Dr Ewan O'Connor

Senior Research Scientist

Web pages:


Senior Research Scientist

Research Interests:

  • Doppler lidar - developing new retrieval techniques for turbulence, wind, and boundary layer properties
  • Integration of active (radar and lidar) and passive remote sensors to derive profiles of atmospheric properties
  • Evaluating the representation of clouds, aerosol and turbulence in numerical weather forecast and climate models

Research Projects:

  • Aerosol Clouds and Trace Gases Infrastructure Network (ACTRIS).
  • Fast-Physics System Testbed and Research (FASTER).
  • Biogenic Aerosol - Effects on Clouds and Climate (BAECC). ARM Mobile Facility deployment to Hyytiälä, Finland
  • High definition clouds and precipitation for advancing climate prediction (HD[CP]2).
  • Observation System for Climate Application at Regional Scale (OSCAR).

Postdoctoral & graduate student supervision

  • Anne Hirsikko (FMI): PostDoc
  • Ville Vakkari (FMI): PostDoc
  • Antti Manninen (University of Helsinki): PhD Student
  • Minttu Tuononen (FMI): PhD Student

Recent Publications:

Publications for e.j.oconnor@reading.ac.uk

Jump to: 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2005 | 2004 | 2003 | 2002
Number of items: 52.


Tuononen, M., O'Connor, E. J., Sinclair, V. A. and Vakkari, V. (2017) Low-level jets over Utö, Finland, based on Doppler Lidar observations. Journal of Applied Meteorology and Climatology, 56 (9). pp. 2577-2594. ISSN 1558-8432 doi: https://doi.org/10.1175/jamc-d-16-0411.1

Suomi, I., Gryning, S.-E., O'Connor, E. J. and Vihma, T. (2017) Methodology for obtaining wind gusts using Doppler lidar. Quarterly Journal of the Royal Meteorological Society, 143 (706). pp. 2061-2072. ISSN 0035-9009 doi: https://doi.org/10.1002/qj.3059

Gryning, S.-E., Mikkelsen, T., Baehr, C., Dabas, A., Gómez, P., O'Connor, E., Rottner, L., Sjöholm, M., Suomi, I. and Vasiljević, N. (2017) Measurement methodologies for wind energy based on ground-level remote sensing. In: Kariniotakis, G. (ed.) Renewable Energy Forecasting: From Models to Applications. Elsevier, pp. 29-56. ISBN 9780081005040 doi: https://doi.org/10.1016/B978-0-08-100504-0.00002-0


Petäjä, T., O'Connor, E. J., Moisseev, D., Sinclair, V. A., Manninen, A. J., Väänänen, R., von Lerber, A., Thornton, J. A., Nicoll, K., Petersen, W., Chandrasekar, V., Smith, J. N., Winkler, P. M., Kruger, O., Hakola, H., Timonen, H., Brus, D., Laurila, T., Asmi, E., Riekkola, M.-L., Mona, L., Massoli, P., Engelmann, R., Komppula, M., Wang, J., Kuang, C., Bäck, J., Virtanen, A., Levula, J., Ritsche, M. T. and Hickmon, N. (2016) BAECC: a field campaign to elucidate the impact of Biogenic Aerosols on Clouds and Climate. Bulletin of the American Meteorological Society, 97 (10). pp. 1909-1928. ISSN 1520-0477 doi: https://doi.org/10.1175/BAMS-D-14-00199.1

Kotthaus, S., O'Connor, E., Münkel, C., Charlton-Perez, C., Haeffelin, M., Gabey, A. M. and Grimmond, C. S. B. (2016) Recommendations for processing atmospheric attenuated backscatter profiles from Vaisala CL31 ceilometers. Atmospheric Measurement Techniques, 9. pp. 3769-3791. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-9-3769-2016

Sporre, M. K., O'Connor, E. J., Håkansson, N., Thoss, A., Swietlicki, E. and Petäjä, T. (2016) Comparison of MODIS and VIIRS cloud properties with ARM ground-based observations over Finland. Atmospheric Measurement Techniques, 9 (7). pp. 3193-3203. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-9-3193-2016

