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SLR (main) field and a table of 1m, 1.5m, 2m SLR for each year

Started by kschmid, December 10, 2009, 02:08:03 PM

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Just wondering what the SLR (main) field relates to in the excel (csv) spread sheet. Also, is anyone aware of a table of the sea level rise values for the various scenarios (1-2 m by 2100) used in SLAMM.
Thanks for any thoughts

Jonathan S. Clough

Actually, the answer for SLAMM5 and SLAMM6 is different:

SLR (main) from SLAMM 5 is the estimated relative SLR since the NWI photodate [simulation start date] by adjusting global eustatic SLR scenarios for local effects using historical SLR rates.  It is labeled "main" because it is relevant for the main or "global" sub-site only.  If there are many sub-sites they may have different historical SLR and different NWI photo dates so the results may differ from one sub-site to the next.

In SLAMM6 uplift and subsidence may be specified with a spatial raster map.  Between that, and the problem with the sub-sites cited above, I gave up trying to quantify the relative SLR and instead just list eustatic SLR for the scenario since the NWI photodate.

-- J

Jonathan S. Clough

Regarding the year by year SLR for 1, 1.5, and 2 meters:

Here they are, (Eustatic SLR since 1990 in CM)

        ((184.4, 276.7,  368.9),    {2025, 1 meter, 1.5 meters, 2 meters}
         (409.2, 613.8,  818.4),    {2050, 1 meter, 1.5 meters, 2 meters}
         (698.1, 1047.2, 1396.3),  {2075, 1 meter, 1.5 meters, 2 meters}
         (1000,  1500, 2000.0));   {2100, 1 meter, 1.5 meters, 2 meters}

As stated in the tech. doc, these were calculated by scaling up the A1B-maximum such that the relative rate of sea level rise is the same between the A1B scenario and the 1, 1½ and 2 meter scenarios but the extent of sea level rise by the year 2100 is allowed to vary. 


Thanks for the help - I saw that there was a previous question on the SLR (main), sorry to double dip. The values seem quite different between the two (SLR and the chart) - is it a function of the upward curving trend and the time shift (i.e., do you use the trend but starting point shifted to NWI photo date?)
Anyway, thanks again

Jonathan S. Clough

Yes, we use the trend, but starting point shifted to the NWI photo date (if the starting point predates the NWI photo date we use the historic trend up until 1990)

However, this is Relative SLR so we also account for differences in the historic trend and the global historic trend (estimated at 1.5 mm/year in SLAMM 5)

So if your site had a historic trend of 3.5 mm/year over the last 100 years or so we would assume that this 2 mm/year differential is the result of local effects, probably land subsidence primarily.  We assume that this differential will remain constant and persist over the next 100 years.  Therefore, to estimate relative SLR we calculate  the eustatic trend (adjusted to 1990) but also add an additional 2 mm/year of SLR on to that trend.

-- Jonathan

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