Albedo Change as the Basis for Recent Northern Planetary Warming-1


by DEMcMillan
Tags: albedo, basis, northern, planetary, warming1
DEMcMillan
DEMcMillan is offline
#1
Jul26-08, 12:29 PM
P: 54
http://www.physicsforums.com/showthread.php?t=245558
The attached table shows polar satellite (MSU) atmospheric temperature patterns posted on UAH covering 29.5 years. Note the LT contrast between the north polar and south polar regions, a 1.3 oC rise vs. a 0.2 oC loss. While the northern third 0.8 oC rise vs. southern third 0.2 oC rise is less striking it involves much more of the planet’s surface. MT contrasts are at least as dramatic.
The Earth’s surface is 71% water. Land distribution is asymmetric with 2/3 in the northern hemisphere. People are even more unequally distributed with 2/3 living on the northern third of the planet. People generate heat in their activities, but estimated total heat generation is less than 1/7 that needed to account for the temperature rise seen. One must rely on radiation imbalance to explain this rise.
Kiehl & Trenberth used 0.31 albedo to estimate solar net radiation. A fall of 0.0038 in albedo is enough to raise Earth’s temperature by 0.393 oC. If this fall is mainly in the top third of the planet, it generates a regional temperature rise. Part of such an albedo fall is mediated by the observed loss of snow, albedo, 0.8, in the Arctic.
A few weeks ago, I visited a 36 year old Santa Barbara County (California) winery. Our guide was a native of the area and commented about how evening temperatures have been falling in the last few years as Pacific air moves in. The addition of a number of local wineries has clearly lowered the albedo and changed the weather. World population has grown 53% in the last 29 years (http://www.census.gov/ipc/www/idb/worldpop.html). Increased human food and beverage cropping can easily be indicted for the rest of the falling albedo.
How do we decide whether lower albedo is a major culprit or at least a serious player in climate change? We can obtain data from our polar orbiting satellites and test the proposition directly. Lower albedo means less sunlight reflection, easily detected by visible light reflection measurements from satellites. Changes in satellite infrared spectra of Earth-based radiation quantify changes in the outgoing part of the balance. The essential need is to ask and answer the balance question.
We should expand the Kiehl & Trenberth model to one that takes regional surface temperature and atmospheric conditions into account. Planetary asymmetries must be used in modeling radiation balance. One look at maps of the polar areas makes this point. The north and south poles differ markedly in many ways. They both receive direct sunlight above 66.5 degrees latitude for only six months. Antarctic albedo exceeds 0.8 all year. Arctic albedo is high mostly when there is no sunlight. Antarctic mountains and snow depth make it much colder and hence less radiative than the arctic region. Models need to take such factors into account. The most difficult variable to model is cloud effect. Clouds raise albedo during the day and block Earth radiation into space both day and night.
I will add two other possible bases to this thread in the next few days.
Phys.Org News Partner Earth sciences news on Phys.org
DEMcMillan
DEMcMillan is offline
#2
Jul29-08, 10:08 AM
P: 54
Stratospheric Hydration as the Basis for Recent Northern Planetary Warming-2
Planetary warming see table http://www.physicsforums.com/showthread.php?t=245558
We must look to large changes in activity from 1979 to now, hopefully with recent slowing, to list potential causes for the warming pattern seen in the above table. One already suggested by others needs serious consideration because it is reasonably reversible. This is stratospheric flight. The contrails we see portray delivery of water vapor into an area of the atmosphere in which north-south circulation is very slow and hemispheric http://en.wikipedia.org/wiki/Ozone_layer. Joining ozone as it warms the stratosphere, water vapor can stay in the sky for a year or more. The northern hemisphere receives much more flight-mediated stratospheric water vapor than the southern hemisphere. The polar stratosphere is loaded with flight routes, but the Brewer Dobson circulation there is downward
