From: Patricia-Anne WinterSun (p-aw@pacbell.net)
Date: Sat Mar 25 2000 - 17:55:48 PST
Date: Sat, 25 Mar 2000 17:55:48 -0800 From: Patricia-Anne WinterSun <p-aw@pacbell.net> Subject: westerlies Message-id: <38DD6E24.E9E5D48@pacbell.net>
Dear Heidi,
The westerlies are the default wind in North America because of the
heating at the equator and the Coriolis Force. The Pacific High, which
is our local part of the system, gives us the Westerlies via the Out of
a High (pressure system) into a Low (pressure system) paradigm. If you
look at the convection cells created by the differential heating of the
planet at the equator, there is a series of them going from the Equator
in either direction toward the Poles. I believe there are three or four
such convection cells. The simple thing to do is to look at the globe
without rotation first. At the equator there is a low pressure area
because the heated air rises, then some distance N or S that heated air
has cooled and falls back to earth creating a high pressure area, this
accounts for the deserts in the 30 degree N. and S. Lat. range. This
High varies in latitude with the seasons, in summer it can be in the
high 30s or low 40s, in winter the low 30s or high 20s. When you add
rotation to the mix you get highs with definite wind directions, not
just "out of a high into a low" so we have in the northern hemisphere
"clockwise out of a high, anticlockwise into a low". Our westerlies
come from this system as our weather is in general determined by the
pacific High. When it is strong (higher lats) it diverts the lows from
the gulf of alaska, when not these cool wet marine systems can come and
give us water, otherwise...
Hope this is helpful, ask more questions if it's not,
Patricia-Anne WinterSun
Subject: Westerlies
From: "Heidi Black" <blackh@exchange.esuhsd.org>
Help-our department is failing to figure the Westerlies out, can't find
a decent explanation on the web...and of course, we had the one student
that asked, "But...."
Heidi
blackh@exchange.esuhsd.org
This archive was generated by hypermail 2b29 : Thu Oct 19 2000 - 11:10:39 PDT