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#################THE GLOBAL OCEAN HEAT CONTENT ROSE APPROXIMATELY 16*10^22 JOULES FROM 1969 to 2008The units used to express Ocean Heat Content (OHC) are 10^22 Joules. Figure 1 from Levitus et al (2009) “Global Ocean Heat Content 1955–2008 In Light Of Recently Revealed Instrumentation Problems” follows. As illustrated, Ocean Heat Content of the upper 700 meters of the global oceans, using the linear trend as reference, rose approximately 16*10^22 Joules from 1969 to 2008, the period Levitus et al elected to use for linear trends. Link to Levitus et al (2009):
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf
http://i50.tinypic.com/2dviqe9.pngLevitus et al (2009) Figure 1
Unfortunately, most people cannot put that rise in Ocean Heat Content into perspective; that is, into familiar terms. Also, the number 16*10^22 Joules is simply too large to comprehend. An AGW proponent might write, “Since 1969, an additional 16*10^22 Joules of heat is being stored in the oceans.” The number is so large it sounds scary. Maybe that’s why it’s used.
BUT WHAT WAS THE TEMPERATURE RISE?
According to the supplemental material furnished with Levitus et al (2009), the temperature of the Global Oceans (0-700 meters) rose about 0.17 deg C from 1969 to 2008. Refer to Table T1 from Levitus et al (2009).
http://i46.tinypic.com/30de5qs.pngLevitus et al (2009) Table T1
This equals a trend of approximately 0.042 Deg C/Decade or less than a half degree per century for the upper 700 meters.
ARE THERE ANY REFERENCES FOR GREATER DEPTHS?
The Abstract of an earlier Levitus et al paper, one from 2005, “The Warming Of The World Ocean: 1955 to 2003” states, “During 1955–1998 world ocean heat content (0–3000 m) increased 14.5 × 10^22 J corresponding to a mean temperature increase of 0.037°C at a rate of 0.20 Wm−2 (per unit area of Earth's total surface area).”
http://www.agu.org/pubs/crossref/2005/2004GL021592.shtml
0.037 Deg C from 1955 to 1998 equals a linear trend of less than 0.009 deg C/ Decade. The rise doesn’t sound catastrophic in those terms.
THE IMPACTS OF NATURAL VARIABLES
There has been a recent push to use Ocean Heat Content as a measure of anthropogenic global warming. Unfortunately for AGW proponents, there is little evidence that anthropogenic greenhouse gases have an effect on Ocean Heat Content.
As illustrated and discussed in the following posts, natural climate variations are the dominant causes of the rises in Global Ocean Heat Content. One simply needs to break the global OHC data down into logical subsets to witness these effects.
ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data
And:
North Atlantic Ocean Heat Content (0-700 Meters) Is Governed By Natural Variables
And:
North Pacific Ocean Heat Content Shift In The Late 1980s
38 comments:
There is apparently a question of measurement error in the 2003 straight line up due to the change over between XBT and Argos being the primary measurement method.
http://pielkeclimatesci.wordpress.com/2009/12/29/comment-from-josh-willis-on-the-upper-ocean-heat-content-data-posted-on-real-climate/
Harrywr2: Thanks. You reminded me about another post I want to do.
And yes, the 2003 surge only appears in only one other OHC dataset, Wijffels...
http://i44.tinypic.com/5uizit.png
...but Wijffels takes a downturn in the 1990s before that unusual rise.
The graph is from "OHC Trends Presented by Levitus et al (2009) Versus Trends Presented by the OHC Data"
...Including Ishii and Kimoto (2009), Domingues et al (2008), and Wijffels et al (2008)
http://bobtisdale.blogspot.com/2009/07/ohc-trends-presented-by-levitus-et-al.html
Regards
Thanks Bob.
I always wanted to know what these numbers really mean, what it meant for other depths and how the ocean temps have changed at different depths. It is spelled out very well.
Mr. Bob Tisdale:
I was thinking about your statement that downward IR radiation only penetrate a few centimetres below the ocean surface.
That ignores that heat is transported by 3 mechanisms:
1)Radiation
2)Conduction
3)Convection
Obviously conduction+convection transport the heat several hundred meters downward. Then the Thermohaline Circulation transport the warmed waters to the Deep Ocean.
