We’ve been waiting for the UC web page to be updated with the most recent sea level data. It finally has been updated for 2008. It looks like the steady upward trend of sea level as measured by satellite has stumbled since 2005. The 60 day line in blue tells the story.
From the University of Colorado web page:
Since August 1992 the satellite altimeters have been measuring sea level on a global basis with unprecedented accuracy. The TOPEX/POSEIDON (T/P) satellite mission provided observations of sea level change from 1992 until 2005. Jason-1, launched in late 2001 as the successor to T/P, continues this record by providing an estimate of global mean sea level every 10 days with an uncertainty of 3-4 mm.
They also say:
Long-term mean sea level change is a variable of considerable interest in the studies of global climate change. The measurement of long-term changes in global mean sea level can provide an important corroboration of predictions by climate models of global warming. Long term sea level variations are primarily determined with two different methods.
Yes, I would agree, it is indeed a variable of considerable interest. The question now is, how is it linked to global climate change (aka global warming) if CO2 continues to increase, and sea level does not?
There’s an interesting event in October 2005 that I’ll come back to in a couple of days.
(h/t to Mike Bryant)
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Ed Scott:
The earth’s tectonic plates move and all three directions. Additionally, satellite orbits vary for various reasons. I’m curious how those (and other) factors are accounted for.
BTW: Sea levels have risen steadily and fairly constantly for 3 centuries. The most logical, reasonable and simple explanation is this is a natural phenomenon and has nothing to do with human activities. Whatever natural forces started the sea level rise 3 centuries ago is ongoing.
I wonder now if the AGW proponents will now savage the TOPEX/POSEIDON data as much as they’ve been beating up on the satellite temperature data. It wouldn’t surprise me it they do since their little game of global warming scaremongering is unraveling.
Oops! Should have also included comments about data from Jason.
Somewhere in mid 2006, a British/Dutch team using a European (polar) satellite reported on ten years of data on the level of the arctic ocean. They reported that the arctic ocean was falling 2 mm per year for that ten years. They didn’t know why, but were very confident of their data.
Two years earlier I predicted that the sea level should fall when the floating sea ice melts; because an astronomical amout of latent heat is extracted from the surrounding ocean to melt all that ice so the sea cools and shrinks (water with a salinity above 2.47% has no maximum density before it freezes) Typical ocean salinity is 3.5%.
You can find my letter in Physics today for Jan 2005.
However their measured results do apparently prove that the floating sea ice was indeed melting during that time. It would be interesting to know what the arctic ocean sea level is doing now that arctic sea ice is evidently recovering.
“What goes up, must come down”
That also applies to sea level.
“The orbital velocity of the satellite depends on its altitude above Earth. The nearer Earth, the faster the required orbital velocity. At an altitude of 124 miles (200 kilometers), the required orbital velocity is just over 17,000 mph (about 27,400 kph). To maintain an orbit that is 22,223 miles (35,786 km) above Earth, the satellite must orbit at a speed of about 7,000 mph (11,300 kph). That orbital speed and distance permits the satellite to make one revolution in 24 hours. Since Earth also rotates once in 24 hours, a satellite at 22,223 miles altitude stays in a fixed position relative to a point on Earth’s surface. Because the satellite stays right over the same spot all the time, this kind of orbit is called “geostationary.” Geostationary orbits are ideal for weather satellites and communications satellites.
The moon has an altitude of about 240,000 miles (384,400 km), a velocity of about 2,300 mph (3,700 kph) and its orbit takes 27.322 days. (Note that the moon’s orbital velocity is slower because it is farther from Earth than artificial satellites.)”
SO basically, if the gravitational constant and the mass of the satellite does not change, a satellite with a constant velocity and a perfect circular orbit can measure the changes in altitude of the ground (or sea) with a radar-type of device.
George
“because an astronomical amount of latent heat is extracted from the surrounding ocean to melt all that ice so the sea cools and shrinks”
Brilliant!!!
Absolutely Brilliant!!
Latent heat, missed that one, I should have thought about that.
Brilliant!!
Flanagan (09:34:58) :
> Making climatic trends over 3 years is at the best naive, not to say misleading.
Not completely. The last time the PDO flipped, in the late 1970s, the climatic response was very quick. Joe D’Aleo likes to refer to it as the Great Pacific Climate Shift. So there is precedence. Not naive, but it is dancing around the error bars a bit. It is nice that data is matching expectations.
Hello B. Kerr,
A very instructive or at least illuminating experiment can be performed by anyone in the kitchen.
