NEW NODC DATASET: THERMOSTERIC SEA LEVEL ANOMALIES
Posted by Bob Tisdale
Just a quick one-graph post.
The NOAA National Oceanographic Data Center (NODC) has added Thermosteric Sea Level Anomaly data to its GLOBAL OCEAN HEAT CONTENT webpage. The NODC describes the data as, “The time series of yearly and 3-month thermosteric sea level anomaly are presented for the 0-700 meters layer. There is one file of yearly and four files of 3-month thermosteric sea level anomaly for each of four major oceanic basins: the World Ocean, the Pacific Ocean, the Atlantic Ocean (which includes the entire Arctic Ocean), and the Indian Ocean. Each file contains the integral for the entire basin (OB), the northern hemisphere part of the basin (NHPB), and the southern hemisphere part of the basin (SHPB).”
The following graph compares the Global and North Atlantic+Arctic Ocean Thermosteric Sea Level anomalies. I suspect that much of the flattening in the global data since 2003 is caused by the significant drop in the North Atlantic+Arctic Ocean data.
To Be Continued
(Yippee, a new dataset to play with.)
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20mm in 55 years?
Looking forward to extended data
So half an inch of rise in 50 years, at that rate it will be a few millenia until my favorite beaches are underwater all of the time. My question is has anyone ever actually noticed this change.
It is interesting to see such a difference between the Global on the one hand and the Atlantic Plus Artic on the other. The latter shows a sharp rise between the early 1980s and 2003 whereas the former shows a significantly flatter rise. Post 2003, as you state, the Global is flat. However, the Atlantic Plus Artic is showing a fall. It will be interesting to see whether those trends continue over the coming decade.
Hi Bob, and thanks for drawing attention to this new dataset. It’s interesting that this shows a 14mm rise from 1993 to 2003, the decade I made a detailed study of. The overall sea level rise in this period was ~33mm according to the TOPEX/JASON satellite altimetry. According to the IPCC, half of the sea level rise then was due to thermal expansion. This creates a discrepancy of around 17% – quite a lot. I have a suspicion this is a further effort to try to match the steric component of sea level rise to the alleged forcing of co2 of around 1.7W/m^2, and further downplay the solar contribution due to the reduction in tropical cloud cover and the peak of cycle 23.
Since no-one has a published methodology for assessing the amount of runoff from glacier melt globally, I’m going to take the calibration of this dataset with a pinch of salt.
It’s no wonder Al Gore likes beach front property, at ~0.3mm per year I would not be too bothered about sea level rises either. If this is truely a global measure it is pretty much consistent with no significant sea level rises in coastal areas in the UK like Emsworth, Havant, Portsmouth, Gosport, Exeter and Plymouth, the latter being a very very old naval port.
Re :Patrick Davis says:
June 11, 2011 at 2:07 am
Hey! Not so fast. “very, very old naval port”? Plymouth (more properly Devonport) became a naval base in 1690. It was King John in the early 1200s who founded his naval base at Pompey (localese for Portsmouth).
The Thermosteric Sea Level Anomaly data is derived from the OHC data?
Any word from Josh Willis on the final update of the ARGO data?
M D Bergeron says:
June 11, 2011 at 12:41 am
So half an inch of rise in 50 years
This is just the contribution due to heat expansion there is another portion from melting ice.
Has anyone alerted the Australian authorities to this? Kinda makes their forecasts of Sydney waterfront properties being swamped and their other catastrophic claims look a bit dodgy, but they are attempting to sell a Carbon Tax!
Are we sure the North Atlantic/Arctic data is correct?
Bob:
Can you briefly explain how they measure Thermosteric Sea Level Anomaly and what the error is in that measurement process?
Thanks
“View from the Solent says:
June 11, 2011 at 2:42 am”
I lived in Pompey too, Clanfield in fact. My post still stands, to the wider audience who may not be equiped with a record of English Naval history. And if you go down to “Old Portsmouth”, there is no significant indication of sea level rises…even since the early 1200’s, as in Plymouth (GUZZ), Emsworth, Havant etc all along the south coast. That is my point.
“Alexander K says:
June 11, 2011 at 2:54 am”
The carbon tax will save us. Trust me, says Gillard.
So, after over 30 years of global warming:
the hottest decade on the record;
the hottest years on the record;
melting Greenland glaciers;
melting glaciers worldwide;
melting ice sheets in W. Antarctica;
water abstraction;
‘thermal expansion’……………………it’s worse than we thought! Head for the hills, evacuate the Maldives…..Ahhhhhh!
HR says: “The Thermosteric Sea Level Anomaly data is derived from the OHC data?”