This is obvious by the next reductio ad absurdum: let’s assume that there is no conduction and no convection in the ocean (a completely unphysical scenario, just to demonstrate that if downward IR heat doesn’ t penetrate deeper than few centimetres then crazy things will occur).
Now the IR can now warm just the upper 10 cm of seawater.
The formula for heat capacity is:
Q = ∆T * CP *V
where:
Q = total heat(J)
∆T = warming/cooling(ºK)
CP = volumetric heat capacity at constant pressure of 1 atm (J/(cm3•K) )
V = volume (cm^3)
So, ∆T in the formula above is:
∆T = ∆Q/ (CP *V)
Differentiating this with respect to time give us the warming rate:
∂T/∂t = P/(CP *V), where P = heat flux (W/m^2)
The measured downward IR imbalance according to Trenberth et al. paper “Earth’s global energy budget”, net LW radiation over the oceans is 57,4 W/m^2.
The heat capacity of liquid water, CP= 4,186 J/(cm^3•K) = 4,186*10^6 J/(m^3•K)
And the volume of 10 cm of water in every m2 is 0,1 m^3
So:
∂T/∂t = 57,4 / (4,186 *10^6 * 0,1) = 1,371* 10^-4 ºK/s = 11,85 ºK/ day!
Without conduction + convection …
… the upper 10 cm of the world ocean will reach the boiling point in just a week!
Now using the total net imbalance of Earth (SW+LW+LH+SH) = 0,9 W/m^2
∂T/∂t = 57,4 / (4,186 *10^6 * 0,1) = 2,15*10^y6 ºK/s = 0,186ºK/ day!
Without conduction + convection …
… the upper 10 cm of the world ocean will reach the boiling point in less than 2 years!
Now assume some limited “convection + conduction depths”:
1,0 m : 6,7 ºK/ year … 11 years before boiling point
10 m : 6,7 ºK/ decade … 110 years before boiling point
100 m: 0,67 ºK/ decade … 1100 years before boiling point
Finally some realistic “convection + conduction depths”:
1000 m: 0,067 ºK/ decade = 0,67 ºK/ century
3000 m: 0,023 ºK/ decade = 0,23 ºK/ century
Is obvious that heat in the ocean is redistributed by convection+conduction.
If this were not the case, Earth will be already an unhabitable super-sauna, as the upper ocean would had turned into hot steam.
Back to the real world …
In 40 years (since the late 1970s) SST increased 0,4 ºK, so:
∂SST / ∂t ≈ 0,13 ºK/decade
Taking the upper 100 meters, and assuming that these warmed equally this is ≈ 20% of the heat accumulated in the oceans.
This is just a rough calculation, so the OHC implied by SST warming may well be several percent different than 20%.
Anonymous 11:18PM: Thank you for your long comment. But I read only as far as your second sentence and stopped after “…three mechanisms…” So I cannot tell if there are any errors in your calculations or logic. Why did I stop reading? As I have repeatedly written and illustrated, there is no evidence that Downward Longwave Radiation from anthropogenic greenhouse gases has any effect on the Ocean Heat Content of the upper 700 meters of the oceans. Refer to:
http://bobtisdale.blogspot.com/2009/09/enso-dominates-nodc-ocean-heat-content.html
and:
http://bobtisdale.blogspot.com/2009/10/north-atlantic-ocean-heat-content-0-700.html
and:
http://bobtisdale.blogspot.com/2009/12/north-pacific-ocean-heat-content-shift.html
Regards
And apart from your links Bob, Anonymous fails to comprehend that since most of the energy from the downwelling LW radiation cannot penetrate beyond it's own wavelength into the ocean surface, it is concentrated in a very shallow depth and causes prompt evaporation which takes the energy straight back into the atmosphere via the latent heat of evaporation and then recondenses high up in the clouds.
Another thing about your post is this: I calculated the average rise in temp of the top 1000m of ocean from 1993-2003 based on thesteric component of sea level rise and found it to be 0.15C. This is equivalent to about 4W/m^2 and cannot be accounted for by Co2's 1.7W/m^2 (claimed by IPCC). So it must have been due to a reduction in cloud cover as measured by the ISSCP and a very active sun.
Levitus figures have to be taken with a large dose of evaporated seawater residue. Take a look at Levitus et al 2000 and you'll see what I mean.
The SATELLITE-MEASURED Energy imbalance of Earth is REALLY HUGE:
NET LW radiation over the oceans = 57,4 W/m^2.
