On 04/02/2019 14:16, N_Cook wrote:
On 02/02/2019 14:19, N_Cook wrote:
Latest projection for global sea level rise , from Jason 3 data
to 29 Nov 2018, public output 02 Feb 2019 on
https://www.aviso.altimetry.fr/en/da...ts-images.html
via best (RMS optimisation) curve-types and curve-fit of 73 datapoints
concattenated to Jason2 and Jason3 data back to 2003.
I suspect the Aviso reference rise of 3.34mm per year has not been
updated (3.34 previous value) as I make the linear slope 0.3377 cm /yr
or 3.37 mm per year and previous
update calculations have come out near enough the same to +/-0.01 mm per
year, nothing like 0.03/0.04 mm . Considering the Jason-3 filtered
(dotted line) output plot is above 8cm for the first time.
Linear
y= 1.394804 + 0.337655 * x
R^2 = 0.983013
year Sea Level Rise (cm)
2020 8.147
2050 18.277
2100 35.16
Exponential
y= 1.925352 -7.599908*(1-e^(0.030612 * x))
R^2 = 0.986048
year Sea Level Rise (cm)
2020 8.343
2050 29.444
2100 156.607
Quadratic
y= 1.996267 + 0.211446*x + 0.005277*x^2
R^2 = 0.986157
year Sea Level Rise (cm)
2020 8.335
2050 25.761
2100 75.91
Indicial
y=2.238733 + 0.108241*x^1.344403
R^2 = 0.986287
year Sea Level Rise (cm)
2020 8.313
2050 23.059
2100 55.107
Upward trend still, for the best curve-fit by R*R goodness factor, by
only a whisker from the quadratic fit.
Resume of these projections from the Aviso Jason3 updates concattenated
to the Jason 1 and Jason 2 data,
for the best-fit of indicial power curves and global sea level rise for
the rest of the century, based purely on the Jason altimetry data .
to year 2100 using Dec 2017 data , 56.15 cm
data to 05 Feb 2018 to 2100 , 60.7 cm
data to 25 May 2018 to 2100 , 52.1 cm
data to 02 Aug 2018 to 2100 , 49.1 cm
Update to 01 Sep 2018, public output 07 Dec 2018
to year 2100 , 50.7 cm
Update to 01 Oct 2018, public output 18 Jan 2019
to year 2100 , 50.9 cm
Update to 29 Nov 2018, public output 02 Feb 2019
to year 2100 , 55.1 cm
So between 49.1cm and 60.7cm SLR to 2100. Well above the 35.2cm of
linear "fit".
Also evidence of the emergence in the Pacific (and so upward global sea
level) of the next
El Nino. Anomaly in degrees C for Nino 3.4 sector/sea area 120 to 165
deg ,+/-5 deg latitude, processed from the NOAA global SST anomaly
image.
https://www.ospo.noaa.gov/data/sst/a....1.31.2019.gif
A few spot values in Jan 2019
Day ; SST anomaly
14 ; +0.75
17 ; +0.63
21; +0.41
24; +0.34
28; +0.36
31; +0.69
Despite the dip late January, the running 3 month mean for NDJ quarter
is probably above the qualifying value of 0.5 , NOAA processed for SON
quarter +0.7 , and OND quarter +0.9 .
https://origin.cpc.ncep.noaa.gov/pro...uff/ONI_v5.php
An updated image of Jason 1 +2 +3 data and image masques to the same
scale , showing linear "fit" and best fit curve, even to the eye a
better fit, visualising balancing of the excursions either side of the
curve.
http://diverse.4mg.com/jason1+2+3_29nov2018.jpg
shame about to the disjunctures between them, but the x,y axes are the
Jason 1 image ones extended on to 8cm and 2020.
For the disjunctures, with no other info about the filters, a matter of
avoiding the last or first 6 months of a mission, compare with the Aviso
Reference image and check the slope of a linear "fit" near enough agrees
with the reference slope , being aware that theirs also includes the
early T/P mission , which I've not included in all this.
