The motivation for this thesis was to study chemical and dynamical processes in the Arctic stratosphere, using data from two ground-based spectrometers (GBSs). The GBSs took atmospheric trace gas measurements at the Polar Environment Atmospheric Research Laboratory (PEARL), which is located at Eureka, Nunavut, Canada (80.05°N, 86.42°W) and operated by the Canadian Network for the Detection of Atmospheric Change. The University of Toronto GBS took measurements at Eureka on a campaign basis from 1999 2011. The PEARL GBS was installed permanently at Eureka in 2006 and has taken measurements during the sunlit part of the year since then.
GBS and other ground based ozone and NO2 column measurements were compared with Atmospheric Chemistry Experiment (ACE) and Optical Spectrograph and Infra Red Imaging System (OSIRIS) satellite measurements above Eureka. Ozone from all instruments agreed within 9.2%, while NO2 from most instruments, including the GBS, agreed to within 20%.
On 1 August 2008, a solar eclipse of 98% totality passed over Eureka. GBS NO2 increased to 1.84 times normal levels. This agrees with a ratio of 1.91 that was calculated using a photochemical model, adjusted for reduced sunlight during the eclipse.
In spring/winter 2011, up to 47% (250 DU) ozone loss was calculated using GBS and modeled passive ozone. This was the largest ozone loss in the 11 year GBS measurement record. GBS OClO was elevated, indicating chlorine activation and NO2 was low, suggesting denitrification. GBS, satellite, and chemical transport model data were used to investigate the 2011 vortex breakup. NOx transport led to middle stratosphere ozone loss within an anticyclone. Furthermore, isolated, or “frozen-in”, vortex and lower-latitude airmasses were observed following the vortex breakup.
Stratospheric BrO was retrieved from spring 2008 GBS zenith sky measurements, using an optimal estimation technique. GBS BrO was compared with OSIRIS and Ozone Monitoring Instrument (OMI) satellite data. Discrepancies are partly attributed to bromine explosions in the boundary layer. New off axis GBS measurements taken in spring 2010 are sensitive to boundary layer bromine. The combination of GBS stratospheric and tropospheric BrO measurements will be useful for future estimates of the Arctic bromine budget.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/33898 |
| Date | 06 December 2012 |
| Creators | Adams, Cristen |
| Contributors | Strong, Kimberly |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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