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Re: Definition of Term
From: Jan Kalivoda
Date: 2003 Jan 25, 11:17 +0100
From: Jan Kalivoda
Date: 2003 Jan 25, 11:17 +0100
Dear Capt. Joe Kliment, I don't know, why you use the low travelling from S to N for your illustration of the changing direction of wind in a low). Maybe it is motivated by your personal or regional experience, but generally these lows are rather rare. In textbooks, the low runing from W to E is invariantly used for this purpose, with two observers to S (wind turning S ->SW->W->NW->N) and N (S->SE->E->NE->N, both cases for the northern hemisphere) of its path, as in the most cases, the observers to the E and W of the low experience the wind of a steady direction (cca N or S), only its strength is changing. Of course, this is only an idealized case, but we all use such simplified patterns in this discussion. As for the theme itself, I skimmed through my scarce texts on meteorology in English and I suppose that they use "backing / veering" for northern regions, but more general terms (e.g. "shifting / turning" with subsequent details) when the southern hemisphere is explicitly meant, so as to avoid a misunderstanding. U.S. Sailing directions for Australia (1931 and later) provide a clear example. Jan Kalivoda ----- Original Message ----- From: "kliment"To: Sent: Saturday, January 25, 2003 5:08 AM Subject: Definition of Term > In the northern hemisphere high pressure systems are associated with > clockwise winds(anticyclonic) while low pressure systems are associated with > counterclockwise winds(cyclonic). This is opposite in the southern hemisphere > with counterclockwise highs and clockwise lows. Your location > with respect to a low will dictate whether the wind will "back" or "veer" > as the low passes. In the northern hemisphere if the low passes east of > your location the winds will "back" from NE ,N, NW, to W and if the low passes > west of your location then winds will "veer" from NE, E, SE, to S. > > By applying Buys Ballot's Law you can determine the location of the center > of the low and > predict it's path with either "backing" or "veering" winds. > > Capt Joe Kliment > W3HZM > Middletown,De.