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Karen Lee Johnson

Senior Applications Engineer

Johnson serves as the data mentor for the scanning and zenith-pointing millimeter cloud radars operated by the DOE Atmospheric Radiation Program. In this role, she contributes to ensuring data quality, facilitates the conversion of raw radar data into ARM-standard form in the ARM Archive and addresses data issues and user inquiries as they arise. In her other major role, she develops value-added products to make ARM instrument observations more readily useable for scientific purposes. She has worked extensively on development and processing of the Active Remote Sensing of CLouds (ARSCL) family of products, which combine cloud radar observations with lidar and other remote sensing measurements to determine cloud boundaries and best-estimate radar moments. She has also developed a user-interface tool to assist ARM data users in Doppler radar spectra data discovery.


  • Florida State University, M.S. Computer Science
  • University of Oklahoma, M.S. Meteorology
  • University of Maryland, B.S. Physical Sciences


  • American Meteorological Society
  • American Geophysical Union

Areas of Interest

  • Radar Meteorology
  • Cloud Properties
  • Data Acquisition and Analysis
  • User Interface Development


  • Senior Applications Engineer, Biological, Environmental & Climate Sciences Department, 2014-Present
  • Advanced Applications Engineer, BECS Dept., 2001-2013
  • Programmer Analyst, BNL Collider-Accelerator Department, 1997-2000
  • Meteorology Research Assistant, Florida State University, 1986-1996

External Service

  • ARM Reprocessing Advisory Board, 2012-Present.
  • Instructor for AMS Radar Short Course, 2011.

Publications (since 2005)

Sokolowsky, G. A., Clothiaux, E. E., Baggett, C. F., Lee, S., Feldstein, S. B., Eloranta, E. W., Cadeddu, M. P., Bharadwaj, N., and Johnson, K. L.  Contributions to the Surface Downwelling Longwave Irradiance during Arctic Winter at Utqiaġvik (Barrow), Alaska.  Journal of Climate 33, 4555-4577 (2020).

Lamraoui, F., Booth, J. F., Naud, C. M., Jensen, M. P., and Johnson, K. L. The interaction between boundary layer and convection schemes in a WRF simulation of post-cold-frontal clouds over the ARM East North Atlantic site. J. Geophys. Res. Atmos. 124, 4699-4721, doi:10.1029/2018JD029370 (2019).

Van Weverberg, K., Morcrette, C. J., Petch, J., Klein, S. A., Ma, H. Y., Zhang, C., Xie, S., Tang, Q., Gustafson, W. I., Qian, Y., Berg, L. K., Liu, Y., Huang, M., Ahlgrimm, M., Forbes, R., Bazile, E., Roehrig, R., Cole, J., Merryfield, W., Lee, W. S., Cheruy, F., Mellul, L., Wang, Y. C., Johnson, K., and Thieman, M. M. CAUSES: Attribution of Surface Radiation Biases in NWP and Climate Models near the U.S. Southern Great Plains. J. Geophys. Res. Atmos. 123, 3612-3644, doi:10.1002/2017JD027188 (2018).

Jensen, M. P., Holdridge, D. J., Survo, P., Lehtinen, R., Baxter, S., Toto, T., and Johnson, K. L. Comparison of Vaisala radiosondes RS41 and RS92 at the ARM Southern Great Plains site. Atmos. Meas. Tech. 9, 3115-3129, doi:10.5194/amt-9-3115-2016 (2016).

Jensen, M. P., Holdridge, D., Survo, P., Lehtinen, R., Baxter, S., Toto, T., and Johnson, K. L. Comparison of Vaisala radiosondes RS41 and RS92 at the ARM Southern Great Plains Site. Atmos. Meas. Tech. Discuss. 8, 11323-11368, doi:10.5194/amtd-8-11323-2015 (2015).

Kollias, P., Bharadwaj, N., Widener, K., Jo, I., and Johnson, K. Scanning ARM Cloud Radars. Part I: Operational Sampling Strategies. J. Atmos. Oceanic Technol. 31, 569-582, doi:10.1175/JTECH-D-13-00044.1 (2014).

