Gå til innhold
  • Send

  • Kategori

  • Sorter etter

  • Antall per side

Fant 844 publikasjoner. Viser side 29 av 36:

Publikasjon  
År  
Kategori

European pollen reanalysis, 1980–2022, for alder, birch, and olive

Sofiev, Mikhail; Palamarchuk, Julia; Kouznetsov, Rostislav; Abramidze, Tamuna; Adams-Groom, Beverley; Antunes, Célia M.; Ariño, Arturo; Bastl, Maximillan; Belmonte, Jordina; Berger, Uwe Edwin; Bonini, Maira; Bruffaerts, Nicolas; Buters, Jeroen T.M.; Cariñanos, Paloma; Celenk, Sevcan; Ceriotti, Valentina; Charalampopoulos, Athanasios; Clewlow, Yolanda; Clot, Bernhard; Dahl, Aslog; Damialis, Athanasios; Linares, Concepción De; Weger, Letty A de; Dirr, Lukas; Ekebom, Agneta; Fatahi, Yalda; González, Maria Fernández; González, Delia Fernández; Fernández-Rodríguez, Santiago; Galán, Carmen; Gedda, Björn; Gehrig, Regula; Bernstein, Carmi Geller; Roldan, Nestor Gonzalez; Grewling, Łukasz; Hajkova, Lenka; Hanninen, Risto; Hentges, François; Jantunen, Juha; Kadantsev, Evgeny; Kasprzyk, Idalia; Kloster, Mathilde; Kluska, Katarzyna; Koenders, Mieke; Lafférsová, Janka; Leru, Poliana Mihaela; Lipiec, Agnieszka; Louna-Korteniemi, Maria; Magyar, Donat; Majkowska-Wojciechowska, Barbara; Mäkelä, Mika; Mitrovic, Mirjana; Myszkowska, Dorota; Oliver, Gilles; Östensson, Pia; Pérez-Badia, Rosa; Piotrowska-Weryszko, Krystyna; Prank, Marje; Przedpelska-Wasowicz, Ewa Maria; Pätsi, Sanna; Rodríguez-Rajo, F. Javier; Ramfjord, Hallvard; Rapiejko, Joanna; Rodinkova, Victoria; Rojo, Jesús; Ruiz-Valenzuela, Luis; Rybnicek, Ondrej; Saarto, Annika; Sauliene, Ingrida; Seliger, Andreja Kofol; Severova, Elena; Shalaboda, Valentina; Sikoparija, Branko; Siljamo, Pilvi; Soares, Joana; Sozinova, Olga; Stangel, Andreas; Stjepanović, Barbara; Teinemaa, Erik; Tyuryakov, Svjatoslav; Trigo, M. Mar; Uppstu, Andreas; Vill, Mart; Vira, Julius; Visez, Nicolas; Vitikainen, Tiina; Vokou, Despoina; Weryszko-Chmielewska, Elzbieta; Karppinen, Ari

The dataset presents a 43 year-long reanalysis of pollen seasons for three major allergenic genera of trees in Europe: alder (Alnus), birch (Betula), and olive (Olea). Driven by the meteorological reanalysis ERA5, the atmospheric composition model SILAM predicted the flowering period and calculated the Europe-wide dispersion pattern of pollen for the years 1980–2022. The model applied an extended 4-dimensional variational data assimilation of in-situ observations of aerobiological networks in 34 European countries to reproduce the inter-annual variability and trends of pollen production and distribution. The control variable of the assimilation procedure was the total pollen release during each flowering season, implemented as an annual correction factor to the mean pollen production. The dataset was designed as an input to studies on climate-induced and anthropogenically driven changes in the European vegetation, biodiversity monitoring, bioaerosol modelling and assessment, as well as, in combination with intra-seasonal observations, for health-related applications.

2024

Contaminants, prolactin and parental care in an Arctic seabird: Contrasted associations of perfluoroalkyl substances and organochlorine compounds with egg-turning behavior

Blévin, Pierre; Shaffer, Scott A.; Bustamante, Paco; Angelier, Frédéric; Picard, Baptiste; Herzke, Dorte; Moe, Børge; Gabrielsen, Geir W.; Bustnes, Jan Ove; Chastel, Olivier

2020

Seasonal Variation of Wet Deposition of Black Carbon at Ny-Ålesund, Svalbard

Mori, Tatsuhiro; Kondo, Yutaka; Ohata, Sho; Goto-Azuma, Kumiko; Fukuda, Kaori; Ogawa-Tsukagawa, Yoshimi; Moteki, Nobuhiro; Yoshida, Atsushi; Koike, Makoto; Sinha, P. R.; Oshima, Naga; Matsui, Hitoshi; Tobo, Yutaka; Yabuki, Masanori; Aas, Wenche

