Continued cool, cool summer here in Illinois. But I understand it’s been hot elsewhere. And it’s time to bet on August UAH.
Note: I did a periodic update and reorganization of the banning software last evening. I’m also implementing some new checks on “post” and “query” strings limiting the number of ‘post’ variables. I guessed ’10’ would be safe maximum. Turns out.. uhmmm… no… I needed 11 for comments. This has affected at least one commenter (probably in the south east of the US. Could be Florida. . .) I unbanned that one.
Bet submissions also involve ‘post’ and ‘query’ strings. I’m tested the betting script out by entering a few insane bets. It seems this script requires at least 14 post variables, I’m setting the limit to 15 post variables. If it turns out that for some unforseen reason and you get caught: remember my email lucia at …. rankexploits.com! Email me and I will unbann. Or click the email link in the warning screen the first time you see it and let me know. (Do not think, “Oh. I’ll just try again. Maybe the ban screen won’t show up. It will. If you try three times, you’ll get banned at Cloudflare. I’ll still unban you. But it’s easier if you just email me and I fix the rule.)
[sockulator(../musings/wp-content/uploads/2011/UAHBets5.php?Metric=UAH TTL?Units=C?cutOffMonth=8?cutOffDay=30?cutOffYear=2013?DateMetric=August, 2013?)sockulator]
Cut off: midnight 8/29
speaking of coolth in the MW, maybe in his spare time mr. mosher could gin up a figure like this one for 2013:
http://curryja.files.wordpress.com/2013/08/presentation2.jpg
Dear Lucia
Please can you help and sorry to trouble you.
I was sent the following link from Skeptical Science which gives emperical evidence of global warming. Playing of course foot loose and fancy free with the word emperical. The person who sent it is a decent human being and I don’t want to respond by dissing cook.
http://www.skepticalscience.com/empirical-evidence-for-global-warming.htm
If you can help it would be very much appreciated and I understand you have better things to do.
By all means reply by email if you don’t want to clog up your blog.
Best regards
Stuart
Stacey,
You addressed to Lucia of course, but to butt in with my two cents, gpwayne’s article is correct. The basics of the greenhouse effect and warming aren’t widely disputed. There is a group (principia scientifica) which does dispute this, but they are wrong, to put it plainly.
What gpwayne isn’t telling you is that this is the basic effect which I’m told only results in an increase of about 1.2C per doubling of CO2 in the atmosphere. This is not generally disputed either. We’ve got good evidence to suggest we were around 280’s in preindustrial times / circa mid 1800’s, we are at about 400 ppm today, we increase by about 2ppm per year in modern times.
1.2C isn’t generally believed to be much of a concern. It’s the feedbacks that make the problem interesting. The mainstream view is that this 1.2C increase will cause positive feedbacks, such as increased humidity / high clouds. Some hold that more methane will make its way into the atmosphere, further enhancing the effect. Etc. A variety of mechanisms are postulated. The positive feedbacks are supposed to result in a temperature increase that is larger than 1.2C per doubling of CO2. 2-4.5C? More? The evidence here is less solid, and in my opinion this is what the argument really is about. Well, this and what if any policies to adopt.
Hope this helps!
Test to see if rule is overstringent. ( ). Add more ( ). test yet again ( )
lucia,
JAXA hasn’t updated for three days now. What’s the rule again for the seven day moving average if there’s bad data?
I noticed that JAXA hadn’t been updated too.
As the minimum is unlikely before September 9th, it shouldn’t be a problem unless the lack of data continues until early September.
In 2002 there seemed to be a gap in data between Sept. 12th and 21st, so let’s hope that doesn’t happen again.
DeWitt–
I think the rule is I compute the minimum over whatever is reported. No filling, nothing. But I’ll have to look back and check!
(More unsolicited opinion regarding the SS link)
I read the link and came upon:
“Like a detective story, first you need a victim, in this case the planet Earth: more energy is remaining in the atmosphere.”
(Ignoring, for the moment, the value judgment implied by ‘victim’ )
This is the basis of ‘climate change’ theory and has an understood causal factor in longwave radiative forcing, which probably does apply, at least to some extent.
But it is important to recognize that the best available measurements
do no corroborate the claim – in fact they contradict it!
