Studies of Stratospheric and Tropospheric Ozone, NO2, and BrO Using UV-Visible Spectroscopy in the Arctic and at Mid-latitudes PDF Download
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Author: Kristof Bognar Publisher: ISBN: Category : Languages : en Pages :
Book Description
This thesis utilizes UV-visible spectroscopy to develop new datasets, study Arctic and urban atmospheric composition, and validate satellite data products. The primary instruments used here (the Ground-Based Spectrometers, or GBSs) have been taking measurements at the Polar Environment Atmospheric Research Laboratory (PEARL, 80.05°N, 86.42°W) since 1999 and 2006, respectively.The GBS dataset, combined with other measurements at PEARL, was used to validate ozone and NO2 measurements from the Atmospheric Chemistry Experiment (ACE) and Optical Spectrograph and InfraRed Imaging System (OSIRIS) satellite instruments. Ozone from all instruments agrees to within 12.0%, while NO2 measurements agree to within 33.2%. There are no apparent systematic changes in the observed differences between the satellite and the ground-based instruments over time. In the winter/spring of 2020, the unusually strong and cold polar vortex led to unprecedented Arctic ozone depletion. Total column ozone was at an all-time low in the 20-year GBS dataset. Chlorine activation inside the vortex was ongoing until the end of March, resulting in mean chemical ozone loss of 111-127 DU (27-31%) over Eureka, which represents similar absolute loss and greater relative loss compared to that in spring 2011. GBS BrO partial columns were used to investigate Arctic tropospheric ozone depletion during four bromine activation seasons. BrO enhancements show two modes differentiated by air mass history. Contact with the snowpack on sea ice corresponds to increased BrO for one of these modes only, while the other mode is related to storms that almost always bring bromine-enriched air to Eureka. The presence of coarse mode aerosols (likely sea salt aerosol) is a necessary and sufficient condition for observing BrO at Eureka, indicating that sea salt aerosols play an active role in bromine activation. A tropospheric NO2 profile dataset was retrieved from 2018-2020 Pandora spectrometer measurements to investigate NO2 pollution in Toronto. Retrievals using optimal estimation and parametric algorithms show good agreement. Seasonal and diurnal variability is apparent in both the NO2 partial column and surface concentration datasets. During the spring 2020 COVID-19 lockdown in Toronto, daily maximum NO2 values showed substantial reductions.
Author: Kristof Bognar Publisher: ISBN: Category : Languages : en Pages :
Book Description
This thesis utilizes UV-visible spectroscopy to develop new datasets, study Arctic and urban atmospheric composition, and validate satellite data products. The primary instruments used here (the Ground-Based Spectrometers, or GBSs) have been taking measurements at the Polar Environment Atmospheric Research Laboratory (PEARL, 80.05°N, 86.42°W) since 1999 and 2006, respectively.The GBS dataset, combined with other measurements at PEARL, was used to validate ozone and NO2 measurements from the Atmospheric Chemistry Experiment (ACE) and Optical Spectrograph and InfraRed Imaging System (OSIRIS) satellite instruments. Ozone from all instruments agrees to within 12.0%, while NO2 measurements agree to within 33.2%. There are no apparent systematic changes in the observed differences between the satellite and the ground-based instruments over time. In the winter/spring of 2020, the unusually strong and cold polar vortex led to unprecedented Arctic ozone depletion. Total column ozone was at an all-time low in the 20-year GBS dataset. Chlorine activation inside the vortex was ongoing until the end of March, resulting in mean chemical ozone loss of 111-127 DU (27-31%) over Eureka, which represents similar absolute loss and greater relative loss compared to that in spring 2011. GBS BrO partial columns were used to investigate Arctic tropospheric ozone depletion during four bromine activation seasons. BrO enhancements show two modes differentiated by air mass history. Contact with the snowpack on sea ice corresponds to increased BrO for one of these modes only, while the other mode is related to storms that almost always bring bromine-enriched air to Eureka. The presence of coarse mode aerosols (likely sea salt aerosol) is a necessary and sufficient condition for observing BrO at Eureka, indicating that sea salt aerosols play an active role in bromine activation. A tropospheric NO2 profile dataset was retrieved from 2018-2020 Pandora spectrometer measurements to investigate NO2 pollution in Toronto. Retrievals using optimal estimation and parametric algorithms show good agreement. Seasonal and diurnal variability is apparent in both the NO2 partial column and surface concentration datasets. During the spring 2020 COVID-19 lockdown in Toronto, daily maximum NO2 values showed substantial reductions.
Author: Xiaoyi Zhao Publisher: ISBN: Category : Languages : en Pages :
Book Description
Two UV-visible differential absorption spectroscopy (DOAS) ground-based spectrometers (GBSs) were installed at the Polar Environment Atmospheric Research Laboratory (PEARL) in the Canadian High Arctic (80.1o N, 86.4o W). These two instruments have been used to measure stratospheric trace gases since 1999 and 2006 respectively. In 2010 and 2014, two solar-tracking systems were integrated with the GBSs to make tropospheric trace gas measurements. One goal of this work was to study surface ozone depletion events (ODEs) in the Arctic, using data from the GBSs. The measurements of ozone and BrO, combined with model results, indicate that both high wind/blowing snow and low wind/stable boundary layer are favorable environmental conditions for bromine explosion events, and in some cases, the combination of these two conditions will extend the lifetime of a bromine explosion event. In addition, during a strong surface ODE (ozone VMR.