Not included the exponential or quadratic curves as only 3 pixels
different at 2010. The original blue gradient lines retained of the 3
images.
I'd not realised before , the Aviso reference curve includes 0.3mm per
year contribution of isostatic rebound correction or GIA glacial
isostatic adjustment. I'd thought there was too much disagreement over
the degree of GIA contribution to SLR, for anyone to use it for primary
reference purposes. Only the one paper by Peltier put a figure to it of
0.3mm/year, then the University of Colorado decided to include that
0.3mm /yr figure in their outputs. Despite loads of assumptions relating
to the known unknowns of the oceans sub-bottom geology. Anyway I'd
thought the answer lay in the term isostatic, ie all balanced out,
swings and roundabouts. For example , in a minor way and simplified (no
account of groundwater abstraction or change of current-streams etc)
for just the UK recovering from the last ice-age.
From BODC data for Lerwick tide gauge, between 1957 and 1999
mean sea level has risen 30 mm relative to the rising land there.
But for Portsmouth between 1962 and 2002, the sea level
relative to isostatic sinking Portsmouth ,had a 170mm rise.
Unfortunately no BODC long term tide gauge data for "middle " England ports.
But simply taking the average of 30 and 170mm and over about 40 years,
gives a ball-park figure of SLR around the UK over those decades to be
about 2.5mm per year, much like the global figure for those decades.
Anyway the Aviso reference data is simply the Jason data plus 0.3mm per
year added. I still have no explantion for the mismatch of curves on the
overlaps of J1 and J2, then J2 and J3 missions. But removing the yearly
pro-rata GIA amounts from the Aviso reference plots , for the periods of
overlap, is very much the lowest values, wheras previously I'd taken the
average, as I had no info on how to handle the transitions of missions.
This now exagerates the
knee of the concattenated J1+J2+J3 plots, revised image showing the
greater deviation from linear and more balanced passes through the plots,
http://diverse.4mg.com/jason1+2+3_29nov2018.jpg
, more of a curve and so higher projected global SLR to 2100.
Same ranking order via R^2 value , same J-3 data to 29 Nov 2018, but
higher projected SLR.
x= year minus 2000, y = Aviso global SLR
73 datapoints
linear
y=1.272075+ 0.343219*x
r*r = 0.976375
year Sea Level Rise (cm)
2020 8.136
2050 18.433
2100 35.593
Exponential
y=2.095669 -3.722926*(1-Exp(0.049906*x))
r*r = 0.984341
year Sea Level Rise (cm)
2020 8.473
2050 43.514
2100 545.734 = 5.46m
same r*r and SLR for this alternative manipulation of that expression
y= -1.630970 + 3.726249*1.051143^x
to sensible number of iterations for the curve-fit
quadratic
y = 2.270613 + 0.133686*x + 0.008761*x^2
r*r = 0.984705
year Sea Level Rise (cm)
2020 8.448
2050 30.857
2100 103.249 = 1.03m
indicial power
y=2.483612 + 0.053029^.575023
r*r = 0.984834
year Sea Level Rise (cm)
2020 8.421
2050 27.627
2100 77.397
for turn of year J3 data output in early 2012, I'll have to remember to
check whether this prediction was nearer the 8.1cm of linear or 8.4cm of
the curves.
Now J3 plot is approaching the longer term gradient, I'll move to
checking my linear fit to J3 only compared to Aviso gradient or mm/yr,
as they are getting closer.
Current Aviso J3 0.312 gradient cm/yr, my reduced datapoint gradient 0.327
revisiting previous Jason 3 data assesments
to decimal year 2018.685, aviso 0.247 gradient, me 0.192
to 2018.441, aviso 0.246 gradient, me 0.196
to 2017.964, aviso 0.241 gradient, me 0.205
A different slant on the 2 Edwards papers referred to elsewhere on this
board under Antarctica.
https://www.newscientist.com/article...creep-upwards/