Guest Post by Willis Eschenbach
Since the late Nineties the US has had seven industrial-strength stations that measure a variety of climate variables every minute, 24/7. These are called “SURFRAD” stations. As a data junkie I’ve been wanting to look at their results for a while … but the data is in an ugly format. They have a single data file for each station for each day of the last 17 years … not my idea of a party.
Anyhow, I finally bit the bullet and downloaded a year’s worth of data, about a quarter of a gigabyte. For no particular reason I picked the SURFRAD station in Goodwin Creek, Mississippi, and the year of 2010. For each minute they have no less than 21 different measurements (see end notes) … so I sorta started digging around in the data to see what stuck out. Here was the first oddity I came across:
Figure 1. Average 10-metre surface air temperature (black, °C) and average downwelling infrared radiation (blue, W/m2) for the year 2010. Measured at the SURFRAD station in Goodwin Creek, Mississippi. Average covers the entire year, and is shown repeated twice (two days) for clarity.
I don’t know why, but I wasn’t exactly expecting that … which is the best part of science. I love surprises, the unexpected, and climate science is chock full of those. I mean, I knew that downwelling radiation was a function of air temperature … I just didn’t expect the alignment with the underlying surface temperature to be so exact. Other than the atmosphere starting to cool a bit earlier in the day than the ground (as we’d expect from the relative masses) they match up perfectly.
Now, seeing how good that match was, I got to wondering how well that fits the theoretical profile that we’d expect from the Stefan-Boltzmann (S-B) relationship. This relationship says that infrared radiation is equal to emissivity times the Boltzmann constant times the temperature to the fourth power. I figured that using that formula, I could calculate an approximate value for the emissivity from the data with a simple linear analysis.
Now, here’s the curious part. When I did that, I got an emissivity of 0.590 … which from everything I’ve read is too low.
So I thought, well, that kinda makes sense, because the temperature up where the radiation is coming from is cooler. But how much cooler? That depends on what altitude the radiation is coming from. Now my bible in these matters is “The Climate Near The Ground”, by Rudolph Geiger, which anyone interested in climate science should read. Geiger gives the following table for downwelling radiation (called “counterradiation” in those days):
Table 5-1 Contribution of various atmospheric layers to counterradiation received at the surface Layer thickness (m) % share of counterradiation 87 72.0 89 6.4 93 4.0 99 3.7 102 2.3 108 1.2
I figured that I could use that to give me at least a first cut at the temperature of the overlying atmosphere at altitude, using the lapse rate of one degree C per each hundred metres of altitude. For the six layers given by Geiger, this gives mid-layer temperature drops of 0.4°, 1.3°, 2.2°, 3.2°, 4.2°, and 5.2° degrees C. A weighted mean of these (allowing for the fourth power relationship) gives an average temperature drop of 0.85°C. This makes sense, because about three-quarters of the downwelling radiation comes from the bottom hundred metres of atmosphere, which is not much cooler than the surface.
However, this doesn’t solve the conundrum. Remember that I got an emissivity of 0.590 using the surface temperature. IF in fact on average the radiation is coming from a temperature which is 0.85°C cooler, then using that temperature it only brings the emissivity up to 0.595 … hmmm.
So that’s my puzzle for today. Is Geiger wrong about the source of the downwelling radiation? Is the emissivity of the atmosphere really on the order of 0.6? Is something else going on?
Inquiring minds wonder …
My best to everyone,
w.
AS USUAL: if you disagree with someone, please quote the exact words you disagree with. This lets all of us understand the exact nature of your objections.
CODE AND DATA: The R code, the functions, and the hundreds of daily files for 2010 are in a zipped folder called “SURFRAD Analysis”. WARNING: 21 megabyte file.
{UPDATE] Prompted by a typically detailed and interesting comment below from Dr. Robert Brown (rgbatduke), here is a scatterplot of the complete temperature and downwelling IR datasets:
[UPDATE 2] The same graph, but for Boulder, Colorado.
