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Sam-Erik Walker

Scientist

+47 63 89 80 83

Urban Environment and Industry Department
Kjeller

sew@nilu.no


Cristin  

Sam-Erik Walker

Sam-Erik Walker has 113 publications at NILU

Report/thesis

Understanding Air Quality Trends in Europe. Focus on the relative contribution of changes in emission of activity sectors, natural fraction and meteorological variability.

Colette, Augustin; Solberg, Sverre; Aas, Wenche; Walker, Sam-Erik
2021

Report/thesis

Appropriate Assimilation Methods for Air Quality Prediction and Pollutant Emission Inversion. An Urban Data Assimilation Systems Report.

Hamer, Paul David; Walker, Sam-Erik; Schneider, Philipp
2021

Journal publication

Quantifying the Impact of the Covid-19 Lockdown Measures on Nitrogen Dioxide Levels throughout Europe

Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp; Guerreiro, Cristina
2021

Conference lecture and academic presentation

Revidert tiltaksutredning for lokal luftkvalitet i Stavanger kommune

Weydahl, Torleif; Johnsrud, Mona; Vo, Dam Thanh; Walker, Sam-Erik; Høiskar, Britt Ann Kåstad; Ranheim, Patrick
2020

Report/thesis

Air quality in Europe - 2020 report

Ortiz, Alberto González; Guerreiro, Cristina; Soares, Joana; Antognazza, Frederico; Gsella, Artur; Houssiau, Michel; Liberti, Luca; Lükewille, Anke; Öztürk, Evrim; Horálek, Jan; Banyuls, Lorena; Targa, Jaume; Schneider, Philipp; Solberg, Sverre; Walker, Sam-Erik; Colette, Augustin
2020

Journal publication

The urban dispersion model EPISODE v10.0 – Part 1: An Eulerian and sub-grid-scale air quality model and its application in Nordic winter conditions

Hamer, Paul David; Walker, Sam-Erik; Sousa Santos, Gabriela; Vogt, Matthias; Vo, Dam Thanh; Lopez-Aparicio, Susana; Schneider, Philipp; Ramacher, Martin O. P.; Karl, Matthias
2020

Part of a book/report

A presentation of the EPISODE urban scale air quality model and its application to Nordic winter conditions

Hamer, Paul David; Walker, Sam-Erik; Sousa Santos, Gabriela; Vogt, Matthias; Vo, Dam Thanh; Lopez-Aparicio, Susana; Ramacher, Martin O. P.; Karl, Matthias
2020

Conference lecture and academic presentation

Hvordan har luftkvalitet i Europa endret seg under lockdown og hvorfor?

Guerreiro, Cristina; Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp
2020

Conference lecture and academic presentation

Networks of air quality sensors and their use for high-resolution mapping of urban air quality

Schneider, Philipp; Castell, Nuria; Hamer, Paul David; Walker, Sam-Erik; Bartonova, Alena
2020

Report/thesis

Statistical modelling for long-term trends of pollutants - Use of a GAM model for the assessment of measurements of O3, NO2 and PM

Solberg, Sverre; Walker, Sam-Erik; Guerreiro, Cristina; Colette, Augustin
2020

Report/thesis

A study of the relative expanded uncertainty formula for comparing low-cost sensor and reference measurements

Walker, Sam-Erik; Schneider, Philipp
2020

Report/thesis

Tiltaksutredning for lokal luftkvalitet i Tromsø

Weydahl, Torleif; Walker, Sam-Erik; Johnsrud, Mona; Vo, Dam Thanh; Ranheim, Patrick
2019

Report/thesis

Trends in measured NO2 and PM. Discounting the effect of meteorology.

Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp
2019

Report/thesis

Monitoring of greenhouse gases and aerosols at Svalbard and Birkenes in 2018. Annual report.

Myhre, Cathrine Lund; Svendby, Tove Marit; Hermansen, Ove; Lunder, Chris Rene; Platt, Stephen Matthew; Fiebig, Markus; Fjæraa, Ann Mari; Hansen, Georg Heinrich; Schmidbauer, Norbert; Krognes, Terje; Walker, Sam-Erik
2019

Journal publication

The Eulerian urban dispersion model EPISODE – Part 2: Extensions to the source dispersion and photochemistry for EPISODE–CityChem v1.2 and its application to the city of Hamburg

Karl, Matthias; Walker, Sam-Erik; Solberg, Sverre; Ramacher, Martin O. P.
2019

Conference lecture and academic presentation

Focused model selection and inference using robust estimators.

Walker, Sam-Erik; Hjort, Nils Lid
2018

Report/thesis

Monitoring of greenhouse gases and aerosols at Svalbard and Birkenes in 2017 - Annual report

Myhre, Cathrine Lund; Svendby, Tove Marit; Hermansen, Ove; Lunder, Chris Rene; Platt, Stephen Matthew; Fiebig, Markus; Fjæraa, Ann Mari; Hansen, Georg Heinrich; Schmidbauer, Norbert; Krognes, Terje; Walker, Sam-Erik
2018

Report/thesis

Discounting the effect of meteorology on trends in surface ozone: Development of statistical tools

Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp; Guerreiro, Cristina; Colette, Augustin
2018

Report/thesis

Bedre byluft. Endringer i 2014 og forskningsresultater av prognoser for meteorologi og luftkvalitet i norske byer vinteren 2013-2014.

Denby, B.R., Sundvor, I., Süld, J., Kristensen, A., Vallejo, I., Walker, S.E.
2015

Journal publication

Modelling atmospheric oxidation of 2-aminoethanol (MEA) emitted from post-combustion capture using WRF-Chem.

Karl, M., Svendby, T., Walker, S.-E., Velken, A.S., Castell, N., Solberg, S.
2015

Report/thesis

Data assimilation and statistical post-processing for numerical air quality predictions.

Steinbakk, G. H, Thorarinsdottir, T. L., Lahoz, W. A., Walker, S.-E.
2014

Report/thesis

Method and tool selection within the pilot study of air quality in Poland: Data fusion methodologies.

Karl, M., Walker, S.-E.
2014

Conference lecture and academic presentation

Ensemble based probabilistic forecasting of meteorology and air quality in Oslo, Norway.

