Kristof Bognar
A5060016808- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Cryospheric studies and observations
- Arctic and Antarctic ice dynamics
- Air Quality Monitoring and Forecasting
- Ocean Acidification Effects and Responses
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Climate change and permafrost
- Stellar, planetary, and galactic studies
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Methane Hydrates and Related Phenomena
- Air Quality and Health Impacts
- Atmospheric aerosols and clouds
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- Geology and Paleoclimatology Research
- Geochemistry and Geologic Mapping
- Isotope Analysis in Ecology
- Astrophysical Phenomena and Observations
- Calibration and Measurement Techniques
University of Toronto
2016-2024
3v Geomatics (Canada)
2022-2023
University of Saskatchewan
2021-2022
Abstract. This paper reports on consolidated ground-based validation results of the atmospheric NO2 data produced operationally since April 2018 by TROPOspheric Monitoring Instrument (TROPOMI) board ESA/EU Copernicus Sentinel-5 Precursor (S5P) satellite. Tropospheric, stratospheric, and total column from S5P are compared to correlative measurements collected from, respectively, 19 Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS), 26 Network for Detection Atmospheric...
Abstract. In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants for period 17 d during the Second Cabauw Intercomparison campaign Nitrogen Dioxide measuring Instruments (CINDI-2) that took place at Cabauw, Netherlands (51.97∘ N, 4.93∘ E). We report on outcome formal semi-blind intercomparison exercise, which was held under umbrella Network Detection Atmospheric Composition Change (NDACC) and European Space Agency (ESA). The three major goals...
Observations of exoplanet atmospheres have revealed the presence cloud particles in their atmospheres. 3D modelling formation extrasolar planets coupled to atmospheric dynamics has long been a challenge. We investigate thermo-hydrodynamic properties processes hot Jupiter exoplanets. simulate dynamic atmosphere HD 189733b with model that couples radiative-hydrodynamics kinetic, microphysical mineral module designed for RHD/GCM simulations. Our simulation includes feedback effects advection...
Abstract. The TROPOspheric Monitoring Instrument (TROPOMI) aboard the Sentinel-5 Precursor satellite (launched on 13 October 2017) is a nadir-viewing spectrometer measuring reflected sunlight in ultraviolet, visible, near-infrared, and shortwave infrared spectral ranges. measured spectra are used to retrieve total columns of trace gases, including nitrogen dioxide (NO2). For ground validation these measurements, Pandora spectrometers, which high-quality NO2 via direct-sun widely used. In...
Abstract. The second Cabauw Intercomparison of Nitrogen Dioxide measuring Instruments (CINDI-2) took place in (the Netherlands) September 2016 with the aim assessing consistency multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements tropospheric species (NO2, HCHO, O3, HONO, CHOCHO and O4). This was achieved through coordinated operation 36 spectrometers operated by 24 groups from all over world, together a wide range supporting reference observations (in situ...
Abstract. After decades of depletion in the 20th century, near-global ozone now shows clear signs recovery upper stratosphere. The column, however, has remained largely constant since turn mainly due to evolution lower stratospheric ozone. In tropical stratosphere, is expected decrease as a consequence enhanced upwelling driven by increasing greenhouse gas concentrations, and this consistent with observations. There recent evidence, that mid-latitude continues well, contrary model...
Abstract In the winter and spring of 2019/2020, unusually cold, strong, stable polar vortex created favorable conditions for ozone depletion in Arctic. Chemical loss started earlier than any previous year satellite era continued until late March, resulting unprecedented reduction column. The was located above Polar Environment Atmospheric Research Laboratory Eureka, Canada (80°N, 86°W) from February to end April, presenting an excellent opportunity examine a single ground station....
After the well-reported record loss of Arctic stratospheric ozone up to 38% in winter 2010–2011, further large depletion 27% occurred 2015–2016. Record low polar vortex temperatures, below threshold for ice cloud (PSC) formation, persisted one month January 2016. This is first observation such an event and resulted unprecedented dehydration/denitrification vortex. Although chemistry–climate models (CCMs) generally predict cooling lower stratosphere with increasing atmospheric concentrations...
This paper presents long-term intercomparisons (2003–2017) between ozone and NO2 measured by the Optical Spectrograph Infra-Red Imager System (OSIRIS) Atmospheric Chemistry Experiment (ACE) satellite instruments, ground-based instruments at Polar Environment Research Laboratory (PEARL), near Eureka, Nunavut, Canada (80∘N, 86∘W). The include four zenith-sky differential optical absorption spectroscopy (DOAS) two Fourier transform infrared (FTIR) spectrometers, a Brewer spectrophotometer....
Abstract Bromine explosions and corresponding ozone depletion events are common in the Arctic spring. The snowpack on sea ice salt aerosols (SSA) both thought to release bromine, but relative contribution of each source is not yet known. Furthermore, role atmospheric conditions fully understood. Long‐term measurements bromine monoxide (BrO) provide useful insight into underlying processes activation. Here we present a 4‐year data set (2016–2019) springtime BrO partial columns retrieved from...
Abstract. Within the framework of International Arctic Systems for Observing Atmosphere (IASOA), we report a modelling-based study on surface ozone across Arctic. We use from six sites – Summit (Greenland), Pallas (Finland), Barrow (USA), Alert (Canada), Tiksi (Russia), and Villum Research Station (VRS) at Nord (North Greenland, Danish realm) ozone-sonde data three Canadian sites: Resolute, Eureka, Alert. Two global chemistry models transport model (parallelised-Tropospheric Offline Model...