Mylläri, F., Asmi, E., Anttila, T., Saukko, E., Vakkari, V., Pirjola, L., Hillamo, R., Laurila, T., Häyrinen, A., Rautiainen, J., Lihavainen, H., O'Connor, E., Niemelä, V., Keskinen, J., Dal Maso, M. and Rönkkö, T. (2016) New particle formation in the fresh flue-gas plume from a coal-fired power plant: effect of flue-gas cleaning. Atmospheric Chemistry and Physics, 16 (11). pp. 7485-7496. ISSN 1680-7324 doi: https://doi.org/10.5194/acp-16-7485-2016

Manninen, A. J., O'Connor, E. J., Vakkari, V. and Petäjä, T. (2016) A generalised background correction algorithm for a Halo Doppler lidar and its application to data from Finland. Atmospheric Measurement Techniques, 9 (2). pp. 817-827. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-9-817-2016

Kivekäs, N., Carpman, J., Roldin, P., Leppä, J., O'Connor, E. J., Kristensson, A. and Asmi, E. (2016) Coupling an aerosol box model with one-dimensional flow: a tool for understanding observations of new particle formation events. Tellus B, 68 (1). 29706. ISSN 1600-0889 doi: https://doi.org/10.3402/tellusb.v68.29706


Fielding, M. D., Chiu, J. C., Hogan, R. J., Feingold, G., Eloranta, E., O'Connor, E. J. and Cadeddu, M. P. (2015) Joint retrievals of cloud and drizzle in marine boundary layer clouds using ground-based radar, lidar and zenith radiances. Atmospheric Measurement Techniques, 8. pp. 2663-2683. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-8-2663-2015

Tonttila, J., O'Connor, E. J., Hellsten, A., Hirsikko, A., O'Dowd, C., Järvinen, H. and Räisänen, P. (2015) Turbulent structure and scaling of the inertial subrange in a stratocumulus-topped boundary layer observed by a Doppler lidar. Atmospheric Chemistry and Physics, 15. pp. 5873-5885. ISSN 1680-7316 doi: https://doi.org/10.5194/acp-15-5873-2015

Wood, R., Wyant, M., Bretherton, C. S., Remilliard, J., Kollais, P., Fletcher, J., Stemmler, J., De Szoeke, S., Yuter, S., Miller, M., Mechem, D., Tselioudis, G., Chiu, J. C., Mann, J. A. L., O'Connor, E., Hogan, R., Dong, X., Miller, M., Ghate, V., Jefferson, A., Min, Q., Minnis, P., Palikonda, R., Albrecht, B., Luke, E., Hannay, C. and Lin, Y. (2015) Clouds, aerosols, and precipitation in the marine boundary layer: an ARM Mobile Facility Deployment. Bulletin of the American Meteorological Society, 96 (3). pp. 419-440. ISSN 1520-0477 doi: https://doi.org/10.1175/BAMS-D-13-00180.1

Font, A., Grimmond, C. S. B., Kotthaus, S., Morguí, J. -A., Stockdale, C., O'Connor, E., Priestman, M. and Barratt, B. (2015) Daytime CO2 urban surface fluxes from airborne measurements, eddy-covariance observations and emissions inventory in Greater London. Environmental Pollution, 196. pp. 98-106. ISSN 0269-7491 doi: https://doi.org/10.1016/j.envpol.2014.10.001

Illingworth, A. J., Cimini, D., Gaffard, C., Haeffelin, M., Lehmann, V., Löhnert, U., O'Connor, E. J. and Ruffieux, D. (2015) Exploiting existing ground-based remote sensing networks to improve high-resolution weather forecasts. Bulletin of the American Meteorological Society, 96 (12). pp. 2107-2125. ISSN 1520-0477 doi: https://doi.org/10.1175/BAMS-D-13-00283.1

