From the University of Arizona:
Sea level spiked for 2 years along northeastern North America
Sea levels from New York to Newfoundland jumped up about four inches in 2009 and 2010 because ocean circulation changed, a University of Arizona-led team reports in an upcoming issue of Nature Communications.
The team was the first to document that the extreme increase in sea level lasted two years, not just a few months.
“The thing that stands out is the time extent of this event as well as the spatial extent of the event,” said first author Paul Goddard, a UA doctoral candidate in geosciences.
Independent of any hurricanes or winter storms, the event caused flooding along the northeast coast of North America. Some of the sea level rise and the resulting flooding extended as far south as Cape Hatteras.
The paper is also the first to show that the unusual spike in sea level was a result of changes in ocean circulation.
Co-author Jianjun Yin, UA assistant professor of geosciences, said, “We are the first to establish the extreme sea level rise event and its connection with ocean circulation.”
Goddard detected the two-year-long spike in sea level by reviewing monthly tide-gauge records, some of which went back to the early 1900s, for the entire Eastern Seaboard. No other two-year period from those records showed such a marked increase.
The team linked the spike to a change in the ocean’s Atlantic Meridional Overturning Circulation and also a change in part of the climate system known as the North Atlantic Oscillation.
The researchers then used computer climate models to project the probability of future spikes in sea level.
The team found that, at the current rate that atmospheric carbon dioxide is increasing, such extreme events are likely to occur more frequently, Goddard said.
Goddard’s and Yin’s research paper, “An Extreme Event of Sea Level Rise along the Northeast Coast of North America in 2009-2010,” is scheduled for online publication in Nature Communications on Feb. 24. Stephen Griffies and Shaoqing Zhang of the National Oceanographic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey, are also co-authors. NOAA funded the research.
Yin’s previous work on climate models suggests that weakening of the Atlantic Meridional Overturning Circulation could cause sea levels to rise faster along the northeast coast of North America.
Yin wondered whether such sea level rise had actually been observed, so he asked Goddard to compile the tide-gauge records for the east coast of North America. The 40 gauges, spanning the coast from Key West, Florida, north to Newfoundland, have been recording sea levels as far back as the 1920s.
Goddard’s work revealed a surprise – that during 2009 and 2010, sea level between New York and Newfoundland rose an average of four inches (100 mm). Sea level from Cape Hatteras to New York also had a notable spike, though not as dramatic.
“The sea level rise of 2009-2010 sticks out like a sore thumb for the Northeast,” Goddard said.
His research also confirmed that, as others have reported, sea level has been gradually rising since the 1920s and that there is some year-to-year variation.
About the time Goddard finished analyzing the tide-gauge records, another group of researchers reported that the Atlantic Meridional Overturning Circulation, or AMOC, had a 30 percent decline in strength in 2009-2010. Those researchers reported the decline started just two months before the tide gauges started recording the spike in sea level.
“To me, it was like putting together a puzzle,” Goddard said.
The more he and his colleagues examined the timing of the AMOC downturn and the subsequent increase in sea level, the more it fit together, he said.
The AMOC brings warm water from the tropics and the southern Atlantic Ocean to the North Atlantic and the polar regions. The water then cools and sinks, eventually flowing south in the deep ocean. Yin’s climate model predicted that when the AMOC weakened, sea level in northeastern North America would rise.
In addition to the weakening AMOC, during 2009-2010 the region’s atmosphere was in a very negative phase of the climate mode called the North Atlantic Oscillation. The NAO flip-flops between negative and positive phases.
“The negative North Atlantic Oscillation changes the wind patterns along the northeast coast, so during the negative NAO the winds push water onto the northeast coast,” Goddard said.
Although the NAO has resumed flipping between positive and negative states, observations show that the AMOC, while somewhat stronger, has still not recovered its previous strength.
Even now, sea level is still higher than before 2009, Yin said. He’s not surprised, because most of the climate models predict a weakening of the AMOC over the 21st century.
Yin said that at the current rate of increase in greenhouse gases, most climate models predict a weakening of the AMOC over the 21st century. Therefore, such extreme sea level rise events and coastal flooding are quite likely to occur along the densely populated northeast coast of North America more often.
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The big rise in sea level from 2008-10 was mainly the result of a similar fall from 2005-07.
https://notalotofpeopleknowthat.wordpress.com/2015/02/25/bbc-ignore-the-facts/
Since 2010 at New York, Boston and Portland, sea levels have actually declined significantly, despite sinking land.
