Cloud, Aerosol, and Boundary Layer Structure across the Northeast Pacific Stratocumulus–Cumulus Transition as Observed during CSET

Christopher S. Bretherton Department of Atmospheric Sciences, University of Washington, Seattle, Washington

Search for other papers by Christopher S. Bretherton in
Current site
Google Scholar
PubMed
Close
,
Isabel L. McCoy Department of Atmospheric Sciences, University of Washington, Seattle, Washington

Search for other papers by Isabel L. McCoy in
Current site
Google Scholar
PubMed
Close
,
Johannes Mohrmann Department of Atmospheric Sciences, University of Washington, Seattle, Washington

Search for other papers by Johannes Mohrmann in
Current site
Google Scholar
PubMed
Close
,
Robert Wood Department of Atmospheric Sciences, University of Washington, Seattle, Washington

Search for other papers by Robert Wood in
Current site
Google Scholar
PubMed
Close
,
Virendra Ghate Argonne National Laboratory, Argonne, Illinois

Search for other papers by Virendra Ghate in
Current site
Google Scholar
PubMed
Close
,
Andrew Gettelman National Center for Atmospheric Research, Boulder, Colorado

Search for other papers by Andrew Gettelman in
Current site
Google Scholar
PubMed
Close
,
Charles G. Bardeen National Center for Atmospheric Research, Boulder, Colorado

Search for other papers by Charles G. Bardeen in
Current site
Google Scholar
PubMed
Close
,
Bruce A. Albrecht Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida

Search for other papers by Bruce A. Albrecht in
Current site
Google Scholar
PubMed
Close
, and
Paquita Zuidema Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida

Search for other papers by Paquita Zuidema in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

During the Cloud System Evolution in the Trades (CSET) field study, 14 research flights of the National Science Foundation G-V sampled the stratocumulus–cumulus transition between Northern California and Hawaii and its synoptic variability. The G-V made vertically resolved measurements of turbulence, cloud microphysics, aerosol characteristics, and trace gases. It also carried dropsondes and a vertically pointing W-band radar and lidar. This paper summarizes these observations with the goals of fostering novel comparisons with theory, models and reanalyses, and satellite-derived products. A longitude–height binning and compositing strategy mitigates limitations of sparse sampling and spatiotemporal variability. Typically, a 1-km-deep decoupled stratocumulus-capped boundary layer near California evolved into 2-km-deep precipitating cumulus clusters surrounded by patches of thin stratus that dissipated toward Hawaii. Low cloud cover was correlated with estimated inversion strength more than with cloud droplet number, even though the thickest clouds were generally precipitating and ultraclean layers indicative of aerosol–cloud–precipitation interaction were common west of 140°W. Accumulation-mode aerosol concentration correlated well with collocated cloud droplet number concentration and was typically largest near the surface. Aitken mode aerosol concentration was typically larger in the free troposphere. Wildfire smoke produced spikes of aerosol and trace gases on some flights. CSET data are compared with space–time collocated output from MERRA-2 reanalysis and from the CAM6 climate model run with winds and temperature nudged toward this reanalysis. The reanalysis compares better with the observed relative humidity than does nudged CAM6. Both vertically diffuse the stratocumulus cloud layer versus observations. MERRA-2 slightly underestimates in situ carbon monoxide measurements and underestimates ozone depletion within the boundary layer.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Christopher S. Bretherton, breth@uw.edu