Löhnert, U., Schween, J. H., Acquistapace, C., Ebell, K., Maahn, M., Barrera-Verdejo, M., Hirsikko, A., Bohn, B., Knaps, A., O'Connor, E.J., Simmer, C., Wahner, A. and Crewell, S. (2015) JOYCE: Jülich Observatory for cloud evolution. Bulletin of the American Meteorological Society, 96 (7). pp. 1157-1174. ISSN 1520-0477 doi: https://doi.org/10.1175/BAMS-D-14-00105.1

Vakkari, V., O'Connor, E. J., Nisantzi, A., Mamouri, R. E. and Hadjimitsis, D. G. (2015) Low-level mixing height detection in coastal locations with a scanning Doppler lidar. Atmospheric Measurement Techniques, 8 (4). pp. 1875-1885. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-8-1875-2015

van Dinther, D., Wood, C. R., Hartogensis, O. K., Nordbo, A. and O'Connor, E. J. (2015) Observing crosswind over urban terrain using scintillometer and Doppler lidar. Atmospheric Measurement Techniques, 8 (4). pp. 1901-1911. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-8-1901-2015


Chiu, J. C., Holmes, J. A., Hogan, R. J. and O'Connor, E. J. (2014) The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements. Atmospheric Chemistry and Physics, 14. pp. 8389-8401. ISSN 1680-7316 doi: https://doi.org/10.5194/acp-14-8389-2014

Hirsikko, A., O'Connor, E., Komppula, M., Korhonen, K., Pfuller, A., Giannakaki, E., Wood, C. R., Bauer-Pfundstein, M., Poikonen, A., Karppinen, T., Lonka, H., Kurri, M., Heinonen, J., Moisseev, D., Asmi, E., Aaltonen, V., Nordbo, A., Rodriguez, E., Lihavainen, H., Laaksonen, A., Lehtinen, K. E. J., Laurila, T., Petäjä, T., Kulmala, M. and Viisanen, Y. (2014) Observing wind, aerosol particles, clouds and precipitation: Finland's new ground-based remote-sensing network. Atmospheric Measurement Techniques, 7. pp. 1351-1375. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-7-1351-2014

Mann, J. A.L., Chiu, J. C., Hogan, R. J., O'Connor, E. J., l'Ecuyer, T. S., Stein, T. H. M. and Jefferson, A. (2014) Aerosol impacts on drizzle properties in warm clouds from ARM Mobile Facility maritime and continental deployments. Journal of Geophysical Research: Atmospheres, 119 (7). pp. 4136-4148. ISSN 2169-8996 doi: https://doi.org/10.1002/2013JD021339


Wood, C. R., Järvi, L., Kouznetsov, R. D., Nordbo, A., Joffre, S., Drebs, A., Vihma, T., Hirsikko, A., Suomi, I., Fortelius, C., O'Connor, E., Moisseev, D., Haapanala, S., Moilanen, J., Kangas, M., Karppinen, A., Vesala, T. and Kukkonen, J. (2013) An overview on the urban boundary-layer atmosphere network in Helsinki. Bulletin of the American Meteorological Society, 94 (11). pp. 1675-1690. ISSN 1520-0477 doi: https://doi.org/10.1175/BAMS-D-12-00146.1


Chiu, J. C., Marshak, A., Huang, C.-H., Carnai, T., Hogan, R. J., Giles, D. M., Holben, B. N., O'Connor, E. J., Knyazikhin, Y. and Wiscombe, W. J. (2012) Cloud droplet size and liquid water path retrievals from zenith radiance measurements: examples from the Atmospheric Radiation Measurement Program and the Aerosol Robotic Network. Atmospheric Chemistry and Physics, 12. pp. 10313-10329. ISSN 1680-7324 doi: https://doi.org/10.5194/acp-12-10313-2012

