Citation: Bock, L. and Burkhardt, U.: Contrail cirrus radiative forcing for future air traffic, Atmos. Chem. Phys., 19, 8163–8174, https://doi.org/10.5194/acp-19-8163-2019, 2019.
\n\"The climate impact of air traffic is to a large degree caused by changes in cirrus cloudiness resulting from the formation of contrails. Contrail cirrus radiative forcing is expected to increase significantly over time due to the large projected increases in air traffic. The authors used ECHAM5-CCMod, an atmospheric climate model with an online contrail cirrus parameterization including a microphysical two-moment scheme, to investigate the climate impact of contrail cirrus for the year 2050. They took into account the predicted increase in air traffic volume, changes in propulsion efficiency and emissions, in particular soot emissions, and the modification of the contrail cirrus climate impact due to anthropogenic climate change.\"
\n\"Global contrail cirrus radiative forcing increases by a factor of 3 from 2006 to 2050, reaching 160 or even 180 mW m−2, which is the result of the increase in air traffic volume and a slight shift in air traffic towards higher altitudes. \"
\n\"Climate change has an insignificant impact on global contrail cirrus radiative forcing, while regional changes are significant. The strong increase in contrail cirrus radiative forcing due to the projected increase in air traffic volume cannot be compensated for by the decrease in initial ice crystal numbers due to reduced soot emissions and improvements in propulsion efficiency.\"
\nhttps://acp.copernicus.org/articles/19/8163/2019/
\nAuthors: Denis Avila , Lance Sherry , Terry Thompson - https://doi.org/10.1016/j.trip.2019.100033
\n\"The anthropogenic (human made) condensation trails, or “contrails,” create a green-house effect by absorbing or directing back to Earth approximately 33% of emitted outgoing longwave radiation. Although this effect is estimated to be <2% of the Earth's total anthropogenic radiative forcing, the effect on global warming is immediate, unlike CO2 emissions which have a two decade delay in affecting global warming. Policy makers and industry have asked what is the potential for mitigating contrails through operational changes in air traffic control and flight planning.\"
\n\"Previous research calculated contrail inventories for the whole U.S. National Airspace System (NAS) over one year: on an average day only 15% of the flights (34% maximum) generated contrails, most of the contrails were generated in the south-eastern United States and the Pacific coast, and 63% of the total Contrail Along Track Distance was generated from June to September. This information suggests a possibility of mitigating the green-house effect of contrails by seasonally targeting a small set of flights.\"
\n\"This paper describes the benefits of adjusting the Cruise Flight Level of a limited number of flights in the U.S. NAS that are flight planned to fly through Ice Super Saturated (ISS) regions that are conducive to the formation of persistent contrails. The analysis found that elevating the Cruise Flight Level of contrail generating flights by 2000′ or 4000′, reduced the number of average daily flights with contrails by an average of −14.8%, the Net Radiative Forcing by an average of −92%, with an average net small decrease in fuel-burn of <1% (due to lower Drag at higher altitudes). The implications of these results and the limitations of the method were discussed.\"
\n\"Analyzing the NRF (Net Radiative Forcing) impact of laying contrails directly on top of each other for flights on the same en-route airways, would require changes to the RF model. Other mitigations take into account the shifting trajectories over existing, natural clouds, shifting trajectories to fly over surface areas with low ALBEDO and away from high ALBEDO surfaces, avoiding ISS (Ice Super Saturated) regions with specific atmospheric properties that result in contrails with greater shortwave ALBEDO and less longwave albedo (e.g. sea salt).
\nhttps://www.sciencedirect.com/science/article/pii/S2590198219300338
\n\"Albedo is defined as the proportion of radiation reflected by a horizontal surface.\"
\n\"Albedo (or solar reflectivity) plays an important role in the thermal behavior of pavements and other ground surfaces and their resultant impacts on humans and the environment.\"
\n\" An empirical relationship between the cooling effect of increased albedo on a pavement’s high temperature and solar radiation was developed. The cooling effect has a positive correlation with the peak solar radiation intensity.\"
\nhttps://www.sciencedirect.com/topics/engineering/albedo
", "messages": [ { "id": 2254388, "postDate": "2023-05-10T22:57:30.510Z", "content": "Citation: Bock, L. and Burkhardt, U.: Contrail cirrus radiative forcing for future air traffic, Atmos. Chem. Phys., 19, 8163–8174, https://doi.org/10.5194/acp-19-8163-2019, 2019.
