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The 2009-�2010 Arctic polar stratospheric cloud season: a CALIPSO perspective

Pitts, M.C. and Poole, L.R. and Dörnbrack, A. and Thomason, L.W. (2011) The 2009-�2010 Arctic polar stratospheric cloud season: a CALIPSO perspective. Atmospheric Chemistry and Physics, 11, pp. 2161-2177. DOI: 10.5194/acp-11-2161-2011.

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Official URL: http://www.atmos-chem-phys.net/11/2161/2011/


Spaceborne lidar measurements from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) are used to provide a vortex-wide perspective of the 2009�2010 Arctic PSC (polar stratospheric cloud) season to complement more focused measurements from the European Union RECONCILE (reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) field campaign. The 2009�2010 Arctic winter was unusually cold at stratospheric levels from mid-December 2009 until the end of January 2010, and was one of only a few winters from the past fifty-two years with synoptic-scale regions of temperatures below the frost point. More PSCs were observed by CALIPSO during the 2009�2010 Arctic winter than in the previous three Arctic seasons combined. In particular, there were significantly more observations of high number density NAT (nitric acid trihydrate) mixtures (referred to as Mix 2-enh) and ice PSCs. We found that the 2009�2010 season could roughly be divided into four periods with distinctly different PSC optical characteristics. The early season (15� 30 December 2009) was characterized by patchy, tenuous PSCs, primarily low number density liquid/NAT mixtures. No ice clouds were observed by CALIPSO during this early phase, suggesting that these early season NAT clouds were formed through a non-ice nucleation mechanism. The second phase of the season (31 December 2009�14 January 2010) was characterized by frequent mountain wave ice clouds that nucleated widespread NAT particles throughout the vortex, including Mix 2-enh. The third phase of the season (15� 21 January 2010) was characterized by synoptic-scale temperatures below the frost point which led to a rare outbreak of widespread ice clouds. The fourth phase of the season (22�28 January) was characterized by a major stratospheric warming that distorted the vortex, displacing the cold pool from the vortex center. This final phase was dominated by STS (supercooled ternary solution) PSCs, although NAT particles may have been present in low number densities, but were masked by the more abundant STS droplets at colder temperatures. We also found distinct variations in the relative proportion of PSCs in each composition class with altitude over the course of the 2009�2010 Arctic season. Lower number density liquid/NAT mixtures were most frequently observed in the lower altitude regions of the clouds (below �18�20 km), which is consistent with CALIPSO observations in the Antarctic. Higher number density liquid/NAT mixtures, especially Mix 2-enh, were most frequently observed at altitudes above 18�20 km, primarily downstream of wave ice clouds. This pattern is consistent with the conceptual model whereby low number density, large NAT particles are precipitated from higher number density NAT clouds (i.e. mother clouds) that are nucleated downstream of mountain wave ice clouds.

Document Type:Article
Title:The 2009-�2010 Arctic polar stratospheric cloud season: a CALIPSO perspective
AuthorsInstitution or Email of Authors
Pitts, M.C.NASA Langley Research Center, Hampton, VA, USA
Poole, L.R.Science Systems and Applications, Inc, Hampton, VA, USA
Dörnbrack, A.DLR
Thomason, L.W.NASA Langley Research Center, Hampton, VA, USA
Journal or Publication Title:Atmospheric Chemistry and Physics
Refereed publication:Yes
In Open Access:Yes
In ISI Web of Science:Yes
Page Range:pp. 2161-2177
Keywords:Arktische Grenzschicht
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space, Transport
HGF - Program Themes:Earth Observation, Transport System
DLR - Research area:Raumfahrt, Transport
DLR - Program:R EO - Erdbeobachtung, V VS - Verkehrssystem
DLR - Research theme (Project):R - Vorhaben LIDAR-Forschung und -Entwicklung, V - Verkehrsentwicklung und Umwelt (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Cloud Physics and Traffic Meteorology
Deposited By: Jana Freund
Deposited On:13 May 2011 14:11
Last Modified:12 Dec 2013 21:17

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