Zhao, C., Xie, S., Klein, S., Protat, A., Shupe, M., McFarlane, S., Comstock, J., Delanoë, J., Deng, M., Dunn, M., Hogan, R. J., Huang, D., Jensen, M., Mace, G., McCoy, R., O'Connor, E. J., Turner, D. and Wang, Z. (2012) Toward understanding of differences in current cloud retrievals of ARM ground-based measurements. Journal of Geophysical Research - Atmospheres, 117. D10206. ISSN 0148-0227 doi: https://doi.org/10.1029/2011JD016792

Bouniol, D., Couvreux, F., Kamsu-Tamo, P.-H., Leplay, M., Guichard, F., Favot, F. and O'Connor, E. J. (2012) Diurnal and seasonal cycles of cloud occurrences, types and radiative impact over West Africa. Journal of Applied Meteorology and Climatology, 51 (3). pp. 534-553. ISSN 1558-8432 doi: https://doi.org/10.1175/JAMC-D-11-051.1

Morcrette, C. J., O'Connor, E. and Petch, J. C. (2012) Evaluation of two cloud parametrization schemes using ARM and Cloudnet observations. Quarterly Journal of the Royal Meteorological Society, 138 (665). pp. 964-979. ISSN 1477-870X doi: https://doi.org/10.1002/qj.969


Tonttila, J., O'Connor, E. J., Niemelä, S., Räisänen, P. and Järvinen, H. (2011) Cloud-base vertical velocity statistics: a comparison between an atmospheric mesoscale model and remote sensing observations. Atmospheric Chemistry and Physics, 11 (17). pp. 9207-9218. ISSN 1680-7316 doi: https://doi.org/10.5194/acp-11-9207-2011

Barlow, J. F., Dunbar, T. M., Nemitz, E. G., Wood, C. R., Gallagher, M. W., Davies, F., O'Connor, E. and Harrison, R. M. (2011) Boundary layer dynamics over London, UK, as observed using Doppler lidar during REPARTEE-II. Atmospheric Chemistry and Physics, 11 (5). pp. 2111-2125. ISSN 1680-7316 doi: https://doi.org/10.5194/acp-11-2111-2011

Protat, A., Bouniol, D., O'Connor, E. J., Klein Baltink , H., Verlinde, H. and Widener, K. (2011) CloudSat as a Global Radar Calibrator. Journal of Atmospheric and Oceanic Technology, 28 (3). pp. 445-452. ISSN 0739-0572 doi: https://doi.org/10.1175/2010JTECHA1443.1

Ebell, K., Crewell, S., Löhnert, U., Turner, D. D. and O'Connor, E. J. (2011) Cloud statistics and cloud radiative effect for a low-mountain site. Quarterly Journal of the Royal Meteorological Society, 137 (S1). pp. 306-324. ISSN 1477-870X doi: https://doi.org/10.1002/qj.748

Protat, A., Delanoë, J., May, P. T., Haynes, J., Jakob, C., O'Connor, E. J., Pope, M. and Wheeler, M. C. (2011) The variability of tropical ice cloud properties as a function of the large-scale context from ground-based radar-lidar observations over Darwin, Australia. Atmospheric Chemistry and Physics, 11 (16). pp. 8363-8384. ISSN 1680-7316 doi: https://doi.org/10.5194/acp-11-8363-2011


O'Connor, E. J., Illingworth, A. J., Brooks, I. M., Westbrook, C. D., Hogan, R. J., Davies, F. and Brooks, B. J. (2010) A method for estimating the turbulent kinetic energy dissipation rate from a vertically pointing Doppler lidar, and independent evaluation from balloon-borne in situ measurements. Journal of Atmospheric and Oceanic Technology, 27 (10). pp. 1652-1664. ISSN 1520-0426 doi: https://doi.org/10.1175/2010JTECHA1455.1

Westbrook, C. D., Hogan, R. J., O'Connor, E. J. and Illingworth, A. J. (2010) Estimating drizzle drop size and precipitation rate using two-colour lidar measurements. Atmospheric Measurement Techniques, 3 (3). pp. 671-681. ISSN 1867-8548 doi: https://doi.org/10.5194/amt-3-671-2010