Black carbon (BC) aerosol deposited in and onto Arctic snow increases the snow's absorption of solar radiation and accelerates snowmelt. Concentrations of BC in the Arctic atmosphere and snow are controlled by wet deposition; however, details of this process are poorly understood owing to the scarcity of time-resolved measurements of BC in hydrometeors. We measured mass concentrations of BC in hydrometeors (CMBC) and in air (MBC) with 16% and 15% accuracies, respectively, at Ny-Ålesund, Svalbard during 2012–2019. Median monthly MBC and CMBC values showed similar seasonal variations, being high in winter-spring and low in summer. Median monthly BC wet deposition mass flux (FMBC) was highest in winter and lowest in summer, associated with seasonal patterns of CMBC and precipitation. Seasonally averaged BC size distributions in hydrometeors were similar except for summer. Measurements of MBC and CMBC in spring 2017 showed a size-independent removal efficiency, indicating that BC-containing particles were efficiently activated into cloud droplets. These observations at Ny-Ålesund were compared with observations at Barrow, Alaska, during 2013–2017. The near-surface MBC at Ny-Ålesund and Barrow had similar seasonal patterns; however, the two sites differed in CMBC and FMBC. In summer, CMBC was low at Ny-Ålesund but moderate at Barrow, likely reflecting differences in MBC in the lower troposphere. Seasonally averaged BC size distributions in hydrometeors were similar at both sites, suggesting that average BC size distributions are similar in the Arctic lower troposphere. The efficiency of BC removal tends to be size-independent during transport, leading to the observed similarity.

2021

Arctic sea-ice loss intensifies aerosol transport to the Tibetan Plateau

Li, Fei; Wan, Xin; Wang, Huijun; Orsolini, Yvan J.; Cong, Zhiyuan; Gao, Yongqi; Kang, Shichang

The Tibetan Plateau (TP) has recently been polluted by anthropogenic emissions transported from South Asia, but the mechanisms conducive to this aerosol delivery are poorly understood. Here we show that winter loss of Arctic sea ice over the subpolar North Atlantic boosts aerosol transport toward the TP in April, when the aerosol loading is at its climatological maximum and preceding the Indian summer monsoon onset. Low sea ice in February weakens the polar jet, causing decreased Ural snowpack via reduced transport of warm, moist oceanic air into the high-latitude Eurasian interior. This diminished snowpack persists through April, reinforcing the Ural pressure ridge and East Asian trough, segments of a quasi-stationary Rossby wave train extending across Eurasia. These conditions facilitate an enhanced subtropical westerly jet at the southern edge of the TP, invigorating upslope winds that combine with mesoscale updrafts to waft emissions over the Himalayas onto the TP.

2020

The fingerprint of the summer 2018 drought in Europe on ground-based atmospheric CO2 measurements

Ramonet, Michel; Ciais, Philippe; Apadula, F.; Bartyzel, Jakub; Bastos, Ana; Bergamaschi, Peter; Blanc, P. E.; Brunner, D; Torchiarolo, L. Caracciolo di; Calzolari, F.; Chen, H.; Chmura, L.; Colomb, A.; Conil, S.; Cristofanelli, P.; Cuevas, E.; Curcoll, R.; Delmotte, M.; Sarra, A. di; Emmenegger, L.; Forster, G.; Frumau, A.; Gerbig, C.; Gheusi, F; Hammer, S.; Haszpra, L.; Hatakka, J.; Hazan, L.; Heliasz, M.; Henne, S.; Hensen, A.; Hermansen, Ove; Keronen, P.; Kivi, R.; Kominkova, K.; Kubistin, D.; Laurent, O.; Laurila, T; Lavric, J. V.; Lehner, I.; Lehtinen, K. E. J.; Leskinen, A.; Leuenberger, M.; Levin, I.; Lindauer, M.; Lopez, M.; Myhre, Cathrine Lund; Mammarella, I; Manca, G; Manning, A; Marek, M. V.; Marklund, P.; Martin, D.; Meinhardt, F; Mihalopoulos, N.; Mölder, M.; Morguí, J.A.; Necki, J.; O'Doherty, S.; O'Dowd, C; Ottosson, M.; Philippon, N.; Piacentino, S.; Pichon, J.M.; Plass-Duelmer, C.; Resovsky, A.; Rivier, L; Rodo, X; Sha, M. K.; Scheeren, H. A.; Sferlazzo, D.; Spain, T. G.; Stanley, K. M.; Steinbacher, M.; Trisolino, P.; Vermeulen, A.; Vitkova, G.; Weyrauch, D.; Xueref-Remy, I.; Yala, K.; Kwok, C. Yvwer

During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO2) exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO2 seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO2 gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO2 cycles from 48 European stations were available for 2017 and 2018. Earlier data were retrieved for comparison from international databases or national networks. Here, we show that the usual summer minimum in CO2 due to the surface carbon uptake was reduced by 1.4 ppm in 2018 for the 10 stations located in the area most affected by the temperature anomaly, mostly in Northern Europe. Notwithstanding, the CO2 transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO2 uptake by photosynthesis and/or a reduction in respiration driven by the depletion of substrate for respiration inherited from the previous months due to the drought. For stations with sufficiently long time series, the CO2 anomaly observed in 2018 was compared to previous European droughts in 2003 and 2015. Considering the areas most affected by the temperature anomalies, we found a higher CO2 anomaly in 2003 (+3 ppm averaged over 4 sites), and a smaller anomaly in 2015 (+1 ppm averaged over 11 sites) compared to 2018.