You start with two equal quantities of water; 8-12 oz or so; doesn’t matter how much so long as they are equal.
You pour one sample into an ice tray and put into the freezer to freeze.
The remaining sample you put into a microwaveable container at least twice as big. It will help to have a 0-100 deg C glass thermometer (doesn’t everybody have one of those).
So once the ice is frozen into cubes you transfer the tray to the refrigerator to let it warm up to closer to zero (but not melt).
So you take the vessel of water and you heat it either with the nuke or on a hot plate stirring with the thermometer, until you get it up to 80 deg C. Pretty damn hot !
So now you have X ounces of ice at about zero deg C, and also X ounces of hot water at 80 deg C.
So you pour the ice cubes into the 80 deg C water, and stir. DO NOT PANIC if you noitice some of the ice melting; it is supposed to do that, in fact it is all going to melt, as you stir; and just as the last vestiges of ice vanish, your whole vessel of water plus melted ice will now be at zero degrees C.
Now your kids do this every day with ice cubes and Coke or Pepsi, but how little do they know how much cooling power is hidden in that latent heat of 80 calories per gram.
Sea level is an almost perfect proxy for the heat content of the “biosphere” of our planet, as the oceans contain almost all of the stored heat, and water expands and contracts very nicely as it is heated and cool.
I simply don’t understand why we don’t use sea level as the ultimate proxy for long term temperature variations – it’s far preferable to surface or even satellite air temperature readings. Although sea temperature trends and atmospheric temperature trends might diverge over the short term, thermodynamically they must converge over the long term.
Note also, sea level has been rising for quite some time. No idea how CO2 caused sea level rises back in 1850.
One little orbital factoid to add to Ray’s post above. If you have a satellite orbiting in a circular orbit at any altitude; and you suddenly increase its speed by square root of 2, the circular orbit will be transformed into a parabolic escape orbit.
I can’t make any use of that, but it is something useful to know if you get stuck on a desert island without Google.
Joshv, I don’t agree. You proposal only works if there is no ice melt at the poles.
John Galt
Are you related to the hero of Ayn Rand’s book, Atlas Shrugged? There is talk of “Going John Galt” to resist the government incursions on the liberties and freedoms and finances of the citizens of the USofA in the presence of the government’s proclivity for spreading our wealth.
An email correspondent and his wife departed for Galt’s Gulch several months ago.
Both tide gauges and satellite radar altimetry are used to measure the present rates of change in sea level. Tide gauges measure sea level relative to the ocean floor whereas the reference for satellite altimetry is the earth’s center.
When measuring sea level by satellite, there are several references, which, by definition, are error free. This leaves only the error of 3-4 mm due to the altimeter measurement. (:-)
From Ray (11:23:07) :
The declining sea level is most likely due to the renewal of the ice shelfs but the only one that would have a great impact is that at the South Pole since the ice at the North Pole displaces it’s own volume of water.
[…]
So, since we are cooling, the concentration of CO2 will rise because less and less water is in the atmosphere.
-end quote
What about all the extra snow on land in the N.H. right now? And the snow in N. Zealand … and the late snow in Australia … and the lake effect snow in New York et. al.? And… Can sea level serve as a proxy for total snow fall globally? (Yes, rampant speculation… that’s where learning starts…) Or is it total precipitation since more rain means more water wandering through the groundwater system for a few decades / centuries…
Also, I’ve often wondered: Doesn’t CO2 dissolve better in cold water than warm? Would not temps down in the -30 to -50 C way up north argue for CO2 extraction into precipitation? I can’t shake the notion that there might be some negative feedback cycle with very frozen water taking CO2 with it at the poles… (again, rampant speculation…)
sea level … has now dropped like a stone.
Sea level looks to be a current indicator of El Nino/La Nina conditions. As I noted in the previous thread, we seem to be going into a new La Nina.
This mean sea temperatures (which determine sea levels due to thermal expansion/contraction) drive atmospheric temperatures, rather than the reverse as AGW theory predicts.
Expect temperatures to fall over the next 6 months.
E.M. Smith – actually there was an article here showing a graph of the solubility of CO2 in water vs Temperature ( http://wattsupwiththat.com/2007/11/04/guest-weblog-co2-variation-by-jim-goodridge-former-california-state-climatologist/ ). But remember that CO2 is actually in equilibrium with carbonic acid in water. Once you freeze that water, all the gaseous CO2 will escape but only the carbonic acid will remain. The CO2 they measure in the ice core are actual bubbles that were trapped as the snow got compacted over time.
