Annica EkmanProfessor of Meteorology
About me
I work as a professor at the Department of Meteorology, Stockholm University. I'm also an editor for the scientific journal Tellus B. My main research interests are clouds and aerosol particles (suspensions of nano- to micrometer sized particles in air) and the various ways aerosol particles can influence weather, circulation and climate. The impact of aerosol particles and clouds on the radiative balance of the Earth constitutes a major uncertainty in our understanding of present-day climate.
Research
Peer-reviewed publications:
2020:
Graham, E. L., Zieger, P., Mohr, C., Wideqvist, U., Hennig, T., Ekman, A. M. L., Krejci, R. Ström, J. & I. Riipinen, 2020. Physical and chemical properties of aerosol particles and cloud residuals on Mt. Åreskutan in Central Sweden during summer 2014, Tellus B: Chemical and Physical Meteorology, 72:1, 1-16, DOI: 10.1080/16000889.2020.1776080.
Bardakov, R., Riipinen, I., Savre, J., Ekman, A. M. L., 2020. A novel framework to study trace gas transport in deep convective clouds, J. Adv. Model. Earth Syst., 12, e2019MS001931, https://doi.org/10.1029/2019MS00193.
Krishnan, S., Ekman, A. M. L., Hansson, H.-C., Riipinen, I., Lewinschal, A., Wilcox, L. J., Dallafior, T., 2020. The roles of the atmosphere and ocean in driving Arctic warming due to European aerosol reductions. Geophysical Research Letters, 47, e2019GL086681, https://doi.org/10.1029/2019GL08668.
Dimitrelos, A., Ekman, A. M. L., Caballero, R. and Savre, J., 2020. A sensitivity study of Arctic air‐mass transformation using large eddy simulation. J. Geophys. Res., 125, e2019JD031738. DOI: 10.1029/2019JD031738.
Sotiropoulou, G., Sullivan, S., Savre, J., Lloyd, G., Lachlan-Cope, T., Ekman, A. M. L. and A. Nenes, 2020. The impact of secondary ice production on Arctic stratocumulus. Atmos. Chem. Phys., 20, 1301–1316, 2020. doi.org/10.5194/acp-20-1301-2020.
Sand, M., Berntsen, T. K. Ekman, A. M. L., Hansson, H.-C., Lewinschal, A., 2020. Surface temperature response to regional Black Carbon emissions: Do location and magnitude matter? Atmos. Chem. Phys, 20, 3079–3089. https://doi.org/10.5194/acp-20-3079-2020.
2019:
Höpner, F., Bender F. A. M., Ekman, A. M. L., Andersson, A., Gustafsson, Ö., Leck, C., 2019. Investigation of Two Optical Methods for Aerosol-Type Classification Extended to a Northern Indian Ocean Site. J. Geophys. Res., 124, 8743-8763, DOI: 10.1029/2018JD029685.
Wilcox, L. J., Dunstone, N., Lewinschal, A., Bollasina, M., Ekman, A. M. L., Highwood, E. J., 2019. Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter. Atmos. Chem. Phys., 19, 9081-9095, DOI: 10.5194/acp-19-9081-2019.
Johansson, E., Devasthale, A., Ekman, A. M. L, Tjernström, M., L’Ecuyer, T., 2019. How does cloud overlap affect the radiative heating in the tropical upper troposphere / lower stratosphere? Geophys. Res. Lett., 46, 5623-5631.
Bulatovic, I., Ekman, A. M. L., Savre, J., Riipinen, I. and Leck, C. Aerosol Indirect Effects in Marine Stratocumulus: The importance of explicitly predicting cloud droplet activation. Geophys. Res. Lett., 46. https://doi.org/10.1029/2018GL081746, 2019.
Thomas, M., Devasthale, A., Tjernström, M. and Ekman, A. M. L., The relation between aerosol vertical distribution and temperature inversions in the Arctic in winter and spring. Geophys. Res. Lett., 46, 2836–2845. https://doi.org/10.1029/2018GL081624, 2019.
Lewinschal, A., Ekman, A. M. L., Hansson, H.-C., Sand, M., Berntsen, T. K., Langner, J. Local and remote temperature response of regional SO2 emissions. Atmos. Chem. Phys., 19, 2385–2403, 2019.
Boy, M. et al., Interactions between the atmosphere, cryosphere, and ecosystems at northern high latitudes. Atmos. Chem. Phys., 19, 2015–2061, 2019.