This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.

2020

Thermodynamic parameters at bio-nano interface and nanomaterial toxicity: A case study on BSA interaction with ZnO, SiO2 and TiO2

Precupas, Aurica; Gheorghe, Daniela; Botea-Petcu, Alina; Leonties, Anca Ruxandra; Sandu, Romica; Popa, Vlad Tudor; Mariussen, Espen; Yamani, Naouale El; Rundén-Pran, Elise; Dumit, Veronica; Xue, Ying; Cimpan, Mihaela Roxana; Dusinska, Maria; Haase, Andrea; Tanasescu, Speranta

Understanding nanomaterial (NM)–protein interactions is a key issue in defining the bioreactivity of NMs with great impact for nanosafety. In the present work, the complex phenomena occurring at the bio/nano interface were evaluated in a simple case study focusing on NM–protein binding thermodynamics and protein stability for three representative metal oxide NMs, namely, zinc oxide (ZnO; NM-110), titanium dioxide (TiO2; NM-101), and silica (SiO2; NM-203). The thermodynamic signature associated with the NM interaction with an abundant protein occurring in most cell culture media, bovine serum albumin (BSA), has been investigated by isothermal titration and differential scanning calorimetry. Circular dichroism spectroscopy offers additional information concerning adsorption-induced protein conformational changes. The BSA adsorption onto NMs is enthalpy-controlled, with the enthalpic character (favorable interaction) decreasing as follows: ZnO (NM-110) > SiO2 (NM-203) > TiO2 (NM-101). The binding of BSA is spontaneous, as revealed by the negative free energy, ΔG, for all systems. The structural stability of the protein decreased as follows: TiO2 (NM-101) > SiO2 (NM-203) > ZnO (NM-110). As protein binding may alter NM reactivity and thus the toxicity, we furthermore assessed its putative influence on DNA damage, as well as on the expression of target genes for cell death (RIPK1, FAS) and oxidative stress (SOD1, SOD2, CAT, GSTK1) in the A549 human alveolar basal epithelial cell line. The enthalpic component of the BSA–NM interaction, corroborated with BSA structural stability, matched the ranking for the biological alterations, i.e., DNA strand breaks, oxidized DNA lesions, cell-death, and antioxidant gene expression in A549 cells. The relative and total content of BSA in the protein corona was determined using mass-spectrometry-based proteomics. For the present case study, the thermodynamic parameters at bio/nano interface emerge as key descriptors for the dominant contributions determining the adsorption processes and NMs toxicological effect.

2020

Impact of solar irradiance and geomagnetic activity on polar NOx, ozone and temperature in WACCM simulations

Tartaglione, N.; Toniazzo, T.; Orsolini, Y.; Otterå, O.H.

The response of the atmosphere to solar irradiance and geomagnetic activity is analyzed in experiments with the Whole Atmosphere Community Climate Model (WACCM) under idealized forcings. Four experiments are carried out combining high (H) and low (L) solar radiative forcing with high (7) and low (3) geomagnetic activity: H7 (with high radiative forcing and high geomagnetic activity), H3, (high/low), L7 (low/high), and L3 (low/low). The comparison between these experiment is used to assess the effects of solar radiative forcing and geomagnetic activity mainly on the stratosphere. A two-step Monte Carlo-based statistical test, which defines an impact score, is used to assess statistically significant impacts on regional scales, on pressure levels, for a few key model variables, like NOx, ozone, and temperature.

Under low solar forcing (L7/L3), a statistically significant relationship between geomagnetic activity and NOx is found in both hemispheres and for all seasons. An equally strong relationship is lacking for ozone and temperature when analyzing these fields on isobaric levels. A statistically significant impact on stratospheric ozone is only seen in austral winter and spring. However, vertical cross sections show statistically significant impact on temperature and ozone mainly in the southern hemisphere (SH) during austral winter and the following spring.

Significant and persistent signals in both SH NOx and ozone concentrations are only produced when the effect of high solar forcing is added to high geomagnetic activity (H7). In this case, statistically significant differences are also found for mesospheric temperatures, ozone and NOx. This latter result appears also under low geomagnetic activity as a result of solar forcing alone, suggesting that solar irradiance significantly affects NOx, ozone and stratospheric temperatures and, in some seasons, even tropospheric temperature.

In summary, geomagnetic activity primarily affects NOx and ozone concentrations in the SH. Solar maximum conditions can reduce the amount of NOx in the stratosphere because of higher ozone production. Thus, we conclude that correlations between changes in solar irradiance and geomagnetic activity are important with respect to their effects on the atmosphere. In particular, geomagnetic activity can modulate atmospheric ozone concentrations and other associated stratospheric and tropospheric variables under conditions of high solar activity.