But when you look at the distribution of CO2 vs latitude, you will also see that the “concentration” of CO2 at the poles (or in altitude) is higher… kind of wonder if that is not because of the lesser concentration of water where it is bitterly cold.
Compared to the enormous mass of water locked in Antartica, the relatively small quantity of solid water that accumulates in some places during winters is almost, but not completely, neglectable. In any case, compared to the rest of the water mass, it’s not much… even if you feel it’s a lot when you look out your window and you will have to shovel it in the morning and when you see the plower coming to push all that back in your driveway. I’s so happy to live on the west coast!
I wonder how much of the rise in ocean level is due to factors like sediments flowing into the oceans, dust falling into the ocean, and those house sized ice comets smashing into the atmosphere every day?
Bob B/Joshv
It’s much more complicated than that. The volume of the oceans is not constant for several reasons.
Land that was weighed down by ice during the last glaciation is still rising (about 4 inches a year in the northern Baltic). On the other hand coasts all around the world are still sinking from the 400 feet of water deposited on them 12000 years ago when the last glaciation ended. The mid ocean ridges swell or shrink with the amount of volcanic activity (this is good for a couple of hundred meters of sea-level change over several million years). Rivers carry sediment into the ocean, while other sediment disappears down into the mantle at subduction zones, probably not at the same rate.
The amount of fresh water in glaciers, lakes, rivers and groundwater is always changing and so is the temperature of the oceans.
To isolate just the last factor is not easy, to put things mildly.
Too many here are not reading the graph correctly.
Sea level is not falling. The rate of sea level rise is declining.
Sea level is still rising. Its just not accelerating as fast as it was when the sun was much more active. Until it stops rising, the AGW clergy will continue to use this as proof of their dogma.
The oceans will hold the heat that accumulated during the last 150 years of warming for many years.
The best evidence of the falsity of the AGW dogma lies elswher, such as in the failure of the models to accurately track the reality of climate, or with Svensmark’s work and the CERN experiments that are to test them.
It should be noted that the satellite data may only indicate a 1.6mm/yr increase as has been noted by several authors ie: http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2007JCLI1840.1
The accuracy of these measurements should be questioned as they are obtained from 200 miles up, measuring a moving surface and compairing it to the center of the earth 300 miles down which is also moving. When the claim is made that sea level rise is accelerating, the satellite data is being compaired to older tide guage data which interestingly enough continues to show about a 2 mm/yr rise. I live in the San Francisco area so I follow the bay measurements http://www.bodc.ac.uk/data/information_and_inventories/gloss_handbook/stations/158/plot/823031/ which shows only about 60 mm rise in over 150 years. To be fair the smoothed slope is probably about 1.5 mm/yr.
It’s almost as if low solar activity somehow affects light incident on bodies of water. Like there’s been more clouds over seas.
Oops thought this was about temp, not melt. Of course, temp is part of sea level rise independent of melt.
Ray (13:48:01) :
It’s really more complicated than that. First, I don’t know what kind of orbit these spacecraft are in but any orbit would be perturbed by various outside factors.
One, the Earth’s mass isn’t completely uniform, so you have strong and weak gravitational spots that will speed or slow the spacecraft – thus changing its altitude.
A second is due to the gravitational effects of the moon, it will tend to pull the spacecraft away from its orbit.
Any spacecraft will have to update its orbit routinely.
One way to minimize the importance of this drift would be to very accurately measure the position of the spacecraft through some other mechanism.
MikeEE
George E. Smith (14:44:39) :
My kids are nuking the Coke before they drink it? I thought they knew better than that! I tried to teach them to make iced tea by making hot tea with half the amount of water (and half the heating time), then dissolve the sugar in the hot water, then add ice to bring the volume up to full and chill the tea, and have a little ice left over. (I skip the warm to freezing step.)
I don’t know where they got the idea to heat the soda. No wonder the soda in the bottle goes flat so quickly. 🙂
MikeEE (18:36:32) :
More on my last post. The Jason 1 is a LEO (Low Earth Orbit) satellite at 1,330 kilometers (860 miles) – see http://topex-www.jpl.nasa.gov/mission/jason-1.html . A GEO (Geosynchronous) wouldn’t be useful as it stays over the same location of the Earth all the time, the LEO eventually gets to see the entire circumference, but depending on its inclination will miss some part around the poles.
While searching for info on Jason 2 I came across this interesting FAQ page that explains a little about sea level at http://www.pol.ac.uk/psmsl/puscience/
I hope I got that tag right this time!
MikeEE