2018:
Pithan, F., Svensson, G. Caballero, R., Chechin, D., Cronin, T. W., Ekman, A. M. L., Neggers, R., Shupe, M. D., Solomon, A., Tjernström, M., Wendish, M., 2018. Role of air-mass transformations in exchange between the Arctic and mid-latitudes. Nature Geoscience, doi:10.1038/s41561-018-0234-1.
Sotiropoulou, G., Tjernström, M., Savre, J., Ekman, A. M. L., Hartung, K., Sedlar, J., 2018. Large Eddy Simulation of a warm-air advection episode in the summer Arctic. Accepted for publication in Q.J.R. Meteorol. Soc., 144, 2449–2462.
Robin G. Stevens, Katharina Loewe, Christopher Dearden, Antonios Dimitrelos, Anna Possner, Gesa K. Eirund, Tomi Raatikainen, Adrian A. Hill, Benjamin J. Shipway, Jonathan Wilkinson, Sami Romakkaniemi, Juha Tonttila, Ari Laaksonen, Hannele Korhonen, Paul Connolly, Ulrike Lohmann, Corinna Hoose, Annica M. L. Ekman, Ken S. Carslaw, and Paul R. Field., 2018. A model intercomparison of CCN-limited tenuous clouds in the high Arctic. Atmos. Chem. Phys., 18, 11041-11071.
Bourgeois, Q., Ekman, A. M. L., Jean-Baptiste Renard, Radovan Krejci, Abhay Devasthale, Frida A.-M. Bender, Ilona Riipinen, Gwenaël Berthet, and Jason L. Tacket., 2018. How much of the global aerosol optical depth is found in the boundary layer and free troposphere? Atmos. Chem. Phys., 18, 7709–7720.
2017:
Igel, A., Ekman, A. M. L., Leck, C., Tjernström, M., Savre, J., Sedlar, J., 2017. The Free Troposphere as a Potential Source of Arctic Boundary Layer Aerosol Particles. Geophys. Res. Lett., 44, DOI: 10.1002/2017GL073808.
Loewe, K., Ekman, A. M. L., Paukert, M., Sedlar, J., Tjernström, M., Hoose, C., 2017. Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS). Atmos. Chem. Phys., 17, 6693-6704.
Rastak, N., Pajunoja, A., Acosta Navarro, J. C., Ma, J., Song, M., Partridge, D. G., Kirkevåg, A., Leong, Y., Hu, W. W., Taylor, N. F., Lambe, A., Cerully, K., Bougiatioti, A., Liu, P., Krejci, R., Petäjä, T., Percival, C., Davidovits, P., Worsnop, D. G., Ekman, A. M. L., Nenes, A., Martin, S., Jimenez, J. L., Collins, D. R., Topping, D. O., Bertram, A. K., Zuend, A., Virtanen, A., Riipinen, I. 2017. Microphysical explanation of the RH-dependent water-affinity of biogenic organic aerosol and its importance for climate. Geophys. Res., Lett., 44, DOI: 10.1002/2017GL073056.
Johansson, E., Devasthale, A., Tjernström, M., Ekman, A. M. L., L’Ecuyer, T. Response of the lower troposphere to moisture intrusions into the Arctic. 2017. Geophys. Res. Lett., 44, 2527–2536, doi:10.1002/2017GL072687.
Possner, A., Ekman, A. M., L., Lohmann, U. 2017. Cloud response and feedback processes in stratiform mixed‐phase clouds perturbed by ship exhaust. Geophys. Res. Lett., 44, doi:10.1002/2016GL071358.
Acosta Navarro, J. C., Ekman, A. M. L., Pausata, F., Lewinschal, A., Varma, V., Seland, Ø., Gauss, M., Iversen, T., Kirkevåg, A., Riipinen, I., Hansson, H.-C., 2017. Future response of temperature and precipitation to reduced aerosol emission as compared with increased greenhouse gas concentrations. Journal of Climate., 30, 939-954. DOI: 10.1175/JCLI-D-16-0466.1
Chiacchio, M, Pausata, F.S. R., Messori, G., Hannachi, A., Chin, M., Önskog, T., Liepert, B., Ekman, A. M. L. and Barrie, L., 2017. On the links between meteorological variables, aerosols, and tropical cyclone frequency in individual ocean basins. J. Geophys. Res. Atmos., 121, doi:10.1002/2015JD024593.
2016:
Pausata, F. S. R., Lindvall, J., Ekman, A. M. L. and Svensson, G. Climate effects of a hypothetical regional nuclear war: Sensitivity to emission duration and particle composition. Earth’s Future, 4 ,doi:10.1002/2016EF000415.