Here is an graph of the ‘Outgoing Longwave Radiation’ (OLR), globally averaged:
http://www.climate4you.com/images/OLR%20Global%20NOAA.gif
described here:
http://www.climate4you.com/GlobalTemperatures.htm#Outgoing%20longwave%20radiation%20global
Notice that the recent amounts of OLR are at a thirty year high – this is not consistent with the earth retaining more energy.
Now, there is good reason for doubt about these measurements.
They come from numerous different satellites over three decades with different radiometers, and different calibration and degradation issues. The earliest measurements appear quite high and the spike in 1994 is troublesome.
But it is the best long enough global measurement that we have.
Further, that’s just the longwave radiation which is the easy one to measure because it is much closer to isotropic ( the same in all directions ).
Shortwave radiation ( the net of what’s reflected by earth – albedo ) is deemed immeasurable because it is anisotropic ( differing in direction depending upon solar angle, cloud component, etc. etc. ).
The models assume albedo hasn’t varied significantly, but the truth is no one knows and existing estimates just for present albedo vary by twice the amount of forcing that is modeled for greenhouse gas increase.
Like the Monty Python skit about using explosives to cure athletes foot:
“eighty-four dead, sixty-five severely wounded and twelve missing believed cured.”, the models treat albedo as: Unknown, believed constant.
For all the pronouncements, the observations of net energy are probably not good enough to prove ( or dis-prove ) global warming.
Climate Weenie,
Oh. Well, two things:
1) Yes, I think you’re right. I’ve read that TOA satellite measurements aren’t exact enough on the absolute scale to conclusively tell us the outgoing radiative budget. The ‘extra’ energy might not even be there in the first place as far as this evidence is concerned.
2) On the other hand, I thought I’d looked at a paper at some point that measured longwave / IR back radiation (over the oceans someplace if memory serves) that was persuasive to me.
Good point.
Still, I think it’s barking up the wrong tree to argue the basics of the GHE, even if the empirical data leaves something to be desired. But that’s just my opinion.
Not disputing the measurable.
But pointing out that “more energy is remaining in the atmosphere” has become axiomatic, not verified.
l_c (Comment #118811)
“speaking of coolth in the MW, maybe in his spare time mr. mosher could gin up a figure like this one for 2013”
You can get to it here, though it’s based on GHCN, not BEST. Yes, plenty of cool in the MidWest – also in the Arctic.
Mark writes “Still, I think it’s barking up the wrong tree to argue the basics of the GHE, even if the empirical data leaves something to be desired.”
Its all about the feedbacks. There is nothing that fundamentally says they cant be negative so that the overall warming is negligible (ie less than the ~1.1W/m2 that CO2 itself imposes)
TTTM,
I agree.
Well, not that I’m aware of. I think Steven Mosher has said this is impossible, but if he’s explained why I’ve never understood the explanation. Not saying Mosher is god or anything. Still at minimum there’s an argument about this I haven’t heard or understood.
I think many if not most people here on the Blackboard would agree with Steve on that.
I, however dont agree and offer the negative feedback of increased evaporation for increased DLR with all other things being equal including atmospheric and ocean temperatures.
To my knowledge nobody has disputed that and so their “positive feedbacks” vs my “negative feedback” becomes instinct. Or you may want to rely on model output to guide your decision. Again I think many if not most on the Blackboard do that and again I dont agree.
TTTM,
Again, I agree; it’s one of the reasons I say I’m a dirty no good gosh darn skeptic instead of a lukewarmer. That there are arguments I don’t know doesn’t mean much except that there are arguments I don’t know, I guess. Maybe it was a pointless observation. I just try to stay aware of my potential for error. 🙂
Re: TimTheToolMan (Aug 21 20:39),
Sure, if you had no idea what they were. But by and large, we do know. The major negative feedback is the Planck response where emission increases with temperature. Another negative feedback would be the lapse rate. A decrease in lapse rate increases TOA emission for the same average temperature. But those are included in current calculations. The lapse rate won’t change unless the humidity goes up. The absorption of water vapor more than cancels out the lapse rate feedback so the net effect is positive rather than negative.
For the overall feedback to be negative, you would have to find a new negative feedback that’s large enough to overwhelm the known positive feedbacks. The only thing that might qualify would be cloud albedo. That has been looked at, though, and it doesn’t seem to be enough. Cloud albedo, btw, is the mechanism for the cosmic ray climate change hypothesis. That remains unproven, to put it tactfully.
