Climate Metrics - Temperature Averaging 8

[TGS4]

In our most recent "climate change" discussion, I made a point about temperature averaging that seemed to be misunderstood. Because of its importance (in my opinion), I wanted to make its own thread.

It is clear to me that there is significant confusion about the cp of air and a global average temperature. Perhaps an example will clear things up:

I have two temperatures: -30°C (for argument's sake, let's say that the RH is 50%) and +30°C with an RH of 50%. The mathematical average of the temperatures is 0°C. However, based on the specific heat capacities:
[ul]
[li]the energy in 1 kg of the -30°C (243.15K) air is 1.005 [kJ/kg*K] * 1 [kg] * 243.15 [K] = 244.36575 kJ[/li]
[li]the energy in 1 kg of the +30°C (303.15K) air is 1.03 [kJ/kg*K] * 1 [kg] * 303.15 [K] = 312.2445 kJ.[/li]
[/ul]
Now, average the energies to get 278.305125 kJ. If you wanted an average temperature based on average energy (something that can actually be averaged), you are stuck in the backwards calculation of which value of specific heat capacity to use.
[ul]
[li]If you use 1.005 [kJ/kg*K], you get an "average temperature" of 276.92K or 3.77°C.[/li]
[li]If you use 1.03 [kJ/kg*K], you get an "average temperature" of 273.20K or -2.95°C.[/li]
[li]If you use the "average" of the specific heat capacities (1.005+1.03)/2=1.0175 [kJ/kg*K], then you get an "average temperature" of 273.52K or 0.37°C.[/li]
[/ul] (Note that these calculations are all at sea-level).

So, which "averaging" calculation is correct? What is the true average temperature? Even IF you know the instantaneous humidity coincident with the temperature reading, you still have a problem in the averaging. But, here's another problem to highlight it even more:

I have two temperatures: +30°C (for argument's sake, let's say that the RH is 10% because it's in Denver) and +30°C with an RH of 100% (Miami). The average of the temperatures is, obviously, 30°C, right? However, based on the specific heat capacities:
[ul]
[li]the energy in 1 kg of the Denver air at 30°C (303.15K) air is 1.01 [kJ/kg*K] * 1 [kg] * 303.15 [K] = 306.1512 kJ[/li]
[li]the energy in 1 kg of the Miami air at 30°C (303.15K) air is 1.056 [kJ/kg*K] * 1 [kg] * 303.15 [K] = 320.1264 kJ.[/li]
[/ul]
Now, average the energies to get 313.1388 kJ. If you wanted an average temperature based on average energy (something that can actually be averaged), you are still stuck in the backwards calculation of which value of specific heat capacity to use.
[ul]
[li]If you use 1.01 [kJ/kg*K], you get an "average temperature" of 310.04K or 36.89°C.[/li]
[li]If you use 1.056 [kJ/kg*K], you get an "average temperature" of 296.53K or 23.38°C.[/li]
[li]If you use the "average" of the specific heat capacities (1.01+1.056)/2=1.033 [kJ/kg*K], then you get an "average temperature" of 303.14K or 29.99°C.[/li]
[/ul]

Again, what's the real metric here. It takes 4.5% more "energy" to heat the Miami air up an additional degree as compared to the Denver air. If we are truly "worried" about energies and fluxes, then why are we even using temperatures at all?

I am most certainly NOT talking about trends or anything else (yet). I am talking about the most basic of metrics used. Why are we using an average temperature?

 

[zdas04]

The discussion will continue to revolve around a single temperature number. It probably shouldn't, but it will. The best I can tell (this seems to be one of those "obvious" things that never get explained) the programs take something like 100000 "adjusted" [adulterated?] temperature readings, add them together, divide by 100000 and get the number. If you were to multiply temperature times density times humidity (in mass/volume terms, not RH) sum the product and then divide by the sum of the product of the individual density times humidity you would get a pretty good surrogate for the specific heat term that TGS4 started this thread with (and would be really difficult to come to an agreement on methodology to assess). Fundamentally this would be equivalent to a "wet bulb" temperature which is a meteorologic measurement that is in pretty wide use, just not in "climate science".