Total NET energy imbalance of Earth(SW+LW+LH+SH) = 0,9 W/m^2
This energy imbalance is more than enought to BOIL AWAY THE OCEAN SURFACE.
So I repeat the conclusion:
WITHOUT CONDUCTION+CONVECTION, THE EARTH WOULD BE ALREADY AN UNHABITABLE SUPER-SAUNA, AS THE UPPER cm OF THE OCEAN WOULD BE TURNED INTO HOT STEAM.
tallbloke:
I have put the numbers INCLUDING EVAPORATION AND SOLAR RADIATION:
"Total net imbalance of Earth (SW+LW+LH+SH) = 0,9 W/m^2
∂T/∂t = 57,4 / (4,186 *10^6 * 0,1) = 2,15*10^y6 ºK/s = 0,186ºK/ day!
Without conduction + convection …
… the upper 10 cm of the world ocean will reach the boiling point in less than 2 years!"
Still more than enought to BOIL AWAY THE OCEAN SURFACE.
Anonymous (11:41AM): Again, the Ocean Heat Content record shows no influence from anthropogenic greenhouse gases.
So then where the 0,9 W/m^2, (corresponding to a total warming of 145*10^20 J/year) have gone?
If all this heat didn't gone to the oceans, it must have gone only to land + atmosphere.
The observed values global energy storage between 2003 and 2008 for land + sea ice + land ice + atmosphere are (in units of 10^20 J/year):
land warming: 2
sea ice melted: 1
land ice melted: 2-3
atmospheric warming: 1
So we have 145 -(2+1+3+1)= 138 *10^20 J/year.
Taking into account that between 2003 and 2008 the solar energy input reduced by 16 *10^20 J/year(we went from solar maximum to solar minimum) we have:
138-16 = 122*10^20 J/year
Where had all this heat gone if "the Ocean Heat Content record shows no influence from anthropogenic greenhouse gases"?
(All these numbers are from the Kevin E Trenberth(2009) paper "An imperative for climate change planning: tracking Earth’s
global energy")
According to the Southampton oceanography team there is a 30W/m^2 hole in the energy balance unaccounted for anyway. Which is probably why Kevin Trenberth's arms resemble windmills recently.
Given that the global average ocean surface temperature is about 18C and the global average air temperature is about 13.5C, I wonder how anonymous thinks lots of heat is going to conduct from the air into the ocean. Is he aware the top 2.5m of ocean has as much heat capacity as the entire atmosphere above it?
tallbloke :
You said:
"Given that the global average ocean surface temperature is about 18C and the global average air temperature is about 13.5C,"
This is just the AVERAGE. There are a lot of places and seasons where the air is hotter than the ocean surface. For example,during Summer in the East Pacific the air can be over 30ºC while the water is near 20ºC thanks to the cold Peruvian Current.(I know that because I live in Peru).
You said:
"I wonder how anonymous thinks lots of heat is going to conduct from the air into the ocean."
I did't afirmed what you are saying I wrote.
By the way, in the situation found in my previous example, some heat from hot Peruvian air may warm the cold ocean surface. But such an exchage will be far smaller than any heating due to SW and LW downward radiation.
However, warm air can indirectly "warm" the seawater: as the air is warmer than the ocean surface, the ocean could only lose heat by LW radiation, not by conduction or convection. In this way, the warm air prevent any conduction+convection mechanism from cooling the seawater previously heated by downward LW+SW radiation.
You said:
"Is he aware the top 2.5m of ocean has as much heat capacity as the entire atmosphere above it?"
Yes, of course I know that seawater (or any water, by the way) has a lot more heat capacity than air. That is quite obvious given:
1)the high specific heat of liquid water
2) the far bigger density of water compared to that of air (a liquid is always far more denser than a gas at 1 atm of pressure)
WRT Anonymous's comments, heat is ambiently re-radiated back into space. It's why your car's windshield freezes first -- it's pointed upwards and doesn't get the Earth's radiated heat. The oceans radiate their heat back to space in the same way. All this fluff about convection and conduction is secondary, because black box equations apply. Same applies to "global warming" -- trace atmosphere gases have only a trivial effect on Earth's black box ambient temperature equilibrium.
"as the air is warmer than the ocean surface, the ocean could only lose heat by LW radiation, not by conduction or convection. In this way, the warm air prevent any conduction+convection mechanism from cooling the seawater previously heated by downward LW+SW radiation."