Protat, A., Delanoë, J., O'Connor, E. J. and L'Ecuyer, T. S. (2010) The evaluation of CloudSat and CALIPSO ice microphysical products using ground-based cloud radar and lidar observations. Journal of Atmospheric and Oceanic Technology, 27 (5). pp. 793-810. ISSN 1520-0426 doi: https://doi.org/10.1175/2009JTECHA1397.1

Westbrook, C. D., Illingworth, A. J., O'Connor, E. J. and Hogan, R. J. (2010) Doppler lidar measurements of oriented planar ice crystals falling from supercooled and glaciated layer clouds. Quarterly Journal of the Royal Meteorological Society, 136 (646). pp. 260-276. ISSN 1477-870X doi: https://doi.org/10.1002/qj.528

Bouniol, D., Protat, A., Delanoe, J. , Pelon, J., Piriou, J.-M., Bouyssel, F., Tompkins, A. M., Wilson, D. R., Morille, Y., Haeffelin, M., O'Connor, E. J., Hogan, R. J., Illingworth, A. J., Donovan, D. P. and Baltink, H.-K. (2010) Using continuous ground-based radar and lidar measurements for evaluating the representation of clouds in four operational models. Journal of Applied Meteorology and Climatology, 49 (9). pp. 1971-1991. ISSN 1558-8424 doi: https://doi.org/10.1175/2010JAMC2333.1

Protat, A., Delanoë, J., Plana-Fattori, A., May, P. T. and O'Connor, E. J. (2010) The statistical properties of tropical ice clouds generated by the West-African and Australian monsoons from ground-based radar-lidar observations. Quarterly Journal of the Royal Meteorological Society, 136 (S1). pp. 345-363. ISSN 1477-870X doi: https://doi.org/10.1002/qj.490


Protat, A., Bouniol, D., Delanoe, J., May, P. T., Plana-Fattori, A., Hasson, A., O'Connor, E. J., Goersdorf, U. and Heymsfield, A. J. (2009) Assessment of CloudSat reflectivity measurements and ice cloud properties using ground-based and airborne cloud radar observations. Journal of Atmospheric and Oceanic Technology, 26. pp. 1717-1741. ISSN 1520-0426 doi: https://doi.org/10.1175/2009JTECHA1246.1

Hogan, R. J., O'Connor, E. J. and Illingworth, A. J. (2009) Verification of cloud-fraction forecasts. Quarterly Journal of the Royal Meteorological Society, 135 (643). pp. 1494-1511. ISSN 1477-870X doi: https://doi.org/10.1002/qj.481

Hogan, R. J., Grant, A. L. M., Illingworth, A. J., Pearson, G. N. and O'Connor, E. J. (2009) Vertical velocity variance and skewness in clear and cloud-topped boundary layers as revealed by Doppler lidar. Quarterly Journal of the Royal Meteorological Society, 135 (640). pp. 635-643. ISSN 1477-870X doi: https://doi.org/10.1002/qj.413

Wood, C. R., O'Connor, E. J., Hurley, R. A., Reynolds, D. R. and Illingworth, A. J. (2009) Cloud-radar observations of insects in the UK convective boundary layer. Meteorological Applications, 16 (4). pp. 491-500. ISSN 1469-8080 doi: https://doi.org/10.1002/met.146

Barrett, A. I., Hogan, R. J. and O'Connor, E. J. (2009) Evaluating forecasts of the evolution of the cloudy boundary layer using diurnal composites of radar and lidar observations. Geophysical Research Letters, 36 (17). L17811. ISSN 0094-8276 doi: https://doi.org/10.1029/2009GL038919


Crewell, S., Mech, M., Reinhardt, T., Selbach, S., Betz, H.-D., Brocard, E., Dick, G., O'Connor, E. J., Fischer, J., Hanisch, T., Hauf, T., Huenerbein , A., Delobbe, L., Mathes, A., Peters, G., Wernli, H., Wiegner, M. and Wulfmeyer, V. (2008) The general observation period 2007 within the priority program on quantitative precipitation forecasting: concept and first results. Meteorologische Zeitschrift, 17 (6). pp. 849-866. ISSN 0941-2948 doi: https://doi.org/10.1127/0941-2948/2008/0336