Walker, S.E.
2014

Journal publication

Uncertainties in assessing the environmental impact of amine emissions from a CO2 capture plant.

Karl, M., Castell, N., Simpson, D., Solberg, S., Starrfelt, J., Svendby, T., Walker, S.-E., Wright, R.F.
2014

Report/thesis

Validation of UncertWeb: Air quality forecasting. UncertWeb Consortium Deliverable 6.3.

Walker, S.E., Denby, B., Pross, B., Cornford, D.
2013

Report/thesis

Report on integrating the traffic/individual modelling with the air quality modelling. UncertWeb Consortium Deliverable 8.3.

Gerharz, L., Helle, K.., Pebesma, E., Pross, B., Stasch, C., Rasouli, S., Timmermans, H., Denby, B., Walker, S.E.
2013

Report/thesis

Using UncertWeb for improved decision making. UncertWeb Consortium Deliverable 3.5.

Heuvelink, G., Helle, K., Pebesma, E., Rasouli, S., Stasch, C., Truong, P., Walker, S.E.
2013

Part of a book/report

Time series analysis of significant wave height data for identification of trends in the ocean wave climate.

Vanem, E., Walker, S.E.
2013

Journal publication

Identifying trends in the ocean wave climate by time series analyses of significant wave heightdata.

Vanem, E., Walker, S.E.
2013

Report/thesis

Probabilistic forecasting of air quality in Oslo. UncertWeb Consortium Deliverable 6.2.

Walker, S.E., Cornford, D.
2012

Conference lecture and academic presentation

Ensemble based probabilistic forecasting of air quality in Oslo and Rotterdam.

Walker, S.E., Denby B.R., Castell-Balaguer, N.
2012

Journal publication

WORM - A new open road line source model for low wind speed conditions.

Walker, S.E.
2011

Report/thesis

NO2-beregninger for 2010 og 2025 i Oslo og Bærum. Bidrag fra dieselbiler og mulige tiltak .

Sundvor, I., Tarrasón, L., Walker, S-E., Tønnesen, D.
2011

Report/thesis

Modellering av luftkvalitet og avsetningsnivå april 2009-april 2010. Miljøovervåking av utslipp til luft fra Snøhvit-Hammerfest LNG.

Liu, L., Walker, S.E., Hak, C., Gjerstad, K.I.
2011

Journal publication

Data assimilation within the Air4EU project: the Athens case.

Slini, T., Walker, S.E., Moussiopoulos, N.
2011

Journal publication

Towards uncertainty mapping in air-quality modelling and assessment.

Denby, B., Dudek, A., Walker, S.E., Costa, A.M., Monteiro, A., van den Elshout, S., Fisher, B.
2011

Report/thesis

Probabilistic modelling of air pollution from road traffic.

Walker, S.-E.
2010

Part of a book/report

The NILU SURFEX-EnKF land data assimilation system.

Lahoz, W., Svendby, T., Walker, S.-E., Mahfouf, J.-F.
2010

Journal publication

Ambient air pollution exposure, residential mobility and term birth weight in Oslo, Norway.

Madsen, C., Gehring, U., Walker, S.E., Brunekreef, B., Stigum, H., Næss, Ø., Nafstad, P.
2010

Report/thesis

The NILU SURFEX-EnKF land data assimilation system.

Lahoz, W., Walker, S.-E., Dammann, D.
2010

Journal publication

Evaluation and inter-comparison of open road line source models currently in use in the Nordic countries.

Berger, J., Walker, S.-E., Denby, B., Berkowicz, R., Løfstrøm, P., Ketzel, M., Härkönen, J., Nikmo, J., Karppinen, A.
2010

Journal publication

Ambient air pollution exposure, residential mobility and term birth weight in Oslo, Norway.

Madsen, C., Gehring, U., Walker, S.E., Brunekreef, B., Stigum, H., Næss, Ø., Nafstad, P.
2009

Journal publication

Modelling long-term averages of local ambient air pollution in Oslo, Norway: evaluation of nitrogen dioxide, PM10 and PM2.5.

Oftedal, B., Walker, S.E., Gram, F., Mc Innes, H., Nafstad, P.
2009

Journal publication

WORM - A new open road line source model for low wind speed conditions.

Walker, S.E.
2008

Conference lecture and academic presentation

WORM - A new open road line source model for low wind speed conditions.

Walker, S.E.
2008

Journal publication

Evaluation and inter-comparison of open road line source models currently in use in the Nordic countries.

Berger, J., Walker, S.E., Denby, B., Berkowicz, R., Løfstrøm, P., Ketzel, M., Härkonen, J., Nikmo, J., Karppinen, A.
2008

Journal publication

Residential outdoor air pollution and lung function in schoolchildren.

Oftedal, B., Brunekreef, B., Nystad, W., Madsen, C., Walker, S.E., Nafstad, P.
2008

Conference lecture and academic presentation

Application of data assimilation in open road line source modelling. Case study Oslo II.

Walker, S.E., Berger, J.
2007

Conference lecture and academic presentation

Quantification of uncertainties associated with an integrated Gaussian line source model using ensembles.

Walker, S.E.
2007

Part of a book/report

Quantification of uncertainties associated with an integrated Gaussian line source model using ensembles.

Walker, S.E.
2007

Part of a book/report

Data assimilation within the Air4EU project: the Athens case.

Slini, T., Walker, S.E., Moussiopoulos, N.
2007

Conference lecture and academic presentation

Data assimilation within the Air4EU project: the Athens case. Powerpoint presentation.

Slini, T., Walker, S.E., Moussiopoulos, N.
2007

Conference lecture and academic presentation

Evaluation and inter-comparison of open road line source (ORLS) models currently being used in the Nordic countries. Powerpoint presentation.

Berger, J., Walker, S.E., Denby, B., Berkowicz, R., Løfstrøm, P., Ketzel, M., Kukkonen, J.
2007

Part of a book/report

Evaluation and inter-comparison of open road line source models currently being used in the nordic countries: a NORPAC project.

Berger, J., Berkowicz, R., Walker, S.E., Denby, B., Løfstrøm, P., Ketzel, M., Kukkonen, J.
2007

Part of a book/report

Uncertainty mapping for air quality modelling and data assimilation.