SURFRAD VARIABLES:
# station_name character station name, e. g., Goodwin Creek
# latitude real latitude in decimal degrees (e. g., 40.80)
# longitude real longitude in decimal degrees (e. g., 105.12)
# elevation integer elevation above sea level in meters
# year integer year, i.e., 1995
# jday integer Julian day (1 through 365 [or 366])
# month integer number of the month (1-12)
# day integer day of the month(1-31)
# hour integer hour of the day (0-23)
# min integer minute of the hour (0-59)
# dt real decimal time (hour.decimalminutes, e.g., 23.5 = 2330)
# zen real solar zenith angle (degrees)
# dw_solar real downwelling global solar (Watts m^-2)
# uw_solar real upwelling global solar (Watts m^-2)
# direct_n real direct-normal solar (Watts m^-2)
# diffuse real downwelling diffuse solar (Watts m^-2)
# dw_ir real downwelling thermal infrared (Watts m^-2)
# dw_casetemp real downwelling IR case temp. (K)
# dw_dometemp real downwelling IR dome temp. (K)
# uw_ir real upwelling thermal infrared (Watts m^-2)
# uw_casetemp real upwelling IR case temp. (K)
# uw_dometemp real upwelling IR dome temp. (K)
# uvb real global UVB (milliWatts m^-2)
# par real photosynthetically active radiation (Watts m^-2)
# netsolar real net solar (dw_solar – uw_solar) (Watts m^-2)
# netir real net infrared (dw_ir – uw_ir) (Watts m^-2)
# totalnet real net radiation (netsolar+netir) (Watts m^-2)
# temp real 10-meter air temperature (?C)
# rh real relative humidity (%)
# windspd real wind speed (ms^-1)
# winddir real wind direction (degrees, clockwise from north)
# pressure real station pressure (mb)
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A similar experiment in Germany seems to have gotten similar emissivities if I’ve understood their table correctly.
http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CDQQFjAD&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F222679178_Downward_atmospheric_longwave_irradiance_under_clear_and_cloudy_skies_Measurement_and_parameterization%2Flinks%2F0912f5072b20c07b49000000&ei=7-p0VJOeCfSCsQS-pIDwDg&usg=AFQjCNGh3ofYnYDUPudTWiJr39qenKzEkw&bvm=bv.80185997,d.cWc
If You use Your emissivity of 0,59 in the formula here:
http://en.wikipedia.org/wiki/Effective_temperature
You get the result that the average temperature of the Earth is 288K or 15°C.
And by that have you reduced the greenhouse effect, as it is usually explained, to null.
Coldlynx,
Actually, the fact that emissivity is not close to 1.0 is *confirmation* of the greenhouse effect. Without an atmosphere that limits outgoing radiation, we would see the (nearly) blackbody radiation from the oceans and lands, and a 288 K surface would rapidly cool. The effective emissivity of ~ 0.6 can only be due to the GHGs (along with aerosols and clouds) that reduce the outgoing radiation so that the surface can warm to 288 K.
What you say applies at night but I’m not so sure that it applies during the day.
Without GHGs day time temperatures would reach maximum within a couple of hours very similar to the moon.
But the Earth warms much slower, it gets nowhere near the moons max temperature even though it warms for on average 6 hours
This slow warming is undoubtedly cooling. The question is which effect is bigger, night time warming or day time cooling.
If warming was bigger, each morning would be a little warmer than before, leading to the maxium quicker than the day before. That’s just not happening and nor is the reverse.
Therefore the effect of a GH atmosphere is to distribute heat, not increase or decrease it. IMHO
Does not the lowered Temperature of the earth simply reflect the fact (pun intended) that the earth has an albedo of 0.35 or 0.39 or whatever, so it does not absorb TSI x pi x R^2 solar energy.
Seems to me that emissivity and albedo are getting confused here.
george e. smith
November 26, 2014 at 12:09 pm
No. I think rather that the “published and accepted” value of earth’s “average albedo” is very carefully set to match (and back-calculate) Trenberth’s “Published and Accepted” flat-plate earth radiation model that is used to demonstrate the flat plate average earth temperature calculations ….
See the circularity there?
Unfortunately the design of the instrumentation reads more than just incoming IR. It also ‘reads’ the kinetic energy of the gas in the enclosure. If you are impressed by the label ‘Scientific Equipment’ without understanding what is truly measured then good luck to you in your delusion.
My goodness, Alex … are you always this unpleasant?
In any case, some evidence to back up your claim would be useful …
I ask for evidence because I did read the ReadMe file, and it says:
Doesn’t sound to me like it is “reading” the kinetic energy of the gas in the enclosure … if you have evidence to the contrary now would be the time to bring it up.
w.
Sorry Willis. I’m not having a go at you. I think you do a marvellous job of analysing data. I had a quick read of the Surfrad website and checked the instrumentation used. My comment was based on that, not on your work. Thermopiles are just thermometers and would read the air temperature as well as the incident IR. Which is why I was not surprised that your graph with the blue line and black line tracked each other so closely. However, I will take your advice and read in more detail about the instrumentation used. I may retract my earlier comment or I will find some links to back up my words.
Thanks, Alex, I’ll be interested in your findings.
w.
Hi Willis.