\n\"The climate impact of air traffic is to a large degree caused by changes in cirrus cloudiness resulting from the formation of contrails. Contrail cirrus radiative forcing is expected to increase significantly over time due to the large projected increases in air traffic. The authors used ECHAM5-CCMod, an atmospheric climate model with an online contrail cirrus parameterization including a microphysical two-moment scheme, to investigate the climate impact of contrail cirrus for the year 2050. They took into account the predicted increase in air traffic volume, changes in propulsion efficiency and emissions, in particular soot emissions, and the modification of the contrail cirrus climate impact due to anthropogenic climate change.\"
\n\"Global contrail cirrus radiative forcing increases by a factor of 3 from 2006 to 2050, reaching 160 or even 180 mW m−2, which is the result of the increase in air traffic volume and a slight shift in air traffic towards higher altitudes. \"
\n\"Climate change has an insignificant impact on global contrail cirrus radiative forcing, while regional changes are significant. The strong increase in contrail cirrus radiative forcing due to the projected increase in air traffic volume cannot be compensated for by the decrease in initial ice crystal numbers due to reduced soot emissions and improvements in propulsion efficiency.\"
\nhttps://acp.copernicus.org/articles/19/8163/2019/
\nAuthors: Denis Avila , Lance Sherry , Terry Thompson - https://doi.org/10.1016/j.trip.2019.100033
\n\"The anthropogenic (human made) condensation trails, or “contrails,” create a green-house effect by absorbing or directing back to Earth approximately 33% of emitted outgoing longwave radiation. Although this effect is estimated to be <2% of the Earth's total anthropogenic radiative forcing, the effect on global warming is immediate, unlike CO2 emissions which have a two decade delay in affecting global warming. Policy makers and industry have asked what is the potential for mitigating contrails through operational changes in air traffic control and flight planning.\"
\n\"Previous research calculated contrail inventories for the whole U.S. National Airspace System (NAS) over one year: on an average day only 15% of the flights (34% maximum) generated contrails, most of the contrails were generated in the south-eastern United States and the Pacific coast, and 63% of the total Contrail Along Track Distance was generated from June to September. This information suggests a possibility of mitigating the green-house effect of contrails by seasonally targeting a small set of flights.\"
\n\"This paper describes the benefits of adjusting the Cruise Flight Level of a limited number of flights in the U.S. NAS that are flight planned to fly through Ice Super Saturated (ISS) regions that are conducive to the formation of persistent contrails. The analysis found that elevating the Cruise Flight Level of contrail generating flights by 2000′ or 4000′, reduced the number of average daily flights with contrails by an average of −14.8%, the Net Radiative Forcing by an average of −92%, with an average net small decrease in fuel-burn of <1% (due to lower Drag at higher altitudes). The implications of these results and the limitations of the method were discussed.\"
\n\"Analyzing the NRF (Net Radiative Forcing) impact of laying contrails directly on top of each other for flights on the same en-route airways, would require changes to the RF model. Other mitigations take into account the shifting trajectories over existing, natural clouds, shifting trajectories to fly over surface areas with low ALBEDO and away from high ALBEDO surfaces, avoiding ISS (Ice Super Saturated) regions with specific atmospheric properties that result in contrails with greater shortwave ALBEDO and less longwave albedo (e.g. sea salt).
\nhttps://www.sciencedirect.com/science/article/pii/S2590198219300338
\n\"Albedo is defined as the proportion of radiation reflected by a horizontal surface.\"
\n\"Albedo (or solar reflectivity) plays an important role in the thermal behavior of pavements and other ground surfaces and their resultant impacts on humans and the environment.\"
\n\" An empirical relationship between the cooling effect of increased albedo on a pavement’s high temperature and solar radiation was developed. The cooling effect has a positive correlation with the peak solar radiation intensity.\"
\nhttps://www.sciencedirect.com/topics/engineering/albedo
", "rawMarkdown": "#Contrail cirrus radiative forcing for future air traffic\n\nCitation: Bock, L. and Burkhardt, U.: Contrail cirrus radiative forcing for future air traffic, Atmos. Chem. Phys., 19, 8163–8174, https://doi.org/10.5194/acp-19-8163-2019, 2019.\n\n\"The climate impact of air traffic is to a large degree caused by changes in cirrus cloudiness resulting from the formation of contrails. Contrail cirrus radiative forcing is expected to increase significantly over time due to the large projected increases in air traffic. The authors used ECHAM5-CCMod, an atmospheric climate model with an online contrail cirrus parameterization including a microphysical two-moment scheme, to investigate the climate impact of contrail cirrus for the year 2050. They took into account the predicted increase in air traffic volume, changes in propulsion efficiency and emissions, in particular soot emissions, and the modification of the contrail cirrus climate impact due to anthropogenic climate change.