Denby, B., Costa, A.M., Monteiro, A., Dudek, A., Walker, S.E., van den Elshout, S., Fisher, B.
2007

Conference lecture and academic presentation

Uncertainty mapping for air quality modelling and data assimilation. Powerpoint presentation.

Denby, B., Costa, A.M., Monteiro, A., Dudek, A., Walker, S.E., van den Elshout, S., Fisher, B.
2007

Conference lecture and academic presentation

Evaluation and inter-comparison of open road line source models currently being used in the nordic countries: a NORPAC project.

Berger, J., Walker, S.E., Denby, B., Løfstrøm, P., Ketzel, M., Berkowicz, R.
2007

Report/thesis

Beregning av veide døgnmiddelverdier av NO2, PM10 og PM2,5 under svangerskap i Oslo 1992-2002. Metodebeskrivelse.

Walker, S.-E.
2007

Part of a book/report

Evaluation and inter-comparison of open road line source models currently being used in the Nordic countries: a NORPAC project.

Berger, J., Walker, S.E., Denby, B., Løfstrøm, P., Ketzel, M., Berkowicz, R.
2007

Part of a book/report

Application of data assimilation in open road line source modelling.

Walker, S.E., Berger, J.
2007

Report/thesis

Individual case study report: 3. Model and observation uncertainty analysis towards data assimilation on the urban scale.

Walker, S.E. (ed.)
2007

Report/thesis

Individual case study report: 4. Data assimilation in open road line source modelling.

Walker, S.E. (ed.)
2007

Report/thesis

Dispersion and exposure calculation of PM10, NO2 and benzene for Oslo and Trondheim for the year 2005.

Slørdal, L.H., Mc Innes, H., Laupsa, H., Walker, S.E.
2006

Report/thesis

Data assimilation. Cross-cutting issue milestone report 6.8 (M.5).

Walker, S.E., Schaap, M.,, Slini, L.
2006

Part of a book/report

An introduction to Sequential Importance Resampling.

Walker, S.E.
2006

Conference lecture and academic presentation

Case study Oslo II: Data assimilation in open road line source modelling. Poster presentation.

Walker, S.E.
2006

Conference lecture and academic presentation

Cross cutting issue 5: Data assimilation. Poster presentation.

Walker, S.E., Schaap, M., Slini, L.
2006

Report/thesis

Oppdatering av regional konsekvensutredning for petroleumsvirksomheten i Nordsjøen. Regulære utslipp til luft - konsekvenser.

Knudsen, S., Solberg, S., Wathne, B.M., Høgåsen, T., Magnusson, J., Tollefsen, K.E., Aarrestad, P.A., Reitan, O., Stebel, K., Walker, S.E.
2006

Report/thesis

ESA Campaign Database (CDB) User Manual.

Vik, A.F., Krognes, T., Walker, S.-E., Bjørndalsæter, S., Stoll, C., Bårde, T., Paltiel, R., Gloslie, B.
2006

Report/thesis

Interpolation and assimilation methods for European scale air quality assessment and mapping. Part 1: Review and recommendations. Final draft.

Denby, B., Horálek, J., Walker, S.E., Eben, K., Fiala, J.
2005

Conference lecture and academic presentation

An introduction to sequential importance resampling. Powerpoint presentation.

Walker, S.E.
2005

Part of a book/report

Development of a simplified photochemistry scheme for urban areas.

Solberg, S., Walker, S.-E., Denby, B.
2005

Part of a book/report

Calculation of person-weighted average concentrations of NO2, PM10 and PM2.5 in Oslo for 1992-2002.

Walker, S.-E., Rosland, P.
2005

Conference lecture and academic presentation

WP3 Data Management. Powerpoint presentation.

Vik, A.F., Krognes, T., Walker, S.E., Bårde, T., Paltiel, R.
2005

Part of a book/report

A generic database for earth observation data. The ESA campaign data service.

Vik, A.F., Krognes, T, Bjørndalsæter, S., Stoll, C., Walker, S.E., Gloslie, B., Paltiel, R., Bårde, T., Våler, R.L.
2005

Conference lecture and academic presentation

Application of Sequential Importance Resampling (SIR) for 1D atmospheric chemical data assimilations.

Walker, S.E., Hatlo, M.
2005

Conference lecture and academic presentation

The RETRO database for observations. Poster presentation.

Vik, A.F., Bjørndalsæter, S., Stoll, C., Krognes, T., Paltiel, R., Bårde, T., Walker, S.-E., Westbye, A., Molin, P.
2005

Conference lecture and academic presentation

Simulated experiments with sequential importance resampling on a 1D advection-diffusion model using pseudo observations.

Walker, S.-E., Hatlo, M.
2005

Conference lecture and academic presentation

Calculation of person-weighted average concentrations of NO2, PM10 and PM 2,5 in Oslo for 1992-2002.

Walker, S.-E., Rosland, P.
2005

Conference lecture and academic presentation

Development of a simplified photochemistry scheme for urban areas.

Solberg, S., Walker, S.-E., Denby, B.
2005

Report/thesis

Rikets Miljøtilstand 2003.

Laupsa, H., Tønnesen, D., Krognes, T., Bruno, M., Walker, S.E.
2005

Conference lecture and academic presentation

Calculation of person-weighted average concentrations of NO2, PM10 and PM2,5 in Oslo for 1992-2002.

Walker, S.E., Rosland, P.
2005

Report/thesis

Metadata guidelines for the ESA Campaign Data Base (CDB). Version 0.02.

Krognes, T., Walker, S.E., Vik, A.F.
2004

Report/thesis

Beregning av NO2, PM10 og PM2,5 i Oslo for helseundersøkelsen HUBRO.

Walker, S-E.
2004

Report/thesis

Bedre byluft - evaluering av prognosemodell for meteorologi og luftkvalitet vinteren 2003/2004.

Ødegaard, V., Gjerstad, K.I., Bjergene, N., Jablonska, H.T.B., Walker, S.E.
2004

Report/thesis

Miljøundersøkelsene hovedveiomlegging Oslo Øst. Sluttundersøkelse. Hovedveiomlegging Oslo Øst-Svartdalstunnelen. Beregning av luftforurensning og eksponering.