Water vapor was recognized by Tyndall as the most important “ice house” gas in warming the Earth. Its concentration near the planet’s surface is much higher than at altitude, letting it scatter much radiated infrared light back to the surface. Its spectrum is also more complex than other scattering gases.Spectroscopy to 100 micron wavelength is needed. Equipment to broaden spectral range has been developed and is now being used http://map.nasa.gov/documents/CLARRE...zakCLARREO.pdf.
Omission of scattering of earthward Stefan-Boltzmann radiation from the stratosphere has confused the role of carbon dioxide in warming
http://www.physicsforums.com/showthread.php?t=243619. The same omission needs to be corrected for water vapor, but observations from space over time will clearly determine the importance of stratospheric water vapor in blocking or facilitating outgoing radiation.
We fly in the stratosphere because it is smoother and cheaper. If it is shown that the increasing stratospheric water vapor is harmful to the planet, flights can be diverted to lower altitudes or any cost of regional increase of Earth’s albedo linked to stratospheric flights. Alternatively, hydrogen-free liquid fuels could be sought.
DEMcMillan
DEMcMillan is offline
#3
Jul31-08, 11:13 PM
P: 54
Nuclear Heat/Hydration as the Basis for Recent Northern Planetary Warming-3
Two thirds of humans live on the northern third of the planet. Their use of energy concentrates warming where they live, especially in cities.
http://www.physicsforums.com/showthread.php?t=247597
www.eia.doe.gov/emeu/aer/txt/stb1101.xls
Energy includes the recent expansion of nuclear-produced electric power. The fraction rose from 1978 to 2006 from 2.3 to 5.9% of the total, principally in Europe where a cleavage of political support is evident. In the US, expansion has been blocked long enough that the application process has grown to four years. Regulating agencies have lost their capabilities. Thirty five years ago, different decisions were made in the US and France about what were then called breeder reactors. The US was concerned about security of shipping of “plutonium pigs” after the processing of spent nuclear fuel. France felt vulnerable to its lack of petroleum and coal resources and saw the advantage of proceeding. The pessimism about primary availability of yellow cake for nuclear fuel was later overcome by geographic expansion of its mining. Commercial re-processing has been made almost unnecessary by yellow cake availability.
Yellow cake abundance, combined with security concerns, has made assessment of the actual efficiency of nuclear electricity generation very difficult. The fuel rods instead of being processed are kept in storage. Storage conditions appear to vary from nation to nation. In France, rods have been transported to a peninsula on the Normandy coast. They are probably kept underground and dry there, but this is unclear. In the US, the solution has been “swimming pools” in at least 33 states. These are actually 10 meter deep steel-lined concrete structures filled with circulating water. Spent rods are placed in them. Several years must pass before the stored rods are cool enough for handling. But handling has not actually happened.
http://learning.berkeley.edu/cipolat...gNukeWaste.pdf
The NAS has expressed concern about this entire situation, its communication impaired by security concerns. Dry storage was advocated and the potential of theft pointed out. While the report indicates defense of their safety by the Bush administration, the problem is much more politically broad. At the beginning of the 1970’s, as nuclear power in the US was expanding, plans for long term storage of waste fuels were made and money collected as part of electric bills. Additionally, waste left at Hanford, WA that had contaminated much Eastern Washington with fission products needed storage as well. http://www.atsdr.cdc.gov/hanford/community/area.html. The Yucca Mountain facility generated for this storage has not been used and the reasons for this are at the heart of American politics and legal processes. The surrounding secrecy keeps assessment of the overall heat and low atmospheric hydration mediated by the World’s nuclear industry inaccurate. Improvement of this assessment is worthy of attention by this forum. My current estimate is 3.6% of the total I showed in the physics forum posting cited above. I may have substantially underestimated the total heat effect of alpha particle and cyclotron products. Does anyone have a better number?

