wind has a definite direction, even at the Poles, and the only
problem is communicating the direction in an unambiguous way. The only
way is to report the angle made by the wind with respect to an agreed
upon direction. Away from the poles, by international agreement, winds
are reported in Degrees True, i.e. the angle made by the wind vector
across the unique circle of longitude passing through the measurement
point. But there is no single, unique circle of longitude passing
through the poles; there are an infinite number of them. For unambiguous
reporting of direction, some particular one of them must be specified.
By international agreement (WMO Manual on codes v. 1, Code Table 878),
within one degree of the North Pole, the Greenwich (0 degree) meridian
is used.
I.e. by international agreement, within about 60 nautical miles of the
North Pole, winds are reported according to a compass face, oriented so
the "North" arrow points toward the 0 degree meridian, and in this
restricted area, "North" no longer refers to the North pole, but to
the observatory in Greenwich, England. Our programs that convert wind
vector data from the computer models to geographical coordinates follow
this convention, and a wind flag oriented at 075 degrees at the pole
means the wind is approaching from the direction of Washington, DC :).
Curiously, we have not been able to find an international standard
concerning reports from the South Pole, which has a similar problem,
even though there is a weather station at the South Pole but not at the
North Pole. The South Pole station in practice uses the compass face
aligned with "North" in the direction of the Greenwich meridian, and
that is what we do within one degree of the South Pole.
Dr. Albion Taylor