Tønnesen, D., Walker, S.E., Haugsbakk, I.
2004

Report/thesis

Beregning av 3-års middelkonsentrasjoner i grunnkretser i Oslo for perioden 1992-2002.

Walker, S. E.
2004

Conference lecture and academic presentation

ASSET data management.

Vik, A.F., Krognes, T., Walker, S.E., Paltiel, R., Bårde, T.
2003

Report/thesis

Further development of a modelling system able to link hemispheric-regional and local air pollution.

Wind, P., Tarrasón, L., Slørdal, L.H., Solberg, S., Denby, B., Walker, S.-E.
2003

Report/thesis

Development and implementation of a simplified EMEP photochemistry scheme for urban areas in EPISODE.

Walker, S.-E., Solberg, S., Denby, B.
2003

Report/thesis

The urban air dispersion model EPISODE applied in AirQUIS2003. Technical description.

Slørdal, L.H., Walker, S.-E., Solberg, S.
2003

Report/thesis

Forurensning som funksjon av avstand fra vei. Målinger på RV159 Nordby-sletta v/Skårer vinteren 2001-2002, og sammenligning med VLUFT.

Hagen, L.O., Larssen, S., Walker, S.-E.
2003

Report/thesis

Bedre byluft. Evaluering av prognosemodell for meteorologi og luftkvalitet vinteren 2002/2003.

Ødegaard, V., Walker, S.-E., Midtbø, K. H., Jablonska, H. T. B., Gjerstad, K. I., Bjergene, N.
2003

Journal publication

The contribution to nitrogen deposition and ozone formation in South Norway from atmospheric emissions related to the petroleum activity in the North Sea.

Solberg, S., Lazaridis, M., Walker, S.E., Knudsen, S., Semb, A.
2003

Report/thesis

Konvertering fra døgn- til timemiddelbaserte varslingsklasser for svevestøv i Bedre byluft.

Walker, S.-E.
2003

Report/thesis

Development of a modeling system able to link hemispheric-regional and local air pollution.

Wind, P., Tarrasón, L., Berge, E., Slørdal, L.H., Solberg, S., Walker, S.E.
2002

Report/thesis

Implementation of extraction routine for ECMWF data through the Calval web-pages. Final development report.

Vik, A.F., Krognes, T., Walker, S.E., Bårde, T., Paltiel, R., Tørnkvist, K.K., Gloslie, B., Larsen, R., Thanh, T.N.
2002

Report/thesis

Operation of an Envisat Validation Data Centre. Estec Contract No 14419/00/NL/SF. Final report.

Krognes, T., Vik, Aa. F., Tørnkvist, K.K., Walker, S.E., Paltiel, R., Bårde, T., Gloslie, B., Larsen, R., Braathen, G.O., Thanh, T.N.
2002

Report/thesis

Bedre Byluft. Evaluering av prognosemodell for meteorologi og luftkvalitet vinteren 2001/2002.

Jablonska, H.T.B., Walker, S.E., Bøhler, T., Køltzow, M.Ø., Berge, E., Bjergene, N.
2002

Report/thesis

Regional konsekvensutredning for oljevirksomheten i Norskehavet. Utslipp til luft - miljømessige konsekvenser.

Solberg, S., Walker, S.E., Skjelkvåle, B.L., Høgåsen, T., Molvær, J., Larssen, T., Aarrestad, P.A., Reitan, O.
2002

Report/thesis

Beregninger av luftkvalitet ved Oslo Lufthavn Gardermoen 2001.

Gram, F., Walker, S.E.
2002

Report/thesis

Anvendelse av modellgenererte bakgrunnskonsentrasjoner i byskalamodellen EPISODE.

Slørdal, L.H., Solberg, S., Walker, S.-E.
2001

Part of a book/report

A real-time operational forecast model for meteorology and air quality during peak air pollution episodes in Oslo, Norway.

Berge, E., Walker, S.E., Sorteberg, A., Lenkopane, M.L., Eastwood, S., Jablonska, H.J., Ødegaard,M.
2001

Journal publication

Long-term measurements and model calculations of formaldehyde at rural European monitoring sites.

Solberg, S., Dye, C., Walker, S.E., Simpson, D.
2001

Report/thesis

Evaluation of urban scale time-dependent dispersion model with subgrid elements, in Oslo, Norway.

Grønskei, K.E., Gram, F., Larssen, S., Walker, S.E.
2000

Journal publication

Air pollution exposure monitoring and estimation VII. Estimation of population exposure in a central European airshed.

Grønskei, K.E., Bartonova, A., Brechler, J., Walker, S.E., Larssen, S.
2000

Journal publication

Air pollution exposure monitoring and estimation. Part II: Model evaluation and population exposure.

Walker, S.E., Slørdal, L.H., Guerreiro, C., Gram, F., Grønskei, K.E.
1999

Journal publication

Air pollution exposure monitoring and estimation. Part IV: Urban exposure in children.

Clench-Aas, J., Bartonova, A., Grønskei, K.E., Walker, S.E.
1999

Journal publication

Air pollution exposure monitoring and estimation. Part V: Traffic exposure in adults.

Bartonova, A., Clench-Aas, J., Gram, F., Grønskei, K.E., Guerreiro, C., Larssen, S. Tønnesen, D., Walker, S.-E.
1999

Journal publication

Air pollution exposure monitoring and estimating. Part VI: Ambient exposure of adults in an industrialised region.

Clench-Aas, J., Bartonova, A., Grønskei, K E., Hagen, L.O., Braathen, O.A., Walker, S.E.
1999

Part of a book/report

Development and evaluation of the urban dispersion model Episode used in evaluating traffic diversion measures in Oslo. Poster presentation.

Walker, S.E., Slørdal, L.H., Guerreiro, C., Grønskei, K.E.
1999

Part of a book/report

Air quality modelling in assessing impacts of traffic measures in Oslo. Poster presentation.

Bartonova, A., Clench-Aas, J., Walker, S E., Tønnesen, D A., Larssen, S.
1999

Report/thesis

Spredningsberegninger for on-line overvåking i Grenland. Programbeskrivelse og brukerveiledning.