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[Enginerd9]

No piss-taking. I was being sarcastic, yes, but not in an effort to jab anyone in particular. More to jab at the topic in general. There's just too many unknowns, too many things to take into account, and a lack of technology to do it all-in-one. I just find it interesting how entrenched in opinion people get about these kinds of topics.

Experience: accumulated knowledge over time.

Talent: the ability to use experience.

Which is more valuable?

 

[TGS4]

rb1957 - that's pretty much my conclusion. Whatever conclusions have been reached to-date are based on inadequate and insufficient data. Our surface air temperature measurements (whether instrument or via satellite) lack the rigour for a true energy-balance measure. Ocean heat content measurements via ARGO seem to have reached "critical mass" in 2007, so that is a good time to set the clock to zero.

 

[rb1957]

david,
IMHO you'd just change one number for another. It is clearly a more defensible number, but it still captures only a tiny portionof the problem; but maybe it is a step along a path to better understand the global system. It is a reasonable question (why climate science isn't based on wet bulb temps ?) but i guess the easy answer is the data collected so far doesn't allow it (mind you i'm not sure if they've looked).

enginerd9,
i think you might characterise the "debate" as between those with absolute certainty that they are right against those who think the former just could be wrong. to paraphase Lost (there's 7 years of TV i wasted ... what an ending !!) "man of faith vs man of science" (i thought it was interesting in Lost how the individuals involved changed sides ... Locke believed untill he felt his belief had been betrayed, Jack questioned untill he ran out of questions and believed).

Quando Omni Flunkus Moritati

 

[zdas04]

When I do the thermodynamics, I need pressure, dry temperature, humidity, density, and specific heat to get from dry bulb to wet bulb theoretically (as opposed to just reading the dial)--it seems to encompass all of the requisite variables implicitly.

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[JohnRBaker]

And for what it's worth, it was 86°(F) at lunchtime today in SoCal ;-)

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[TGS4]

Thanks John. Maybe you'll have something of value to add tomorrow. (I'm a wee bit jealous after having had to use the snow blower again yesterday. I guess it beats shovelling the snow...)

 

[SomptingGuy]

When I do thermodynamics simulation, I like to conserve things like mass and energy. Temperature is not so easy to use as a primary variable.

- Steve

 

[JohnRBaker]

TGS4, I know how you feel having myself spent 33 years in Michigan before moving West, and now we've been here in SoCal exactly that same period of time. I'd move back in a minute, but my wife, who's also from Northern Michigan, has come to love the warm weather and sunshine (and the total absence of mosquitoes).

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[rconnor]

Thanks for the clarification and taking the time to run some numbers.

As I've said before, I agree with your statement that energy is the true issue.

It takes <X>% more "energy" to heat <more humid> air up an additional degree as compared to the <less humid> air

I've expanded your quote to make it more general but, again, I agree. But the question is – what does that mean for climate science?

First, I’ll address the false position that, while global temperatures are increasing, actual energy content could be decreasing. If both humidity and temperatures are increasing, we can dismiss this concern.

NOAA tracks humidity as well.
[image

http://www.climate.gov/sites/defaul...Humidity_land_ocean_71-2012.png?itok=TVgMhYuS

]
Surface humidity has increased.

You also said that “If the tropics are not heating up, then the total amount of energy in the atmosphere can’t really be increasing, can it?”. The tropics are heating up (from NASA GISS):[image

http://www.giss.nasa.gov/research/features/200711_temptracker/global_temperature_anomaly_532.gif

]

Or you can look at the GISS data per zone per year.

So with global temperature (at both the polar regions AND tropics) and humidity increasing, the energy content is increasing as well.