DeWitt writes “Sure, if you had no idea what they were. But by and large, we do know.”
But you never even mentioned the cooling effect on the ocean due to increased evaporation due to increased DLR. Nobody ever seems to mention it…
DeWitt,
I basically agree with you too, but:
Lest we start to feel undue confidence in our mental model of the system, remember that our GCMs run hot. And I don’t think it’s because the models are crap, far from it. I think the models probably reflect our best effort to compute what’s going on. If there’s a problem with the GCMs, one possible explanation is that there is a problem with our understanding of the system.
To me this implies we ought to be careful of assuming we’ve got this nailed.
Re: TimTheToolMan (Aug 22 07:18),
Nobody mentions it because it doesn’t happen. Shining a heat lamp on a pan of water doesn’t cool the water. That being said, it’s not at all clear that changes in the relative proportion of heat transfer from the surface to the atmosphere and then to space by convection vs radiation is modeled correctly. As I remember, the models with the lowest sensitivity have the largest increase in precipitation with temperature. But again, this is a known feedback.
Good point. I have this tendency to think of the multi-model mean and forget that there are individual models there, and that some perform better than others with respect to some metrics. Thanks.
DeWitt writes “Nobody mentions it because it doesn’t happen. Shining a heat lamp on a pan of water doesn’t cool the water.”
But DLR and a heat lamp are entirely different. A heat lamp is adding additional energy but DLR is recycling the ocean’s energy. I bet adding the heat lamp increases evaporation though. Especially if it was in the 15nm range…
I dont think I’m being particularly clear on this point actually.
The heat lamp analogy still works because if the heat lamp were adding say 1W of energy to the surface of the ocean then some of that energy would warm the ocean and some would cause additional evaporation idependently of all other factors.
So overall less than 1W is warming the ocean and ideed the ocean loses additional energy as a result of that evaporation. Thats the negative feedback and why I think we cant say that 1W of DLR definitely feeds back to greater than 1W of forcing.
TTTM,
Woa. Latent heat (due to ocean surface evaporation) is still energy in the system, just as is warming of the ocean. These things do not represent feed-backs at all, at least not by any commonly understood meaning of the word ‘feedback’. They represent only a transformation of energy from one form (DLW radiation) to others. An increase in clouds, leading to higher albedo, due to greater ocean surface evaporation, would be a negative ‘feedback’, as that word is commonly used.
.
Unfortunately, higher water vapor also adds to opacity of the atmosphere in the infrared, and increased clouds at night reduce loss of infrared to space (compared to a cloud-free sky), so there are opposing factors associated with increased ocean surface evaporation. The data are not good enough to say for sure which is more important, though claims that increasing clouds are a net positive feedback are very uncertain (see Troy Master’s paper showing that Dessler (2010) cherry pick… er…. ‘carefully selected’ the data used (‘reanalysis data’… it’s models all the way down) to ‘prove’ clouds have a positive net feedback. Masters shows that most actual data (not reanalysis) suggest the opposite is true, but it is still an open question. The reality of slower warming does tend to cast doubt on the accuracy of climate models, and climate models almost uniformly treat clouds with a net positive feed-back, and a strong one for many models. My expectation is that when modelers are forced by reality to revise their models’ sensitivities downward, it will be the strong net-positive cloud feedback which is adjusted to bring the model projection back in line with reality.
SteveF writes “Woa. Latent heat (due to ocean surface evaporation) is still energy in the system”
Its a negative feedback to surface warming. The latent heat in the water vapour on the whole bypasses the lower atmosphere and reappears much higher up. So, AGW is about surface warming and this reduces the surface warming.
TTTM,
” So, AGW is about surface warming and this reduces the surface warming.”
Pielke Sr. suggests that accumulation of heat in the oceans/atmosphere is a fair definition of global warming. I agree with him. You can of course make up your own definition for feedback.
I’ve written “Its a negative feedback to surface warming.”
To be fair perhaps calling it feedback isn’t the right use of the term but its certainly a process that removes energy from the surface and moves it higher into the atmosphere and more DLR means more energy is moved all things being equal.
It is my opinion that when people think about DLR at the surface, they’re generally fixated on land and not ocean. That is a mistake IMO because the ocean behaves quite differently.
