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Post by duwayne on Sept 18, 2016 22:32:44 GMT
I’ve started this thread to discuss the “Greenhouse Effect” since it is viewed as being off topic on the Astro thread.
Nautonnier, you made a post on Astro’s thread and a copy is it at the bottom of this post if you need to refresh your memory.
I have a few questions but I’ll just ask one at a time….
In the third paragraph you say Air that contains water vapor is lighter than dry air (O2 and N2 are heavier than H2O) so will convect upward even if at the same or slightly cooler temperature as the ambient air.
Are you saying that air components preferentially stratify (based their molecular weights) rather than mix?
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For reference, your original post
But it goes further than that. The claim is that the absorbance and emission of photons actually warms the atmosphere in a way that 'traps heat'. That remains to be proven.
Remember all of Arrhenius' experiments were in a closed tube. In actuality what happens when air is warmed even slightly is that it rises, the convection carries the warmer air upward and due to the lapse rate it cools (Avogadro and Charles' law) there is no heating effect at the level of absorption.
All that happens is the atmospheric mixing increases. Infra red that is scattered (absorbed then re-emitted) by CO2 that reaches the surface has a 70% or higher chance of hitting water molecules either in the air or on the surface. The IR penetrates microns or less and initiates evaporation taking latent heat of evaporation from the water surface - thus cooling the surface. Air that contains water vapor is lighter than dry air (O2 and N2 are heavier than H2O) so will convect upward even if at the same or slightly cooler temperature as the ambient air. Drier air is then pulled in to replace the convecting moist air and there is now a breeze across the surface increasing evaporative cooling (just like blowing on a cup of hot coffee).
So - air that is increased in temperature convects upward and cools 70% of the surface is cooled by IR if any reaches the surface.
Convince me that there is actually a greenhouse effect. Convection overwhelms any warming.
When you try to prove it do NOT use temperature - the CO2 is not trapping temperature, it is trapping energy. So use the metric kilojoules per kilogram of atmosphere that will account for enthalpy of the moist lapse rate.
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Post by Ratty on Sept 18, 2016 23:24:09 GMT
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Post by nautonnier on Sept 19, 2016 8:10:02 GMT
Duwayne
No, I was pointing out that a volume of humid air in a larger volume of dry air will convect upward in the same way as warmer air in a larger volume of colder air - like a lava lamp. However, you will only notice the convection when condensation occurs and you see mist or clouds.
However, although that was not my point, it is not to say that the air cannot stratify based on humidity and temperature, that is why clouds are described as stratiform - nimbostratus, cirrostratus etc. Sometimes these layers only appear when disturbed such as the so called 'contrail level' a layer of air with supercooled water which when an aircraft dumps more humidity from its engine exhaust results in condensation trails normally of ice crystals. When you fly you often see extremely precise layer boundaries in clouds and haze.