2020

Interlaboratory Comparison Reveals State of the Art in Microplastic Detection and Quantification Methods

Ciornii, Dmitri; Hodoroaba, Vasile-Dan; Benismail, Nizar; Maltseva, Alina; Ferrer, Juan F.; Wang, Jiamin; Parra, Raquel; Jézéquel, Ronan; Receveur, Justine; Gabriel, Dina; Scheitler, Andreas; Oversteeg, Christa van; Roosma, Jorg; Duivenbode, Alex van Renesse van; Bulters, Tim; Zanella, Michela; Perini, Alessandro; Benetti, Federico; Mehn, Dora; Dierkes, Georg; Soll, Michael; Ishimura, Takahisa; Bednarz, Marius; Peng, Guyu; Hildebrandt, Lars; Peters, Mathias; Kim, Seung-Kyu; Türk, Jochen; Steinfeld, Felix; Jung, Jaehak; Hong, Sanghee; Kim, Eun-Ju; Yu, Hye-Weon; Klockmann, Sven; Krafft, Christoph; Süssmann, Julia; Zou, Shan; Halle, Alexandra ter; Giovannozzi, Andrea M.; Sacco, Alessio; Fadda, Marta; Putzu, Mara; Im, Dong-Hoon; Nhlapo, Nontete; Carrillo-Barragán, Priscilla; Schmidt, Natascha; Herzke, Dorte; Gomiero, Alessio; Jaén-Gil, Adrián; Cabanes, Damien J. E.; Doedt, Martin; Cardoso, Vitor; Schmitz, Antje; Hawly, Moritz; Mo, Huajuan; Jacquin, Justine; Mechlinski, Andy; Adediran, Gbotemi A.; Andrade, Jose; Muniategui-Lorenzo, Soledad; Ramsperger, Anja; Löder, Martin G. J.; Laforsch, Christian; Velickovic, Tanja Cirkovic; Fabbri, Daniele; Coralli, Irene; Federici, Stefania; Scholz-Böttcher, Barbara M.; Nasa, Jacopo la; Biale, Greta; Rauert, Cassandra; Okoffo, Elvis D.; Undas, Anna; An, Lihui; Wachtendorf, Volker; Fengler, Petra; Altmann, Korinna

2025

Global soil nitrous oxide emissions since the preindustrial era estimated by an ensemble of terrestrial biosphere models: Magnitude, attribution, and uncertainty

Tian, Hanqin; Yang, Jia; Xu, Rongting; Lu, Chaoqun; Canadell, Josep G.; Davidson, Eric A.; Jackson, Robert B.; Arneth, Almut; Chang, Jinfeng; Ciais, Philippe; Gerber, Stefan; Ito, Akihiko; Joos, Fortunat; Lienert, Sebastian; Messina, Palmira; Olin, Stefan; Pan, Shufen; Peng, Changhui; Saikawa, Eri; Thompson, Rona Louise; Vuichard, Nicolas; Winiwarter, Wilfried; Zaehle, Sönke; Zhang, Bowen

2019

Validation of new satellite aerosol optical depth retrieval algorithm using Raman lidar observations at radiative transfer laboratory in Warsaw

Zawadzka, Olga; Stachlewska, Iwona S.; Markowicz, Krzysztof M.; Nemuc, Anca; Stebel, Kerstin

During an exceptionally warm September of 2016, the unique, stable weather conditions over Poland allowed for an extensive testing of the new algorithm developed to improve the Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) aerosol optical depth (AOD) retrieval. The development was conducted in the frame of the ESA-ESRIN SAMIRA project. The new AOD algorithm aims at providing the aerosol optical depth maps over the territory of Poland with a high temporal resolution of 15 minutes. It was tested on the data set obtained between 11-16 September 2016, during which a day of relatively clean atmospheric background related to an Arctic airmass inflow was surrounded by a few days with well increased aerosol load of different origin. On the clean reference day, for estimating surface reflectance the AOD forecast available on-line via the Copernicus Atmosphere Monitoring Service (CAMS) was used. The obtained AOD maps were validated against AODs available within the Poland-AOD and AERONET networks, and with AOD values obtained from the PollyXT-UW lidar. of the University of Warsaw (UW).

2018

Stochastic and deterministic processes in Asymmetric Tsetlin Machine

Elmisadr, Negar; Belaid, Mohamed-Bachir; Yazidi, Anis

This paper introduces a new approach to enhance the decision-making capabilities of the Tsetlin Machine (TM) through the Stochastic Point Location (SPL) algorithm and the Asymmetric Steps technique. We incorporate stochasticity and asymmetry into the TM's process, along with a decaying normal distribution function that improves adaptability as it converges toward zero over time. We present two methods: the Asymmetric Probabilistic Tsetlin (APT) Machine, influenced by random events, and the Asymmetric Tsetlin (AT) Machine, which transitions from probabilistic to deterministic states. We evaluate these methods against traditional machine learning algorithms and classical Tsetlin (CT) machines across various benchmark datasets. Both AT and APT demonstrate competitive performance, with the AT model notably excelling, especially in complex datasets.

