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, 13:02 -0500
From: Herbert Prinz
Date: 2006 Jul 8, 13:02 -0500
Fred, Just look at some of these graphs, whether from tidal data or from satellites. They can be fitted much better with straight lines than with curved ones. While it is true that you can fit any curve with a straight line, you can fit it *better* with a curve only if it's really a curve. Herbert Fred Hebard wrote: >On Jul 8, 2006, at 11:31 AM, Herbert Prinz wrote: > > > >>Yes, and that's also confirmed world wide by satellite data, even for >>places in the middle of the ocean. But the global trend has been a >>linear increase of 2-3 mm / year. >> >> > > >Just to clarify the statistics of linear trends. One can find a >linear trend whenever a response variable is increasing or >decreasing, even if there is statistically significant curvature in >the line. For instance, a parabola starting from a minimum or >maximum will show a significant linear trend. It additionally will >show a significant quadratic trend, indicating that the line is >curved as well as rising or falling. However, if you look at points >symmetrically distributed around the inflection point of a parabola >(the minimum or maximum), then there will be no significant linear >trend, but the significant quadratic trend will still be there. > >What this boils down to is that the linear trend of increasing ocean >levels over the past century and a half does not indicate that the >trend is ONLY linear. Those data may not be at variance with the >evidence for global warming. > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---