Thursday, 8 May 2008

McQ: I like raisins but I HATE CURRENTS!!

Wednesday afternoons, years back, oceanography lectures at NOCS with Professor (I think) Harry Something-other, (sorry I forgot your surname). He was American and a brilliant lecturer and I used to really enjoy Wednesday afternoons... until, that is, the day that we learnt about the Coriolis Effect. No longer was my simple but understandable spinny explanation that I had in my brain, satisfactory, no, this day saw the coriolis force become a series of equations that took pages and pages and pages to decipher. I recall lots of something about standing on ice (an analogy for a frictionless surface would be a guess, perhaps??) and throwing a ball in the air and then some fiendishly complicated differentiation (probably) followed by some fiendishly complicated integration (probably) followed by more fiendishly complicated integration (probably and so we aren't back to where we started) And there in front of me, six curly pictures of integral signs, rho's, deltas and x,y,z's to describe what used to be a simple spinny concept in my brain.

Anyway, totally digressing... I remember, too, a day where a slide went up depicting in 3D the surface currents and deep water currents across the oceans- it looked a bit like a London Tube map wrapped around a notional sphere, but with arrows clearly showing which currents go where (totally to do with good old coriolis in fact, so not digressing so much after all) And they, suprisingly enough go round and round, replacing each other. There were two pics, one for atlantic side and one for pacific side. What I definitely DO NOT recall is the Pacific one showing one great big current flowing from Canada to Tasmania, forever. I am sure it is impossible!!! Should there not be a generally north flow on the western side, in the northern hemisphere, to start with, and then the rest of the ocean currents follow round???

So, Professor Harry, MJC, Simon R, Andy F, anyone in fact who knows these things, please please explain why oh why oh why have we had at least a knot of current pushing us SW ever since Sydney (EAC excepted)and when will it stop????????????? It just can't keep pushing us SW forever!!!! I don't believe it!!!
(It isn't calibration error as boat speed at 6knots and SOG 4, heading north, we are only covering 4 mins latitude in an hour so its got to be current, surely!!)

Meanwhile, I'm going to stick to raisins.
Lots of love
McQueen
xxx