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Post by duwayne on Sept 19, 2016 12:46:40 GMT
Ratty, I read the article you referenced until I came to this sentence. “In particular, it (the anthropogenic warming theory) assumes that the heat transfer in atmosphere occurs exclusively by radiation.” That to me is a strawman argument which is pretty easy to rebut. I haven’t read anything from any scientist who believes that the heat transfer in atmosphere occurs exclusively by radiation. Ratty, if you can find one who does, that would be interesting. On the other hand scientists do believe that radiation is the only way to transfer heat into and away from the earth’s atmosphere (into and from space). Radiation into and out of the earth’s atmosphere plays a major role in global temperatures. Greenhouse gases play a significant role in that transfer. |
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Post by duwayne on Sept 19, 2016 14:29:24 GMT
Duwayne No, I was pointing out that a volume of humid air in a larger volume of dry air will convect upward in the same way as warmer air in a larger volume of colder air - like a lava lamp. However, you will only notice the convection when condensation occurs and you see mist or clouds. However, although that was not my point, it is not to say that the air cannot stratify based on humidity and temperature, that is why clouds are described as stratiform - nimbostratus, cirrostratus etc. Sometimes these layers only appear when disturbed such as the so called 'contrail level' a layer of air with supercooled water which when an aircraft dumps more humidity from its engine exhaust results in condensation trails normally of ice crystals. When you fly you often see extremely precise layer boundaries in clouds and haze. Nautonnier, I'm having trouble with the idea that nitrogen and oxygen molecules that are slightly cooler than the surrounding air will rise because there is a water vapor molecule nearby. I'll just note here that I wonder if clouds are an example of air stratification since they are condensed water and bring particulates into play. But unless that is a significant point in your arguments, let's not get into a side discussion. |
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Post by nautonnier on Sept 19, 2016 16:26:54 GMT
Duwayne No, I was pointing out that a volume of humid air in a larger volume of dry air will convect upward in the same way as warmer air in a larger volume of colder air - like a lava lamp. However, you will only notice the convection when condensation occurs and you see mist or clouds. However, although that was not my point, it is not to say that the air cannot stratify based on humidity and temperature, that is why clouds are described as stratiform - nimbostratus, cirrostratus etc. Sometimes these layers only appear when disturbed such as the so called 'contrail level' a layer of air with supercooled water which when an aircraft dumps more humidity from its engine exhaust results in condensation trails normally of ice crystals. When you fly you often see extremely precise layer boundaries in clouds and haze. Nautonnier, I'm having trouble with the idea that nitrogen and oxygen molecules that are slightly cooler than the surrounding air will rise because there is a water vapor molecule nearby. I'll just note here that I wonder if clouds are an example of air stratification since they are condensed water and bring particulates into play. But unless that is a significant point in your arguments, let's not get into a side discussion. You should look at Avogadro's Hypothesis and Charles Law. It is a volume of air containing millions of molecules and in a particular volume at the same temperature and pressure Avogadro's Hypothesis (law in some docs) is that there will be the same number of molecules. If a percentage of molecules in a volume of air are lighter the volume of air will tend to rise. The same way that if a number of molecules have more kinetic energy so tend to take up more room due to their more energetic collisions (temperature and pressure is higher) the volume of gas will tend to rise. |
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Post by Andrew on Sept 19, 2016 17:38:44 GMT
Nautonnier, I'm having trouble with the idea that nitrogen and oxygen molecules that are slightly cooler than the surrounding air will rise because there is a water vapor molecule nearby. I'll just note here that I wonder if clouds are an example of air stratification since they are condensed water and bring particulates into play. But unless that is a significant point in your arguments, let's not get into a side discussion. You should look at Avogadro's Hypothesis and Charles Law. It is a volume of air containing millions of molecules and in a particular volume at the same temperature and pressure Avogadro's Hypothesis (law in some docs) is that there will be the same number of molecules. If a percentage of molecules in a volume of air are lighter the volume of air will tend to rise. The same way that if a number of molecules have more kinetic energy so tend to take up more room due to their more energetic collisions (temperature and pressure is higher) the volume of gas will tend to rise. But in practice the air does not tend to rise apart from when the air is unstable and prone to such movements, otherwise it would be a piece of cake to strap into a glider get towed to a few thousand feet and stay up there all day long every day of the year. We find in practice that even on days when it is as hot as hell on the ground there is no upwards movement of air until very many hours of sunshine have been able to create upwards movement at local trigger points such as hills, particular kinds of vegetation or suburban areas. Warm moist air finds it particularly difficult to move through the dryer colder layer of air above it, so it has to have a means whereby it can penetrate the upper layer. |