\"\n\n\"Global contrail cirrus radiative forcing increases by a factor of 3 from 2006 to 2050, reaching 160 or even 180 mW m−2, which is the result of the increase in air traffic volume and a slight shift in air traffic towards higher altitudes. \" \n\n\"Climate change has an insignificant impact on global contrail cirrus radiative forcing, while regional changes are significant. The strong increase in contrail cirrus radiative forcing due to the projected increase in air traffic volume cannot be compensated for by the decrease in initial ice crystal numbers due to reduced soot emissions and improvements in propulsion efficiency.\"\n\nhttps://acp.copernicus.org/articles/19/8163/2019/\n\n#Reducing global warming by airline contrail avoidance: A case study of annual benefits for the contiguous United States\n\nAuthors: Denis Avila , Lance Sherry , Terry Thompson - https://doi.org/10.1016/j.trip.2019.100033\n\n\"The anthropogenic (human made) condensation trails, or “contrails,” create a green-house effect by absorbing or directing back to Earth approximately 33% of emitted outgoing longwave radiation. Although this effect is estimated to be <2% of the Earth's total anthropogenic radiative forcing, the effect on global warming is immediate, unlike CO2 emissions which have a two decade delay in affecting global warming. Policy makers and industry have asked what is the potential for mitigating contrails through operational changes in air traffic control and flight planning.\"\n\n\"Previous research calculated contrail inventories for the whole U.S. National Airspace System (NAS) over one year: on an average day only 15% of the flights (34% maximum) generated contrails, most of the contrails were generated in the south-eastern United States and the Pacific coast, and 63% of the total Contrail Along Track Distance was generated from June to September. This information suggests a possibility of mitigating the green-house effect of contrails by seasonally targeting a small set of flights.\"\n\n\"This paper describes the benefits of adjusting the Cruise Flight Level of a limited number of flights in the U.S. NAS that are flight planned to fly through Ice Super Saturated (ISS) regions that are conducive to the formation of persistent contrails. The analysis found that elevating the Cruise Flight Level of contrail generating flights by 2000′ or 4000′, reduced the number of average daily flights with contrails by an average of −14.8%, the Net Radiative Forcing by an average of −92%, with an average net small decrease in fuel-burn of <1% (due to lower Drag at higher altitudes). The implications of these results and the limitations of the method were discussed.\"\n\n\"Analyzing the NRF (Net Radiative Forcing) impact of laying contrails directly on top of each other for flights on the same en-route airways, would require changes to the RF model. Other mitigations take into account the shifting trajectories over existing, natural clouds, shifting trajectories to fly over surface areas with low ALBEDO and away from high ALBEDO surfaces, avoiding ISS (Ice Super Saturated) regions with specific atmospheric properties that result in contrails with greater shortwave ALBEDO and less longwave albedo (e.g. sea salt).\n\nhttps://www.sciencedirect.com/science/article/pii/S2590198219300338\n\n#Albedo\n\n\"Albedo is defined as the proportion of radiation reflected by a horizontal surface.\"\n\n\"Albedo (or solar reflectivity) plays an important role in the thermal behavior of pavements and other ground surfaces and their resultant impacts on humans and the environment.\"\n\n\" An empirical relationship between the cooling effect of increased albedo on a pavement’s high temperature and solar radiation was developed. The cooling effect has a positive correlation with the peak solar radiation intensity.\"\n\nhttps://www.sciencedirect.com/topics/engineering/albedo", "votes": 6 }, { "id": 2277322, "postDate": "2023-05-27T15:52:47.383Z", "content": "While this competition is helping reduce the global warming by ML, there are articles on how ML and AI are contributing to large scale carbon emmission.
\nIn this competition, as many teams will be simultaneously running ML on large data sets,
\nCarbon foot print of this activity can be manifolds.
\nCompetition rules should also facilitate carbon emmission reduction.
\nFollow the kaggle discussion thread on this topic
\nhttps://www.kaggle.com/discussions/general/413224
Very interesting topic Kumar. Another point-of-view of AI and carbon emissions.
", "rawMarkdown": "Very interesting topic Kumar. Another point-of-view of AI and carbon emissions." } ] } ], "comments": [ { "id": 2277322, "author_name": "C R Suthikshn Kumar", "author_url": "", "post_date": "2023-05-27T15:52:47.383000", "content": "While this competition is helping reduce the global warming by ML, there are articles on how ML and AI are contributing to large scale carbon emmission.
\nIn this competition, as many teams will be simultaneously running ML on large data sets,
\nCarbon foot print of this activity can be manifolds.
\nCompetition rules should also facilitate carbon emmission reduction.
\nFollow the kaggle discussion thread on this topic
\nhttps://www.kaggle.com/discussions/general/413224
Very interesting topic Kumar. Another point-of-view of AI and carbon emissions.
