On Thu, Jul 26, 2018 at 2:00 PM, Chris Adams <cma@cmadams.net> wrote:
Once upon a time, William Herrin <bill@herrin.us> said:
On Thu, Jul 26, 2018 at 12:58 PM, Jason Kuehl <jason.w.kuehl@gmail.com> wrote:
"The first graph tracks the change in sea level since 1993 as observed by satellites."
I *really* want to understand the technology that lets a satellite hundreds of miles in the sky detect a 3mm change in average global sea level between the start and end of the year with an error bar that grows to only 4mm over a quarter of a century.
Well, you must not *really* want to understand, since there's a "Learn more" link to follow on the above page that (after a couple more clicks) would lead you to this page that has some explanation:
Chris, I understand how radar altimetry works. I would like to understand how they achieve the claimed precision. 3.2mm is one heck of a precise measurement from a flying platform hundreds of kilometers away, particularly when that requires the platform itself to be located with even higher precision against some reference points deemed stable for the purpose of making the measurement. On Thu, Jul 26, 2018 at 3:09 PM, Jameson, Daniel <Daniel.Jameson@tdstelecom.com> wrote:
Its not satellite data, The data is from tidal sensors
The second chart is from tidal sensors. Regards, Bill Herrin -- William Herrin ................ herrin@dirtside.com bill@herrin.us Dirtside Systems ......... Web: <http://www.dirtside.com/>