Confusion reigns.
The seawater is only heated by LW on the very surface, which causes it to promptly evaporate and this is not prevented by 18C air or 22C air or even 30C air, because the large numbers of W/m^2 sizzle the topmost molecules of water on the ocean surface to temperatures high enough for evaporation and subsequently the water vapour heads upwards at a high speed due to water vapour being a lot less dense than air.
Downwelling LW does not heat the ocean. Full stop, end of story.
Tallbloke:
Can you explain where 138 *10^20 J/year had ended if they have not warmed the oceans?
Where are they?
There is not a Black Hole in Earth that could magically suck all that heat.
NZ Willy, you said:
"The oceans radiate their heat back to space in the same way. All this fluff about convection and conduction is secondary, because black box equations apply. Same applies to "global warming" -- trace atmosphere gases have only a trivial effect on Earth's black box ambient temperature equilibrium."
Earth is NOT in equilibrium.
It absorbs 0,9 W/m^2 more energy than it re-radiates back to space.
This was MEASURED by SATELLITES, NOT deduced from any climate model and NOT deduced from any sum of heat accumulated in the oceans + land + atmosphere + melting ice.
Earth is warming, BECAUSE of this imbalance.
There is no way,according to the laws of physics, that the Earth could not warm if it is accumulating heat (remeber, at a rate of 0,9 W/m^2)
And also according to measurements, the heat used in warming the atmosphere and the land + the heat used in melting the glacier ice + sea ice is much less than the amount of heat that the whole Planet has accumulated since 2003.
So this heat MUST have gone somewhere. And only place that remains in the list as heat reservoir are the oceans.
Hi Bob -
Quick question regarding the latest (Dec. 30th) OIv2 temperature map.
I notice the large anomaly in the South Pacific (which you pointed out in an older post that Trenberth has shown is correlated with El Nino).
This will show my lack of knowledge about the ocean-atmosphere coupled nature of El Nino.
Will that spot have the same lagged effect on atmospheric temperature that is credited to El Nino? Given the correlation, is it proper to view that spot as part of the El Nino? Does it factor into the warming of other oceans (and thus atmospheres) as your analyses has shown?
Based on the current map, a rough eyeball view makes me think that spot contains at least 50% more anomalously warm water than the traditional Nino waters around the equator.
Bob,
Have you looked at the most recent SST data from Unisys?
http://weather.unisys.com/surface/sst_anom.gif
Note the large pools of cold waters surrounding NINO 3.4 region. How does that compare to previous El Nino years, and will it render it neutered? Also, the warm region south. Wow.
As for OHC, IMO there is nowhere near enough data available since ARGO has been implemented. There seems to be much disagreement amongst the various analyses as to how much if any heat has accumulated in the last several years.
Bob,
It is good to put claims of "warming in the pipeline" in perspective as your post effectively does.
One thing I noted was how close the 0-3000 meter heat accumulation and top 700 meter accumulation are to each other. If the top 700 meters warmed at a rate of about 0.042 degree per decade while the top 300 meters warmed at a rate of about 0.009 degree per decade, then this implies the fraction of warming from 700-3000 meters probably represents less than 10% of the total ocean heat accumulation, on the order of 0.02 watt per square meter. This deep ocean heat accumulation represents only a tiny fraction of the total solar flux at the ocean surface, so any "long term delay" in warming due to increases in radiative forcing has to be very small. What delay there is is limited mainly to the warming delay of the top 700 meters (and most of this is actually warming in the top 300 meters!).
Steve Fitzpatrick:
You said:"If the top 700 meters warmed at a rate of about 0.042 degree per decade while the top 300 meters warmed at a rate of about 0.009 degree per decade, then this implies the fraction of warming from 700-3000 meters probably represents less than 10% of the total ocean heat accumulation, on the order of 0.02 watt per square meter."
Actually this statement is false, according to ARGO data showed in the Schuckmann 2009 paper "Global hydrographic variability patterns during 2003–2008".
It shows the warming rate(in terms of heat content) of the oceans down to 2000 meters between 2003 and 2008 is 0.77 ± 0.11 W/m^−2.
As the warming in the upper 700 meters in the 2003-2008 period is nearly zero (as was showed in many posts of this blog), obviously DEEP OCEAN (700m to 2000m deep) WARMING REPRESENTS NEARLY 100% OF OCEAN WARMING.