vanesch
vanesch is offline
#4
Nov22-08, 12:06 AM
Emeritus
Sci Advisor
PF Gold
P: 6,238

Albedo Change as the Basis for Recent Northern Planetary Warming-1


Quote Quote by DEMcMillan View Post
The surrounding secrecy keeps assessment of the overall heat and low atmospheric hydration mediated by the World’s nuclear industry inaccurate. Improvement of this assessment is worthy of attention by this forum. My current estimate is 3.6% of the total I showed in the physics forum posting cited above. I may have substantially underestimated the total heat effect of alpha particle and cyclotron products. Does anyone have a better number?
Thinking that nuclear spend fuel is doing two things:
- putting so much water vapor in the air that it changes the greenhouse gas balance
- heats the earth directly

is totally, totally erroneous, for many many reasons, but the most important one is this:

The fuel spent much more heat when it was in the reactor than when it will cool, over its entire "radioactive life".

The other reasons are that the eventual contributions, if you calculate them, are puny compared to other contributions. But even without going into this, you can logically derive its invalidity. BTW, there is absolutely no "secrecy" around the heat of spend waste (you find it in every good nuclear engineering book) and there are normally reports where you can find the storage of them - so drop the "conspiracy" here.

But about the logical deduction of the unimportance of nuclear waste, here we go:
- most of the fission energy is liberated, well, during fission, and from the short-lived fission products, which give off their heat within the reactor. The long-lived fission products only have a few percent of the entire energy left, and with that fraction, they will have to "heat the waste" for the rest of the time. So the amount of heat that will come out of spend fuel is at most a few percent of the amount of heat that was delivered in the reactor.

Now, about 2/3 of the heat of the reactor is lost in cooling towers because of the steam cycle. So 2/3 of the heat of the reactor goes into evaporating water ; the rest of the heat is turned into electricity, which will be turned again into heat at the consumer's place. So we have:

- 2/3 of the reactor heat makes water vapor
- all the reactor heat "heats the earth".

Only a tiny tiny fraction of this will be the evaporation and the "heating" due to the stored waste compared to this.

AAH, you say, it is not the spend fuel then that "heats the earth" and "puts vapor in the air", it is the reactors themselves ! Of course!
Yes.

And now comes the final point: but a coal fired plant does the same, and there are much more of them (4 times more). A coal fired plant also puts about 2/3 of the heat into water vapor, and about 1/3 of the heat into electricity which will again be turned into heat at the consumer's place. So the coal fired plant puts as much heat and vapor in the air as does a nuclear plant for the same power.

So IF it were true that spend fuel "puts vapor in the air and heats the air", then nuclear plants themselves do so ten or more times more so, and coal fired plants still 4 times more. QED.

However, this was silly from the start, for two reasons:

- water vapor in the atmosphere is in direct equilibrium with the oceans, and the cycle time is very short (I think of the order of 5 days from the top of my head). So in order to change the water vapor in the air, you need to have sources which are comparable to the amount of vapor that oceans put in the air in about 5 days. Power plants or cooking spaghetti doesn't really change the vapor cycle significantly.

- Total human electricity consumption is 2 TW ; solar influx is 176 PW. We are a 10 ppm player in the direct heating of the earth, and MOST of that is due to fossil fuels.
DEMcMillan
DEMcMillan is offline
#5
Nov28-08, 05:52 AM
P: 54
“Now, about 2/3 of the heat of the reactor is lost in cooling towers because of the steam cycle. So 2/3 of the heat of the reactor goes into evaporating water; the rest of the heat is turned into electricity, which will be turned again into heat at the consumer's place. So we have: - 2/3 of the reactor heat makes water vapor - all the reactor heat "heats the earth".”

Despite your lack of concern about heat, water vapor and radiation from the ‘swimming pools”, originally planned for six months use http://library.thinkquest.org/17940/...te_storage.htm you gave new life to my calculations by pointing out the low efficiency of simple thermal electricity generation. I had been used the efficiency of turbine generators in my effort to calculate the thermally direct contribution to the 29 year warming of 0.4 oK measured by MSU. I focused on listing other sources and used an assumed turbine efficiency of 0.68 in adding to the btu table made available by eia. They actually used an efficiency of one third in their conversion of electrical energy in kwh to btu (10,338 instead of 3,412). I am currently traveling and will next week add a revised direct heating estimate to this thread and link it elsewhere to correct prior statements. In doing so, I need to base nuclear overall heat production on an estimated duration of fuel rod use before “swimming pool” emplacement. I plan to use three years. Such a figure falls within range in my reading, but the number should be better defined than I have been able to uncover. Does this number meet your expectations? In my secrecy statement, I was only echoing the NAS committee and the reporter’s assertions.

By the way, I looked again at other thermal efficiencies and found that “combined combustion” allows efficiencies of 50-60% by using combustion heat to generate steam and more electricity http://www.eia.doe.gov/cneaf/electri.../chapter3.html . I was aware that natural gas could be used in this way but I now note that coal gasification allows higher efficiency as well. Our home’s power source thermal efficiency shows an increase from 0.325 in 1997 to 0.361 last year. http://www.tampaelectric.com/data/fi...AndExhibit.pdf The testimony also gives remarkable declines in NOx and SO2 output levels. Are you aware of the possibility of any “combined” technique for nuclear?
vanesch
vanesch is offline
#6
Dec2-08, 06:23 AM
Emeritus
Sci Advisor
PF Gold
P: 6,238
Quote Quote by DEMcMillan View Post
Are you aware of the possibility of any “combined” technique for nuclear?
There is no principal limit to nuclear efficiency: it only comes from engineering considerations. Why is nuclear limited at something like 34% efficient for the best plants ? Simply because it uses in its current application, the steam cycle, and you are limited to about 300 degrees centigrade in a steam cycle (because you come near to the critical point for steam). Carnot and some technical inefficiency does the rest: the steam cycle cannot be much more efficient than something like ~40%, regardless of the heat source.