", "votes": 0, "replies": [] } ] } ], "raw_markdown_by_id": { "2254388": "#Contrail cirrus radiative forcing for future air traffic\n\nCitation: Bock, L. and Burkhardt, U.: Contrail cirrus radiative forcing for future air traffic, Atmos. Chem. Phys., 19, 8163–8174, https://doi.org/10.5194/acp-19-8163-2019, 2019.\n\n\"The climate impact of air traffic is to a large degree caused by changes in cirrus cloudiness resulting from the formation of contrails. Contrail cirrus radiative forcing is expected to increase significantly over time due to the large projected increases in air traffic. The authors used ECHAM5-CCMod, an atmospheric climate model with an online contrail cirrus parameterization including a microphysical two-moment scheme, to investigate the climate impact of contrail cirrus for the year 2050. They took into account the predicted increase in air traffic volume, changes in propulsion efficiency and emissions, in particular soot emissions, and the modification of the contrail cirrus climate impact due to anthropogenic climate change.\"\n\n\"Global contrail cirrus radiative forcing increases by a factor of 3 from 2006 to 2050, reaching 160 or even 180 mW m−2, which is the result of the increase in air traffic volume and a slight shift in air traffic towards higher altitudes. \" \n\n\"Climate change has an insignificant impact on global contrail cirrus radiative forcing, while regional changes are significant. The strong increase in contrail cirrus radiative forcing due to the projected increase in air traffic volume cannot be compensated for by the decrease in initial ice crystal numbers due to reduced soot emissions and improvements in propulsion efficiency.\"\n\nhttps://acp.copernicus.org/articles/19/8163/2019/\n\n#Reducing global warming by airline contrail avoidance: A case study of annual benefits for the contiguous United States\n\nAuthors: Denis Avila , Lance Sherry , Terry Thompson - https://doi.org/10.1016/j.trip.2019.100033\n\n\"The anthropogenic (human made) condensation trails, or “contrails,” create a green-house effect by absorbing or directing back to Earth approximately 33% of emitted outgoing longwave radiation. Although this effect is estimated to be <2% of the Earth's total anthropogenic radiative forcing, the effect on global warming is immediate, unlike CO2 emissions which have a two decade delay in affecting global warming. Policy makers and industry have asked what is the potential for mitigating contrails through operational changes in air traffic control and flight planning.\"\n\n\"Previous research calculated contrail inventories for the whole U.S. National Airspace System (NAS) over one year: on an average day only 15% of the flights (34% maximum) generated contrails, most of the contrails were generated in the south-eastern United States and the Pacific coast, and 63% of the total Contrail Along Track Distance was generated from June to September. This information suggests a possibility of mitigating the green-house effect of contrails by seasonally targeting a small set of flights.\"\n\n\"This paper describes the benefits of adjusting the Cruise Flight Level of a limited number of flights in the U.S. NAS that are flight planned to fly through Ice Super Saturated (ISS) regions that are conducive to the formation of persistent contrails. The analysis found that elevating the Cruise Flight Level of contrail generating flights by 2000′ or 4000′, reduced the number of average daily flights with contrails by an average of −14.8%, the Net Radiative Forcing by an average of −92%, with an average net small decrease in fuel-burn of <1% (due to lower Drag at higher altitudes). The implications of these results and the limitations of the method were discussed.\"\n\n\"Analyzing the NRF (Net Radiative Forcing) impact of laying contrails directly on top of each other for flights on the same en-route airways, would require changes to the RF model. Other mitigations take into account the shifting trajectories over existing, natural clouds, shifting trajectories to fly over surface areas with low ALBEDO and away from high ALBEDO surfaces, avoiding ISS (Ice Super Saturated) regions with specific atmospheric properties that result in contrails with greater shortwave ALBEDO and less longwave albedo (e.g. sea salt).\n\nhttps://www.sciencedirect.com/science/article/pii/S2590198219300338\n\n#Albedo\n\n\"Albedo is defined as the proportion of radiation reflected by a horizontal surface.\"\n\n\"Albedo (or solar reflectivity) plays an important role in the thermal behavior of pavements and other ground surfaces and their resultant impacts on humans and the environment.\"\n\n\" An empirical relationship between the cooling effect of increased albedo on a pavement’s high temperature and solar radiation was developed. The cooling effect has a positive correlation with the peak solar radiation intensity.\"\n\nhttps://www.sciencedirect.com/topics/engineering/albedo", "2277322": "While this competition is helping reduce the global warming by ML, there are articles on how ML and AI are contributing to large scale carbon emmission.\nIn this competition, as many teams will be simultaneously running ML on large data sets, \nCarbon foot print of this activity can be manifolds.\n**Competition rules should also facilitate carbon emmission reduction.**\nFollow the kaggle discussion thread on this topic\nhttps://www.kaggle.com/discussions/general/413224\n" } }