I note there was a big jump in about 1870 or so. I think everyone would agree that occurred pre-IPCC.
They like to throw around the term “extreme events”. But this extreme event took place for two years and apparently no body noticed.
it was extremely unnoticeable. models project more of these extremely unnoticeable events will be found in the future, leading to an overall increase in extreme events due to CO2.
That’s because the data were an outlier and needed to be adjusted out. This study obviously used the raw data which is just wrong.
Sea-level rise (or fall) is a complex process and even direct observations are subject to significant error-inducing assumptions. It will be interesting to read the actual study and its caveats and specific conclusions. But the basic finding (winds/currents changed due to ocean circulation trends) is not new.
See, for example, “Glacial ghosts set sea-level trap for East Coast” from 2012 (http://www.eenews.net/stories/1059972339) which links to “Hotspot of accelerated sea-level rise on the Atlantic coast of North America” (http://www.nature.com/nclimate/journal/v2/n12/full/nclimate1597.html).
Wouldn’t we then have an offset and/or inverse example of lower tides somewhere else?
that problem was solved by adding a 3mm rebound correction for areas that never had glaciers.
My impression is that the logic for having a Glacial Isostatic Adjustment for say Dakar is that the weight of the glaciers displaced magma deep in the Earth from under North America and Eurasia. The magma had to go somewhere so it flowed slowly to more equatorial latitudes. When the glaciers melted, the magma flowed — ever so slowly — back toward the poles lifting the high latitude portions of the Earth. The magma is still — ever so slowly — sloshing about.
Could be.
Even if it’s actually true, I have some doubts that current estimates of radial distance change and rate of change of a few locations can be extrapolated to the whole earth with any great accuracy. But what do I know?
Did Dakar rise as the displaced magma ‘over-inflated’ chambers beneath it, or did it subside due to the added weight?
Have you ever, as a kid, mixed puzzle pieces up? You can. There are standard puzzle shapes and sizes that when mixed, can create Picasso like pictures. Looks great and is very creative. Doesn’t mean the pieces were ever meant to be together in a consistent picture.
El Niño events cause coherent changes of up to 20-30cm (8-12 inches) in sea level from the eastern Pacific Ocean to the eastern Indian Ocean.
http://www.cmar.csiro.au/sealevel/sl_drives_seas_dec.html
It amazes me that so many claims of sea level rise have the implicit assumption that continental land masses are rigid. Michelson measured the tidal effect of the gravitation of the sun and moon on the earth itself and found that the land rises and falls nearly half as much as the sea. Anything that is a thousand times longer and/or wider than it’s thickness will be flexible.
I’m suspicious. The tides starting in Boston and going north past Maine and up into the Bay of Fundy, the red dots, are large to very large. Boston tides average 9.5 feet and can be over 12 feet during a spring tide. Tides along the coast of Maine run up to 15 feet and in the Bay of Fundy 30 feet and up to 50 feet in places. You can actually see sea level change from minute to minute during midtide ebb and flood in the Bay of Fundy. That’s quite a job of signal detection to extract a 4 inch shift in sea level in the presence of these tides.
This study was originally published in 2013. Why is it being dredged up again for this Nature Communications piece, just in time for the IPCC meeting?
Nature Communications = Macmillan Publishers Limited = Georg von Holtzbrinck GmbH & Co. KG
So we have a local phenomenon that we are supposed to extrapolate to massive sea rises taking place worldwide? The data doesn’t support it and the effect was temporary, anyway. This says nothing to climate change or the CAGW argument.
I’d like to ask the knowledgebale people here if the depth of the water at the shore would casue higher tides. The reason I ask is that I grew up on a canal on Long Island, NY. When I was a young child and teen I remember the canals being dredged periodically to keep the canals a certain depth. I guess as the land erodes it deposits the soil near the coastline and makes the water shallower.
I can’t remember the last time I saw a dredging project going on. I don’t know if there were any type of environmental concerns over dredging which may have put a stop to it, or drastically reduced it, but I’m curious to know if that would change tide readings.
Sheesh, sometimes spell check doesn’t work. *Knowledgeable
http://www.hugopickfordwardle.com/thenewpeople/wp-content/uploads/2013/07/nolege.jpg
Note that the gauges for the southeast US coast show no “spike” according to the term used in this study. In fact, NOAA mean sea level trends for that coast show no increase in sea level for the past 15-20 years for that coast and a flat trend also for Gulf coast gauge data and also for west coast gauge data, except where there is local subsidence, as at Grande Isle, LA.