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Post by icefisher on Sept 19, 2016 23:44:00 GMT
But in practice the air does not tend to rise apart from when the air is unstable and prone to such movements, otherwise it would be a piece of cake to strap into a glider get towed to a few thousand feet and stay up there all day long every day of the year. In a heavier than air glider? Its my impression that a skilled glider flier can stay up longer by taking advantage of updrafts out of experience about where to find them and stay in them when they do find them. You actually fly them? We find in practice that even on days when it is as hot as hell on the ground there is no upwards movement of air until very many hours of sunshine have been able to create upwards movement at local trigger points such as hills, particular kinds of vegetation or suburban areas. Warm moist air finds it particularly difficult to move through the dryer colder layer of air above it, so it has to have a means whereby it can penetrate the upper layer. LOL! You are talking about perceptible convection. If you lay the same standard onto increased backradiation that would perceive it you would conclude there was no greenhouse effect also. Convection does not occur until later morning because the surface starts out colder than the atmosphere. However, a process known as diffusion goes on all the time. When the sun is heating the atmosphere and at night when the atmosphere is cooling. Thats because greenhouse gases in the atmosphere begin to absorb and emit more heat than O2 and N2. Convection produces higher air velocities than diffusion precisely because of the higher emissivity of the surface absorbs more heat than the atmosphere absorbs. Diffusion though will continue all night long because of the cooling of elevated greenhouse gas molecules that begin falling in relationship to the less emissive molecules of O2 and N2. So what makes you think it doesn't happen? Friction? |
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Post by nautonnier on Sept 20, 2016 0:26:51 GMT
You should look at Avogadro's Hypothesis and Charles Law. It is a volume of air containing millions of molecules and in a particular volume at the same temperature and pressure Avogadro's Hypothesis (law in some docs) is that there will be the same number of molecules. If a percentage of molecules in a volume of air are lighter the volume of air will tend to rise. The same way that if a number of molecules have more kinetic energy so tend to take up more room due to their more energetic collisions (temperature and pressure is higher) the volume of gas will tend to rise. But in practice the air does not tend to rise apart from when the air is unstable and prone to such movements, otherwise it would be a piece of cake to strap into a glider get towed to a few thousand feet and stay up there all day long every day of the year. We find in practice that even on days when it is as hot as hell on the ground there is no upwards movement of air until very many hours of sunshine have been able to create upwards movement at local trigger points such as hills, particular kinds of vegetation or suburban areas. Warm moist air finds it particularly difficult to move through the dryer colder layer of air above it, so it has to have a means whereby it can penetrate the upper layer. exactly now define what unstable air is " To be "unstable", the lowest layers of an air mass must be so warm and/or humid that, if some of the air rises, then that air parcel is warmer than its environment, and so it continues to rise. This is called moist convection." www.weatherquestions.com/What_is_an_unstable_air_mass.htm |
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Post by Ratty on Sept 20, 2016 0:59:47 GMT
[ Snip ] Ratty, I read the article you referenced until I came to this sentence. “In particular, it (the anthropogenic warming theory) assumes that the heat transfer in atmosphere occurs exclusively by radiation.” That to me is a strawman argument which is pretty easy to rebut. I haven’t read anything from any scientist who believes that the heat transfer in atmosphere occurs exclusively by radiation. Ratty, if you can find one who does, that would be interesting. On the other hand scientists do believe that radiation is the only way to transfer heat into and away from the earth’s atmosphere (into and from space). Radiation into and out of the earth’s atmosphere plays a major role in global temperatures. Greenhouse gases play a significant role in that transfer. Duwayne, I've been an interested onlooker in the whole debate for over twenty years but I have no scientific background and - at 71 - may have insufficient time left to build up an understanding.   EDIT: If you neglect the straw man, do you think the paper has any merit? PS: The title and use of language ** may suggest a hidden agenda? ** "Thus, petroleum production and other anthropogenic activities ..... " |
