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An Unprecedented Arctic Ozone Depletion Event During Spring 2020 and Its Impacts Across Europe
The response of the ozone column across Europe to the extreme 2020 Arctic ozone depletion was examined by analyzing ground-based observations at 38 European stations. The ozone decrease at the northernmost site, Ny-Ålesund (79°N) was about 43% with respect to a climatology of more than 30 years. The magnitude of the decrease declined by about 0.7% deg−1 moving south to reach nearly 15% at 40°N. In addition, it was found that the variations of the ozone column at each of the selected stations in March-May were similar to those observed at Ny-Ålesund but with a delay increasing to about 20 days at mid-latitudes with a gradient of approximately 0.5 days deg−1. The distributions of reconstructed ozone column anomalies over a sector covering a large European area show decreasing ozone that started from the north at the beginning of April 2020 and spread south. Such behavior was shown to be similar to that observed after the Arctic ozone depletion in 2011. Stratospheric dynamical patterns in March–May 2011 and during 2020 suggested that the migration of ozone-poor air masses from polar areas to the south after the vortex breakup caused the observed ozone responses. A brief survey of the ozone mass mixing ratios at three stratospheric levels showed the exceptional strength of the 2020 episode. Despite the stronger and longer-lasting Arctic ozone loss in 2020, the analysis in this work indicates a similar ozone response at latitudes below 50°N to both 2011 and 2020 phenomena.
American Geophysical Union (AGU)
2023
An overview of the uses of per- And polyfluoroalkyl substances (PFAS)
Royal Society of Chemistry (RSC)
2020
2010
2010
Here we provide an overview of the newly commenced project ‘ReGAME - Reliable Global Methane Emissions estimates in a changing world’, funded by Research Council of Norway from 2021-2025, where we combine new developments in atmospheric methane observations: isotopic ratios (deuterium and 13C in methane), and the Integrated Carbon Observation System (ICOS) ground-based station network with atmospheric models (the chemistry transport model OsloCTM, and inversion model FLEXINVERT) to understand how and why atmospheric methane levels are increasing. The project has a particular focus on understanding the state of Arctic methane reservoirs such as ocean seeps and high latitude wetlands. This includes plans for a new observing system aboard the ice breaking vessel RV Kronprins Haakon and ocean observations, e.g., dynamics of Seep fluxes assessed during 1 year of continuous measurements at a seep site the NorEMSO project, updated information on spatial seep distribution via echo sounding, as well as high resolution high-latitude inversion modeling of atmospheric methane with FLEXINVERT. Furthermore, we investigate the utility of including of satellite data (TROPOMI aboard the Sentinel 5P mission) together with ground-based data, in inversion modeling. The inclusion of satellite data into inversion models is quite novel and offers rewards by increasing spatial coverage compared to ground based networks alone, potentially reducing uncertainties in the model outputs, and challenges due to satellite data uncertainties, spatial/ temporal coverage, and handling large data fields
2022
2009
2021
2013
2014
2015
2021
2008
2013
2020
Radiocarbon (14C) analysis of carbonaceous aerosols is used for source apportionment, separating the carbon content into fossil vs. non-fossil origin, and is particularly useful when applied to subfractions of total carbon (TC), i.e. elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC), and water-insoluble OC (WINSOC). However, this requires an unbiased physical separation of these fractions, which is difficult to achieve. Separation of EC from OC using thermal–optical analysis (TOA) can cause EC loss during the OC removal step and form artificial EC from pyrolysis of OC (i.e. so-called charring), both distorting the 14C analysis of EC. Previous work has shown that water extraction reduces charring. Here, we apply a new combination of a WSOC extraction and 14C analysis method with an optimised separation that is coupled with a novel approach of thermal-desorption modelling for compensation of EC losses. As water-soluble components promote the formation of pyrolytic carbon, water extraction was used to minimise the charring artefact of EC and the eluate subjected to chemical wet oxidation to CO2 before direct 14C analysis in a gas-accepting accelerator mass spectrometer (AMS). This approach was applied to 13 aerosol filter samples collected at the Arctic Zeppelin Observatory (Svalbard) in 2017 and 2018, covering all seasons, which bear challenges for a simplified 14C source apportionment due to their low loading and the large portion of pyrolysable species. Our approach provided a mean EC yield of 0.87±0.07 and reduced the charring to 6.5 % of the recovered EC amounts. The mean fraction modern (F14C) over all seasons was 0.85±0.17 for TC; 0.61±0.17 and 0.66±0.16 for EC before and after correction with the thermal-desorption model, respectively; and 0.81±0.20 for WSOC.
2023
2005
2022
2016