Importance of Orography for Greenland cloud and melt response to atmospheric blocking
Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. Importan...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/26251 2023-05-15T16:23:49+02:00 Importance of Orography for Greenland cloud and melt response to atmospheric blocking Hahn, Lily Storelvmo, Trude Hofer, Stefan Parfitt, Rhys Ummenhofer, Caroline C. 2020-04-16 https://hdl.handle.net/1912/26251 unknown American Meteorological Society https://doi.org/10.1175/JCLI-D-19-0527.1 Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. (2020). Importance of Orography for Greenland cloud and melt response to atmospheric blocking. Journal of Climate, 33(10), 4187-4206. https://hdl.handle.net/1912/26251 doi:10.1175/JCLI-D-19-0527.1 Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. (2020). Importance of Orography for Greenland cloud and melt response to atmospheric blocking. Journal of Climate, 33(10), 4187-4206. doi:10.1175/JCLI-D-19-0527.1 Ice sheets Blocking Cloud cover Topographic effects Climate change Climate variability Article 2020 ftwhoas https://doi.org/10.1175/JCLI-D-19-0527.1 2022-05-28T23:03:50Z Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. Importance of Orography for Greenland cloud and melt response to atmospheric blocking. Journal of Climate, 33(10), (2020): 4187-4206, doi:10.1175/JCLI-D-19-0527.1. More frequent high pressure conditions associated with atmospheric blocking episodes over Greenland in recent decades have been suggested to enhance melt through large-scale subsidence and cloud dissipation, which allows more solar radiation to reach the ice sheet surface. Here we investigate mechanisms linking high pressure circulation anomalies to Greenland cloud changes and resulting cloud radiative effects, with a focus on the previously neglected role of topography. Using reanalysis and satellite data in addition to a regional climate model, we show that anticyclonic circulation anomalies over Greenland during recent extreme blocking summers produce cloud changes dependent on orographic lift and descent. The resulting increased cloud cover over northern Greenland promotes surface longwave warming, while reduced cloud cover in southern and marginal Greenland favors surface shortwave warming. Comparison with an idealized model simulation with flattened topography reveals that orographic effects were necessary to produce area-averaged decreasing cloud cover since the mid-1990s and the extreme melt observed in the summer of 2012. This demonstrates a key role for Greenland topography in mediating the cloud and melt response to large-scale circulation variability. These results suggest that future melt will depend on the pattern of circulation anomalies as well as the shape of the Greenland Ice Sheet. This research was supported by the Woods Hole Oceanographic Institution Summer Student Fellow program, by the U.S. National Science Foundation under AGS-1355339 to ... Article in Journal/Newspaper Greenland Ice Sheet Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Greenland Storelvmo ENVELOPE(15.540,15.540,67.382,67.382) Journal of Climate 33 10 4187 4206 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
unknown |
topic |
Ice sheets Blocking Cloud cover Topographic effects Climate change Climate variability |
spellingShingle |
Ice sheets Blocking Cloud cover Topographic effects Climate change Climate variability Hahn, Lily Storelvmo, Trude Hofer, Stefan Parfitt, Rhys Ummenhofer, Caroline C. Importance of Orography for Greenland cloud and melt response to atmospheric blocking |
topic_facet |
Ice sheets Blocking Cloud cover Topographic effects Climate change Climate variability |
description |
Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. Importance of Orography for Greenland cloud and melt response to atmospheric blocking. Journal of Climate, 33(10), (2020): 4187-4206, doi:10.1175/JCLI-D-19-0527.1. More frequent high pressure conditions associated with atmospheric blocking episodes over Greenland in recent decades have been suggested to enhance melt through large-scale subsidence and cloud dissipation, which allows more solar radiation to reach the ice sheet surface. Here we investigate mechanisms linking high pressure circulation anomalies to Greenland cloud changes and resulting cloud radiative effects, with a focus on the previously neglected role of topography. Using reanalysis and satellite data in addition to a regional climate model, we show that anticyclonic circulation anomalies over Greenland during recent extreme blocking summers produce cloud changes dependent on orographic lift and descent. The resulting increased cloud cover over northern Greenland promotes surface longwave warming, while reduced cloud cover in southern and marginal Greenland favors surface shortwave warming. Comparison with an idealized model simulation with flattened topography reveals that orographic effects were necessary to produce area-averaged decreasing cloud cover since the mid-1990s and the extreme melt observed in the summer of 2012. This demonstrates a key role for Greenland topography in mediating the cloud and melt response to large-scale circulation variability. These results suggest that future melt will depend on the pattern of circulation anomalies as well as the shape of the Greenland Ice Sheet. This research was supported by the Woods Hole Oceanographic Institution Summer Student Fellow program, by the U.S. National Science Foundation under AGS-1355339 to ... |
format |
Article in Journal/Newspaper |
author |
Hahn, Lily Storelvmo, Trude Hofer, Stefan Parfitt, Rhys Ummenhofer, Caroline C. |
author_facet |
Hahn, Lily Storelvmo, Trude Hofer, Stefan Parfitt, Rhys Ummenhofer, Caroline C. |
author_sort |
Hahn, Lily |
title |
Importance of Orography for Greenland cloud and melt response to atmospheric blocking |
title_short |
Importance of Orography for Greenland cloud and melt response to atmospheric blocking |
title_full |
Importance of Orography for Greenland cloud and melt response to atmospheric blocking |
title_fullStr |
Importance of Orography for Greenland cloud and melt response to atmospheric blocking |
title_full_unstemmed |
Importance of Orography for Greenland cloud and melt response to atmospheric blocking |
title_sort |
importance of orography for greenland cloud and melt response to atmospheric blocking |
publisher |
American Meteorological Society |
publishDate |
2020 |
url |
https://hdl.handle.net/1912/26251 |
long_lat |
ENVELOPE(15.540,15.540,67.382,67.382) |
geographic |
Greenland Storelvmo |
geographic_facet |
Greenland Storelvmo |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. (2020). Importance of Orography for Greenland cloud and melt response to atmospheric blocking. Journal of Climate, 33(10), 4187-4206. doi:10.1175/JCLI-D-19-0527.1 |
op_relation |
https://doi.org/10.1175/JCLI-D-19-0527.1 Hahn, L. C., Storelvmo, T., Hofer, S., Parfitt, R., & Ummenhofer, C. C. (2020). Importance of Orography for Greenland cloud and melt response to atmospheric blocking. Journal of Climate, 33(10), 4187-4206. https://hdl.handle.net/1912/26251 doi:10.1175/JCLI-D-19-0527.1 |
op_doi |
https://doi.org/10.1175/JCLI-D-19-0527.1 |
container_title |
Journal of Climate |
container_volume |
33 |
container_issue |
10 |
container_start_page |
4187 |
op_container_end_page |
4206 |
_version_ |
1766012150664396800 |