2025

Simulating CH4 and CO2 over South and East Asia using the zoomed chemistry transport model LMDz-INCA

Lin, Xin; Ciais, Philippe; Bousquet, Philippe; Ramonet, Michel; Yin, Yi; Balkanski, Yves; Cozic, Anne; Delmotte, Marc; Evangeliou, Nikolaos; Indira, Nuggehalli K.; Locatelli, Robin; Peng, Shushi; Piao, Shilong; Saunois, Marielle; Swathi, Panangady S.; Wang, Rong; Yver-Kwok, Camille; Tiwari, Yogesh K.; Zhou, Lingxi

The increasing availability of atmospheric measurements of greenhouse gases (GHGs) from surface stations can improve the retrieval of their fluxes at higher spatial and temporal resolutions by inversions, provided that transport models are able to properly represent the variability of concentrations observed at different stations. South and East Asia (SEA; the study area in this paper including the regions of South Asia and East Asia) is a region with large and very uncertain emissions of carbon dioxide (CO2) and methane (CH4), the most potent anthropogenic GHGs. Monitoring networks have expanded greatly during the past decade in this region, which should contribute to reducing uncertainties in estimates of regional GHG budgets. In this study, we simulate concentrations of CH4 and CO2 using zoomed versions (abbreviated as "ZAs") of the global chemistry transport model LMDz-INCA, which have fine horizontal resolutions of  ∼ 0.66° in longitude and  ∼ 0.51° in latitude over SEA and coarser resolutions elsewhere. The concentrations of CH4 and CO2 simulated from ZAs are compared to those from the same model but with standard model grids of 2.50° in longitude and 1.27° in latitude (abbreviated as "STs"), both prescribed with the same natural and anthropogenic fluxes. Model performance is evaluated for each model version at multi-annual, seasonal, synoptic and diurnal scales, against a unique observation dataset including 39 global and regional stations over SEA and around the world. Results show that ZAs improve the overall representation of CH4 annual gradients between stations in SEA, with reduction of RMSE by 16–20% compared to STs. The model improvement mainly results from reduction in representation error at finer horizontal resolutions and thus better characterization of the CH4 concentration gradients related to scattered distributed emission sources. However, the performance of ZAs at a specific station as compared to STs is more sensitive to errors in meteorological forcings and surface fluxes, especially when short-term variabilities or stations close to source regions are examined. This highlights the importance of accurate a priori CH4 surface fluxes in high-resolution transport modeling and inverse studies, particularly regarding locations and magnitudes of emission hotspots. Model performance for CO2 suggests that the CO2 surface fluxes have not been prescribed with sufficient accuracy and resolution, especially the spatiotemporally varying carbon exchange between land surface and atmosphere. In addition, the representation of the CH4 and CO2 short-term variabilities is also limited by model's ability to simulate boundary layer mixing and mesoscale transport in complex terrains, emphasizing the need to improve sub-grid physical parameterizations in addition to refinement of model resolutions.

2018

Mesospheric nitric acid enhancements during energetic electron precipitation events simulated by WACCM‐D

Orsolini, Yvan; Smith-Johnsen, Christine; Marsh, Daniel R.; Stordal, Frode; Rodger, Craig J.; Verronen, Pekka T.; Clilverd, Mark A.

While observed mesospheric polar nitric acid enhancements have been attributed to energetic particle precipitation through ion cluster chemistry in the past, this phenomenon is not reproduced in current whole‐atmosphere chemistry‐climate models. We investigate such nitric acid enhancements resulting from energetic electron precipitation events using a recently developed variant of the Whole Atmosphere Community Climate Model (WACCM) that includes a sophisticated ion chemistry tailored for the D‐layer of the ionosphere (50–90 km), namely, WACCM‐D. Using the specified dynamics mode, that is, nudging dynamics in the troposphere and stratosphere to meteorological reanalyses, we perform a 1‐year‐long simulation (July 2009–June 2010) and contrast WACCM‐D with the standard WACCM. Both WACCM and WACCM‐D simulations are performed with and without forcing from medium‐to‐high energy electron precipitation, allowing a better representation of the energetic electrons penetrating into the mesosphere. We demonstrate the effects of the strong particle precipitation events which occurred during April and May 2010 on nitric acid and on key ion cluster species, as well as other relevant species of the nitrogen family. The 1‐year‐long simulation allows the event‐related changes in neutral and ionic species to be placed in the context of their annual cycle. We especially highlight the role played by medium‐to‐high energy electrons in triggering ion cluster chemistry and ion‐ion recombinations in the mesosphere and lower thermosphere during the precipitation event, leading to enhanced production of nitric acid and raising its abundance by 2 orders of magnitude from 10−4 to a few 10−2 ppb.