Walker, S. E., Grønskei, K. E.
1992

Sam-Erik Walker has 113 publications at NILU

Report/thesis

Understanding Air Quality Trends in Europe. Focus on the relative contribution of changes in emission of activity sectors, natural fraction and meteorological variability.

Colette, Augustin; Solberg, Sverre; Aas, Wenche; Walker, Sam-Erik
2021

Report/thesis

Appropriate Assimilation Methods for Air Quality Prediction and Pollutant Emission Inversion. An Urban Data Assimilation Systems Report.

Hamer, Paul David; Walker, Sam-Erik; Schneider, Philipp
2021

Journal publication

Quantifying the Impact of the Covid-19 Lockdown Measures on Nitrogen Dioxide Levels throughout Europe

Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp; Guerreiro, Cristina
2021

Conference lecture and academic presentation

Revidert tiltaksutredning for lokal luftkvalitet i Stavanger kommune

Weydahl, Torleif; Johnsrud, Mona; Vo, Dam Thanh; Walker, Sam-Erik; Høiskar, Britt Ann Kåstad; Ranheim, Patrick
2020

Report/thesis

Air quality in Europe - 2020 report

Ortiz, Alberto González; Guerreiro, Cristina; Soares, Joana; Antognazza, Frederico; Gsella, Artur; Houssiau, Michel; Liberti, Luca; Lükewille, Anke; Öztürk, Evrim; Horálek, Jan; Banyuls, Lorena; Targa, Jaume; Schneider, Philipp; Solberg, Sverre; Walker, Sam-Erik; Colette, Augustin
2020

Journal publication

The urban dispersion model EPISODE v10.0 – Part 1: An Eulerian and sub-grid-scale air quality model and its application in Nordic winter conditions

Hamer, Paul David; Walker, Sam-Erik; Sousa Santos, Gabriela; Vogt, Matthias; Vo, Dam Thanh; Lopez-Aparicio, Susana; Schneider, Philipp; Ramacher, Martin O. P.; Karl, Matthias
2020

Part of a book/report

A presentation of the EPISODE urban scale air quality model and its application to Nordic winter conditions

Hamer, Paul David; Walker, Sam-Erik; Sousa Santos, Gabriela; Vogt, Matthias; Vo, Dam Thanh; Lopez-Aparicio, Susana; Ramacher, Martin O. P.; Karl, Matthias
2020

Conference lecture and academic presentation

Hvordan har luftkvalitet i Europa endret seg under lockdown og hvorfor?

Guerreiro, Cristina; Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp
2020

Conference lecture and academic presentation

Networks of air quality sensors and their use for high-resolution mapping of urban air quality

Schneider, Philipp; Castell, Nuria; Hamer, Paul David; Walker, Sam-Erik; Bartonova, Alena
2020

Report/thesis

Statistical modelling for long-term trends of pollutants - Use of a GAM model for the assessment of measurements of O3, NO2 and PM

Solberg, Sverre; Walker, Sam-Erik; Guerreiro, Cristina; Colette, Augustin
2020

Report/thesis

A study of the relative expanded uncertainty formula for comparing low-cost sensor and reference measurements

Walker, Sam-Erik; Schneider, Philipp
2020

Report/thesis

Tiltaksutredning for lokal luftkvalitet i Tromsø

Weydahl, Torleif; Walker, Sam-Erik; Johnsrud, Mona; Vo, Dam Thanh; Ranheim, Patrick
2019

Report/thesis

Trends in measured NO2 and PM. Discounting the effect of meteorology.

Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp
2019

Report/thesis

Monitoring of greenhouse gases and aerosols at Svalbard and Birkenes in 2018. Annual report.

Myhre, Cathrine Lund; Svendby, Tove Marit; Hermansen, Ove; Lunder, Chris Rene; Platt, Stephen Matthew; Fiebig, Markus; Fjæraa, Ann Mari; Hansen, Georg Heinrich; Schmidbauer, Norbert; Krognes, Terje; Walker, Sam-Erik
2019

Journal publication

The Eulerian urban dispersion model EPISODE – Part 2: Extensions to the source dispersion and photochemistry for EPISODE–CityChem v1.2 and its application to the city of Hamburg

Karl, Matthias; Walker, Sam-Erik; Solberg, Sverre; Ramacher, Martin O. P.
2019

Conference lecture and academic presentation

Focused model selection and inference using robust estimators.

Walker, Sam-Erik; Hjort, Nils Lid
2018

Report/thesis

Monitoring of greenhouse gases and aerosols at Svalbard and Birkenes in 2017 - Annual report

Myhre, Cathrine Lund; Svendby, Tove Marit; Hermansen, Ove; Lunder, Chris Rene; Platt, Stephen Matthew; Fiebig, Markus; Fjæraa, Ann Mari; Hansen, Georg Heinrich; Schmidbauer, Norbert; Krognes, Terje; Walker, Sam-Erik
2018

Report/thesis

Discounting the effect of meteorology on trends in surface ozone: Development of statistical tools

Solberg, Sverre; Walker, Sam-Erik; Schneider, Philipp; Guerreiro, Cristina; Colette, Augustin
2018

Report/thesis

Bedre byluft. Endringer i 2014 og forskningsresultater av prognoser for meteorologi og luftkvalitet i norske byer vinteren 2013-2014.

Denby, B.R., Sundvor, I., Süld, J., Kristensen, A., Vallejo, I., Walker, S.E.
2015

Journal publication

Modelling atmospheric oxidation of 2-aminoethanol (MEA) emitted from post-combustion capture using WRF-Chem.

Karl, M., Svendby, T., Walker, S.-E., Velken, A.S., Castell, N., Solberg, S.
2015

Report/thesis

Data assimilation and statistical post-processing for numerical air quality predictions.

Steinbakk, G. H, Thorarinsdottir, T. L., Lahoz, W. A., Walker, S.-E.
2014

Report/thesis

Method and tool selection within the pilot study of air quality in Poland: Data fusion methodologies.

Karl, M., Walker, S.-E.
2014

Conference lecture and academic presentation

Ensemble based probabilistic forecasting of meteorology and air quality in Oslo, Norway.