This is what I found.
http://www.eppleylab.com/instrumentation/precision_infrared_radiometer.htm
Very light on detail and has the same mistake as on the Surfrad website ie using the word ‘silicone’ instead ‘silicon’. What a wild goose chase that was.
Wikipedia had a description and diagrams of the equipment
http://en.wikipedia.org/wiki/Pyrgeometer
There is a little nonsense in the equations. Mainly the implication that downwelling IR heats the sensor and makes it hot which then emits IR and that somehow balances things. I could say the same thing about a thermometer I left in the sun.
The main thing I was looking for was confirmed in the diagram. There is a pocket of air in the measuring chamber which would clearly have to be at the temperature of the surroundings. So that air temperature would be read by the thermopile sensor. The only way to subtract the influence of the air in the chamber is to remove the air completely and make it a vacuum chamber.
My other concern is with the optical filter. Optical filters in IR work are a real nuisance.
There is no broad spectrum optical filter. These filters only work in narrow-ish bands.
http://www.pmoptics.com/silicon.html
that is far different to the band claimed to be measured in the wikipedia article on pyrgeometers.
http://www.bing.com/images/search?q=wg295+glass&qpvt=WG295+glass&FORM=IGRE This is just an example of some filters.
Optical filters also get hot and emit radiation but probably not as blackbodies or graybodies but as ‘non-gray’ bodies which have emission curves in different wavelengths and don’t look remotely like blackbody curves. So in actuality I don’t really know what that instrument is reading. Although I know if I took that instrument into a darkened room it would only read the ambient air temperature-and that is so wrong.
I also feel that the term PIR is misapplied to this type of instrumentation. It is, admittedly, a passive device like a liquid in glass thermometer and not a platinum resistance thermometer or a thermistor that require an active circuit to function.
In my world this is a PIR
http://en.wikipedia.org/wiki/Passive_infrared_sensor
and not this
http://en.wikipedia.org/wiki/Thermopile
I hope I haven’t rambled on too long
Well as far as I am aware, these broad band radiation sensitive detectors (thermal) ONLY read correctly when they are in “thermal equilibrium”.
That means the entire cavity (and its contents) have reached thermal equilibrium with the incoming radiation, so the radiation emitted from the cavity aperture, exactly matches the incoming radiation both in amount and spectral composition.
This is one of the few o.ccasions wherein Kirchoff’s theorem is applicable, and emission equals absorption.
So Alex, I believe your gizmo is not reading the correct Temperature UNTIL it and the air it contains have reached an isothermal equilibrium state with the incoming radiation.
If it is not in such a condition, the cavity and thermopile sensor are still increasing in Temperature, along with the contained air.
So I think Willis is in good standing on this.
That is just my personal opinion, and should be viewed in light of an expert’s opinion, that I should forever more refrain from even attempting to discuss physics in learned company (such as that expert).
With a emissivity of 0.59 is the “greenhouse effect” 100% explained by the atmosphere emissivity by GHG. Not by radiation from higher and by that colder altitudes, as the greenhouse effect is usually explained,
The classical claim of radiative transfer of heat in the atmosphere to colder altitudes is not in the above linked formula still is Willis emissivty value spot on to calculate the real temperature for our Earth.
I know very well that GHG cause the emissivity in the atmosphere but in the common simplified explanation of greenhouse effect is often using a much higher emissivity value, close to 1, and then explain the 33K greenhouse effect with radiative transfer models in the atmosphere.
Willis emissivity value in the formula reduced the radiative transfer explanation to null since all of grenhouse effect of 33 K is included in a lower and acutually measured real emissivity value.
I qoute Wilis:
“I don’t know why, but I wasn’t exactly expecting that … which is the best part of science.”
PS
Note what happend with temperature with changed emissivity values in the formula.
Higher emissivity value reduce temperature. Just saying….
DS
Are these data from a IRTS-P sensor used by NOOA weather stations? They explain:” The IRTS-P sensor is mounted vertically downward near the end of one of the 3-meter cross-member arms, 1.3 meters above the ground surface. The sensor is inserted into a Holleander tubing cross fitting perpendicular to the 3-meter cross-member and pointed downward….
This temperature is measured to determine the effective “skin temperature” of the “field of view” ground surface. Ground Surface (Skin) Temperature, along with wind speed and solar radiation provide information to allow for correction of observed air temperature data due to solar heating.”
“Now my bible in these matters is “The Climate Near The Ground”, by Rudolph Geiger, which anyone interested in climate science should read.”
A copy of which has been scanned and made freely available in a number of formats by Archive.org here: https://archive.org/details/climatenearthegr032657mbp with the PDF version here: https://ia700504.us.archive.org/4/items/climatenearthegr032657mbp/climatenearthegr032657mbp.pdf.