SteveF writes “Pielke Sr. suggests that accumulation of heat in the oceans/atmosphere is a fair definition of global warming. I agree with him.”
Right. But if CO2 causes say 1W of DLR and the ocean warms by say 0.4W then that is less than the 1W you started with. That is not a positive feedback situation is it.
TTTM/SteveF,
So wouldn’t sea level rise be a good proxy for heat in the climate system (atmosphere, glaciers, ocean). Not a feedback metric per se, just a plain old response to a forcing. Just wondering?
TTTM,
What you are suggesting makes sense if you want to try to do a surface energy balance. Evaporation is a sort of feedback. (Ramanathan wrote out the equations for this back in 1981, and they are still good today.) However, most energy balances are done at top-of-atmosphere (TOA), and the normal canonical form of feedback as used by the IPCC relates to the rate of change of the TOA restorative flux with respect to a change in the surface temperature.
Using this canonical form, you do not need to know why the surface has achieved a certain temperature, only that it has done so, and this then determines the change in outgoing TOA flux. This is why a TOA balance typically doesn’t need to include any terms for DLR, evaporation etc, but a surface balance does.
AJ,
My two cents worth – it’s pretty difficult.
If I recall correctly, there are 5 or 6 things controlling sea level.
Temperature, time variation in temperature distribution, time variations in salt content, time variations in oceanic water mass (river systems, ice melt, man-made retained water, bio-retention and (small) atmospheric variation, groundwater variation), isostatic rebound, depositional changes to coasts.
Measurement is very difficult and the various elements need to be reconciled.
AJ writes “So wouldn’t sea level rise be a good proxy for heat in the climate system (atmosphere, glaciers, ocean). Not a feedback metric per se, just a plain old response to a forcing. Just wondering?”
Yes. But its not about whether energy is accumulating, I think it is.
Its about whether we can expect a doubling of CO2 (ie 1.1W/m2 forcing) to manifest as an accumulation of more than 1.1W/m2 (ie positive feedback) or less than 1.1W/m2 (ie negative feedback)
Conventional wisdom has it as quite a strong positive feedback and the “off the cuff” reason given is increased water vapour means even more DLR and hence more warming but I think this is false reasoning.
Regarding feedbacks, I think it is not too important just yet if they are positive or negative. The important problem is we don’t know what the sign is. And it is a travesty that we don’t. Observed response to date is the current pause shows no end in sight and demonstrates either the alarmists are wrong about feedbacks or the alarmists are ignorant of and unaware of something important.
The other side of the travesty coin is there are those who reflexively adopt the precautionary principle without so much as a nod to cost nor to giving serious consideration to the costs of undoing any damage they create should they be wrong. If you’re going to knock the pins out from under the global economy it is in accordance with the precautionary principle to take out an insurance policy, just in case.
We know what the cost is for for them thinking they’re right and we can’t afford it. What will it cost to undo decades of alarmist policy if they are proved beyond dispute to be wrong?
I have contacted JAXA and normal service has now been resumed with no apparent gaps in the figures.
Paul_k writes “However, most energy balances are done at top-of-atmosphere (TOA), and the normal canonical form of feedback as used by the IPCC relates to the rate of change of the TOA restorative flux with respect to a change in the surface temperature.”
I agree. The thing is that the actual measurements aren’t good enough to actually establish the TOA energy flux. They’re way off. So its assumed to be allowed to be derived from the measured OHC and that in turn is assumed to be “caused” by increased DLR due to increased CO2.
So my main problem is that at every turn CO2 is assumed to be the cause for observed warming and feedbacks are assumed to make up the shortfall because they need a cause and “unknown” isn’t valid in a model.
TTTM,
I stated above that latent heat transfer is included in the surface energy balance and it does affect the climate sensitivity. The surface temperature is several degrees cooler than it would be if latent heat transfer didn’t exist. But it isn’t being ignored as you seem to claim. There is uncertainty about how much latent heat transfer will change for a given change in surface temperature, but it can’t possibly change anywhere near enough to eliminate the increase in surface temperature from an increase in DLR, i.e. 100% negative feedback.
DeWitt writes ” But it isn’t being ignored as you seem to claim.”
Well I think it is. Remember I’ve been talking about whether feedbacks are positive or negative and the reasons for believing positive don’t include discussion of this negative feedback.