Secondly, let’s look at zdas04’s statement that “”temperature” is a horrible surrogate for “state””. Temperature is certainly not the only metric that is reviewed. I’ll point you to NOAA’s “State of Climate” page. You can read the entire 2012 document here, the highlights here or the briefing slides here.

Some pretty pictures:

What’s going on with Arctic Sea Ice: Decreasing.

[image

http://www.climate.gov/sites/default/files/seaice1979-2012_final.png

]

What’s going on with Antarctic Land Ice: Decreasing. (for discussion on sea ice, which is increasing, see Zhang 2007 and Bingtanga et al. 2013 for an explanation on why that is so)

[image

http://www.sciencemag.org/content/338/6111/1183/F5.large.jpg

]

(from Shepherd 2012)

What’s going on with Glaciers: Decreasing.

[image

http://www.climate.gov/sites/defaul...ic/glacierloss1980-2011_620.jpg?itok=ho6Uw1ow

]

What’s going on with Sea Levels: Increasing.

[image

http://www1.ncdc.noaa.gov/pub/data/cmb/images/indicators/sea-level-rise.gif

]

What’s going on with Ocean Heat Content: Increasing.

[image

http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/totalster_700_2000m.png

]

So what’s the common link between OHC increasing, sea levels increasing, ice volumes decreasing, humidity increasing AND temperatures increasing – they all require an increase in energy. Don't like temperatures, fine, use OHC, sea level, humidity, etc. Energy uptake on Earth is increasing, no matter what metric you look at.

But wait, we need not finish there! Let's look at a few more of the observed climate changes from IPCC AR5 SPM , all of which are expected from the anthropogenic climate change theory:
- Increased precipitation in mid-latitudes (increasing confidence from data after 1951)
- Increased frequency and severity of heat waves (increased confidence for Europe, Asia and Australia)
- Increased salinity in areas expected to increase, decreased salinity in areas expected to decrease
- Decreased snow coverage in the Northern Hemisphere
- Increased permafrost temperatures
- Decreased ocean pH (not related to energy, due to increased CO2 emissions)

And a look at the radiative forcing numbers for AR5 SPM:
[image

http://www.climatechange2013.org/images/figures/WGI_AR5_FigSPM-5.jpg

]

Multiple lines of evidence show that there is a positive energy imbalance that is causing increased energy accumulation, consistent with the theory. This has lead to numerous, observable changes in climate, consistent with the theory.

Just because some of you don’t know about the full range of research in the area, doesn’t mean it doesn’t exist. Believe it or not, the experts in the field MAY actually know more about the subject than you or I. The only reason temperature is commonly referenced and quoted because it is the most intuitive metric for people. Furthermore, many of the observed and theorized effects are easy to calculate when working with temperature changes than energy content changes. For people, such as yourselves that have a heightened understanding of the science, there is a mountain of research, data and evidence out there for your consumption. Quarendo Invenietis.

To wrap things up, AR5 Fig. SMP6:
[image

http://www.climatechange2013.org/images/figures/WGI_AR5_FigSPM-6.jpg

]

 

[TGS4]

Good data, rconnor. Do you have a reference for the humidity metric? What's the data coverage (temporally and spatially) for it?

All-in-all, I think that you have presented a rather broad-based set of metrics that all point to the earth increasing in energy in the last 30-40 years. Oddly enough, that's not something that I generally disagree with - one can't deny these observations.

I do get really bent our of shape on the use of "global average temperature" with no consideration for humidity as a metric - especially when it is calculated to 0.01°C (and the source measurements are, at best measured to 0.1°C, but most likely measured to 1°C. It's just not a good metric.

Some of the other "indicators" have a poor temporal resolution for understanding the intricacies that make up our planet's weather: sea level rise, glacier advancing/retreat, sea ice, etc. And some indicators, such a glaciers, may be more an indication of precipitation than energy. And sea ice may be more a measure of energy distribution (think ocean currents) than energy content.