I will be ordering the referenced book “The Climate Near The Ground”, by Rudolph Geiger. Amazon ics currently out of stock on the hard back 6th edition
A paper back is fine with me. Have the later editions been corrupted? There may be “used” copies available and at this point I’m motivated. I downloaded a pdf and scanned through it but the old time way of white pages works best for me.
Any feed back will be appreciated.
O/T I was looking for the above book and during a ‘google’ search came across this :
http://wattsupwiththat.com/2012/06/18/time-lags-in-the-climate-system/
It was a while back
Hi Willis,
I suspect a plot of upwelling IR minus downwelling IR versus temperature would be informative, in that it would show how net radiative heat loss from the surface changes with surface temperature.
Further SURFRAD results … the same as above, but for Boulder Colorado 2010.
As is often the case it seems the limit at the hot end is much clearer than the limit at the bottom end. Interesting differences from the Mississippi data.
w.
A thermostat maybe?
neither colored curve fit (red nor blue) actually follows the data trend very well. Sure, there is lots of scatter, but the grouping, the general trend of the data is not tracking with that those two approximations (particularly at the lower (less than 5 deg C) levels.).
mpainter,
As Mi Cro has pointed out, both you and Bill Illis need to take downwelling solar radiation into account. Neither water vapor nor CO2 nor any other “greenhouse” gas are heat sources in the sense that they are not adding any additional energy to the system. Only the Sun does that in a significantly life-giving way, and good thing for us that it does. GHGs effectively act as insulators — they reduce the rate at which the planet is able to dissipate absorbed solar energy back into space. Again, good thing for us that they do or it would be quite cold on this rock.
One need look no further to understand this than our natural satellite the Moon; lacking an appreciable atmosphere but having the same solar constant its average surface temperature is somewhere on the order of -5°C even though its albedo of ~0.12 is less than half that of the Earth’s which presently averages ~0.28. There are other differences and complexities, but the significantly cooler average surface temperature is easily explained by the Moon’s lack of an insulating atmospheric blanket. No argument from this “warmist” that GHGs are essential for life as we have evolved to know it.
Now that I’ve reintroduced the overlooked downwelling radiation from the largest fusion reactor in the local neighborhood, I can address your main question which is a good one. Speaking first in net global terms, the bulk of solar energy dispersion at the surface is accomplished via water evaporation and vertical mass transfer due to thermal convection. Obviously a dry desert doesn’t contain much surface moisture, so thermals are pretty much it.
How significant is that you ask. Well, you’d be hating life on a hot day if you didn’t have sweat glands in your skin, but let’s put some numbers to this. To Trenberth’s (in)famous graphic we go: http://www.cgd.ucar.edu/cas/Topics/Fig1_GheatMap.png
Slightly out of date (IIRC the net downward flux imbalance is presently estimated at ~0.4 W/m^2 with a healthy error margin) but it works for this purpose: evapotransportation accounts for 80 W/m^2, thermals 17. These are net global figures, mind, so applying them naively to local conditions isn’t the most robust scientific practice but we might be able to derive a decent 0th approximation from them. Let me see if I can.
Tallying up the all net fluxes at the surface I come up with 18 W/m^2. Multiply by the canonical value of 0.8°C/W*m^2 and we get 14.2°C for the average global surface temperature. [1] If I back out the entire 80 W/m^2 evapotranspiration component to represent a perfectly (unrealistic) dry desert net flux at the surface jumps to 98 W/m^2, multiplied by 0.8°C/W*m^2 gets a whopping 78.4°C which cannot remotely be correct, so what gives?
Well, just as the Saharan surface is dry, so is the atmosphere above it. From the diagram the net greenhouse effect is 157 W/m^2 [2]. From memory I know that about 60% of the net global effect is due to water vapor and clouds which don’t happen too often in the Sahara.
However, absent water vapor the part of CO2’s absorption spectrum that normally overlaps with water picks up some of the slack. So let’s call the net greenhouse effect in the desert 50% of the global average or 78.5 W/m^2. Subtract that from our previously calculated 98 W/m^2 and we get 19.5 W/m^2. Multiply that by 0.8°C/W*m^2 and the result is 15.6°C. Add back to that the world average of 14.4°C and we get an average of 30°C for the Sahara.
Google the phrase: “average temperature of the sahara desert” and an info box pops up which says: The Sahara desert generally features an arid climate. The Sahara desert is one of the hottest regions of the world, with a mean temperature over 30 °C (86 °F). Variations may also be huge, from over 50 °C (120 °F) during the day during the summer, to temperatures below 0 at night in summer.