Leung, W.-Y. H. Savre, J., Bender, F. A.-M., Komppula, M., Portin, H., Romakkaniemi, S., Sedlar, J., Noone, K. J., Ekman, A. M. L. 2016. Sensitivity of a continental nighttime stratocumulus-topped boundary layer to varying environmental conditions. Q.J.R. Meteorol. Soc., 142: 2911–2924. doi:10.1002/qj.2877.
Bourgeois, Q., Ekman, A. M. L., Igel, M. R., Krejci, R. 2016. The forgotten clouds of the tropical middle troposphere. Nature Communications, 7, 12432, doi:10.1038/ncomms12432.
Acosta Navarro, J. C. & Varma, V., Riipinen, I., Seland, Ø., Kirkevåg, A., Struthers, H., Iversen, T., Hansson, H.-C., Ekman, A. M. L. 2016. Amplification of Arctic warming by past air pollution reductions in Europe. Nature Geoscience, 9, 277–281, doi:10.1038/ngeo2673.
Höpner, F. Bender, F. A. M., Ekman, A. M. L, Praveen, P. S., Bosch, C., Ogren, J. A., Andersson, A., Gustafsson, Ö. and V. Ramanathan. 2016. Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 2012. Atmospheric Chemistry and Physics, 6, 1045-1064, doi:10.5194/acp-16-1045-2016.
2015:
Johansson, E., Devasthale, A., L’Ecuyer, T., Ekman, A. M. L. and M. Tjernström. 2015. The vertical structure of cloud radiative heating over the Indian subcontinent during summer monsoon. Atmospheric Chemistry and Physics, 15, 11557–11570.
Bourgeois, Q., Ekman, A. M. L. and R. Krejci, 2015. Aerosol transport over the Andes from the Amazon Basin to the remote Pacific Ocean: A multiyear CALIOP assessment, J. Geophys. Res., 120, doi:10.1002/2015JD023254
Murphy, B. N., Julin, J. Riipinen, I., Ekman, A. M. L. Organic aerosol processing in tropical deep convective clouds: Development of a new model (CRM-ORG) and implications for sources of particle number. Accepted for publication in Journal of Geophysical Research.
Savre, J. and Ekman, A. M. L., 2015. Large-Eddy Simulation of three mixed phase cloud events during ISDAC: conditions for persistent heterogeneous ice formation. Journal of Geophysical Research, 120, 7699–7725, doi:10.1002/2014JD023006.
Savre, J. and Ekman, A. M. L., 2015. A theory-based parameterization for heterogeneous ice nucleation and implications for the simulation of ice processes in atmospheric models. Journal of Geophysical Research, 120, 4937-4961.
2014:
Rastak, N. Silvergren, S., Zieger, P., Widequvist, U., Ström, J., Svenningsson, B., Maturilli, M., Tesche, M., Ekman, A. M. L., Tunved, P., Riipinen, I., 2014. Seasonal variation of aerosol water uptake and its impact on the direct radiative effect at Ny-Ålesund, Svalbard. Atmospheric Chemistry Physics, 14, 7445-7460.
Savre, J., Ekman, A. M. L., Svensson, G. Tjernström, M., 2014. Large-Eddy Simulations of an Arctic mixed-phase stratiform cloud observed during ISDAC: sensitivity to moisture aloft, surface fluxes and large-scale forcing. Quarterly Journal of the Royal Meteorological Society, DOI:10.1002/qj.2425.
Acosta Navarro J.C., Smolander, S., Struthers, H., Zorita, E. Ekman, A.M.L., Kaplan, J. O., Guenther, A., Arneth, A. Riipinen, I., 2014. Global emissions of terpenoid volatile organic compounds from terrestrial vegetation in the last millennium. Journal of Geophysical Research, 119, 6867-6885.
Park, H. Chung, C. E., Ekman, A. M. L., Choi, J.-O., 2014. Evaluation of ACCMIP simulated fine-mode AOD and its implication for aerosol forcing. Asia-Pacific Journal of Atmospheric Sciences, DOI:10.1007/s13143-014-0025-6.
Savre, J., Ekman, A. M. L., Svensson, G., 2014. Technical note: Introduction to MIMICA, a large-eddy simulation solver for cloudy planetary boundary layers. Journal of Advances in Modelling Earth Systems, 6, doi:10.1002/2013MS000292.
Wesslén, C., Tjernström, M., Bromwich, D. H., de Boer, G., Ekman, A. M. L., Bai, L.-S and Wang, S.-H., 2014. The Arctic summer atmosphere: An evaluation of reanalyses using ASCOS data. Atmospheric Chemistry and Physics, 14, 2605–2624.