I have different reasons for being sceptical about them in models but I don’t doubt the effect exists in there to some degree of parametrised simplification.
Re: TimTheToolMan (Aug 23 15:52),
So far, all you have given us is your opinion and some hand waving. Increasing DLR by itself doesn’t increase evaporation, increasing temperature does, at least until the humidity stabilizes. The feedback is total precipitation. This is a subject of ongoing research. If total precipitation increases with surface temperature, then there will be some negative feedback. But that’s a fairly big if. The average specific humidity of the atmosphere could increase without an increase of total precipitation.
There’s very little total water vapor in the atmosphere and the lifetime is very short so it equilibrates rapidly. If there were a large increase in precipitation with temperature, we would have seen it by now. The evidence, therefore, is that the increase, if any, is small and so the resulting feedback is small too.
DeWitt writes “Increasing DLR by itself doesn’t increase evaporation, increasing temperature does”
This is where I fundamentally disagree with you. DLR is absorbed into the top 10um of the ocean’s cool skined surface. With everything else being equal, how can it possibly not increase evaporation?
and then “If there were a large increase in precipitation with temperature, we would have seen it by now.”
But there only needs to be a small increase as the latent heat of vaporisation is, itself large. Measuring the precipitation isn’t easy as its particularly weather dependent. I think it could take quite a while to get enough data to see it. That is another arm waving opinion by the way.
DeWitt writes ““Increasing DLR by itself doesn’t increase evaporation, increasing temperature does—
I thought it was worthwhile giving a little empirical evidence of my statement. Humid, muggy days are cloudy ones. Cloud increases DLR enormously (100W/m2 or so)
Trenberth’s heat budget helps here. Globally, the surface gains 161 W/m2 SW, and 333 W/m2 via DLWR. At sea, the SW is absorbed at depth, but almost all has to come back through the surface. To balance, 80 W/m2 is lost as LH and 396 as LWR, (and 17 as convection). Ocean probably has a bit more LH and less LW.
Both upward losses are temp sensitive, and the temperature adjusts to balance the fluxes. If DLWR rises, both upfluxes will increase to balance. The LH probaby takes a greater share, because the Clausius-Clapeyron increase is relatively faster than S-B.
Note that while some people say the opacity of water to IR blocks absorption, in fact the surface layer is a nett emitter.
Nick Stokes,
“At sea, the SW is absorbed at depth, but almost all has to come back through the surface.”
.
Well, I guess that depends on what you mean by “almost all”. There are probably about 10 W/M^2 which go toward warming upwelling abyssal water (on the order of 4 meters per year of rise globally averaged below ~40N/S). The interesting thing (well, interesting to me) is that the depth of the bottom of the well mixed layer ought to represent the ‘cut-off’ depth where all SW solar energy absorbed above that depth goes back to the surface via convection, and SW solar absorbed below that depth (that is, whatever SW solar energy reaches the top of the thermocline) goes into warming of upwelling cold water at greater depths. This should be evident in the shape of the temperature profile between the bottom of the well mixed layer and the top ~100-200 meters of the thermocline.
Re: SteveF (Comment #118942)
I’m a bit unclear on what should be “evident” here. Are you saying that SW absorbed in the ML communicates with the surface because it’s the ML, and SW heating that penetrates below has to find some other way (besides ML convection) to return to the surface?
Oliver,
No. I am saying that heat lost at high latitudes (producing cold abyssal water in regions of deep convection) must be “replaced” when that water upwells and warms at lower latitudes. That is, some solar energy (on the order of 10 watts per square meter on average) at low latitudes warms upwelling water to the temperature of the well mixed layer.
.
This energy does not “escape” from the local surface of the ocean, it is transported by surface currents to high latitudes, where it is lost to space. So a heat balance at low latitudes needs to include the energy used to warm that upwelling water. WRT ‘evident’: Were the ocean opaque to SW solar energy, there would be no clearly defined well mixed (thermally convective) layer with a thermocline below it… there would just be a fairly steep drop in temperature with depth starting quite close to the surface. The portion of solar energy which passes the bottom of the well mixed layer (nearly all blue, violet, and UV) declines exponentially in intensity with increasing depth, so the rate of solar warming below the well mixed layer must also decline exponentially with depth (the first derivative of an exponential is an exponential). Therefore, the slope of the temperature change (below the WML) with depth at lower latitudes ought to gradually become steeper as the residual solar intensity declines, reaching a maximum steepness some distance below the well mixed layer (maybe ~100 meters below the base of the well mixed layer), followed by a return to the expected nearly exponential shape by ~200 meters (becoming less steep with increasing depth).