2018

Model evaluation of short-lived climate forcers for the Arctic Monitoring and Assessment Programme: a multi-species, multi-model study

Whaley, Cynthia; Mahmood, Rashed; Salzen, Knut von; Winter, Barbara; Eckhardt, Sabine; Arnold, Stephen R.; Beagley, Stephen; Becagli, Silvia; Chien, Rong-You; Christensen, Jesper; Damani, Sujay Manish; Dong, Xinyi; Eleftheriadis, Konstantinos; Evangeliou, Nikolaos; Faluvegi, Gregory; Flanner, Mark G.; Fu, Joshua S.; Gauss, Michael; Giardi, Fabio; Gong, Wanmin; Hjorth, Jens Liengaard; Huang, Lin; Im, Ulas; Kanaya, Yugo; Srinath, Krishnan; Klimont, Zbigniew; Kuhn, Thomas; Langner, Joakim; Law, Kathy S.; Marelle, Louis; Massling, Andreas; Oliviè, Dirk Jan Leo; Onishi, Tatsuo; Oshima, Naga; Peng, Yiran; Plummer, David A.; Pozzoli, Luca; Popovicheva, Olga; Raut, Jean-Christophe; Sand, Maria; Saunders, Laura; Schmale, Julia; Sharma, Sangeeta; Skeie, Ragnhild Bieltvedt; Skov, Henrik; Taketani, Fumikazu; Thomas, Manu Anna; Traversi, Rita; Tsigaridis, Kostas; Tsyro, Svetlana; Turnock, Steven T; Vitale, Vito; Walker, Kaley A.; Wang, Minqi; Watson-Parris, Duncan; Weiss-Gibbons, Tahya

While carbon dioxide is the main cause for global warming, modeling short-lived climate forcers (SLCFs) such as methane, ozone, and particles in the Arctic allows us to simulate near-term climate and health impacts for a sensitive, pristine region that is warming at 3 times the global rate. Atmospheric modeling is critical for understanding the long-range transport of pollutants to the Arctic, as well as the abundance and distribution of SLCFs throughout the Arctic atmosphere. Modeling is also used as a tool to determine SLCF impacts on climate and health in the present and in future emissions scenarios.

In this study, we evaluate 18 state-of-the-art atmospheric and Earth system models by assessing their representation of Arctic and Northern Hemisphere atmospheric SLCF distributions, considering a wide range of different chemical species (methane, tropospheric ozone and its precursors, black carbon, sulfate, organic aerosol, and particulate matter) and multiple observational datasets. Model simulations over 4 years (2008–2009 and 2014–2015) conducted for the 2022 Arctic Monitoring and Assessment Programme (AMAP) SLCF assessment report are thoroughly evaluated against satellite, ground, ship, and aircraft-based observations. The annual means, seasonal cycles, and 3-D distributions of SLCFs were evaluated using several metrics, such as absolute and percent model biases and correlation coefficients. The results show a large range in model performance, with no one particular model or model type performing well for all regions and all SLCF species. The multi-model mean (mmm) was able to represent the general features of SLCFs in the Arctic and had the best overall performance. For the SLCFs with the greatest radiative impact (CH4, O3, BC, and SO), the mmm was within ±25 % of the measurements across the Northern Hemisphere. Therefore, we recommend a multi-model ensemble be used for simulating climate and health impacts of SLCFs.

Of the SLCFs in our study, model biases were smallest for CH4 and greatest for OA. For most SLCFs, model biases skewed from positive to negative with increasing latitude. Our analysis suggests that vertical mixing, long-range transport, deposition, and wildfires remain highly uncertain processes. These processes need better representation within atmospheric models to improve their simulation of SLCFs in the Arctic environment. As model development proceeds in these areas, we highly recommend that the vertical and 3-D distribution of SLCFs be evaluated, as that information is critical to improving the uncertain processes in models.

2022

Eastward-propagating planetary waves prior to the January 2009 sudden stratospheric warming

Rhodes, Christian Todd; Limpasuvan, Varavut; Orsolini, Yvan J.

Eastward-propagating planetary waves (EPWs) were investigated prior to the boreal January 2009 major sudden stratospheric warming (SSW) event simulated by the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model with specified dynamics. About 22 days before SSW onset, a background flow with jet maxima around the upper polar stratosphere and subtropical mesosphere developed due to the net forcing by gravity and planetary waves. The mesospheric wind structure was largely unstable and supported a wave geometry conducive to overreflection. With a zonal phase speed of ∼10 m s−1, EPWs appeared near their turning and critical layers as wavenumber-2 perturbations in the stratosphere and mesosphere. Accompanied by upward EPW activity from the lower stratosphere, EPW growth exhibited characteristics of wave instability and overreflection.

