This study deal with interactions between thermal and radiative energy flow in experimental situations of varying complexity. Of special interest is how IR energy, re-emitted from CO<sub>2</sub> gas, behav...This study deal with interactions between thermal and radiative energy flow in experimental situations of varying complexity. Of special interest is how IR energy, re-emitted from CO<sub>2</sub> gas, behaves in an earth/atmosphere simulated setup. Such an experiment was performed by Hermann Harde and Michael Schnell where they show that IR radiation emitted from CO<sub>2</sub> can warm a small black-body metal plate. In a control experiment, we verified this result. However, in their experiment, the amount of IR radiation from the heating element was strongly attenuated. In a modified experiment, where IR emission from the heating source is present, no heating but a slight cooling of a black object is found when air is replaced by CO<sub>2</sub>. The modified experimental situation is also more like the earth/atmosphere situation. The presence of IR radiation from a heated surface (like when the sun heats the earth’s surface) strongly attenuates the heating ability of increasing backscatter from increased amount of CO<sub>2</sub> in the atmosphere. This result has consequences for the climate change models used by IPCC.展开更多
A simple experiment is described where the IR (infrared) radiation level is kept constant while the temperature of an IR absorbing and a non-absorbing solid object are changed. The two objects, made from black-painted...A simple experiment is described where the IR (infrared) radiation level is kept constant while the temperature of an IR absorbing and a non-absorbing solid object are changed. The two objects, made from black-painted and highly polished Al foil envelopes, respectively, are placed in a chamber where the temperature is controlled. When heated by the surrounding air the black object becomes about 40% colder than the non-IR absorbing object! However, when the two objects are cooled by the surrounding air, the black becomes ca. 40% warmer than the non-IR absorbing object (and the surrounding air). This effect was surprising to us, and it gave us an opportunity to quantify the relationship between IR radiation flow and thermal energy flow. The unexpected large value of the (Fourier) thermal conductivity coefficient was found to be the reason for the reduced warming/cooling of the black object. The interaction between radiative and thermal energy transfer, when an IR absorbing object (like the surface of the Earth) is warmed, should be included in the climate models used by the Intergovernmental Panel on Climate Change (IPCC), since the global land temperature is measured in the air above Earth’s surface. This leads to ca. 15% of the temperature increase predicted by the climate models.展开更多
The Greenhouse Effect was simulated in a laboratory setup, consisting of a heated ground area and two chambers, one filled with air and one filled with air or CO2. While heating the gas the temperature and IR radiatio...The Greenhouse Effect was simulated in a laboratory setup, consisting of a heated ground area and two chambers, one filled with air and one filled with air or CO2. While heating the gas the temperature and IR radiation in both chambers were measured. IR radiation was produced by heating a metal plate mounted on the rear wall. Reduced IR radiation through the front window was observed when the air in the foremost chamber was exchanged with CO2. In the rear chamber, we observed increased IR radiation due to backscatter from the front chamber. Based on the Stefan Boltzmann’s law, this should increase the temperature of the air in the rear chamber by 2.4 to 4 degrees, but no such increase was found. A thermopile, made to increase the sensitivity and accuracy of the temperature measurements, showed that the temperature with CO2 increased slightly, about 0.5%.展开更多
文摘This study deal with interactions between thermal and radiative energy flow in experimental situations of varying complexity. Of special interest is how IR energy, re-emitted from CO<sub>2</sub> gas, behaves in an earth/atmosphere simulated setup. Such an experiment was performed by Hermann Harde and Michael Schnell where they show that IR radiation emitted from CO<sub>2</sub> can warm a small black-body metal plate. In a control experiment, we verified this result. However, in their experiment, the amount of IR radiation from the heating element was strongly attenuated. In a modified experiment, where IR emission from the heating source is present, no heating but a slight cooling of a black object is found when air is replaced by CO<sub>2</sub>. The modified experimental situation is also more like the earth/atmosphere situation. The presence of IR radiation from a heated surface (like when the sun heats the earth’s surface) strongly attenuates the heating ability of increasing backscatter from increased amount of CO<sub>2</sub> in the atmosphere. This result has consequences for the climate change models used by IPCC.
文摘A simple experiment is described where the IR (infrared) radiation level is kept constant while the temperature of an IR absorbing and a non-absorbing solid object are changed. The two objects, made from black-painted and highly polished Al foil envelopes, respectively, are placed in a chamber where the temperature is controlled. When heated by the surrounding air the black object becomes about 40% colder than the non-IR absorbing object! However, when the two objects are cooled by the surrounding air, the black becomes ca. 40% warmer than the non-IR absorbing object (and the surrounding air). This effect was surprising to us, and it gave us an opportunity to quantify the relationship between IR radiation flow and thermal energy flow. The unexpected large value of the (Fourier) thermal conductivity coefficient was found to be the reason for the reduced warming/cooling of the black object. The interaction between radiative and thermal energy transfer, when an IR absorbing object (like the surface of the Earth) is warmed, should be included in the climate models used by the Intergovernmental Panel on Climate Change (IPCC), since the global land temperature is measured in the air above Earth’s surface. This leads to ca. 15% of the temperature increase predicted by the climate models.
文摘The Greenhouse Effect was simulated in a laboratory setup, consisting of a heated ground area and two chambers, one filled with air and one filled with air or CO2. While heating the gas the temperature and IR radiation in both chambers were measured. IR radiation was produced by heating a metal plate mounted on the rear wall. Reduced IR radiation through the front window was observed when the air in the foremost chamber was exchanged with CO2. In the rear chamber, we observed increased IR radiation due to backscatter from the front chamber. Based on the Stefan Boltzmann’s law, this should increase the temperature of the air in the rear chamber by 2.4 to 4 degrees, but no such increase was found. A thermopile, made to increase the sensitivity and accuracy of the temperature measurements, showed that the temperature with CO2 increased slightly, about 0.5%.
