In message <[email protected]>, "Finklema n, Dave" writes: >I finally get a chance to look like I might know something. > >Neiher Gravity nor the Geoid are "standardized."
Indeed. I was surprised when I tried to confirm my recollection about the TAI/MSL thing earlier today and didn't find anything even remotely resembling a definition of of "MSL". I guess the magnitudes of uncertainty this introduces are below the noise-limit still, but I wonder if another meter of ex-polar-icecap water would start to skew the results measurably time/frequency wise. There is a very interesting bit of research going on right now trying to find out where the meltwater is/will be going, and the results are anything but intuitive. If all the Greenland ice melted, but the Antarctic ice didn't, the meltwater would largely pile up around Antarctica, and generally lower MSL on the nothern hemisphere. Melt Antarctica and see water rise around Greenland and drop on the southern hemisphere. This is a counterintuitive result, until you realize that both places a LOT of ice is sitting above MSL, exerting a significant "upwards" gravitationa force. I've seen some yet unpublished models which shows that an extra meter of MSL will distribute unevenly, roughly from from 0 to 170cm, depending on geography, but the uncertainties are still too big to be useful for anything. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [email protected] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
