NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sea level rise
From: Herbert Prinz
Date: 2006 Jul 8, 13:22 -0500
From: Herbert Prinz
Date: 2006 Jul 8, 13:22 -0500
Fred Hebard wrote: >Aren't there also precision astrometric data from observatories going >back to the 1800s? > > There is no way of establishing your elevation astronomically. Any elevation measurements of observatories would be established by geodetic surveys with reference to sea level and thus be subject to the same criticism as tide gauges. They measure some local difference in elevation between land and sea. The satellite measurements, on the other hand, establish the sea level with reference to a globally defined geodetic reference frame that is centered on the earth and fixed with respect to it (i.e. rotating with it). Not only are they by far more accurate, they can also be made anywhere in the middle of the ocean. Herbert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