Field evidence has confirmed a new sea salt aerosol (SSA) source on ice, which may significantly affect polar boundary layer chemistry and winter climate. While the SSA production rate from blowing snow been previously parameterised (Yang et al., 2008) then validated by measurements at both Poles, some key parameters involved are not yet fully constrained, leading to uncertainties when using numerical models compare with field assess their environmental climate impacts. In this presentation,...
Abstract. Ground-based, satellite, and reanalysis datasets were used to identify two similar cyclone-induced surface ozone depletion events at Eureka, Canada (80.1° N, 86.4° W), in March 2007 April 2011. These coincident with observations of hydrogen deuterium oxide (HDO) depletion, indicating that condensation sublimation occurred during the transport ozone-depleted air masses. Ice clouds (vapour crystals) aerosols detected by lidar radar when ozone- HDO-depleted masses arrived over Eureka....
Abstract. We present different methods for in-field elevation calibration of MAX-DOAS (Multi AXis Differential Optical Absorption Spectroscopy) instruments that were applied and inter-compared during the second Cabauw Intercomparison campaign Nitrogen Dioxide measuring Instruments (CINDI-2). One necessary prerequisite consistent retrievals is a precise accurate angles systems. Therefore, this to several campaign, results inter-compared. This work first introduces explains methods, namely...
Abstract. Zenith-Sky scattered light Differential Optical Absorption Spectroscopy (ZS-DOAS) has been used widely to retrieve total column ozone (TCO). ZS-DOAS measurements have the advantage of being less sensitive clouds than direct-sun measurements. However, presence still affects quality TCO. Clouds are thought be largest contributor random uncertainty in TCO, but their impact on data needs quantified. This study two goals: (1) investigate whether a significant and (2) develop...
Abstract. Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) is a well-established ground-based measurement technique for the detection of aerosols and trace gases particularly in boundary layer lower troposphere: ultraviolet- visible radiation spectra skylight are analysed to obtain information on different atmospheric parameters, integrated over light path from space instrument. An appropriate set recorded under viewing geometries ("Multi-Axis") allows retrieval...
Abstract. This study explores the role of snowpack in polar boundary layer chemistry, especially as a direct source reactive bromine (BrOx = BrO + Br) and nitrogen (NOx NO NO2) Arctic springtime. Surface snow samples were collected daily from Canadian high location at Eureka, Nunavut (80° N, 86° W) end February to March 2018 2019. The was sampled several sites representing distinct environments: sea ice, inland close level, hilltop ∼ 600 m above level (a.s.l.). At sites, surface salinity has...
Abstract. This paper reports on consolidated ground-based validation results of the atmospheric NO2 data produced operationally since April 2018 by TROPOMI instrument board ESA/EU Copernicus Sentinel-5 Precursor (S5p) satellite. Tropospheric, stratospheric, and total column from S5p are compared to correlative measurements collected from, respectively, 19 Multi-Axis DOAS (MAX-DOAS), 26 NDACC Zenith-Scattered-Light (ZSL-DOAS), 25 PGN/Pandora instruments distributed globally. The methodology...
Abstract. This paper reports on ground-based validation of the atmospheric OClO data record produced within framework EUMETSAT's Satellite Application Facility Atmospheric Chemistry Monitoring (AC SAF) using Global Ozone Experiment (GOME)-2A and GOME-2B instrument measurements, covering 2007–2016 2013–2016 periods, respectively. slant column densities are compared to correlative measurements collected from nine Zenith-Scattered-Light Differential Optical Absorption Spectroscopy (ZSL-DOAS)...
Abstract. In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants for period 17 days during the Second Cabauw Intercomparison campaign Nitrogen Dioxide measuring Instruments (CINDI-2) that took place at Cabauw, The Netherlands (51.97° N, 4.93° E). We report on outcome formal semi-blind intercomparison exercise, which was held under umbrella Network Detection Atmospheric Composition Change (NDACC) and European Space Agency (ESA). three major...
Abstract. The TROPOspheric Monitoring Instrument (TROPOMI) on-board the Sentinel-5 Precursor satellite (launched on 13 October 2017) is a nadir-viewing spectrometer measuring reflected sunlight in ultraviolet, visible, near-infrared, and shortwave infrared spectral ranges. measured spectra are used to retrieve total columns of trace gases, including nitrogen dioxide (NO2). For ground validation these measurements, Pandora spectrometers, which high-quality NO2 via direct-sun widely used. In...
Abstract. Within the framework of International Arctic Systems for Observing Atmosphere (IASOA), we report a modelling-based study on surface ozone across Arctic. We use from six sites: Summit (Greenland), Pallas (Finland), Barrow (USA), Alert (Canada), Tiksi (Russia), and Villum Research Station (VRS) at Nord (North Greenland, Danish Realm), ozonesonde data three Canadian Resolute, Eureka, Alert. Two global chemistry models: transport model (p-TOMCAT) climate (UKCA), are used model-data...
This study explores the role of snowpack in polar boundary layer chemistry, especially as a direct source reactive bromine (BrOX=BrO+Br) and nitrogen (NOX=NO+NO2) Arctic springtime. Surface snow samples were collected daily from Canadian high location at Eureka, Nunavut (80°N, 86°W) end February to March 2018 2019. The was sampled several sites representing distinct environments: sea ice, inland close level, hilltop ~600 m above level.  At all sites, sodium...