Walker, S.E.
2014

Journal publication

Uncertainties in assessing the environmental impact of amine emissions from a CO2 capture plant.

Karl, M., Castell, N., Simpson, D., Solberg, S., Starrfelt, J., Svendby, T., Walker, S.-E., Wright, R.F.
2014

Report/thesis

Validation of UncertWeb: Air quality forecasting. UncertWeb Consortium Deliverable 6.3.

Walker, S.E., Denby, B., Pross, B., Cornford, D.
2013

Report/thesis

Report on integrating the traffic/individual modelling with the air quality modelling. UncertWeb Consortium Deliverable 8.3.

Gerharz, L., Helle, K.., Pebesma, E., Pross, B., Stasch, C., Rasouli, S., Timmermans, H., Denby, B., Walker, S.E.
2013

Report/thesis

Using UncertWeb for improved decision making. UncertWeb Consortium Deliverable 3.5.

Heuvelink, G., Helle, K., Pebesma, E., Rasouli, S., Stasch, C., Truong, P., Walker, S.E.
2013

Part of a book/report

Time series analysis of significant wave height data for identification of trends in the ocean wave climate.

Vanem, E., Walker, S.E.
2013

Journal publication

Identifying trends in the ocean wave climate by time series analyses of significant wave heightdata.

Vanem, E., Walker, S.E.
2013

Report/thesis

Probabilistic forecasting of air quality in Oslo. UncertWeb Consortium Deliverable 6.2.

Walker, S.E., Cornford, D.
2012

Conference lecture and academic presentation

Ensemble based probabilistic forecasting of air quality in Oslo and Rotterdam.

Walker, S.E., Denby B.R., Castell-Balaguer, N.
2012

Journal publication

WORM - A new open road line source model for low wind speed conditions.

Walker, S.E.
2011

Report/thesis

NO2-beregninger for 2010 og 2025 i Oslo og Bærum. Bidrag fra dieselbiler og mulige tiltak .

Sundvor, I., Tarrasón, L., Walker, S-E., Tønnesen, D.
2011

Report/thesis

Modellering av luftkvalitet og avsetningsnivå april 2009-april 2010. Miljøovervåking av utslipp til luft fra Snøhvit-Hammerfest LNG.

Liu, L., Walker, S.E., Hak, C., Gjerstad, K.I.
2011

Journal publication

Data assimilation within the Air4EU project: the Athens case.

Slini, T., Walker, S.E., Moussiopoulos, N.
2011

Journal publication

Towards uncertainty mapping in air-quality modelling and assessment.

Denby, B., Dudek, A., Walker, S.E., Costa, A.M., Monteiro, A., van den Elshout, S., Fisher, B.
2011

Report/thesis

Probabilistic modelling of air pollution from road traffic.

Walker, S.-E.
2010

Part of a book/report

The NILU SURFEX-EnKF land data assimilation system.

Lahoz, W., Svendby, T., Walker, S.-E., Mahfouf, J.-F.
2010

Journal publication

Ambient air pollution exposure, residential mobility and term birth weight in Oslo, Norway.

Madsen, C., Gehring, U., Walker, S.E., Brunekreef, B., Stigum, H., Næss, Ø., Nafstad, P.
2010

Report/thesis

The NILU SURFEX-EnKF land data assimilation system.

Lahoz, W., Walker, S.-E., Dammann, D.
2010

Journal publication

Evaluation and inter-comparison of open road line source models currently in use in the Nordic countries.

Berger, J., Walker, S.-E., Denby, B., Berkowicz, R., Løfstrøm, P., Ketzel, M., Härkönen, J., Nikmo, J., Karppinen, A.
2010

Journal publication

Ambient air pollution exposure, residential mobility and term birth weight in Oslo, Norway.

Madsen, C., Gehring, U., Walker, S.E., Brunekreef, B., Stigum, H., Næss, Ø., Nafstad, P.
2009

Journal publication

Modelling long-term averages of local ambient air pollution in Oslo, Norway: evaluation of nitrogen dioxide, PM10 and PM2.5.

Oftedal, B., Walker, S.E., Gram, F., Mc Innes, H., Nafstad, P.
2009

Journal publication

WORM - A new open road line source model for low wind speed conditions.

Walker, S.E.
2008

Conference lecture and academic presentation

WORM - A new open road line source model for low wind speed conditions.

Walker, S.E.
2008

Journal publication

Evaluation and inter-comparison of open road line source models currently in use in the Nordic countries.

Berger, J., Walker, S.E., Denby, B., Berkowicz, R., Løfstrøm, P., Ketzel, M., Härkonen, J., Nikmo, J., Karppinen, A.
2008

Journal publication

Residential outdoor air pollution and lung function in schoolchildren.

Oftedal, B., Brunekreef, B., Nystad, W., Madsen, C., Walker, S.E., Nafstad, P.
2008

Conference lecture and academic presentation

Application of data assimilation in open road line source modelling. Case study Oslo II.

Walker, S.E., Berger, J.
2007

Conference lecture and academic presentation

Quantification of uncertainties associated with an integrated Gaussian line source model using ensembles.

Walker, S.E.
2007

Part of a book/report

Quantification of uncertainties associated with an integrated Gaussian line source model using ensembles.

Walker, S.E.
2007

Part of a book/report

Data assimilation within the Air4EU project: the Athens case.

Slini, T., Walker, S.E., Moussiopoulos, N.
2007

Conference lecture and academic presentation

Data assimilation within the Air4EU project: the Athens case. Powerpoint presentation.

Slini, T., Walker, S.E., Moussiopoulos, N.
2007

Conference lecture and academic presentation

Evaluation and inter-comparison of open road line source (ORLS) models currently being used in the Nordic countries. Powerpoint presentation.

Berger, J., Walker, S.E., Denby, B., Berkowicz, R., Løfstrøm, P., Ketzel, M., Kukkonen, J.
2007

Part of a book/report

Evaluation and inter-comparison of open road line source models currently being used in the nordic countries: a NORPAC project.

Berger, J., Berkowicz, R., Walker, S.E., Denby, B., Løfstrøm, P., Ketzel, M., Kukkonen, J.
2007

Part of a book/report

Uncertainty mapping for air quality modelling and data assimilation.