Re: SteveF (Comment #118944)
I’m pretty sure this is not true. First of all, nocturnal cooling at the surface could trigger convection even without SW penetration. Secondly, the mixed layer depth is not set solely by thermal convection (as we have discussed in the past).
Is this what would happen, hypothetically, in an opaque ocean?
SteveF,
“Well, I guess that depends on what you mean by “almost allâ€.”
Well, it could mean all but 10 W/m2, if that’s the amount that goes into a deeper transport mechanism. But even that still comes up somewhere (unless it goes “missing”). This was a global average budget.
“Were the ocean opaque to SW solar energy, there would be no clearly defined well mixed (thermally convective) layer with a thermocline below it… there would just be a fairly steep drop in temperature with depth starting quite close to the surface. “
I think that over-rates the stillness of the ocean. Here is an animation of the motion forced by waves. It goes quite deep, and far exceeds thermal convection. Here is a map of mixed layer depths. It’s deepest in winter in cold wavy places.
From your second like Nick, it looks like large scale overturning (in Winter) is the main driver for mixing.
I would think that the colder the surface gets, the deeper the overturn.
Must go lower, must go lower, more ice everywhere. Will go for negative when total ice over zero 2 months in a row.
Is the re freeze starting fingers crossed
Re: TimTheToolMan (Aug 23 17:24),
You have it exactly backwards. The humidity causes clouds as the humid air reaches the lifting condensation level. Also, while cloud cover increases DLWR, it reduces DSWR. This gets into the problem of whether clouds are a negative or positive feedback. If DSWR is reduced more than DLWR is increased, then clouds are probably a negative feedback and vice versa.
Re: Nick Stokes (Aug 23 20:24),
CC determines, as it were, the size of the bucket, i.e. the total volume of water in the atmosphere. It’s not at all clear that the flow through the bucket, total precipitation, will increase once the atmosphere equilibrates to the new temperature. Which, as I pointed out above, is quite rapid. Latent heat transfer and total precipitation are intimately linked. You can calculate one from the other.
As I remember, you can initialize a GCM with zero atmospheric humidity and the humidity equilibrates within a few weeks. Total precipitable water amounts to only about one inch of liquid water globally.
DW ‘Total precipitable water amounts to only about one inch of liquid water globally’
“The average annual precipitation of the entire surface of our planet is estimated to be about 1050 millimeters per year or approximately 88 millimeters per month.”
Pidwirny, M. Global Distribution of Precipitation. Fundamentals of Physical Geography, 2nd Edition. 17 April 2008.
http://hypertextbook.com/facts/2008/VernonWu.gif
average for land is 1.5 meters per year and for the oceans its 1.1 meters per year.
River pump 3.7*10^13 m3 or 37,000 cubic km or fresh water into the oceans every year.
Peixoto, J.P. and M.A. Kettani. “The Control of the Water Cycle.” Scientific American. Vol. 228, No. 4 (April 1973): 46-61.
http://hypertextbook.com/facts/2008/VernonWu.shtml
Re: Nick Stokes (Comment #118946)
Note that the example is quite “exaggerated” to show the particle orbits — the wavelength is stated to be twice the water depth. If you look closely at the wave motion, you may notice first of all the exponential decay of velocity from the surface down. In the real ocean this length scale tends to be more like tens of meters, which is definitely NOT beyond the reach of convective overturning.
Also notice that the particles end up nearly where they were before at the end of each cycle — that is, there’s very little to no “rearrangement” of particles (especially in the vertical).
Cold wavy places are also cold windy/stormy places, which tends to be associated with, e.g., Ekman pumping, strong mixed layer motions/shear instability at the ML base and frontal features.
DeWitt writes “You have it exactly backwards.”
I dont think I do. The humidity I’m talking about is at ground level, not cloud level. I have no doubt the evaporated water vapour adds to the clouds, no doubt at all.
But you just dont get particularly humid days that aren’t cloud covered and with your reasoning of cause and effect, particularly with respect to timing, …you should.