That is, not the 0.02 W/m^−2 that you estimated, but ...
0.77 ± 0.11 W/m^−2 !
So with most of the oceanic warming sequestered in the deep oceans, nearly all of those 0.77 ± 0.11 W/m^−2 are still waiting for heating the surface!
Anonymous (4:31PM): You wrote, "So with most of the oceanic warming sequestered in the deep oceans, nearly all of those 0.77 ± 0.11 W/m^−2 are still waiting for heating the surface!"
And how did you come to that conclusion?
Anonymous (3:59PM): In your reply to Steve Fitzpatrick, you referred to von Schuckmann (2009).
von Schuckmann is the outlier. With the exception of von Schuckmann, recent OHC and steric sea level studies show little to no rise in the data since 2003.
BTW, my friend from Peru, you're a regular commenter here. If you'd identify yourself, I wouldn't have to call you Anonymous. That would save me a few clicks to see if it again you, the constant referrer to von Schuckmann or if someone else is jumping on your bandwagon.
And again, we've been through the fact that since the upper 700 meters of the ocean show no signs of anthropogenic warming, longwave radiation from greenhouse gases cannot bypass the upper layers and warm the oceans below it.
Regards
Mr Bob. Tisdale:
You said "And how did you come to that conclusion?"
Because this 0.77 ± 0.11 W/m^−2 had not warmed the surface still, and until the surface warms enought to increase the OLW to outer space by this same amount(that is, until thermal equilibrium is restored), the surface will continue to warm.
Well, unless a series of BIG VOLCANOS create a strong negative forcing that last long enought to cancel this (positive) energy imbalance
(and this seems very unlikely, as Big Eruptions like Pinatubo are rare events and their effects last only few years)
Mr Bob Tisdale:
How you know my location?
If you like, I will firm "From Lima, Peru" as I have not a google account.
The Shuckmann et al. paper is an oulier BECAUSE he includes ARGO measurement down to 2000 meters, while most of papers only use data down to 700 meters.
So the upper 700 meters almost didn't warmed, while the waters below accumulated the "missing warming".
And if deep waters accumulate heat and surface waters not, then evidently the Thermohaline Circulation subduct the warmer waters with high efficiency, so the heat had not time to accumulate in upper waters before being subducted by the Thermohaline Circulation-driven downwelling currents.
Greetings,
From Lima, Peru
Anonymous from Lima: You wrote, “The Shuckmann et al. paper is an oulier BECAUSE he includes ARGO measurement down to 2000 meters, while most of papers only use data down to 700 meters.”
Your comment only addresses the OHC portion of my comment. It does not address the steric sea level portion, which reflects the thermal expansion and salinity changes. Steric sea level serves as a proxy for OHC from the surface to the bottom of the oceans. Refer to Pielke Sr discussion here about von Schuckmann et al:
http://pielkeclimatesci.wordpress.com/2009/12/23/further-comments-on-the-inadequate-epa-response-to-reviewer-comments-on-ocean-heat-content/
You wrote, “And if deep waters accumulate heat and surface waters not, then evidently the Thermohaline Circulation subduct the warmer waters with high efficiency, so the heat had not time to accumulate in upper waters before being subducted by the Thermohaline Circulation-driven downwelling currents.”
And again I’ll repeat, if the upper waters (0-700 meters) show no sign of greenhouse gas forcing, and if the upper waters are being downwelled by THC or MOC as you suggest, then the downwelled waters cannot have any greenhouse gas forcing either.
The increases in OHC regardless of the depth do not result from a gradual increase in longwave radiation. I've linked the OHC posts that discussed this many times above.
Deep waters accumulating heat?
Steric sea level data:
1993–2003
Ocean thermal expansion contributed by 50% to the 3.1 mm/yr observed global mean sea level rise during the decade.
2003–2008
Steric sea level rate 0.3 mm/yr
Source:
Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo
Global and Planetary Change, Volume 65, Issues 1-2, January 2009, Pages 83-88
A. Cazenave, K. Dominh, S. Guinehut, E. Berthier, W. Llovel, G. Ramillien, M. Ablain, G. Larnicol
Jovian: Thanks for the reference. von Schuckmann continues as the outlier.
To save some time for those reading through the comments, here's a link to Cazenave et al (2009):
http://penoflight.com/climatebuzz/Docs/SeaLevelRise2008.pdf
d: Sorry about the late reply to your comment. Got side tracked with the visit from the alarmist.