I did not look it up beforehand though I will admit I had a fair idea it would be in that neighborhood. I left lots of stuff out and greatly oversimplified a few things [3], so some of this is pure dumb luck on my part [4]. But as a “blind” estimate I’m still rather pleased with the result.
——————–
[1] Which is the published value circa 2009, so yes this chart is definitely out of date — more recently published figures put average temps at ~16°C … lookit that, in 3 years we wily alarmists have conjured 1.8°C of warming out of thin air!
[2] The math here is 356 W/m^2 upwelling IR from the surface absorbed in the troposphere, less 169 + 30 emitted into space at TOA giving 157 W/m^2.
[3] One missing thing to think about is that thermals are quite a bit stronger in the desert, especially hot ones, so 17 W/m^2 heat loss from the surface is likely quite a bit low. What goes up must come back down, and it does so a bit cooler than when since at higher altitudes there’s a clearer free path for GHGs to emit into space. On the other hand as Mi Cro has correctly pointed out, at night dry/cloudless air allows for greater radiative heat loss than a humid/cloudy one which would also tend to bring down the average temperature. On the gripping hand, it rains a lot in the jungle, which means cloud cover that blocks incoming sunlight during the daytime, plus brings cooled water down to the surface. This stuff really is NOT simple.
Brandon Gates, this thread was shaping up to be one of the most interesting ones I’ve read on this site and then you come along and make it twice as interesting in a few compelling, easy to understand paragraphs (I’m a geologist and mining/processing engineer – not a physicist). You mention you are a ‘warmist’, but I don’t detect you to consider us on our way to the alarmist’s perilous future from Anthropogenic GHG increases.
The hottest temp RECORDED supposedly is the Death Valley one of about 57C so I’m sure we have exceeded 65C frequently. Given ”trade wind” type air flow over the Sahara and other winds (Sirocco northwards over the Mediterranean and the harmattan that blows southward toward the equatorial region) this air replacement could account for the dozen degrees moderation of your calculated 78C.
Gary,
Thank you for the kind compliment. I too am enjoying this very interesting thread. Unfortunately the math in the comment you’re responding to is badly off. I should have known better than to be able to get to a ballpark approximation doing arithmetic using the global energy budget and relying on memory for the little bit I’ve read about deserts. I’m now in the midst of a crash course and will publish a correction sometime tonight or tomorrow.
I did understand that max temperatures get into the 50s and 60s but I was intentionally going after the annual mean.
Gary, PS:
Mostly correct. By default I reject politics of fear no matter who engages in them. That doesn’t mean I’m not concerned about potential risks, however I recognize that the current state of the science has far more uncertainties looking forward than back. In short, my view comes from a risk management perspective — when uncertain err on the side of caution. As a practical matter, ruining the economy by doubling energy prices would be immediately catastrophic. From a political perspective, selling risky and potentially expensive economic solutions is a dog that won’t hunt. Where I look for balance and compromise, others are engaged in a winner-take-all mentality. I think we do know how to mitigate and reduce risk (reduce emissions) but the best near term solutions (nuclear, geothermal) don’t happen and decent compromises which have evolved because of a favorable market (shale gas replacing coal) are vehemently opposed. Makes me a tad cranky at times.
Brandon you said…
I disagree with the above WADR
There is no point talking about ‘average’ temperatures. Both the Moon and Earth have a day cycle. We know that during the day, both warming and cooling takes place, and during the night cooling only takes place.
In order to understand the (so called) GHE, we’d first need to understand what happens during the day and what happens during the night.
Taking your example of the Moon, the dramatic drop in temperatures as soon as the sun sets is never experienced near the surface on Earth. The closest we get is at desert locations where the GHE is the weakest. We experience the exact opposite at tropical wet regions where the cooling is slowed.
This is a WARMING EFFECT.
On the other hand, the exact opposite hapens during daylight hours. On the Moon, temperatures rise well above the highest on Earth within a couple of hours [so the argument that the Lunar surface gets warmer because of the length of day (14 earth days) doesn’t wash.]
Likewise, dry desert regions reach a higher temperature than wet tropical regions EVEN THOUGH THE DESERT STARTS THE DAY AT A LOWER TEMPERATURE. So the GHE reduces the rate of warming during the day.
This is a COOLING EFFECT [Note: If a reduction in the rate of cooling can be expressed as a warming effect (as many have argued), then a reduction in the rate of warming may be expressed as a cooling effect]
So then, in order to be able to claim the GHE warms or cools this planet, one would need to determine which effect is greater. The answer is obvious, occams razor.
Mi Cro,
Nowhere are these factors better known than amongst the researchers responsible for your understanding of them. I know where your knowledge comes from because I’ve read a bunch of their papers, x2 explanations from secondary sources to help translate unfamiliar terminology into lay language I can better comprehend.