2021

Assessment of source contributions to the urban air quality for the Bristol ClairCity pilot case

Oliveira, Kevin; Rodrigues, Vera; Coelho, Silvia; Fernandes, Ana Patrícia; Rafael, Sandra; Faria, Carlos; Ferreira, Joana; Borrego, Carlos; Husby, Trond; Diafas, Iason; Nielsen, Per Sieverts; Liu, Xiufeng; Kewo, Angreine; Trozzi, Carlo; Piscitello, Enzo; Vanherle, Kris; Knudsen, Svein; Bouman, Evert; Barnes, Jo; Slingerland, Stephan; Hayes, Enda; Bolscher, Hans; Lopes, Myriam

2019

Climatological Westward‐Propagating Semidiurnal Tides and Their Composite Response to Sudden Stratospheric Warmings in SuperDARN and SD‐WACCM‐X

Zhang, J.; Limpasuvan, Varavut; Orsolini, Yvan J.; Espy, Patrick Joseph; Hibbins, Robert

Using the Super Dual Auroral Radar Network observations (clustered around 60°N) and NCAR CESM2.0 extended Whole Atmosphere Community Climate Model nudged with reanalyzes, we examine the climatology of semidiurnal tides in meridional wind associated with the migrating component (SW2) and non‐migrating components of wavenumbers 1 (SW1) and 3 (SW3). We then illustrate their composite response to major sudden stratospheric warmings (SSWs). Peaking in late summer and winter, the climatological SW2 amplitude exceeds SW1 and SW3 except around late Fall and Spring. The winter climatological peak is absent in the model perhaps due to the zonal wind bias at the observed altitudes. The observed SW2 amplitude declines after SSW onset before enhancing ∼10 days later, along with SW1 and SW3. Within the observed region, the simulated SW2 only amplifies after SSW onset, with minimal SW1 and SW3 responses. The model reveals a stronger SW2 response above the observed location, with diminished amplitude before and enhancement after SSW globally. This enhancement appears related to increased equatorial ozone heating and background wind symmetry. The strongest SW1 and SW3 growth occurs in the Southern Hemisphere before SSW. SW2 and quasi‐stationary planetary wave activities are temporally collocated during SSW suggesting that their interactions excite SW1 and SW3. After SSW, the model also reveals (1) semidiurnal‐tide‐like perturbations generated possibly by the interactions between SW2 and westward‐traveling disturbances and (2) the enhancement of migrating semidiurnal lunar tide in the Northern Hemisphere that exceeds non‐migrating tidal and semidiurnal‐tide‐like responses. The simulated eastward‐propagating semidiurnal tides are briefly examined.

2021

Estimation of the atmospheric hydroxyl radical oxidative capacity using multiple hydrofluorocarbons (HFCs)

Thompson, Rona Louise; Montzka, Stephen A.; Vollmer, Martin K.; Arduini, Jgor; Crotwell, Molly; Krummel, Paul B.; Lunder, Chris Rene; Mühle, Jens; O'doherty, Simon; Prinn, Ronald G.; Reimann, Stefan; Vimont, Isaac; Wang, Hsiang; Weiss, Ray F.; Young, Dickon

The hydroxyl radical (OH) largely determines the atmosphere's oxidative capacity and, thus, the lifetimes of numerous trace gases, including methane (CH4). Hitherto, observation-based approaches for estimating the atmospheric oxidative capacity have primarily relied on using methyl chloroform (MCF), but as the atmospheric abundance of MCF has declined, the uncertainties associated with this method have increased. In this study, we examine the use of five hydrofluorocarbons (HFCs) (HFC-134a, HFC-152a, HFC-365mfc, HFC-245fa, and HFC-32) in multi-species inversions, which assimilate three HFCs simultaneously, as an alternative method to estimate atmospheric OH. We find robust estimates of OH regardless of which combination of the three HFCs are used in the inversions. Our results show that OH has remained fairly stable during our study period from 2004 to 2021, with variations of

2024

Simulation of volcanic ash ingestion into a large aero engine: particle–fan interactions

Vogel, Andreas; Durant, Adam; Cassiani, Massimo; Clarkson, Rory J.; Slaby, Michal; Diplas, Spyridon; Krüger, Kirstin; Stohl, Andreas

Volcanic ash (VA) clouds in flight corridors present a significant threat to aircraft operations
as VA particles can cause damage to gas turbine engine components that lead to a
reduction of engine performance and compromise flight safety. In the last decade,
research has mainly focused on processes such as erosion of compressor blades and
static components caused by impinging ash particles as well as clogging and/or corrosion
effects of soft or molten ash particles on hot section turbine airfoils and components.
However, there is a lack of information on how the fan separates ingested VA particles
from the core stream flow into the bypass flow and therefore influences the mass concentration
inside the engine core section, which is most vulnerable and critical for safety. In
this numerical simulation study, we investigated the VA particle–fan interactions and
resulting reductions in particle mass concentrations entering the engine core section as a
function of particle size, fan rotation rate, and for two different flight altitudes. For this,
we used a high-bypass gas-turbine engine design, with representative intake, fan, spinner,
and splitter geometries for numerical computational fluid dynamics (CFD) simulations
including a Lagrangian particle-tracking algorithm. Our results reveal that
particle–fan interactions redirect particles from the core stream flow into the bypass
stream tube, which leads to a significant particle mass concentration reduction inside the
engine core section. The results also show that the particle–fan interactions increase
with increasing fan rotation rates and VA particle size. Depending on ingested VA size
distributions, the particle mass inside the engine core flow can be up to 30% reduced
compared to the incoming particle mass flow. The presented results enable future calculations
of effective core flow exposure or dosages based on simulated or observed atmospheric
VA particle size distribution, which is required to quantify engine failure
mechanisms after exposure to VA. As an example, we applied our methodology to a
recent aircraft encounter during the Mt. Kelud 2014 eruption. Based on ambient VA concentrations
simulated with an atmospheric particle dispersion model (FLEXPART), we
calculated the effective particle mass concentration inside the core stream flow along the
actual flight track and compared it with the whole engine exposure.