Kollias, P., Jo, I., Borque, P., Tatarevic, A., Lamer, K., Bharadwaj, N., Widener, K., Johnson, K., and Clothiaux, E. E. Scanning ARM Cloud Radars. Part II: Data Quality Control and Processing. J. Atmos. Oceanic Technol. 31, 583-598, doi:10.1175/JTECH-D-13-00045.1 (2014).

Xie, S., R. B. McCoy, S. A. Klein, R. T. Cederwall, W. J. Wiscombe, M. P. Jensen, K. L. Johnson, E. E. Clothiaux, K. L. Gaustad, C. N. Long, J. H. Mather, S. A. McFarlane, Y. Shi, J.-C. Golaz, Y. Lin, S. D. Hall, R. A. McCord, G. Palanisamy, D. D. Turner, 2010: CLOUDS AND MORE: ARM Climate Modeling Best Estimate Data. Bull. Amer. Meteor. Soc., 91, 13-20, doi: 10.1175/2009BAMS2891.1

Huang, D., K. Johnson, Y. Liu, and W. Wiscombe, 2009: High resolution retrieval of liquid water vertical distributions using collocated Ka-band and W-band cloud radars, Geophys. Res. Lett., 36, L24807, doi:10.1029/2009GL041364.

Luke, E. P., P. Kollias, K. L. Johnson, E. E. Clothiaux, 2008: A Technique for the Automatic Detection of Insect Clutter in Cloud Radar Returns. J. Atmos. Oceanic Technol., 25, 1498–1513. doi: 10.1175/2007JTECHA953.1

Turner, D. D., A. M. Vogelmann, K. Johnson, M. Miller, R. T. Austin, J. C. Barnard, C. Flynn, C. Long, S. A. McFarlane, K. Cady-Pereira, S. A. Clough, J. C. Chiu, M. M. Khaiyer, J. Liljegren, B. Lin, P. Minnis, A. Marshak, S. Y. Matrosov, Q. Min, W. O'Hirok, Z. Wang, W. Wiscombe, 2007: Thin liquid water clouds: their importance and our challenge. Bull. Amer. Meteor. Soc., 88, 177-190. doi: 10.1175/BAMS-88-2-177

Kollias, P., M. A. Miller, E. P. Luke, K. L. Johnson, E. E. Clothiaux, K. P. Moran, K. B. Widener, B. A. Albrecht, 2007: The Atmospheric Radiation Measurement Program Cloud Profiling Radars: Second-Generation Sampling Strategies, Processing, and Cloud Data Products. J. Atmos. Oceanic Technol., 24, 1199–1214. doi: 10.1175/JTECH2033.1

Mather, J. H., S. A. McFarlane, M. A. Miller, and K. L. Johnson, 2007: Cloud properties and associated radiative heating rates in the tropical western Pacific, J. Geophys. Res., 112, D05201, doi:10.1029/2006JD007555.

Kollias, P., E. E. Clothiaux, B. A. Albrecht ,M. A. Miller, K. P. Moran, K. L. Johnson, 2005: The Atmospheric Radiation Measurement Program cloud profiling radars: an evaluation of signal processing and sampling strategies, J. Atmos. and Oceanic Technol., 22, 930-948. doi: 10.1175/JTECH1749.1

Xie, S., M. Zhang, M. Branson, R. T. Cederwall, A. D. DelGenio, Z. A. Eitzen, S. J. Ghan, S. F. Iacobellis, K. L. Johnson, M. Khairoutdinov, S. A. Klein, S. K. Krueger, W. Lin, U. Lohmann, M. A. Miller, D. A. Randall, R. C. J. Somerville, Y. Sud, G. K. Wallker, A. Wolf, X. Wu, K. Xu, J. J. Yio, G. Zhang, J. Zhang, 2005: Simulations of midlatitude frontal clouds by single-column and cloud-resolving models during the Atmospheric Radiation Measurement March 2000 cloud intensive operational period, J. Geophys. Res., 110, D15S03, doi:10.1029/2004JD005119.