Now, the planet is composed of dry cold, dry hot, wet cold and wet hot regions, both land and ocean. Latitude affects the incident angle of incoming solar energy. Albedos differ by locale and/or season. It’s cloudy in some places year round, clear in other places year round, mixed depending on season in others. Big cities absorb more solar energy during the day than rural areas. As big cities get bigger, they incrementally do more of that over time.
As the growing UHI effect is something that is generally understood conceptually here — and oft discussed — it stymies me that so many here can’t apply a similar line of thinking to the incremental increase of well-mixed GHGs over the course of increased industrialization. To wit: gradual long-term changes can have a cumulative effect on the mean over extended periods of time even though their contributions are a fractional percentage of the instantaneous net.
Logically then, if The Pause “falsifies” CO2’s role, it also nukes the much emphasized UHI effect too. Amirite? Maybe, maybe not. That’s where making observations and doing a heck of a lot of math to quantify things becomes essential.
When the scope of study is global, one hopes all that math arrives at an approximate global estimate of the NET effects of ALL the reasonably known and understood individual component dynamics. Of COURSE the Sahara is going to work differently than the Amazon. Anyone having more than average familiarity with climate science knows that the Arctic and Antarctic behave differently despite their facile similarities — as in both are at much higher latitudes and friggin cold and dry compared to northern Brazil.
To your credit you remembered that downwelling solar flux needs to be accounted for before I got around to reminding Bill and mpainter. I don’t know about you, but the two of them are still stuck on the notion that if upwelling IR is always greater than downwelling IR from the atmosphere then the lot of us on the consensus side of the fence must be bonkers. Well that’s silly, not just because they left the dang Sun out of their “gotcha” rebuttal, they obviously haven’t stopped to consider the implications of net flux on the RATE of energy transfer.
So back to my question for Bill Illis and now you and mpainter: if the RATE of outgoing flux is reduced but incoming flux remains constant, what happens to temperature?
C’ Mon, Brandon, pay attention. I have answered your question. The atm with the higher greenhouse gas concentration has the lowest air temp., under constant insolation. Earth says so. Your model says otherwise.
What will you do Brandon? Will you claim water vapor is a positive feedback to increased atm. CO2? That is what your experts claim. I repeat: higher greenhouse gas concentrations —-> lower max air temp.
mpainter,
Oh but I am.
‘Fraid not old bean. I asked an easy 1st year physics theoretical question and you’ve responded with anecdotal evidence that is factually correct and that’s about it. I may as well tell you that as the number of pirates decreases temperature goes up. It’s an awfully pretty correlation, no?
Also higher min air temp in the Amazon. In the Sahara, the min nightly temp routinely goes below freezing in SUMMER. Both places work out to an average annual temperature of …. drumroll please …. ~30°C, though the Amazon runs cooler at ~27°C. Think daytime cloud cover, and rainfall (any time of day) for starters.
Now for the third time, tell me what reducing the rate of outgoing flux does to temperature when incoming flux is constant?
Okay Brandon,
You say “reducing the rate of outgoing flux”, so what reduces the rate of outgoing flux in your book? I assume that you mean by this the effect of increased concentration of greenhouse cases, and by this the rate of outgoing flux (IR) is reduced (more correctly, however, retarded). This is the assumption upon which I based my reply. Now, pay close attention. Go to the Sahara. There, the daytime highs exceed 125°F in summer. The concentration of ghg there is very low, compared to the tropics. You wish to see what happens when you increase greenhouse gas (which by your AGW theory increases DWIR). Go to the tropics, where the atm. concentration of GHG is much higher. Does max air temp. increase?
No. So why did not the increase of DWIR raise max air temp.? Please answer, as I have tried to answer you.
Brandon, you might not be able to overcome your indoctrination of AGW theory. That’s okay, I understand. But that does not mean that I lack intelligence. You cannot explain, by your theory, why max temps are higher where the GHE is lower, and vice versa. You speak in terms of DWIR. Well, my friend, your theory has been thrown into the ditch by this curve in the road.
Now, once again:
Higher ghg (tropics)–>lower max temp;
Lower ghg (Sahara)–> higher max.
Explain again what all of that DWIR is supposed to do, please and thank you.
And Brandon,
The example is not “anecdotal” as you said, but empirical. I recognize that some theorists are not capable of addressing the issue empirically. I suspect that this may be the case here.
Also Brandon, you grant that my example as “factually correct but that’s about it”.
My method is to obtain the facts and proceed from there.
What is your method, pray tell.