You asked, "Note the large pools of cold waters surrounding NINO 3.4 region. How does that compare to previous El Nino years, and will it render it neutered?"
I was going to point you to a post about an animation about global SST anomalies since 1981, but then I realized I hadn't posted it anywhere. Maybe in the next couple of days. Then you can just stop the animation during the El Nino events.
Will those cool spots neuter it? The surrounding cool spots may be a product of the convection taking place. That is, is the rising warm air drawing the surface waters toward it, revealing the cooler waters below? And a quick look at the response of global SSTs for December reveals that it hasn't been neutered.
Jovian: You said:
"Deep waters accumulating heat?
(...)
2003–2008:
Steric sea level rate 0.3 mm/yr
Source:
Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo
The paper you cite assumes a SLR rate of aproximately 2,5 mm/yr of total sea level rise. This result was an artifact of the 2007-2008 La Niña.
Now that that Stronmg La Niña is over, the updated data of SLR from the TOPEX/POSEIDON-Jason1-Jason2, the value of SLR rate is near 3,3 mm/yr.
Substactring the von Schuckmann value for thermo-steric SLR rate of 1.01mm/yr(+-0,13mm/yr) from this:
3,3-1,01-0,13= 2,16 mm/yr
3,3-1,01+0,13= 2,42 mm/yr
This rate is SLR from melting land glaciers and land freshwater.
Very close to the GRACE values for Non-thermal SLR that aapear in the paper (where it was near 2 mm/yr)
Von Shuckmann was right!
Anonymous from Lima, Peru: Regarding your 4:32PM comment, the IPCC notes that the steric component of the rise in Sea Level from 1993 to 2003 represents ~50% of the 3.1mm/year trend. Or steric sea level from 1993 to 2003 is ~1.55mm/year. That’s from Cazenave et al (2009) “Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo”:
http://penoflight.com/climatebuzz/Docs/SeaLevelRise2008.pdf
Table 1 of Antonov et al (2005) “Thermosteric sea level rise, 1955–2003” lists the thermosteric sea level rise over that period as 1.23mm/yr.
http://i47.tinypic.com/23vkb5g.png
For the period of 2003 to 2008, Cazenave et al (2009) then list the altimetry-based sea level rise as 0.3mm/year and the ARGO-based sea level rise as 0.37mm/year. But von Schuckmann have found it to be 1.01mm/year. Referring again to the Pielke post…
http://pielkeclimatesci.wordpress.com/2009/12/23/further-comments-on-the-inadequate-epa-response-to-reviewer-comments-on-ocean-heat-content/
…von Schuckmann is the outlier.
Mr Bob Tisdale:
You said:
"Table 1 of Antonov et al(2005) “Thermosteric sea level rise, 1955–2003”
Thermo-steric SLR(1993-2003): 1.23mm/yr.
For the period of 2003 to 2008, Cazenave et al (2009) then list:
Thermo-steric SLR(1993-2003):0.3 mm/yr (altimetry-based)
Thermo-steric SLR(1993-2003): 0.37mm/yr (ARGO-based)
But von Schuckmann have found it to be 1.01mm/year"
Well, in my previous comment I substracted the Von Shuckmann et al. value for thermo-steric SLR from the total to ontain the non-thermosteric SLR:
Total(altimetric) SLR: 3,3 mm/yr
Thermo-steric SLR : 1.01mm/yr(+-0,13mm/yr)
and found values(the difference):
3,3-1,01-0,13= 2,16 mm/yr
3,3-1,01+0,13= 2,42 mm/yr
consistent with the found by Cazenave et al.(2008) that used GRACE data:
Ocean mass (GRACE; 2003–2008) 1.9 +/−0.1 mm/yr
Sum of ice and waters: 2.2 +/−0.28 mm/yr
Well, let's now follow the method of Cazenave et al.(2008)to find the Thermo-steric SLR:
Total SLR:3,3 mm/yr
Thermo-steric SLR (Total-GRACE(2003-2008)):
3,3 mm/yr - (1.9 +/−0.1 mm/yr) = 1,4+/-0,1 mm/yr
Thermo-steric SLR (Total-Sum of ice and waters):
3,3 mm/yr - (2.2 +/−0.28 mm/yr) = 1,1+/−0.28 mm/yr
Why Cazenave et al estimated a value for thermo-steric SLR of just 0,3-0,4 mm/yr?