2019

Spatial distribution of residential wood combustion emissions in the Nordic countries: How well national inventories represent local emissions?

Paunu, Ville-Veikko; Karvosenoja, Niko; Segersson, David; Lopez-Aparicio, Susana; Nielsen, Ole-Kenneth; Plejdrup, Marlene S.; Thorsteinsson, Throstur; Niemi, Jarkko V; Vo, Dam Thanh; Gon, Hugo A.C. Denier van der; Brandt, Jørgen; Geels, Camilla

Residential wood combustion (RWC) is a major source of air pollutants in the Nordic and many other countries. The emissions of the pollutants have been estimated with inventories on several scopes, e.g. local and national. An important aspect of the inventories is the spatial distribution of the emissions, as it has an effect on health impact assessments. In this study, we present a novel residential wood combustion emission inventory for the Nordic countries based on national inventories and new gridding of the emissions. We compare the emissions of the Nordic inventory, and especially their spatial distribution, to local assessments and European level TNO-newRWC-inventory to assess the spatial proxies used. Common proxies used in the national inventories in the Nordic countries were building data on locations and primary heating methods and questionnaire-based wood use estimates for appliances or primary heating methods. Chimney sweeper register data was identified as good proxy data, but such data may not be available in an applicable format. Comparisons of national inventories to local assessments showed the possibility to achieve similar spatial distributions through nation-wide methods as local ones. However, this won't guarantee that the emissions are similar. Comparison to the TNO-newRWC-inventory revealed the importance of how differences between urban and rural residential wood combustion are handled. The comparison also highlighted the importance of local characteristics of residential wood combustion in the spatial distribution of emissions.

2021

Assessing the Relocation Robustness of on Field Calibrations for Air Quality Monitoring Devices

Esposito, E; Salvato, M; Vito, S. De; Fattoruso, G; Castell, Nuria; Karatzas, K.; Francia, G Di

2018

Ingestion of car tire crumb rubber and uptake of associated chemicals by lumpfish (Cyclopterus lumpus)

Hägg, Fanny; Herzke, Dorte; Nikiforov, Vladimir A.; Booth, Andy M.; Sperre, Kristine Hopland; Sørensen, Lisbet; Egeness, Mari Jystad; Halsband, Claudia

Car tire rubber constitutes one of the largest fractions of microplastics emissions to the environment. The two main emission sources are tire wear particles (TWPs) formed through abrasion during driving and runoff of crumb rubber (CR) granulate produced from end-of-life tires that is used as infill on artificial sports fields. Both tire wear particles and crumb rubber contain a complex mixture of metal and organic chemical additives, and exposure to both the particulate forms and their leachates can cause adverse effects in aquatic species. An understanding of the exposure pathways and mechanisms of toxicity are, however, scarce. While the most abundant metals and organic chemicals in car tire rubber have multiple other applications, para-phenylenediamines (PDs) are primarily used as rubber antioxidants and were recently shown to cause negative effects in aquatic organisms. The present study investigated the responses of the marine lumpfish (Cyclopterus lumpus) to crumb rubber exposure in a controlled feeding experiment. Juvenile fish were offered crumb rubber particles with their feed for 1 week, followed by 2 weeks of depuration. Crumb rubber particle ingestion occurred in >75% of exposed individuals, with a maximum of 84 particles observed in one specimen. Gastrointestinal tract retention times varied, with some organisms having no crumb rubber particles and others still containing up to 33 crumb rubber particles at the end of the experiment. Blood samples were analyzed for metals and organic chemicals, with ICP-MS analysis revealing there was no uptake of metals by the exposed fish. Interestingly, high resolution GC-MS analysis indicated that uptake of PDs into lumpfish blood was proportionate to the number of ingested CR particles. Three of the PDs found in blood were the same as those identified in the additive mixture Vulkanox3100. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) was the most concentrated PD in both the crumb rubber and lumpfish blood. The transformation product 6PPD-quinone was detected in the rubber material, but not in the blood. This study demonstrates that PDs are specific and bioavailable chemicals in car tire rubber that have the potential to serve as biomarkers of recent exposure to tire chemicals, where simple blood samples could be used to assess recent tire chemical exposure in vertebrates, including humans.

2023

Publikasjon
År
Kategori