Author: Annemarie Catherine Fraser Publisher: ISBN: 9780494579886 Category : Languages : en Pages : 642
Book Description
A ground-based, zenith-sky, UV-visible triple grating spectrometer was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) in the Canadian High Arctic during polar springtime from 2004 to 2007 as part of the Canadian Arctic ACE (Atmospheric Chemistry Experiment) Validation Campaigns. From the solar spectra, ozone, NO2, and BrO vertical column densities (VCDs) have been retrieved using the DOAS (Differential Optical Absorption Spectroscopy) technique. This spectrometer, the UT-GBS (University of Toronto Ground-Based Spectrometer), was also deployed as part of the fourth Middle Atmosphere Nitrogen TRend Assessment (MANTRA) campaign in Vanscoy, Saskatchewan in August and September 2004.Ozone and NO2 DSCDs and VCDs from the UT-GBS were compared to the DSCDs and VCDs from three other UV-visible, ground-based, grating spectrometers that also participated in the MANTRA and Eureka campaigns. Two methods developed by the UV-visible Working Group of the NDACC (Network for the Detection of Atmospheric Composition Change) were followed. During MANTRA, the instruments were found to partially meet the NDACC standards. The comparisons from Eureka were an improvement on the MANTRA comparisons, and also partially met the NDACC standards. In 2007, the columns from the UT-GBS and PEARL-GBS were compared, and were found to agree within the NDACC standards for both species.Ozone and NO2 VCDs from the ground-based instruments were also compared to integrated partial columns from the ACE-FTS (ACE-Fourier Transform Spectrometer) and ACE-MAESTRO (ACE-Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) on board the ACE satellite. ACE-FTS partial columns were found to agree with the ground-based total columns, while the ACE-MAESTRO partial columns were found to be smaller than expected for ozone and larger than expected for NO 2.A near-identical spectrometer, the PEARL-GBS, was permanently installed at PEARL in August 2006 as part of the refurbishment of the laboratory by CANDAC (Canadian Network for the Detection of Atmospheric Change). Since then, the instrument has been making continuous measurements, with the exception of during polar night. Vertical columns of ozone and NO2 can be retrieved year-round. During the 2007 sunrise campaign, differential slant column densities (DSCDs) of OClO and VCDs of BrO were also retrieved.
Author: H. Niki Publisher: Springer Science & Business Media ISBN: 3642782116 Category : Science Languages : en Pages : 431
Book Description
The Arctic troposphere (0 to ca. 8 km) plays an important role in environmental concerns for global change. It is a unique chemical reactor influenced by human activity and the Arctic ocean. It is surrounded by industrialized continents that in winter contribute gaseous and particulate pollution (Arctic haze). It is underlain by the flat Arctic ocean from which it is separated by a crack-ridden ice membrane 3 to 4 m thick. Ocean to atmosphere exchange of heat, water vapor and marine biogenic gases influence the composition of the reactor. From September 21 to December 21 to March 21, the region north of the Arctic circle goes from a completely sunlit situation to a completely dark one and then back to light. At the same time the lower troposphere is stably stratified. This hinders vertical mixing. During this light period, surface temperature reaches as low as -40°C. In this environment, chemical reactions involving sunlight are generally much slower than further south. Thus, the abundance of photochemically reactive compounds in the atmosphere can be high prior to polar sunrise. Between complete dark in February and complete light in April, a number of chemical changes in the lower troposphere take place.
Author: Dwayne Heard Publisher: John Wiley & Sons ISBN: 1405171448 Category : Science Languages : en Pages : 528
Book Description
Almost all of the breakthroughs in understanding the atmospherehave been initiated by field observations, using a range ofinstrumental techniques. Developing or deploying instruments tomake further observations demands a thorough understanding of thechemical and spectroscopic principles on which such measurementsdepend. Written as an authoritative guide to the techniques of instrumentalmeasurement for the atmospheric scientist, research student orundergraduate, Analytical Techniques for Atmospheric Measurementfocuses on the instruments used to make real time measurements ofatmospheric gas and aerosol composition. Topics covered include howthey work, their strengths and weaknesses for a particular task,the platforms on which they have been deployed and how they arecalibrated. It explains the fundamental principles upon which theinstrumental techniques are based (ie what property of a moleculecan be exploited to enable its detection), what limits instrumentalsensitivity and accuracy, and the information that can be gainedfrom their use.
Author: Kristof Bognar
Author: Kristof Bognar
Author: Xiaoyi Zhao
Author: Cristen Adams
Author: Annemarie Fraser
Author: 
Author: Annemarie Catherine Fraser
Author: 
Author: H. Niki
Author: Dwayne Heard
Author: Cristen Luna Frith Adams