I assume the same temperature profiles are used for the NODC thermosteric sea level.
tallbloke says: “Since no-one has a published methodology for assessing the amount of runoff from glacier melt globally, I’m going to take the calibration of this dataset with a pinch of salt.”
Since (I assume) it’s based on the same profiles used for OHC data, it has few observations in the Southern Hemisphere before ARGO, so maybe two pinches of salt should be used, maybe more.
I am probably just missing something obvious, but could someone explain NOAA’s NODC chart, as well as Geophsical Letters’ L07608 chart? These charts are labeled “0-700m Global Ocean Heat Content”, but they appear as an anomally charts, (can’t have negative heat content), right?
Millimeters. 25.4 of them to the inch. Wow.
Just think about it: The rise of sea levels is going at the pace of a glaciated snail.
Reminds me of one of those geological studies where they could see dirt & rock slowly creeping down a canyon into a stream over decades of still photos.
I’m not even sure that anyone bothered to take time-lapse photos of rising sea levels, the pace is so excruciatingly lethargic. Too late now: Rigor Mortis has set into sea level rise.
In theory, one cannot calculate thermal expansion of an ocean with numbers from the top 700m. If there is to be ocean level rise from heating, the whole volume of the ocean has, on average, to heat (except that some different things happen in the 0-4 deg C range). Since there is a sparse data set from places like the deep South Pacific, where there is also ocean floor spreading with heat and volcanos, and since there is a far greater volume of water below 700m than above, the assertion is flawed. Besides, there is some intermixing of water over the 700m interface that complicates calculations that assume the heat source is only from the surface down.
The slow processes like isostativc rebound and tectonic shift make it near impossible to recreate ocean level changes to a few mm from data strings shorter than 100 years.
The whole topic has ripe cherries on it.
MattN says:
June 11, 2011 at 3:08 am
Are we sure the North Atlantic/Arctic data is correct?
Why aren’t you querying the Pacific and Indian ocean data Matt?
/Bob Tisdale says:
June 11, 2011 at 3:28 am
HR says: “The Thermosteric Sea Level Anomaly data is derived from the OHC data?”
I assume the same temperature profiles are used for the NODC thermosteric sea level./
Thanks for the answer, I had a go at answering my own question.
Graphed the OHC and TSLA for the N.Atlantic to see the comparison.
http://i51.tinypic.com/xpal3p.jpg
(OHC is X10 to bring both in line)
They are similar but with some small differences. I’m guessing to do with SLP or some other factor.
Hey Bob, very interesting, but even with the flattening We are not returning to 1990’s, 80’s, or 70’s, levels. Why? Because there is more heat in the oceans. Now some would say that heat is residual heat from ENSO events, but over such a long time frame, ENSO by itself, which is a balancing of heat or thermostat for the oceans, would not be adding so much heat to the oceans. It seems something else seems to be adding heat over a longer time frame. Of course, there is one theory as to what that something is, and that theory gets corroborating evidence from measurements of deeper arctic waters and the longer term decline of arctic sea ice that’s been going on. The 40% increase in CO2 since the 1700’s when factored into global climate models would explain this long term rise in ocean heat content as well as the long term decline in arctic sea ice, which, is melted from both solar insolation as well as warm water from below. The warmest waters in 2000 years have been found flowing into the arctic. Hard to not wonder as to the cause.
I just came home from a week long trip to Ireland. We spent a few days in the ancient harbor town of Youghal, an ancestral home. The old piers and quays from the early 1800s are still there and still in active use–not flooded out yet–and at low tide, many small boats are beached as they sit tied to the quay. Even better, the ancient Water Gate, which allowed boat owners to bring their boats into a walled gated protected area, and dates from about the 1400s, is now about 100 yards inland. Even allowing for some fill, it begs the question–what sea level rise?
“Climate warming since 1995 is now statistically significant, according to Phil Jones, the UK scientist targeted in the “ClimateGate” affair.”
http://www.bbc.co.uk/news/science-environment-13719510
“HadCRUT shows a warming 1995-2010 of 0.19C – consistent with the other major records, which all use slightly different ways of analysing the data in order to compensate for issues such as the dearth of measuring stations in polar regions.”
I particularly notice Phil’s unilateral declaration that:
“Since then, nothing has emerged through mainstream science to challenge the IPCC’s basic picture of a world warming through greenhouse gas emissions.”
So it is obvious, that Sea Level will commence a disastrous rise shortly. After-all, we can’t have significant rising temperatures and a flattening seal level… Can we?? GK
MattN says: “Are we sure the North Atlantic/Arctic data is correct?”
It’s the same relationship with OHC:
http://i56.tinypic.com/2m2hq1v.jpg
The OHC graph is from this post
http://bobtisdale.wordpress.com/2010/10/18/update-and-changes-to-nodc-ocean-heat-content-data/