Brandon Gates
November 26, 2014 at 2:48 pm and 4:24 pm
=============
I’m not sure what to make of your two previous comments. I will read yet again carefully.
eyesonu,
Well the one to mpainter has a pretty stupid math error in it. I got very lucky to get the correct answer.
A correct answer? I would need to read it all again to look for one.
eyesonu,
30°C average temperature for the Sahara was my calculated answer, and that’s the published value. The stupid error is the final step, “Multiply that by 0.8°C/W*m^2 and the result is 15.6°C. Add back to that the world average of 14.4°C and we get an average of 30°C for the Sahara.” Adding back the world average is double counting and I can’t do that. My reasoning about the lack of evaporative cooling from the surface jibes with published literature but pretty much the rest of my math falls apart. I’m wrong, and I wish I could take that post back but I can’t.
Brandon Gates
Try instead a day-to-day radiation budget: You have the right idea, but are trying to get “flat plate worldwide averages” from a single location at a single latitude with a single combination of air temperature (day and night, humidity, atmosphere clarity, solar radiation, and thermal mass.
Just do a day-and-night cycle at one point.
Get that right.
Then extrapolate over a full season at that latitude. With that latitude’s weather conditions (humidity, clarity, pressure, clouds, etc.)
You’ve got the right idea: And starting with the Sahara (dry, little or no evaporation, no phase changes, no ice or water conflict, steady winds, low latitude so radiation is predictable over the whole year) are almost as “easy” as getting the moon right. 8<)
RACookPE1978,
Good suggestions, thanks. My first inclination is to pick a grid and mine KNMI for data, though I might be limited to monthly resolution. I’ll try that first, but I think looking at things like temperature and humidity at up to hourly resolution might tell me something that even daily min/max/means wouldn’t. Ideas?
No.
Be humble. And get the radiation and IR (inbound) and LW (outbound) and thermal mass correct for the simplest problem first.
The moon. At its equator. 8<)
Then … When you are satisfied with your results against experimental results, work on the Sahara.
Brandon
That’s why I bought a cheap weather station, I wanted to “see” how weather evolved.
What I’ve found really interesting is that while absolute humidity changes slowly, rel humidity (which drives a lot of surface processes), swings wildly with temp changes.
I’m not sure if I uploaded it to SourceForge or not, but I have daily data on 1×1 degree cells if you want it.
Brandon Gates,
Why don’t you put your current “project” on hold and follow what Willis has presented and use your energy to help sort out that which Willis has so gratefully brought forth. This may be a holy grail in understanding climate related topics. Follow the lead or take it within the context of this thread. This thread may lead to the biggest breakthrough in a long time. Don’t let a golden opportunity pass. Focus! If you know the answer let us know. If you don’t then start looking.
Brandon Gates
November 26, 2014 at 11:20 am
================
In your comment earlier in this thread you stated that you had downloaded the data that Willis is looking at. Why don’t you plot several days at each station in a similar manner as Bill Illis (November 25, 2014 at 5:58 am) did in one of his earlier comments. Do include temps also. No averaging, just raw data. Place those results on a site and provide link here so we can all see.
eyesonu, I’m working on them.
Willis: The GHG’s in the atmospheric don’t absorb or emit in the “window” (8-14 um). The main source of radiation at some of these wavelengths is space (which is filled with blackbody radiation appropriate for 3 degK).
Emissivity is a problematic concept to apply to any anything that is partially transparent and/or lacks homogeneous temperature. The atmosphere has both complications. By definition, emissivity is the ratio of emitted radiation to the radiation emitted by a blackbody of the “same” temperature. At the infrared wavelengths where the atmosphere is totally or partially transparent, the radiation comes from above the atmosphere – where it is 3 degK.
When you tell me that the calculated emissivity is 0.59, I feel like asking 59% of what? Our partially atmosphere as a blackbody or greybody. The appropriate question to ask is does the DLR we observed match the predictions of radiative transfer theory.
mpainter,
1) GHGs and clouds reduce outgoing flux.
2) The Sahara gets relatively hot during the day mainly because a) there is little cooling effect from water evaporating at the surface, b) there are few clouds to block incoming sunlight, c) its low latitude gives sunlight a high angle of incidence and d) it doesn’t rain very often. These daytime factors in sum offset the decreased DWIR due to atmospheric moisture in wetter climates at similar latitudes.
3) At night in the Sahara the dearth of atmospheric moisture and cloud cover means less DWIR, so it cools far more rapidly and get far colder than rain forests at similar latitudes.
4) My use of “anecdotal” in this context means non-representative. As in a) too small a sample and b) not considering other relevant and available observations. Yes, your two data points (max daytime temp, minimal atmospheric moisture content) are factual observations so formally they are empirical evidence. However they are too narrowly applied.