If anything, I'd rather hang my hat on ocean heat content. And as I said in the other thread, we have been getting good data with good coverage from ARGO since 2007. In about 40-50 years, we should have enough data to know something.

Of course, we can talk about how much the net energy has increased/decreased, but the real issue (that makes this much more than an academic exercise) is attribution. There's nothing in any of the data (empirical or inferred) that shows the 1980's heating to be any different from the 1930's heating, or that the energy is different from the Medieval Warm Period, or the Roman Warm Period, or the Minoan Warm Period, etc. Even the imperfect temperature metric of 1980-2010 is virtually indistinguishable from 1920-1950.

So, on a variety of metrics, do I think that the earth has more energy (heat) now as compared to 40 years ago: yes. Do I think that we know the cause: no. Is CO2 the cause: I don't think that the empirical data can say either way, yet.

Anyway, rconnor, thank you for your respectful engagement. I think that I may have learned something today, and any day that I learn something new is a good day.

 

[rb1957]

looking at the AR5 SPM (Summary of Policy Makers ... sort of like the Coles notes version of the report) ...
is it surprising that the one biggest contributor is CO2 and the confidence that this forcing is correct is Very High ?

and were are clouds in this ? ok, there's something about "clouds due to aerosols" but i thought there was a significant interaction between clouds and climate.

and how to they define those nice looking error bars ? is that the range that they put into their models ?

Quando Omni Flunkus Moritati

 

[rconnor]

TGS4,

It’s NOAA data from here. Sorry for not including it, I forgot that I included the NOAA State of Climate links after i used that grpah. To clarify, all other non-referenced graphs are from the NOAA State of Climate 2012 report.

The coverage is based on in situ observations from HadISDH (Willett et al. 2013) for land and NOCS v2.0 (Berry and Kent 2009, 2011) for oceans.

It was an interesting point you raised. I had not looked at humidity (specifically surface humidity) in much depth before, so it was a learning experience for me as well. Your last line reminds me of one of my favourite Neil DeGrasse Tyson quotes “I am driven by two main philosophies: know more today about the world than I knew yesterday and, along the way, lessen the suffering of others. You’d be surprised how far that gets you.” I can tell you that I have learnt from this discourse and it certainly has lessened my suffering to be able to engage in discussion with someone that demonstrates true skepticism.

rb1957,

I would say it’s not a surprised but for reasons completely different than why you aren’t surprised haha.

Clouds are a huge area of study but their relative trending change in forcing is a response to other aspects because there is no mechanism inherent within clouds that would develop a long term change by themselves. That is why it is listed as “clouds due to aerosols”. As an example, another external mechanism would be “cloud seeding” by galactic cosmic rays but I while back a listed a number of papers that said this theory had a statistically insignificant impact on forcing.

Real climate has an article on this figure if you are interested.

 

[TGS4]

Thanks for the reference to HadISDH. I will be investigating that further. Very glad to see that at least some thought is being put to this topic.

One disappointing feature, though is from the HadISDH webpage. They have "links" to discussion about uncertainty:

Measurement, climatological and homogeneity adjustment uncertainty was estimated for each month. Further in formation on uncertainty estimates can be found here.

Given the uneven distribution of stations over time and space, sampling uncertainty was estimated for each gridbox month. Further information on uncertainty estimates can be found here.

Each of their "here" went to a page that says "coming soon". Sigh.

And at first glance, I saw a lot about homogenization and reanalysis. That's double-speak for using a GCM (or GCM-like model) to "generate" data where none exist. Oh boy do I have problems with that...

 

[berkshire]

Now for the latest piece of hysteria :
B.E.

You are judged not by what you know, but by what you can do.