Combined gas plants can be more efficient, because you can use the higher temperatures of the gas flame. There are designs possible (and some exist) with gas cooling instead of a steam cycle, and then you will reach similar efficiencies as with combined gas plants.

4th generation reactors are planned to work between 500 degrees C and one even hopes to reach 800 degrees, although there are serious material engineering problems beyond something like 550 degrees. The UK uses advanced gas cooled reactors with a thermal efficiency of 41%, but they are not overall much more efficient than PWR who have a better fuel burnup.

But your approach is bizarre to me. As I said, most of the heat of a nuclear combustion is released during the reaction in the reactor and the decay of short-lived fission products (also in the reactor). This overall heat production is converted for about 1/3 into electricity (which is then later again dissipated as heat). So all the reactor heat ends up, in a matter of hours at most, as heat in the environment. With a 1/3 efficient coal fired plant, you produce EXACTLY AS MUCH HEAT for the same electrical power, and with a gas-fired plant, you will produce about two thirds of it for the same electrical power.

So if you consume, say, 1 TW of electricity, then you will have generated in any case a certain amount of heat, which will be 3 TW if it was of coal or gas origin, and 2 TW if it were of gas origin. Now, given that world-wide, nuclear power is only about 17% of electricity offer, it cannot be the major source of direct heating of the earth.

As to your consideration of the spend fuel, the amount of heat that a spend fuel will give off during the whole of its lifetime (until it is no more active, say, 1 million years from now) is a very very small fraction as compared to the amount of heat that it gave off when it was in the reactor. That is because of the 200 MeV or so that is the binding energy difference between a U-235 nucleus, and the binding energy of stable end fission products, most of it was released in the reactor or sent off as neutrinos.

So, of the available potential energy of something like 200 MeV, maybe 195 MeV or so (I don't have exact numbers handy, it can be calculated, but is tedious, because you have to look at all the fission channels) has been "heating the reactor", and only 5 MeV or so is still available for heating the waste over the rest of its lifetime.
DEMcMillan
DEMcMillan is offline
#7
Dec4-08, 11:19 AM
P: 54
vanesch writes:
There is no principal limit to nuclear efficiency: it only comes from engineering considerations. Why is nuclear limited at something like 34% efficient for the best plants ? Simply because it uses in its current application, the steam cycle, and you are limited to about 300 degrees centigrade in a steam cycle (because you come near to the critical point for steam). Carnot and some technical inefficiency does the rest: the steam cycle cannot be much more efficient than something like ~40%, regardless of the heat source.
You were again quite informative. I spent some time looking at the Areva site and French post-reactor practices. Areva’s ability to organize yellow cake production has markedly reduced rod use in MOX-plutonium production and its associated potential problems. I understand the yellow cake price is rising now. Will this have any effect on US reprocessing policy? I have not looked at Swedish practices but will try to do so in the future.

The fall in neutron density leads to lower heat production in the months after removal but the rods will remain more active than the source yellow cake forever due to Plutonium generation. The French are now making a plan to store their waste underground in Northeastern France. You have added to the water vapor problem that I constructed from storage by pointing out the cooling towers. Urban areas now generate incredible amounts of water vapor as their populations have risen, altering the air temperature patterns above our cities. Nuclear production contributes similar amounts of water vapor at generation sites.

I am recalculating the reduction in direct heat production caused by my failure to realize the threefold treatment of electric power production in the EIA table. Direct heat production will undoubtedly be less than 10% of that needed to explain the observed 30 year Earth warming. The heat hazard of post-nuclear power storage may be less but the high energy radiation hazard remains to be appropriately evaluated. Maybe I should start a thread for this discussion area in the future. It appears to be a lesser evil analysis, but underground storage should reduce both problems. Do you agree?
vanesch
vanesch is offline
#8
Dec5-08, 07:52 AM
Emeritus
Sci Advisor
PF Gold
P: 6,238
I think that further discussion of nuclear power issues do not belong anymore in the earth forum (the only reason to continue posting here was that you related it to global warming). If you want to discuss nuclear power and related issues, may I refer to our nuclear engineering forum, where there are already threads on this, or you can eventually start a new thread if you feel that you have a particular issue to discuss.


Register to reply

Related Discussions
Change of basis Quantum Physics 3
Change of basis Calculus & Beyond Homework 3
change of basis Advanced Physics Homework 2
Warming/climate change poll General Discussion 15
Change of basis General Math 5