Loehnert, U., Crewell, S., Krasnov, K., O'Connor, E. J. and Russchenberg, H. (2008) Advances in continuously profiling the thermodynamic state of the boundary layer: integration of measurements and methods. Journal of Atmospheric and Oceanic Technology, 25 (8). pp. 1251-1266. ISSN 1520-0426 doi: https://doi.org/10.1175/2007JTECHA961.1


Illingworth, A. J., Hogan, R. J., O'Connor, E. J., Bouniol, D., Brooks, M. E., Delano, J., Donovan, D. P., Eastment, J. D., Gaussiat, N., Goddard, J. W. F., Haeffelin, M., Klein Baltink, H., Krasnov, O. A., Pelon, J., Piriou, J. -M., Protat, A., Russchenberg, H. W. J., Seifert, A., Tompkins, A. M., van Zadelhoff, G. -J., Vinit, F., Willen, U., Wilson, D. R. and Wrench, C. L. (2007) Continuous Evaluation of Cloud Profiles in Seven Operational Models Using Ground-Based Observations. Bulletin of the American Meteorological Society, 88 (6). pp. 883-898. ISSN 1520-0477 doi: https://doi.org/10.1175/BAMS-88-6-883

Westbrook, C. D., Hogan, R. J., Illingworth, A. J. and O'Connor, E. J. (2007) Theory and observations of ice particle evolution in cirrus using Doppler radar: evidence for aggregation. Geophysical Research Letters, 34. L02824. ISSN 0094-8276 doi: https://doi.org/10.1029/2006GL027863


O'Connor, E. J., Hogan, R. J. and Illingworth, A. J. (2005) Retrieving stratocumulus drizzle parameters using Doppler radar and lidar. Journal Of Applied Meteorology, 44 (1). pp. 14-27.


O'Connor, E. J., Hogan, R. J., Illingworth, A. and Brenguier, J. -L. (2004) Characteristics of drizzle and non-drizzling stratocumulus as revealed by vertically pointing cloud radar and lidar. In: 14th International Conference on Clouds and Precipitation, Bologna.

Hogan, R. J., Behera, M. D., O'Connor, E. J. and Illingworth, A. J. (2004) Estimate of the global distribution of stratiform supercooled liquid water clouds using the LITE lidar. Geophysical Research Letters, 31 (5). L05106. doi: https://doi.org/10.1029/2003GL018977.

O'Connor, E. J., Illingworth, A. J. and Hogan, R. J. (2004) A technique for autocalibration of cloud lidar. Journal Of Atmospheric And Oceanic Technology, 21 (5). pp. 777-786.


Hogan, R.J., Bouniol, D., Ladd, D.N., O'Connor, E.J. and Illingworth, A.J. (2003) Absolute calibration of 94/95-GHz radars using rain. Journal Of Atmospheric And Oceanic Technology, 20. pp. 572-580.

Hogan, R.J., Illingworth, A.J., O'Connor, E.J. and Baptista, J. (2003) Characteristics of mixed-phase clouds. II: A climatology from ground-based lidar. Quarterly Journal of the Royal Meteorological Society, 129. pp. 2117-2134. ISSN 1477-870X


Stephens, G.L., Vane , D.G., Boain, R.J., Mace, G.G., Sassen, K., Wang, Z., Illingworth, A., O'Connor, E., Rossow, W.B., Durden, S.L., Miller, S.D., Austin, R.T., Benedetti, A., Mitrescu, C. and the CloudSat Science Team, (2002) The CloudSat mission and the A-train: a new dimension of space-based observations of clouds and precipitation. Bulletin of the American Meteorological Society, 83 (12). pp. 1771-1790. ISSN 1520-0477 doi: https://doi.org/10.1175/BAMS-83-12-1771

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