 

[rb1957]

i'm actually starting to get really sick of the cimlate change argument.

follow up any of the references ... every piece of data is disputed (as possibly it should be in a scientific discussion). some love surface temperature data, some detest it ('cause there are "many" data points that are corrupt). some say doubling the CO2 will cause negligible temperature (<1deg) ('cause the impact of increased CO2 looks parabolic, so there's "diminishing returns" as you keep doubling). some say it's all (and i mean All) due to man, others say man's contribution is negligible (compared to nature's. one decade we're heading for a new ice age, the next we're heading for a hot house, the next nothing changing so it's "just wait, we're all doomed". but the thing that gets me are the ad hominem attacks by both sides ... "belivers" are in league with a government (or green) conspiracy, "deniers" are in league with "big oil".

skrew it, i'm going to to join the "great uncaring", the uncaring majority. i'm going to pay for my gas and i'm going to pay my taxes, and i'm going to continue just as i have. eff it all.

Quando Omni Flunkus Moritati

 

[zdas04]

Me too, but I've found that the more that thinking people bow out of the discussion, the more that unscrupulous people bend it to an agenda (both sides do this). While these threads are incredibly frustrating, this is the only place I know where someone without an agenda can hear major portions of the arguments from both sides ("believers" only go to "denier" sites to cherry pick outrageous statements, and vice versa).

If there weren't so much money at stake it would not be a big deal. Regardless of who is closer to "right", either we will waste trillions of dollars on curbing CO2 for no result or the damages caused by global warming will cost trillions of dollars and millions of lives to rising sea level and increasingly unsettled weather. These are staggeringly large numbers. A lot of folks have skin in this game and not all of them are particularly honest. You go to CFACT.com and "the hoax is revealed, it is all a global wealth-redistribution scam". You go to IPCC.ch and "the science is settled and we have passed a tipping point where the damage can no longer be corrected".

I'm also ready to throw up my hands in disgust, but literally thousands of fence-sitters have browsed these threads and dozens of them have gotten new insights into the discussion, several have joined the conversation. I can't think of another place where people from both sides of this discussion are welcome and treated (mostly) with respect and some amount of dignity. When I read comments under articles on the advocate pages I am very distressed at the tone of the discussion. Here it is more or less focused on the issues and personalities are not brought into every single post.

Bailing from the conversation leaves one fewer thinking person to defend your position.

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[rb1957]

i wtached one "believer" video ... "the global warming swindle rebunked" ... seemed quite rational, tied in the hints of GW from the 50s with today's story, but completely overlooked the GC predicted in the 70s. i've another video queued up apparently refuting the 800 year lag between heating and CO2 increases.

i do believe that most climate scientists are honest, respectable people but i do believe there are a few "crooks" mixed amongst them. and yes, i'll drag out the Mann hockey stick as proof that people get focused on the results and are willing to accept something at aligns with their expectations. in the same way i believe that most "deniers" are honet, respectable people, with a few crooks mixed in.

i do believe that there is a strong "green" movement behind the GW ... my take is something like "the people still aren't being green enough, let's scare them with GW, the science is settled, blah, blah, blah". and so the message became "the CO2 we're producing today is responsible for changing the climate today" ... a much clearer "call to arms".

i believe the "true" science message should be something closer to "putting a bunch of CO2 into the atmosphere from burning FF might affect the future climate" ... but that's way too wishy-washy for people to react to, for governments to raise taxes around. and as for "our models are way too unsophicated to accurately model global climate ... well

i do believe that there is a component of "world governance", maybe not as strong as the video put out ... ok, it isn't Just about the US, GW isn't anti-US IMHO, i do see it as mulit-national goverance telling national goverments what to do. i've heard that the EU has recently done a significant "about face" ... reducing wind turbine subsidies, building coal powerstations ... i'll have to find out more.



Quando Omni Flunkus Moritati

 

[GregLocock]

That last sentence is correct. Germany is building new coal power stations, because they are somewhat trapped by 2 policies - fear of nuclear, and reliance on wind turbines, which are unreliable sources of energy especially when power is needed.

Also the EU has told the UK to reduce windpower subsidies.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[swall]

rb1957--What would a dishonest GW denier have to gain?