keithwms
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Concerning the pole movement and reversal, let me refer everyone to a wonderful article in Sci. Am. coauthored by Peter Olson from Johns Hopkins, who I was fortunate to entice to my department as a colloquium speaker some time ago.
http://webusers.astro.umn.edu/~larry/CLASS/GLASSDARKLY/Glatzaier-SciAmerican.pdf
The geodynamo is very interesting, to say the least. Several things surprised me, in particular: (1) the poles are wobbling and always have been; (2) satellite data show substantial movement of regions of flux reversal over a ~20 yr period of observation; (3) we don't know when a flip is due; they have happened at odd periods and scientists are only just now beginning to do realistic models of this behavior. And most fun of all (4) when a flip does happen, there will be, who knows, ~5-10 kyr of magnetic chaos characterized by many flux reversal patches moving all over the globe. So it's not like there will be a fast flip and that's it.
Oh there was one other thing that I learned from Peter's talk that was a surprise to me, namely that ancient mariners knew about flux reversal patches long ago and constructed very detailed correction maps by reconciling star data with compass measurements.
I asked Peter to speculate on what effect the preflipping movement may have on weather (after all, the van Allen belt will be less able to screen us from ionizing solar radiation during this period), but he politely and wisely declined to comment on this on the record, noting that we just don't have the models and the experimental evidence to even begin to speculate. I think I did get him to agree that it is "possible" that the geodynamo affects weather indirectly.
http://webusers.astro.umn.edu/~larry/CLASS/GLASSDARKLY/Glatzaier-SciAmerican.pdf
The geodynamo is very interesting, to say the least. Several things surprised me, in particular: (1) the poles are wobbling and always have been; (2) satellite data show substantial movement of regions of flux reversal over a ~20 yr period of observation; (3) we don't know when a flip is due; they have happened at odd periods and scientists are only just now beginning to do realistic models of this behavior. And most fun of all (4) when a flip does happen, there will be, who knows, ~5-10 kyr of magnetic chaos characterized by many flux reversal patches moving all over the globe. So it's not like there will be a fast flip and that's it.
Oh there was one other thing that I learned from Peter's talk that was a surprise to me, namely that ancient mariners knew about flux reversal patches long ago and constructed very detailed correction maps by reconciling star data with compass measurements.
I asked Peter to speculate on what effect the preflipping movement may have on weather (after all, the van Allen belt will be less able to screen us from ionizing solar radiation during this period), but he politely and wisely declined to comment on this on the record, noting that we just don't have the models and the experimental evidence to even begin to speculate. I think I did get him to agree that it is "possible" that the geodynamo affects weather indirectly.
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