Because the paper was written in 2008, and thanks to the strong 2007-2008 La Niña, the Total SLR trend nearly flattened between 2006and 2008, introducing a strong bias in the 2003-2008 trend, that was estimated to be 2.5 +/−0.4 mm/yr.
Now that such La Niña is over, the new Jason-2 data shows the value of 3,3 mm/yr for total(altimetric)SLR that I used in the above calculations.
A link to updated altimetric SLR trends:
http://www.cmar.csiro.au/sealevel/sl_hist_last_15.html
Regards,
From Lima, Peru
Anonymous from Lima, Peru (9:05PM): Refer to the steric sea level graph in von Schuckmann et al (2009). It's cell c of Figure 11. Please describe from that graph how the La Nina impacted steric sea level between the end of 2007 and the end of 2008. I don't see what you're claiming.
Regards
You asked me:
"Please describe from that graph how the La Nina impacted steric sea level between the end of 2007 and the end of 2008"
Well, there is a fall in (total)Sea Level at mid-late 2007 that is likely the result of La Niña.
This could be caused by either:
1)transient cooling that cause a reduction in thermo-steric SL
2)Increased rainfall in La Niña events that causes mass transfer from the Global Ocean to the Global Land.
Whatever the cause for late 2007 Sea Level drop, my point is that the 2007-2008 La Niña biased the value of TOTAL SLR trends, giving a misleading value of 2,5 mm/yr for the period 2003-2007 that is used in the Cazenave et al paper "Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo"
When UPDATED TRENDS OF SLR (until September 2009) are used, we have values around 3.2 mm/yr in altimetric SLR.
After using this data one gets the numbers calculated above for thermo-steric SLR trends, that are quite consistent with the Von Shuckmann ones.
Anonymous from Lima, Peru: If you were to exclude the 2008 data from von Schuckmann so that you were comparing the same time period as Cazenave, would the von Schuckmann trend drop down into the ranges of the other papers?
Anonymous from Lima: The point I was trying to make with my earlier question about deleting the 2008 data from von Schuckmann is this. If I can use the NODC OHC data as an example, the additional variations due to the switch from a significant La Nina makes no difference to the linear trends. Here’s the linear trend from 2003 to the end of 2007:
http://i45.tinypic.com/2who2vn.png
And here’s the linear trend from 2003 to the end of 2008:
http://i45.tinypic.com/97l1ds.png
The change from the strong La Nina had no influence.
You said:
"The point I was trying to make with my earlier question about deleting the 2008 data from von Schuckmann is (...)
The change from the strong La Nina had no influence."
I did NOT said that after deleting the Oceanic Heat Content data after 2007 there will be a strong influence in the OHC trend.
I was talking about SEA LEVEL RISE.
And to make it more clear, NOT THERMO-steric SLR but TOTAL(altimetric) SLR.
The the Cazenave et al. paper "Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo" uses a TOTAL sea level rise of 2,5 mm/yr.
And is this value(2,5 mm/yr) that was affected by La Niña. As I said before, this could be caused by:
1)transient cooling that cause a reduction in thermo-steric SL
2)Increased rainfall in La Niña events that causes mass transfer from the Global Ocean to the Global Land.
You, as Von Shuckmann did also, found no great influence on OHC from the 2007-2008 La Niña. This rules out the possibility 1) above leaving us with the possibility 2) above.
Whatever the cause is, the SLR value of 2,5 mm/yr used in the Cazenave et al. paper is OBSOLETE, as new measures show a rebound in SLR after the 2007-2008 La Niña, so the trend has returned to the "old" value, near 3,2 mm/yr.
And when you follow the Cazenave method of substracting the ocean mass SLR from the Cazenave paper(between 2 mm/yr and 2,2 mm/yr)from the Total(altimetric) SLR, we have, as I done above, a thermo-steric SLR between 1 mm/yr and 1,5 mm/yr.
And this is consistent with the Von Shuckmann value around 1 mm/yr (Actually Von Shuckmann maybe slightly UNDER-estimated thermo-steric SLR).
I hope to have clarified my line of reasoning. By the way, you could repeat the "post-2007 truncation" using TOTAL (altimetric) SLR data to show how the 2007-2008 sea level transient dip skewed the SLR trend downwards, and how that effect now have disappeared.
Regards,
From Lima, Peru.
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