Denby, B., Costa, A.M., Monteiro, A., Dudek, A., Walker, S.E., van den Elshout, S., Fisher, B.
2007

Conference lecture and academic presentation

Uncertainty mapping for air quality modelling and data assimilation. Powerpoint presentation.

Denby, B., Costa, A.M., Monteiro, A., Dudek, A., Walker, S.E., van den Elshout, S., Fisher, B.
2007

Conference lecture and academic presentation

Evaluation and inter-comparison of open road line source models currently being used in the nordic countries: a NORPAC project.

Berger, J., Walker, S.E., Denby, B., Løfstrøm, P., Ketzel, M., Berkowicz, R.
2007

Report/thesis

Beregning av veide døgnmiddelverdier av NO2, PM10 og PM2,5 under svangerskap i Oslo 1992-2002. Metodebeskrivelse.

Walker, S.-E.
2007

Part of a book/report

Evaluation and inter-comparison of open road line source models currently being used in the Nordic countries: a NORPAC project.

Berger, J., Walker, S.E., Denby, B., Løfstrøm, P., Ketzel, M., Berkowicz, R.
2007

Part of a book/report

Application of data assimilation in open road line source modelling.

Walker, S.E., Berger, J.
2007

Report/thesis

Individual case study report: 3. Model and observation uncertainty analysis towards data assimilation on the urban scale.

Walker, S.E. (ed.)
2007

Report/thesis

Individual case study report: 4. Data assimilation in open road line source modelling.

Walker, S.E. (ed.)
2007

Report/thesis

Dispersion and exposure calculation of PM10, NO2 and benzene for Oslo and Trondheim for the year 2005.

Slørdal, L.H., Mc Innes, H., Laupsa, H., Walker, S.E.
2006

Report/thesis

Data assimilation. Cross-cutting issue milestone report 6.8 (M.5).

Walker, S.E., Schaap, M.,, Slini, L.
2006

Part of a book/report

An introduction to Sequential Importance Resampling.

Walker, S.E.
2006

Conference lecture and academic presentation

Case study Oslo II: Data assimilation in open road line source modelling. Poster presentation.

Walker, S.E.
2006

Conference lecture and academic presentation

Cross cutting issue 5: Data assimilation. Poster presentation.

Walker, S.E., Schaap, M., Slini, L.
2006

Report/thesis

Oppdatering av regional konsekvensutredning for petroleumsvirksomheten i Nordsjøen. Regulære utslipp til luft - konsekvenser.

Knudsen, S., Solberg, S., Wathne, B.M., Høgåsen, T., Magnusson, J., Tollefsen, K.E., Aarrestad, P.A., Reitan, O., Stebel, K., Walker, S.E.
2006

Report/thesis

ESA Campaign Database (CDB) User Manual.

Vik, A.F., Krognes, T., Walker, S.-E., Bjørndalsæter, S., Stoll, C., Bårde, T., Paltiel, R., Gloslie, B.
2006

Report/thesis

Interpolation and assimilation methods for European scale air quality assessment and mapping. Part 1: Review and recommendations. Final draft.

Denby, B., Horálek, J., Walker, S.E., Eben, K., Fiala, J.
2005

Conference lecture and academic presentation

An introduction to sequential importance resampling. Powerpoint presentation.

Walker, S.E.
2005

Part of a book/report

Development of a simplified photochemistry scheme for urban areas.

Solberg, S., Walker, S.-E., Denby, B.
2005

Part of a book/report

Calculation of person-weighted average concentrations of NO2, PM10 and PM2.5 in Oslo for 1992-2002.

Walker, S.-E., Rosland, P.
2005

Conference lecture and academic presentation

WP3 Data Management. Powerpoint presentation.

Vik, A.F., Krognes, T., Walker, S.E., Bårde, T., Paltiel, R.
2005

Part of a book/report

A generic database for earth observation data. The ESA campaign data service.

Vik, A.F., Krognes, T, Bjørndalsæter, S., Stoll, C., Walker, S.E., Gloslie, B., Paltiel, R., Bårde, T., Våler, R.L.
2005

Conference lecture and academic presentation

Application of Sequential Importance Resampling (SIR) for 1D atmospheric chemical data assimilations.

Walker, S.E., Hatlo, M.
2005

Conference lecture and academic presentation

The RETRO database for observations. Poster presentation.

Vik, A.F., Bjørndalsæter, S., Stoll, C., Krognes, T., Paltiel, R., Bårde, T., Walker, S.-E., Westbye, A., Molin, P.
2005

Conference lecture and academic presentation

Simulated experiments with sequential importance resampling on a 1D advection-diffusion model using pseudo observations.

Walker, S.-E., Hatlo, M.
2005

Conference lecture and academic presentation

Calculation of person-weighted average concentrations of NO2, PM10 and PM 2,5 in Oslo for 1992-2002.

Walker, S.-E., Rosland, P.
2005

Conference lecture and academic presentation

Development of a simplified photochemistry scheme for urban areas.

Solberg, S., Walker, S.-E., Denby, B.
2005

Report/thesis

Rikets Miljøtilstand 2003.

Laupsa, H., Tønnesen, D., Krognes, T., Bruno, M., Walker, S.E.
2005

Conference lecture and academic presentation

Calculation of person-weighted average concentrations of NO2, PM10 and PM2,5 in Oslo for 1992-2002.

Walker, S.E., Rosland, P.
2005

Report/thesis

Metadata guidelines for the ESA Campaign Data Base (CDB). Version 0.02.

Krognes, T., Walker, S.E., Vik, A.F.
2004

Report/thesis

Beregning av NO2, PM10 og PM2,5 i Oslo for helseundersøkelsen HUBRO.

Walker, S-E.
2004

Report/thesis

Bedre byluft - evaluering av prognosemodell for meteorologi og luftkvalitet vinteren 2003/2004.

Ødegaard, V., Gjerstad, K.I., Bjergene, N., Jablonska, H.T.B., Walker, S.E.
2004

Report/thesis

Miljøundersøkelsene hovedveiomlegging Oslo Øst. Sluttundersøkelse. Hovedveiomlegging Oslo Øst-Svartdalstunnelen. Beregning av luftforurensning og eksponering.

