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2019
2018
Recent methane surges reveal heightened emissions from tropical inundated areas
Record breaking atmospheric methane growth rates were observed in 2020
and 2021 (15.2±0.5 and 17.8±0.5 parts per billion per year), the highest since the
early 1980s. Here we use an ensemble of atmospheric inversions informed by
surface or satellite methane observations to infer emission changes during
these two years relative to 2019. Results show global methane emissions
increased by 20.3±9.9 and 24.8±3.1 teragrams per year in 2020 and 2021,
dominated by heightened emissions from tropical and boreal inundated areas,
aligning with rising groundwater storage and regional warming. Current
process-based wetland models fail to capture the tropical emission surges
revealed by atmospheric inversions, likely due to inaccurate representation of
wetland extents and associated methane emissions. Our findings underscore
the critical role of tropical inundated areas in the recent methane emission
surges and highlight the need to integrate multiple data streams and modeling
tools for better constraining tropical wetland emissions.
Springer Nature
2024
2015
Recent Trends in Maintenance Costs for Façades Due to Air Pollution in the Oslo Quadrature, Norway
MDPI
2019
Recent Trends in Stratospheric Chlorine From Very Short-Lived Substances
Very short‐lived substances (VSLS), including dichloromethane (CH2Cl2), chloroform (CHCl3), perchloroethylene (C2Cl4), and 1,2‐dichloroethane (C2H4Cl2), are a stratospheric chlorine source and therefore contribute to ozone depletion. We quantify stratospheric chlorine trends from these VSLS (VSLCltot) using a chemical transport model and atmospheric measurements, including novel high‐altitude aircraft data from the NASA VIRGAS (2015) and POSIDON (2016) missions. We estimate VSLCltot increased from 69 (±14) parts per trillion (ppt) Cl in 2000 to 111 (±22) ppt Cl in 2017, with >80% delivered to the stratosphere through source gas injection, and the remainder from product gases. The modeled evolution of chlorine source gas injection agrees well with historical aircraft data, which corroborate reported surface CH2Cl2 increases since the mid‐2000s. The relative contribution of VSLS to total stratospheric chlorine increased from ~2% in 2000 to ~3.4% in 2017, reflecting both VSLS growth and decreases in long‐lived halocarbons. We derive a mean VSLCltot growth rate of 3.8 (±0.3) ppt Cl/year between 2004 and 2017, though year‐to‐year growth rates are variable and were small or negative in the period 2015–2017. Whether this is a transient effect, or longer‐term stabilization, requires monitoring. In the upper stratosphere, the modeled rate of HCl decline (2004–2017) is −5.2% per decade with VSLS included, in good agreement to ACE satellite data (−4.8% per decade), and 15% slower than a model simulation without VSLS. Thus, VSLS have offset a portion of stratospheric chlorine reductions since the mid‐2000s.
American Geophysical Union (AGU)
2019
Recommendations for a composite surface-based aerosol network. European Network of Networks (ENAN) workshop, Emmetten, Switzerland, 28-29 April 2009. GAW - Global atmosphere watch, 207
2013
This report aims to support the on-going revision of the Ambient Air Quality Directives by providing a series of recommendations on the reciprocal exchange of information and reporting of ambient air quality (e-reporting) following the Commission Implementing Decision (2011/850/EU). It builds on the experience and understanding from the EEA and technical experts at its European Topic Centre for Human Health and the Environment (ETC HE) working with implementing provisions for reporting (IPR) and identifies areas for further efficiency gains in e-reporting, in particular concerning the H-K dataflows.
ETC/HE
2022
2013
A reliable determination of equivalent black carbon (eBC) mass concentrations derived from filter absorption photometers (FAPs) measurements depends on the appropriate quantification of the mass absorption cross-section (MAC) for converting the absorption coefficient (babs) to eBC. This study investigates the spatial–temporal variability of the MAC obtained from simultaneous elemental carbon (EC) and babs measurements performed at 22 sites. We compared different methodologies for retrieving eBC integrating different options for calculating MAC including: locally derived, median value calculated from 22 sites, and site-specific rolling MAC. The eBC concentrations that underwent correction using these methods were identified as LeBC (local MAC), MeBC (median MAC), and ReBC (Rolling MAC) respectively. Pronounced differences (up to more than 50 %) were observed between eBC as directly provided by FAPs (NeBC; Nominal instrumental MAC) and ReBC due to the differences observed between the experimental and nominal MAC values. The median MAC was 7.8 ± 3.4 m2 g-1 from 12 aethalometers at 880 nm, and 10.6 ± 4.7 m2 g-1 from 10 MAAPs at 637 nm. The experimental MAC showed significant site and seasonal dependencies, with heterogeneous patterns between summer and winter in different regions. In addition, long-term trend analysis revealed statistically significant (s.s.) decreasing trends in EC. Interestingly, we showed that the corresponding corrected eBC trends are not independent of the way eBC is calculated due to the variability of MAC. NeBC and EC decreasing trends were consistent at sites with no significant trend in experimental MAC. Conversely, where MAC showed s.s. trend, the NeBC and EC trends were not consistent while ReBC concentration followed the same pattern as EC. These results underscore the importance of accounting for MAC variations when deriving eBC measurements from FAPs and emphasize the necessity of incorporating EC observations to constrain the uncertainty associated with eBC.
Elsevier
2024
2015
Publications Office of the European Union
2022
2011
2007
2007
2010
Publications Office of the European Union
2019
2013
2024
2015