Re: Rising sea levels are going to mess with the internet

[William Herrin <bill () herrin us>]

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:
> > > Science https://climate.nasa.gov/vital-signs/sea-level/
> >
> > "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:
>
> https://www.aviso.altimetry.fr/en/techniques/altimetry.html

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/>