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Post by sigurdur on Sept 20, 2016 3:59:06 GMT
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Post by Andrew on Sept 20, 2016 4:51:26 GMT
But in practice the air does not tend to rise apart from when the air is unstable and prone to such movements, otherwise it would be a piece of cake to strap into a glider get towed to a few thousand feet and stay up there all day long every day of the year. We find in practice that even on days when it is as hot as hell on the ground there is no upwards movement of air until very many hours of sunshine have been able to create upwards movement at local trigger points such as hills, particular kinds of vegetation or suburban areas. Warm moist air finds it particularly difficult to move through the dryer colder layer of air above it, so it has to have a means whereby it can penetrate the upper layer. exactly now define what unstable air is " To be "unstable", the lowest layers of an air mass must be so warm and/or humid that, if some of the air rises, then that air parcel is warmer than its environment, and so it continues to rise. This is called moist convection." www.weatherquestions.com/What_is_an_unstable_air_mass.htmFor example when a high pressure area is forming the air is expanding which makes it easier to push away the upper layer trapping the warmer layers below, but when the high pressure area is decaying the air is descending and the air becomes 'stable'. Regardless, warm moist air cannot simply move upwards and pass through the layers of air that trap this huge mass of air nearer to the ground. The whole issue is however irrelevant anyway because it does not matter if the heat is down there or up there. Emission will cause the earth to be warmer than it would be without those emissions. Your theory depends entirely on some half baked idea you can cool things by heating them, which months ago i did my best to explain to you and Sigurdur was a complete misconception of the way IR heats water where it is not possible for IR to free the top molecules of water without most of the IR passing thru a layer of tens of thousands of other molecules to penetrate the water by some amount that is not at the absolute surface. |
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Post by Ratty on Sept 20, 2016 10:31:09 GMT
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Post by duwayne on Sept 20, 2016 11:40:50 GMT
[ Snip ] Ratty, I read the article you referenced until I came to this sentence. “In particular, it (the anthropogenic warming theory) assumes that the heat transfer in atmosphere occurs exclusively by radiation.” That to me is a strawman argument which is pretty easy to rebut. I haven’t read anything from any scientist who believes that the heat transfer in atmosphere occurs exclusively by radiation. Ratty, if you can find one who does, that would be interesting. On the other hand scientists do believe that radiation is the only way to transfer heat into and away from the earth’s atmosphere (into and from space). Radiation into and out of the earth’s atmosphere plays a major role in global temperatures. Greenhouse gases play a significant role in that transfer. Duwayne, I've been an interested onlooker in the whole debate for over twenty years but I have no scientific background and - at 71 - may have insufficient time left to build up an understanding. EDIT: If you neglect the straw man, do you think the paper has any merit? PS: The title and use of language ** may suggest a hidden agenda? ** "Thus, petroleum production and other anthropogenic activities ..... " Ratty, I only have a couple of minutes a day to spend on this site. I save time by not reading anything that Icefisher writes. But I want to finish my discussion with Nautonnier before I look further at the paper. |
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Post by duwayne on Sept 20, 2016 11:56:02 GMT
Nautonnier, I'm having trouble with the idea that nitrogen and oxygen molecules that are slightly cooler than the surrounding air will rise because there is a water vapor molecule nearby. I'll just note here that I wonder if clouds are an example of air stratification since they are condensed water and bring particulates into play. But unless that is a significant point in your arguments, let's not get into a side discussion. You should look at Avogadro's Hypothesis and Charles Law. It is a volume of air containing millions of molecules and in a particular volume at the same temperature and pressure Avogadro's Hypothesis (law in some docs) is that there will be the same number of molecules. If a percentage of molecules in a volume of air are lighter the volume of air will tend to rise. The same way that if a number of molecules have more kinetic energy so tend to take up more room due to their more energetic collisions (temperature and pressure is higher) the volume of gas will tend to rise. Nautonnier, the first sentence is supported by Avagadro, the third sentence is supported by Charles. But I don’t see any support for the middle sentence. Remember, we're not talking about a contained volume such as the contents of a balloon. But let’s go on to a second question concerning your original post (the one I copied from Astro’s site). Concerning the photons that are absorbed and reemitted by CO and based on your description of what happens to the photon energy, how much of that photon energy remains in the earth’s system? |
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