English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Spaceborne lidar measurements from CALIPSO (Cloud-Aerosol Lidar and InfraredPathfinder Satellite Observations) are used to provide a vortex-wideperspective of the 2009–2010 Arctic PSC (polar stratospheric cloud) seasonto complement more focused measurements from the European Union RECONCILE(reconciliation of essential process parameters for an enhancedpredictability of Arctic stratospheric ozone loss and its climateinteractions) field campaign. The 2009–2010 Arctic winter was unusually coldat stratospheric levels from mid-December 2009 until the end of January2010, and was one of only a few winters from the past fifty-two years withsynoptic-scale regions of temperatures below the frost point. More PSCs wereobserved by CALIPSO during the 2009–2010 Arctic winter than in the previousthree Arctic seasons combined. In particular, there were significantly moreobservations of high number density NAT (nitric acid trihydrate) mixtures(referred to as Mix 2-enh) and ice PSCs. We found that the 2009–2010 seasoncould roughly be divided into four periods with distinctly different PSCoptical characteristics. The early season (15–30 December 2009) wascharacterized by patchy, tenuous PSCs, primarily low number densityliquid/NAT mixtures. No ice clouds were observed by CALIPSO during thisearly phase, suggesting that these early season NAT clouds were formedthrough a non-ice nucleation mechanism. The second phase of the season (31 December 2009–14 January 2010) was characterized by frequent mountainwave ice clouds that nucleated widespread NAT particles throughout thevortex, including Mix 2-enh. The third phase of the season (15–21 January 2010) was characterized by synoptic-scale temperatures below the frost pointwhich led to a rare outbreak of widespread ice clouds. The fourth phase ofthe season (22–28 January) was characterized by a major stratosphericwarming that distorted the vortex, displacing the cold pool from the vortexcenter. 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. Wealso found distinct variations in the relative proportion of PSCs in eachcomposition class with altitude over the course of the 2009–2010 Arcticseason. Lower number density liquid/NAT mixtures were most frequentlyobserved in the lower altitude regions of the clouds (below ~18–20 km), which is consistent with CALIPSO observations in the Antarctic. Highernumber density liquid/NAT mixtures, especially Mix 2-enh, were mostfrequently observed at altitudes above 18–20 km, primarily downstream ofwave ice clouds. This pattern is consistent with the conceptual modelwhereby low number density, large NAT particles are precipitated from highernumber density NAT clouds (i.e. mother clouds) that are nucleated downstreamof mountain wave ice clouds

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