Kim, D. Wang, C., Ekman, A. M. L., Barth, M. C., Lee, D.-I., 2014. The Responses of Cloudiness to the Direct Radiative Effect of Sulfate and Carbonaceous Aerosols. Journal of Geophysical Research, 119,1172-1185.
Decremer, D., Chung, C. E., Ekman, A. M. L., Brandefelt, J., 2014. Which significance test performs the best in climate simulations? Tellus A., 66, 23139.
2013:
Zábori, J., Krejci, R., Ström, J., Vaattovaara, P., Ekman, A. M. L., Mårtensson, E. M., Nilsson, E. D., 2013. Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties. Atmos. Chem. Phys., 13, 4783-4799.
Ekman, A. M. L., 2014. Do sophisticated parameterizations of aerosol-cloud interactions in CMIP5 models improve the representation of recent observed temperature trends? Journal of Geophysical Research, 119, 817-832.
A. Kirkevåg, T. Iversen, Ø. Seland, C. Hoose, J. E. Kristjansson, H. Struthers, A. M. L. Ekman, S. Ghan, J. Griesfeller, E. D. Nilsson, and M. Schulz., 2013. Aerosol-climate interactions in the Norwegian Earth System Model – NorESM1-M. Geophysical Model Development, 6, 207-244.
Struthers, H., Ekman, A. M. L., Glantz, P., Mårtensson, E. M., Noone, K., Nilsson, E. D., 2013. Climate-induced changes in sea salt aerosol number emissions: 1870 to 2100. Journal of Geophysical Research, 118, 1-13, doi:10.1002/jgrd.50129.
Lewinschal, A., Ekman, A. M. L., Körnich, H., 2013. The role of precipitation in aerosol-induced changes in northern hemisphere wintertime stationary waves. Climate Dynamics, 41, 647-661.
2012:
Zábori, J., Krejci, R., Ekman, A. M. L., Mårtensson, E. M., Ström, J., de Leeuw, G. and E. D. Nilsson, 2012. Wintertime Arctic Ocean sea water properties and primary marine aerosol concentrations. Atmospheric Chemistry and Physics, 12, 10405–10421.
Liu, X. R. C. Easter, S. J. Ghan, R. Zaveri, P. Rasch, X. Shi, J.-F. Lamarque, A. Gettelman, H. Morrison, F. Vitt, A. Conley, S. Park, R. Neale, C. Hannay, A. M. L. Ekman, P. Hess, N. Mahowald, W. Collins, M. J. Iacono, C. S. Bretherton, M. G. Flanner, D. Mitchell., 2012. Toward a Minimal Representation of Aerosol Direct and Indirect Effects: Model Description and Evaluation in the Community Atmosphere Model CAM5. Geoscientific Model Development, 5, 709-739.
D. G. Partridge, J. A. Vrugt, P. Tunved, A. M. L. Ekman, H. Struthers, and A. Sorooshian., 2012. Inverse Modeling of Cloud-Aerosol Interactions - Part 2: Sensitivity tests on liquid phase clouds using a Markov Chain Monte Carlo based simulation approach. Atmospheric Chemistry and Physics, 12, 2823-2847.
Ekman, A. M. L., M. Hermann, P. Groß, J. Heintzenberg, D. Kim, C. Wang, 2012. Sub-micrometer Aerosol Particles in the Upper Troposphere/Lowermost Stratosphere as Measured by CARIBIC and Modeled Using the MIT-CAM3 Global Climate Model. Journal of Geophysical Research, 117, D11202, doi:10.1029/2011JD016777.
2011:
Partridge, D. G., J. A. Vrugt, P. Tunved, A. M. L. Ekman, D. Gorea, and A. Sorooshian., 2011. Inverse Modeling of Cloud-Aerosol Interactions - Part A: Detailed Response Surface Analysis. Atmospheric Chemistry and Physics. 11, 7269-7287.
Bender, F. A.-M., Charlson, R. J., Ekman, A. M. L., Leahy, L. V. 2011. Quantification of Monthly Mean Regional-Scale Albedo of Marine Stratiform Clouds in Satellite Observations and GCMs. Journal of Applied Meteorology and Climatology, 50, 2130-2148.
Struthers, H., Ekman, A. M. L., Glantz, P., Iversen, T., Kirkevåg, A., Mårtensson, E. M., Seland, Ø., Nilsson, E. D., 2011. The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance of the Arctic. Atmospheric Chemistry and Physics. 11, 3459-3477.