Re: DocMartyn (Aug 24 07:19),
The amount of water in the atmosphere, specific humidity/total precipitable water, at any given time, and total annual precipitation are two different things. The average lifetime of a water molecule in the atmosphere is about 9 days.
DeWitt writes “You have it exactly backwards.â€
Just to add to my previous comment, my experience is that the most humid days of all (ie greatest evaporation) is where its a hot day obviously and there is thin high level cloud that the sun can still get through.
Clearly the evaporation didn’t cause that humidity and then form those high level thin clouds. Cause and effect (in my mind at any rate) is quite clear on this and I’m also confident on the physical mechanism.
Re: TimTheToolMan (Aug 24 09:01),
But then you’re talking more about DWSR, than DWLR. Total downwelling solar radiation in minimally cloudy conditions peaks at about 1,000 W/m². That’s a lot higher than the DWLR. Thin clouds mainly change the ratio of direct to diffuse solar radiation.
As Nick Stokes pointed out above, that 10 μm water surface layer is a net emitter of radiation. The heat transfer by radiation is upward, not downward because the effective temperature of the atmosphere is almost always lower than that of the surface. Increasing DLR reduces net emission so the surface layer warms from below, not above.
Oliver,
If the ocean were opaque to solar SW, then the only penetration of heat would be due to physical mixing… continuously opposed by bouyancy of the warmer surface layer. This is a qualitatively different situation from a transparent ocean, where much heat is deposited well below (tens to hundreds of meters) the surface. The nocturnal overturning results mainly from daytime heat deposition below the surface. There would be a very shallow nightime overturning of course, but most of the driving force for overturning would disappear absent solar penetration. You correctly point out to Nick that wave motion disappears rapidly with depth.
DeWitt Payne (Comment #118950)
“CC determines, as it were, the size of the bucket,”
It also affects the rate. The sea maintains a layer of saturated air near its surface, which the wind advects away. The amount advected depends on the moisture content of that layer, though the dryness of the wind ls also a factor.
DeWitt writes “As Nick Stokes pointed out above, that 10 μm water surface layer is a net emitter of radiation. The heat transfer by radiation is upward, not downward”
I’ve pointed this out myself on many occasions and am fully aware the ocean is always cooling through its cool skin. I agree that despite the additional say 100W of DLR from the clouds, the net IR is still upwards.
Think of the effect of the clouds as concentrating energy at the surface. All the ocean’s energy leaves through the surface but with clouds, more of the energy that has leaving is radiated back towards the ocean. And it lands right on the top 10um to enhance the evaporation.
Just a quick interlude to point out that TroyCa has a new post up Points where I don’t find Andrew Dessler’s >2C ECS video to be convincing.
Lead in paragraph:
Carrick,
Thanks for the link. Troy’s analysis is spot on: Dessler’s papers carefully note that there is vast uncertainty in cloud feedbacks, but most of his public pronouncements are another story….. little or no mention of uncertainty, but endless haranguing on the absolute need to cut fossil fuel use immediately. Andy’s act quickly grows tiresome, even if you ignore the fact that he is probably wrong.
Heat in, heat out.deep oceans no heat in, a bit like 2 kilometres under the crust.
Surface temps , land and water temps vary up and down in a range reflecting the solar input.
Yes There are variations but over the time scale of human life these are minuscule. Speaking of forcings of 2 degrees lasting for any length of time is pointless.
The more heat in the more out until it balances again around the mean.
It doesn’t stay in the deep ocean it cannot get into it and any mixed heat at the ocean surface layers works itself back to the surface and out very quickly.
Re: SteveF (Comment #118968)
Sure. Without radiative transfer you’d need physical motion.
SW penetrates well below the surface, but the (nominally) exponential heating profile tells you that the surface is actually heated more by solar heating than the underlying water. That means solar heating actuallyenhances the stable stratification during the daytime. It’s surface cooling at night that triggers stronger penetrative convection and the “unloading” of the diurnal jet.
I suppose you could say that, without SW penetration, the underlying water would be less warm and thereby support less convective deepening after sunset. Maybe the fact that the ML is deeper as you go poleward suggests that the underlying water would be warm enough anyway (due to poleward heat transport), relative to the surface temperature.
Oliver,
“Maybe the fact that the ML is deeper as you go poleward suggests that the underlying water would be warm enough anyway (due to poleward heat transport), relative to the surface temperature.
