From the “models aren’t the same as reality unless you have a bigger computer” department.
Global climate is a tremendously complex phenomenon, and researchers are making painstaking progress, year by year, to try to develop ever more accurate models. Now, an international group including researchers from the Advanced Institute for Computational Science (AICS) in Japan, using the powerful K computer, have for the first time accurately calculated the effects of aerosols on clouds in a climate model.
Aerosols play a key role in cloud formation, as they provide the “seeds”–called cloud condensation nuclei–that allow clouds to form and affect their life cycle. The water in the air condenses onto the tiny particles, and gradually grow into droplets and finally into raindrops that precipitate. The action of aerosols is an important element of research on climate change, as they partially counteract the heating action of greenhouse gases.
It was previously believed that increasing aerosol density would always lead to more clouds, but recent satellite observations showed that this is not necessarily true. It is now understood that, due to temperature differences between the top and bottom layers of clouds, there is a delicate balance of evaporation and condensation, with aerosols in the lower parts of the clouds promoting cloud formation, but those in the upper parts allowing the water to evaporate.
Previously, climate models were unable to model the response of these micro-processes within the clouds to aerosol variation, but using the K computer, the RIKEN-led group combined a model that simulates the entire global weather over a year, at a horizontal resolution of just 14 kilometers, with a simulation of how the aerosols behave within clouds. Unlike conventional models, which show a uniform increase in clouds over the earth when there is an increase in aerosols, the high-resolution model, which takes into account the vertical processes inside clouds, accurately depicted how large areas experience a drop in cloud cover.
According to Yosuke Sato from the Computational Climate Science Research Team at RIKEN AICS and Nagoya University, “It was very gratifying to see that we could use a powerful supercomputer to accurately model the microphysics of clouds, giving a more accurate picture of how clouds and aerosol behave in the real world. In the future, we hope to use even more powerful computers to allow climate models to have more certainty in climate prediction.”
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The paper: https://www.nature.com/articles/s41467-018-03379-6
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To me the problem with all of these computer modelling systems is that they appear to be based on the concept of radiative forcing, where climate balance is involved. Whereas in reality it is the transfer, movement and morphing of enthalpy that is the process which needs to be considered.
The Hydro system is in fact a Rankine Cycle, with clouds being intimately involved at the micro level. This cycle ensures the movement of large amounts of energy upwards to enable eventual dissipation into space and occurs oblivious of whatever greenhouse effects are in play due to the simple fact that gaseous water is lighter than dry air and therefore rises and carries its latent heat upwards.
Aerosols obviously have their effect in that they influence the points at which phase changes take place; but the radiative forcing element is of minimal influence.
Unless these models include the Rankine Cycle thermodynamics in their calculations they are totally useless in addition to the fact that a chaotic system cannot be solved by a set of linear equations.
As an aside: Note that where water is concerned, at phase change the climate sensitivity is ZERO; but the gravitational forces involved change.
No one has been able to explain that when the latent heat is released by water vapou when it condenses where does that latent heat go? When it is released it is actually real sensible heat so one of 2 things happen. 1) It either goes off into space or 2) it goes into troposhere into the green house gases and thus the earth would warm with every rainstorm. If 1 happens then it is the water cycle that overwhelms any possible CO2 effect being that water vapour is 20 times more prevalent than CO2 and therefore no forcing of H2) by CO2 happens.. If No 2 happens then the earth would have been a runaway global warming planet a long time ago.
Alan:
You ask a good question. I will attempt to explain; but it can get complicated if you are not an engineer.
At surface evaporation the incoming radiation gets converted to latent heat ( or I would prefer Latent Enthalpy; as Heat suggests temperature).
Also the water physically reduces its density to the point where it is lighter that dry air.
Both of these processes occur at constant temperature which in climate science terms means at Zero sensitivity.
Once evaporated the water rises against gravity and thus does Work by which the latent enthalpy is converted to Potential energy. Think of the energy required to pump 20 Tonnes of water up into that small cloud 2000 feet above you.
Also in this process enthalpy is dissipated into the surrounding atmosphere, which is the part 2 element in you query. This again coming from the Latent enthalpy; but at the same time incoming radiation is still providing energy to the water; so there is a complex balance taking place.
This continues as the water rises until such time that the enthalpy runs out and condensation takes place again at constant temperature.
The point/height at which this occurs varies greatly with a proportion of the water reaching up into the cirrus clouds nudging the top of the atmosphere while the rest returns to earth as rain, ice or snow to restart the cycle.
Now in the cirrus clouds the latent enthalpy involved is that of fusion where ice crystals grow. So the behaviour is slightly different. However as these crystals grow it means that they are dissipating more energy into space than they are receiving and when they reach a certain size gravity again takes control and they descend. This comprises element 1 of your query.
The root control of this fine and complex balance is gravity for it is gravity which determines the vapour pressure of water at the various heights which balances against its partial pressure in the surrounding atmosphere.
The whole process is called the Rankine Cycle in engineering terms; but it never seems to get a mention in the climate debate, albeit that it involves very large transfers and movements of energy in comparison with the Greenhouse Effect.
In trite terms one might say that the Earth sweats to keep cool, such like you and I !
Hope this help. Sorry it’s a bit rough.
Regards.
Rankine cycle is a good model for thermodynamics of the atmosphere. The heat source is the sun. The heat sink is outgoing radiation to space. Temperature differential is surface temperature minus TOA temperature. Work done equals increase in gravitational potential energy of rising warm air. The role of greenhouse effect is to increase surface temperature by decreasing outgoing radiation to space. This is essentially slowing down the cooling process. The devil is in the details. Putting right numbers in the Rankine cycle.
Dr. Strangelove:
Yes you are essentially right. The temperature differential does drive the Rankine Cycle. However a great deal is known about this cycle and its thermodynamics, ever since the first steam engines. The trouble is that whereas the engineers deal in actual energy transfers the scientists still appear to be only considering radiation as the driving force; so get confused.
Radiation is only a means by which energy is transferred. It is not energy itself until it arrives at its destination at which point it can manifest itself in various ways; not only by temperature.
The Rankine Cycle demonstrates this as in a boiler at a fixed pressure the temperature remains the same however much energy you put into it. ( OK you do need a safety valve!!)
In the atmosphere this cycle ; as you rightly point out , transfers energy against gravity up from the surface to the TOA for dissipation. It is a process independent of but ancillary to radiation from the surface to space and involves large amounts of energy. (circa 680 WattHrs/Kg. of water).
One may well ask how this is accounted for in all these models.
How much do you wanna bet that the connection CO2 causes dust causes something or other to clouds causes warming will eventually be made?
Quote: ” In the future, we hope to use even more powerful computers to allow climate models to have more certainty in climate prediction.”
If you have no certainty at all (at present with 100% failure), should you gain some degree of certainty, is that considered “more” certainty?