See. NOAA mean seal level trends for the individual guages, of which there are several score individual charts.
Note please that this gauge data, not satellite altimetry. I regard the gauge data as more reliable. According to this data, sea level trends have been flat for 15-20 years.
All that will happen is that the ACC liars will bleat about the ocean currents being “anthropogenic climate change” events..
They win, no matter what happens.
If you care to look at the tide gauges, then you see a drop the years after. What is that consistent with?
That the sea level is higher now than before is no wonder. The sea level has been steadily rising with same speed long before CO2 became the cause.
I learned something new from this post and a similar prior post on sea levels in the Pacific. In my mind, I guess I subconsciously thought of the atmosphere as a uniform ball, providing equal pressure to every point on earth’s surface. Even though I read about, and saw on the news stories about low pressure fronts moving in and bringing storm fronts, hurricanes, etc. I never put 2 and 2 together in my mind and figured out that it’s not just the moon affecting sea level via tidal pull. Changes in air pressure thanks to weather fronts also cause the sea to rise disproportionately in low pressure areas and fall in high pressure areas.
Interesting. The timing pf that sea level spike clearly corresponds to the El Nino peak of 2010. If true, it makes us wonder whether it may have happened in coordination with other El Nino peaks as well. The 1997/98 super El Nino would be a candidate. It is not clear why the influence of an El Nino could have been confined to the northern latitudes only unless we are dealing with the effect of westerlies. And that is hard to see because their effect should be the reverse of observations. Too bad the cutoff dates for this study are too short to check this out.
Is the NAO getting ready for a complete and pervasive state change?
Slowing of the AMOC is a big deal. Generally this means cooling – eventually – less poleward heat transport in the North Atlantic. The unstable switching on and off of AMOC (due to the salinity positive feedback alluded to in the article) is the main cause of sudden climate fluctuations in the NH such as the Younger Dryas, in contrast to the much slower and smoother temperature oscillations in the SH where there is no equivalent to the AMOC. During glaciation the AMOC turns off completely.
As a result of the 1964 earthquake, some areas near Kodiak, Alaska (~200miles SW of Anchorage) were permanently raised by 30 feet (9.1 m). Southeast of Anchorage, areas around the head of Turnagain dropped as much as 8 feet (2.4 m) – Wikipedia. Did atmospheric carbon dioxide trigger this event and the subsequent and instantaneous changes in sea level at two different places but in opposite directions, as in one up and one down? It’s a pity that geologists can’t be dragged into this argument, given that they have no experience in matters of climate.
Holy Moly, that’s a lot of research for one climate topic from one country.
https://usclivar.org/sites/default/files/webform/meetings/2014/summit-presentations/danabasoglu_usamoc_clivar_summit_july2014.pdf
U.S. AMOC Program
• Assessment of AMOC state, variability, and change;
• Assessment of AMOC variability mechanisms and predictability;
• Assessment of the role of AMOC in global climate and ecosystems
65 funded projects (~125 scientists) supported by 4 agencies
This has me curious. How is this statement:
coherent with this previous one?
Did I miss the part about CO2 controlling the frequency of these cycles?
They felt that there was no need to insert that data as everyone knows that co2 is the instigator. {mildly sarc} as in their eyes they likely hold no doubt.
They were good until “climate models”…
Slightly OT – Antarctic sea ice looks like its just turned the corner (passed minimum), slightly higher than last year continuing an upward trend:
http://nsidc.org/data/seaice_index/images/daily_images/S_stddev_timeseries.png
another unmistakable warming signature of CO2
(/sarc)
I realize the Macondo well blew out in 2010 and the oil spill was thought by some to change the current patterns in the Gulf and Atlantic, but this whole study doesn’t make a lot of sense with the attempt to tie it to carbon dioxide since about then, the ice caps started to rebuild, not melt. It does seem to make a wonderful case for subsidence, though. OMG!!! global warming causes coastal subsidence!! It’s worse than we thought!!
Once described by Dr. Jane Lubchenco, a former NOAA administrator, as providing “instantaneous” sea-level changes, the NASA GISS satellite data are subject to the same tidal variations as the terrestrial measurements. In the time is takes to scan one area of the ocean, the surrounding waters have already moved from place to place. Due to instrumentation drift, the data require constant correction using surface tidal stations as reference. See Impact of Altimeter Data Processing on Sea Level Studies.
She has also described the IPCC as having the “gold standard” in climate change data.