Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts
The Arctic region has seen dramatic changes over the past several decades, from polar amplification of global temperature rise to ecosystem changes to the decline of the sea ice. While there has been much speculation as to when the world will see an ice-free Arctic, the radiative impacts of an event...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20170007896 2023-05-15T13:10:30+02:00 Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts Eisenman, I. Pistone, K. Ramanathan, V. Unclassified, Unlimited, Publicly available July 16, 2017 application/pdf http://hdl.handle.net/2060/20170007896 unknown Document ID: 20170007896 http://hdl.handle.net/2060/20170007896 Copyright, Distribution under U.S. Government purpose rights CASI Earth Resources and Remote Sensing ARC-E-DAA-TN44791 Radiation amd Climate - Gordan Research Conference; 16-21 Jul. 2017; Lewiston, ME; United States 2017 ftnasantrs 2019-07-20T23:28:36Z The Arctic region has seen dramatic changes over the past several decades, from polar amplification of global temperature rise to ecosystem changes to the decline of the sea ice. While there has been much speculation as to when the world will see an ice-free Arctic, the radiative impacts of an eventual disappearance of the Arctic sea ice are likely to be significant regardless of the timing. Using CERES radiation and microwave satellite sea ice data, Pistone et al (2014) estimated the radiative forcing due to albedo changes associated with the Arctic sea ice retreat over the 30 years of the satellite data record. In this study, we found that the Arctic Ocean saw a decrease in all-sky albedo of 4% (from 52% to 48%), for an estimated increase in solar heating of 6.4 W/m(exp 2) between 1979 and 2011, or 0.21 W/m(exp 2) when averaged over the globe. This value is substantial--approximately 25% as large as the forcing due to the change in CO2 during the same period. Here we update and expand upon this previous work and use the CERES broadband shortwave observations to explore the radiative impacts of a transition to completely ice-free Arctic Ocean. We estimate the annually-averaged Arctic Ocean planetary albedo under ice-free and cloud-free conditions to be 14% over the region, or approximately 25% lower in absolute terms than the Arctic Ocean cloud-free albedo in 1979. However, the question of all-sky conditions (i.e. including the effects of clouds) introduces a new level of complexity. We explore several cloud scenarios and the resultant impact on albedo. In each of these cases, the estimated forcing is not uniformly distributed throughout the year. We describe the relative contributions of ice loss by month as well as the spatial distributions of the resulting changes in absorbed solar energy. The seasonal timing and locationin addition to magnitudeof the altered solar absorption may have significant implications for atmospheric and ocean dynamics in the Arctic and at lower latitudes; this observationally-based estimate of the large-scale characteristics of an ice-free Arctic thus provides a valuable tool to complement and validate model-based assessments of future climate. Other/Unknown Material albedo Arctic Arctic Ocean Sea ice NASA Technical Reports Server (NTRS) Arctic Arctic Ocean |
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NASA Technical Reports Server (NTRS) |
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Earth Resources and Remote Sensing |
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Earth Resources and Remote Sensing Eisenman, I. Pistone, K. Ramanathan, V. Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts |
topic_facet |
Earth Resources and Remote Sensing |
description |
The Arctic region has seen dramatic changes over the past several decades, from polar amplification of global temperature rise to ecosystem changes to the decline of the sea ice. While there has been much speculation as to when the world will see an ice-free Arctic, the radiative impacts of an eventual disappearance of the Arctic sea ice are likely to be significant regardless of the timing. Using CERES radiation and microwave satellite sea ice data, Pistone et al (2014) estimated the radiative forcing due to albedo changes associated with the Arctic sea ice retreat over the 30 years of the satellite data record. In this study, we found that the Arctic Ocean saw a decrease in all-sky albedo of 4% (from 52% to 48%), for an estimated increase in solar heating of 6.4 W/m(exp 2) between 1979 and 2011, or 0.21 W/m(exp 2) when averaged over the globe. This value is substantial--approximately 25% as large as the forcing due to the change in CO2 during the same period. Here we update and expand upon this previous work and use the CERES broadband shortwave observations to explore the radiative impacts of a transition to completely ice-free Arctic Ocean. We estimate the annually-averaged Arctic Ocean planetary albedo under ice-free and cloud-free conditions to be 14% over the region, or approximately 25% lower in absolute terms than the Arctic Ocean cloud-free albedo in 1979. However, the question of all-sky conditions (i.e. including the effects of clouds) introduces a new level of complexity. We explore several cloud scenarios and the resultant impact on albedo. In each of these cases, the estimated forcing is not uniformly distributed throughout the year. We describe the relative contributions of ice loss by month as well as the spatial distributions of the resulting changes in absorbed solar energy. The seasonal timing and locationin addition to magnitudeof the altered solar absorption may have significant implications for atmospheric and ocean dynamics in the Arctic and at lower latitudes; this observationally-based estimate of the large-scale characteristics of an ice-free Arctic thus provides a valuable tool to complement and validate model-based assessments of future climate. |
format |
Other/Unknown Material |
author |
Eisenman, I. Pistone, K. Ramanathan, V. |
author_facet |
Eisenman, I. Pistone, K. Ramanathan, V. |
author_sort |
Eisenman, I. |
title |
Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts |
title_short |
Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts |
title_full |
Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts |
title_fullStr |
Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts |
title_full_unstemmed |
Radiative Impacts of Further Arctic Sea Ice Melt: Using past Observations to Inform Future Climate Impacts |
title_sort |
radiative impacts of further arctic sea ice melt: using past observations to inform future climate impacts |
publishDate |
2017 |
url |
http://hdl.handle.net/2060/20170007896 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
albedo Arctic Arctic Ocean Sea ice |
genre_facet |
albedo Arctic Arctic Ocean Sea ice |
op_source |
CASI |
op_relation |
Document ID: 20170007896 http://hdl.handle.net/2060/20170007896 |
op_rights |
Copyright, Distribution under U.S. Government purpose rights |
_version_ |
1766231691805851648 |