5) My method is to obtain as many relevant facts as are available and/or that I can reasonably comprehend.
Again, your question is a good, properly skeptical, one. Your adamant refusal to consider other observations and pointers toward other physical processes is not good.
Brandon
You claim that clouds warm by “reducing outgoing flux” and that they cool by ” blocking incoming sunlight”.
You need to resolve that. Do clouds cool in the day or warm ( please recall the issue is max temp.)? My belief is clouds cool in daytime, not warm.
Otherwise I agree that humidity makes the difference, that is, water and water vapor. Note that the GHE is due to water, mainly, and humidity ( water and vapor) determines t-max, hence the higher the humidity, the greater GHE, the lower t-max.
That bears repeating:
higher humidity—>greater GHE—>
Lower t-max.
In short, the strength of the GHE, locally, depends on local humidity, as rgb was at pains to point out up thread.
In conclusion, the role of water is misapprehended by AGW theory because water acts as a coolant in all its phases in daytime (which reminds me: you omitted the convective factor in your above response).
mpainter,
I am aware of that. Max temps usually occur during the daytime suggesting that the dominant radiative effect is the Sun. Since one half of the planet is is in darkness at any given moment, it seems folly to ignore that part of the equation.
Yes, we agree. Clouds not only block sunlight from reaching the surface, they have high albedos which reflect incoming solar radiation back into space. During the daytime, clouds will tend to lower max temps. At night, clouds do the opposite and tend to raise min temps. Both are radiative effects.
I mentioned convection in the form of thermals several posts ago. I’ve explained the physics of non-radiative water effects several times now. Your turn to explain instead of just repeating the same assertions over and over.
Brandon,
We seem to agree substantially. Here we part company, I imagine.
The GHE in fact moderates air temp. of the earth during solar forcing. That AGW crowd would have us believe otherwise but our empirical observations are conclusive, as in the tmax of the Sahara vs. the tropics.
Atm. water vapor derives from surface cooling and the vapor phase is a stage of the cooling process that involves both surface and atm. The next step is convection of latent heat aloft where it is released far above the earth’s surface. The radiative flux is the dominant process under scant GHE, but it is subsumed in the cooling effect of water, water vapor, and the phase changes, this being the climate process of the tropics.
HENCE, the stronger the GHE, the lesser the role of IR flux in determining air tmax.
Night, under no solar forcing, is subject to different considerations.
mpainter commented on
IMO the issue is that while both water vapor and Co2 are GHG’s, water also has other roles in the climate that Co2 does not. They are not equal!
Surface temps cover all three states of water, Co2 is only a gases. Clouds while comprised by water, they do not acts the same as a GHG, We don’t see clouds of Co2.
On an snowball earth, I think Co2 acts to kick start global warming, until the water cycle starts again.
RACookPE1978,
Since SURFRAD is the main topic of this thread, ATM I’m working on those data for Colorado, Las Vegas, Missouri and West Virgina. If I have time before comments close I’ll take another swipe at the Moon vs. the Sahara vs. the Amazon.
(Very minor) errata: Illinois, not West Virginia.
RACookPE1978,
I loaded a bunch of files for Missouri, Nevada and Colorado up to a publicly shared Google Drive folder: https://drive.google.com/drive/#folders/0B1C2T0pQeiaSM2JmNks4cFgyQmM
mpainter,
I think you meant to write that water vapor derives from surface heating. At least I hope you did.
I mostly agree. Technically latent heat is energy released or absorbed by a phase change.
That statement is quite odd since by definition GHGs are molecules with strong vibrational modes in the IR spectrum.
Yes, the system behaves differently when not being pumped by solar energy. Sort of like your freezer behaves differently when you unplug it from the wall outlet. But I promise you that none of the underlying physics change when it gets dark or pull the plug on your fridge.
Brandon,
Still stuck in the IR rut?
Then are you content to repeat the mistakes of your teachers?
The GHE moderates temperature because it is essentially water. AGW theory incorrectly has it raising temp., but observations tell us otherwise. So go plug the fridge back in, relax, have a beer, and reflect on the wonderful benefits of atm. CO2.
wxobserver commented
First, I presume you’re used both at the same time, to make sure they measured they same Tzenith.
The 3-4 W/m^2 forcing is just the increase in human Co2. So, it doesn’t really surprise me, what this says is that the spectrum isn’t a black body, which if I thought about it, makes sense.
I would like to see what the spectrum looks like though (as opposed to the one shown in the thread rgb referenced).
Do you have any technical info on the 5-20u thermometer?