Ekman, A. M. L., Engström, A., Söderberg, A. 2011. Impact of two-way aerosol-cloud interaction and changes in aerosol size distribution on simulated aerosol-induced deep convective cloud sensitivity. Journal of the Atmospheric Sciences, 68, 685-698.
2010:
Engström, A. and Ekman, A. M. L., 2010. Impact of meteorological factors on the correlation between aerosol optical depth and cloud fraction. Geophysical Research Letters, 37, L18814.
W. Hazeleger, C. Severijns, T. Semmler, S. E. Ştefănescu, S. Yang, X. Wang, K. Wyser, J.S. Baldasano, G. Balsamo, P. Bechtold, R. Bintanja, R. Caballero, E. Dutra, A. M. L. Ekman, J. H. Christensen, B. van den Hurk, P. Jimenez, C. Jones, P. Kållberg, T. Koenigk, R. McGrath, P.M. A. Miranda, F. Molteni, T. van Noije, T. Palmer, E. Rodriguez Camino, T. Schmith, F. Selten, T. Storelvmo, A. Sterl, H. Tapamo, P. Viterbo, U. Willén, 2010. EC-Earth: a seamless earth system prediction approach in action. Bulletin of the American Meteorological Society, 91,1357-1363.
Lohmann, U., Rotstayn, L., Storelvmo, T., Jones, A., Menon, S., Quaas, J., Ekman, A. M. L., Koch, D. and Ruedy, R., 2010. Total aerosol effect: forcing or radiative flux perturbation? Atmospheric Chemistry and Physics, 10, 3235-3246.
Bender, F. A.-M., Ekman, A. M. L., Rodhe, H., 2010. Response to the eruption of Mount Pinatubo in relation to climate sensitivity in CMIP3 models. Climate Dynamics, 35, 875-886, 2010.
2009:
Wang, C., Kim, D., Ekman, A. M. L., Barth, M. C., Rasch, P. J., 2009. Modeling the impact of absorbing aerosols on Indian summer monsoon. Geophysical Research Letters, 36, L21704, doi:10.1029/2009GL040114
Engström, A., Ekman, A. M. L., Krejci, R., DeReus, M., Ström, J., Wang, C., 2008. Observational and Modelling Evidence of Tropical Deep Convective Clouds as a Source of Mid-Tropospheric Accumulation Mode Aerosols. Geophys. Res. Lett., 35, L23813, doi:10.1029/2008GL035817.
Ekman, A. M. L., Krejci, R., Engström, A., Ström, J., deReus M., Williams, J., Andreae, M. O., 2008. Do organics contribute to small particle formation in the Amazonian upper troposphere? Geophys. Res. Lett., 35, L17810, doi:10.1029/2008GL034970.
2002-2008:
Kim, D., Wang, C., Ekman, A. M. L., Barth, M. C. and Rasch, P. J., 2008. Distribution and Direct Radiative Forcing of Anthropogenic Aerosols in an Interactive Size-Resolving Aerosol-Climate Model. J. Geophys. Res., 113, D16309, doi:10.1029/2007JD009756
Ekman, A. M. L., Engström, A., Wang, C., 2007. The effect of aerosol composition and concentration on the development and anvil properties of a continental deep convective cloud. Q. J. R. Meteorol. Soc., 133, 1439-1452.
Bender, F. A.-M., Rodhe, H., Charlson, R. J., Ekman, A. M. L., Loeb, N., 2006. 22 views of the global albedo - comparison between 20 GCMs and two satellites. Tellus, 58, 320-330.
Ekman, A. M. L., Wang, C., Ström, J., Krejci, R., 2006. Explicit simulation of aerosol physics in a cloud-resolving model: Aerosol Transport and Processing in the Free Troposphere. Journal of the Atmospheric Sciences, Vol. 63, No. 2, 682–696.
Ekman, A. M. L., Wang, C., Wilson, J. and Ström, J., 2004. Explicit simulations of aerosol physics in a cloud-resolving model: A sensitivity study based on an observed convective cloud. Atmospheric Chemistry and Physics, 4, 773-791.
Ekman, A. M. L. and Rodhe, H., 2004. Regional temperature response due to indirect sulfate aerosol forcing: impact of model resolution. Climate Dynamics, 21, 1-24.
Ekman, A. M. L., 2002. Small-scale patterns of sulfate aerosol climate forcing simulated with a high-resolution regional climate model. Tellus, 54, 143-162.