Tønnesen, D., Walker, S.E., Haugsbakk, I.
2004

Report/thesis

Beregning av 3-års middelkonsentrasjoner i grunnkretser i Oslo for perioden 1992-2002.

Walker, S. E.
2004

Conference lecture and academic presentation

ASSET data management.

Vik, A.F., Krognes, T., Walker, S.E., Paltiel, R., Bårde, T.
2003

Report/thesis

Further development of a modelling system able to link hemispheric-regional and local air pollution.

Wind, P., Tarrasón, L., Slørdal, L.H., Solberg, S., Denby, B., Walker, S.-E.
2003

Report/thesis

Development and implementation of a simplified EMEP photochemistry scheme for urban areas in EPISODE.

Walker, S.-E., Solberg, S., Denby, B.
2003

Report/thesis

The urban air dispersion model EPISODE applied in AirQUIS2003. Technical description.

Slørdal, L.H., Walker, S.-E., Solberg, S.
2003

Report/thesis

Forurensning som funksjon av avstand fra vei. Målinger på RV159 Nordby-sletta v/Skårer vinteren 2001-2002, og sammenligning med VLUFT.

Hagen, L.O., Larssen, S., Walker, S.-E.
2003

Report/thesis

Bedre byluft. Evaluering av prognosemodell for meteorologi og luftkvalitet vinteren 2002/2003.

Ødegaard, V., Walker, S.-E., Midtbø, K. H., Jablonska, H. T. B., Gjerstad, K. I., Bjergene, N.
2003

Journal publication

The contribution to nitrogen deposition and ozone formation in South Norway from atmospheric emissions related to the petroleum activity in the North Sea.

Solberg, S., Lazaridis, M., Walker, S.E., Knudsen, S., Semb, A.
2003

Report/thesis

Konvertering fra døgn- til timemiddelbaserte varslingsklasser for svevestøv i Bedre byluft.

Walker, S.-E.
2003

Report/thesis

Development of a modeling system able to link hemispheric-regional and local air pollution.

Wind, P., Tarrasón, L., Berge, E., Slørdal, L.H., Solberg, S., Walker, S.E.
2002

Report/thesis

Implementation of extraction routine for ECMWF data through the Calval web-pages. Final development report.

Vik, A.F., Krognes, T., Walker, S.E., Bårde, T., Paltiel, R., Tørnkvist, K.K., Gloslie, B., Larsen, R., Thanh, T.N.
2002

Report/thesis

Operation of an Envisat Validation Data Centre. Estec Contract No 14419/00/NL/SF. Final report.

Krognes, T., Vik, Aa. F., Tørnkvist, K.K., Walker, S.E., Paltiel, R., Bårde, T., Gloslie, B., Larsen, R., Braathen, G.O., Thanh, T.N.
2002

Report/thesis

Bedre Byluft. Evaluering av prognosemodell for meteorologi og luftkvalitet vinteren 2001/2002.

Jablonska, H.T.B., Walker, S.E., Bøhler, T., Køltzow, M.Ø., Berge, E., Bjergene, N.
2002

Report/thesis

Regional konsekvensutredning for oljevirksomheten i Norskehavet. Utslipp til luft - miljømessige konsekvenser.

Solberg, S., Walker, S.E., Skjelkvåle, B.L., Høgåsen, T., Molvær, J., Larssen, T., Aarrestad, P.A., Reitan, O.
2002

Report/thesis

Beregninger av luftkvalitet ved Oslo Lufthavn Gardermoen 2001.

Gram, F., Walker, S.E.
2002

Report/thesis

Anvendelse av modellgenererte bakgrunnskonsentrasjoner i byskalamodellen EPISODE.

Slørdal, L.H., Solberg, S., Walker, S.-E.
2001

Part of a book/report

A real-time operational forecast model for meteorology and air quality during peak air pollution episodes in Oslo, Norway.

Berge, E., Walker, S.E., Sorteberg, A., Lenkopane, M.L., Eastwood, S., Jablonska, H.J., Ødegaard,M.
2001

Journal publication

Long-term measurements and model calculations of formaldehyde at rural European monitoring sites.

Solberg, S., Dye, C., Walker, S.E., Simpson, D.
2001

Report/thesis

Evaluation of urban scale time-dependent dispersion model with subgrid elements, in Oslo, Norway.

Grønskei, K.E., Gram, F., Larssen, S., Walker, S.E.
2000

Journal publication

Air pollution exposure monitoring and estimation VII. Estimation of population exposure in a central European airshed.

Grønskei, K.E., Bartonova, A., Brechler, J., Walker, S.E., Larssen, S.
2000

Journal publication

Air pollution exposure monitoring and estimation. Part II: Model evaluation and population exposure.

Walker, S.E., Slørdal, L.H., Guerreiro, C., Gram, F., Grønskei, K.E.
1999

Journal publication

Air pollution exposure monitoring and estimation. Part IV: Urban exposure in children.

Clench-Aas, J., Bartonova, A., Grønskei, K.E., Walker, S.E.
1999

Journal publication

Air pollution exposure monitoring and estimation. Part V: Traffic exposure in adults.

Bartonova, A., Clench-Aas, J., Gram, F., Grønskei, K.E., Guerreiro, C., Larssen, S. Tønnesen, D., Walker, S.-E.
1999

Journal publication

Air pollution exposure monitoring and estimating. Part VI: Ambient exposure of adults in an industrialised region.

Clench-Aas, J., Bartonova, A., Grønskei, K E., Hagen, L.O., Braathen, O.A., Walker, S.E.
1999

Part of a book/report

Development and evaluation of the urban dispersion model Episode used in evaluating traffic diversion measures in Oslo. Poster presentation.

Walker, S.E., Slørdal, L.H., Guerreiro, C., Grønskei, K.E.
1999

Part of a book/report

Air quality modelling in assessing impacts of traffic measures in Oslo. Poster presentation.

Bartonova, A., Clench-Aas, J., Walker, S E., Tønnesen, D A., Larssen, S.
1999

Report/thesis

Spredningsberegninger for on-line overvåking i Grenland. Programbeskrivelse og brukerveiledning.

Walker, S. E., Grønskei, K. E.
1992