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The deeper ML at higher latitudes is a seasonal effect, and has nothing to do with nocturnal overturning at lower latitudes. There is summertime stratification even at very high latitudes. The resultant surface warming disappears the following winter with re-establishment of the deep ML, characteristic of high latitudes, during winter.
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All I am saying is that
All I am saying is that absorption of solar energy below the ML should define the shape of the transition between the ML and the thermocline. Any low latitude heat balance needs to include heat ‘used’ to warm upwelling water.
SteveF, OLiver, DeWitt, etc. What in the ocean water is absorbing the large amount of visible and UV light that impinges and penetrates? Biological organisms (algae, plankton)? Oxyanions? There must be very weak absorptivity to allow such a long pathlength.
Owen,
If there is a lot of biological absorption then the penetration depth can be very small, sometimes less than 10 m. The 150-m scale only happens if there’s not much but the seawater itself.
Owen,
Water, like all “clear” materials, absorbs light. The rate of absorbance depends on wavelength, with very low absorbance in the violet (and near UV), and much stronger in the red. Which is why a swimming pool with a white bottom looks very blue. Search for “visible absorbace spectrum water” with Google.
Re: Owen (Aug 25 16:56),
If you go here ( http://www.lsbu.ac.uk/water/vibrat.html ) and scroll down to near the bottom there is a graph of the absorption spectrum of water. Note that the range of absorption is greater than 10^10 from less than 10^-4 at the minimum in the near UV at about 400 nm to 10^6 at about 60 nm wavelength. But there is nothing that is perfectly transparent, perfectly reflective or even perfectly absorptive. You can have zero transparency, but there will always be some reflectivity.
There’s a course on underwater photography that has a nice section on this too. Link.
Oliver, Steve, and DeWitt, Thanks for your responses. I especially appreciate link to the absorption spectrum of liquid water. Working with standard 1-cm cuvettes I had always considered water to be totally transparent to visible light. What a difference a long pathlength makes. Those very low absorptivities make possible the deep penetration of light energy.
The Earth’s surface temperature is driven by the surface energy budget. Heat exchange at the surface is multimodal and cooling of the surface is mostly non-radiative, with evaporation dominating (in average). Atmosphere has an insulating effect, but it’s the bulk of the atmosphere (N2 and O2) that insulates, because it cannot radiate to space significantly. The so called GHGs are the atmospheric coolants.
http://science-edu.larc.nasa.gov/EDDOCS/images/Erb/components2.gif
Re: Edim (Aug 28 04:59),
CO2 does a really good job cooling the atmosphere of Venus. /sarc
That cartoon you link is only part of the energy budget at the surface. This one is a little more realistic because it includes downward long wave emission to the surface as well as upward to space although the details of the incoming solar energy budget are slightly different.
I am a bit puzzled as to why I am shown as having two identical bets, the first of which is cancelled. As I recall, I only placed a single bet. I notice that a few others are in the same position.
Here is my analysis of this month’s betting. I have excluded the four highest temperatures as they are probably errors and including them makes the figures a bit meaningless.
The resulting mean is only marginally lower than the figure for July, although a small majority are betting on a lower figure and the median is lower.
NO. OF BETS 45
MAX 0.408
MIN 0.012
MEAN 0.169
MEDIAN 0.145
STD DEV 0.093
MEAN 1-23 0.165
MEAN 23-45 0.174
MEAN PLUS 1 SD 0.263
MEAN MINUS 1 SD 0.076
WITHIN +/- 1 SD (%) 71.11
ABOVE MEAN (%) 44.44
BELOW MEAN (%) 55.56
DeWit, how do you know it doesn’t? The carton I link is complete. Upward LW minus downward is the net LW, which is upward in average.
Ray
Something must have doubled entered for some reason. Gremlins?
Re: Edim (Aug 30 06:24),
Without the gross fluxes, you have no idea of the magnitude of the surface temperature. A net flux energy flow diagram of Venus would show only a few W/m² of solar energy reaching the surface. You would have no idea that the surface temperature could melt lead or why it was that high.
According to latest JAXA data, there was a gain of 37,813 square km on August 29th, which seems to be the largest daily gain before September 12th, since at least 2002.
However the 7 day mean still fell by over 40,000 square km.
Oops, meant 0.0913