Abstract

During the Cloud System Evolution in the Trades (CSET) field study, 14 research flights of the National Science Foundation G-V sampled the stratocumulus–cumulus transition between Northern California and Hawaii and its synoptic variability. The G-V made vertically resolved measurements of turbulence, cloud microphysics, aerosol characteristics, and trace gases. It also carried dropsondes and a vertically pointing W-band radar and lidar. This paper summarizes these observations with the goals of fostering novel comparisons with theory, models and reanalyses, and satellite-derived products. A longitude–height binning and compositing strategy mitigates limitations of sparse sampling and spatiotemporal variability. Typically, a 1-km-deep decoupled stratocumulus-capped boundary layer near California evolved into 2-km-deep precipitating cumulus clusters surrounded by patches of thin stratus that dissipated toward Hawaii. Low cloud cover was correlated with estimated inversion strength more than with cloud droplet number, even though the thickest clouds were generally precipitating and ultraclean layers indicative of aerosol–cloud–precipitation interaction were common west of 140°W. Accumulation-mode aerosol concentration correlated well with collocated cloud droplet number concentration and was typically largest near the surface. Aitken mode aerosol concentration was typically larger in the free troposphere. Wildfire smoke produced spikes of aerosol and trace gases on some flights. CSET data are compared with space–time collocated output from MERRA-2 reanalysis and from the CAM6 climate model run with winds and temperature nudged toward this reanalysis. The reanalysis compares better with the observed relative humidity than does nudged CAM6. Both vertically diffuse the stratocumulus cloud layer versus observations. MERRA-2 slightly underestimates in situ carbon monoxide measurements and underestimates ozone depletion within the boundary layer.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Christopher S. Bretherton, breth@uw.edu
Save
  • Ahlgrimm, M., R. Forbes, R. J. Hogan, and I. Sandu, 2018: Understanding global model systematic shortwave radiation errors in subtropical marine boundary layer cloud regimes. J. Adv. Model. Earth Syst., 10, 20422060, https://doi.org/10.1029/2018MS001346.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Albrecht, B. A., C. S. Bretherton, D. Johnson, W. Schubert, and A. S. Frisch, 1995: The Atlantic Stratocumulus Transition Experiment (ASTEX). Bull. Amer. Meteor. Soc., 76, 889903, https://doi.org/10.1175/1520-0477(1995)076<0889:TASTE>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Albrecht, B. A., and Coauthors, 2019: Cloud System Evolution in the Trades (CSET): Following the evolution of boundary layer cloud systems with the NSF–NCAR GV. Bull. Amer. Meteor. Soc., 100, 93121, https://doi.org/10.1175/BAMS-D-17-0180.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bretherton, C. S., and R. Pincus, 1995: Cloudiness and marine boundary layer dynamics in the ASTEX Lagrangian experiments. Part I: Synoptic setting and vertical structure. J. Atmos. Sci., 52, 27072723, https://doi.org/10.1175/1520-0469(1995)052<2707:CAMBLD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bretherton, C. S., and M. C. Wyant, 1997: Moisture transport, lower tropospheric stability, and decoupling of cloud-topped boundary layers. J. Atmos. Sci., 54, 148167, https://doi.org/10.1175/1520-0469(1997)054<0148:MTLTSA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bretherton, C. S., P. Austin, and S. T. Siems, 1995: Cloudiness and marine boundary layer dynamics in the ASTEX Lagrangian experiments. Part II: Cloudiness, drizzle, surface fluxes, and entrainment. J. Atmos. Sci., 52, 27242735, https://doi.org/10.1175/1520-0469(1995)052<2724:CAMBLD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bretherton, C. S., S. K. Krueger, M. C. Wyant, P. Bechtold, E. van Meijgaard, B. Stevens, and J. Teixeira, 1999: A GCSS boundary layer model intercomparison study of the first ASTEX Lagrangian experiment. Bound.-Layer Meteor., 93, 341380, https://doi.org/10.1023/A:1002005429969.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Comstock, K. K., R. Wood, S. E. Yuter, and C. S. Bretherton, 2004: Reflectivity and rain rate in and below drizzling stratocumulus. Quart. J. Roy. Meteor. Soc., 130, 28912918, https://doi.org/10.1256/qj.03.187.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cornish, C. R., C. S. Bretherton, and D. B. Percival, 2006: Maximal overlap wavelet statistical analysis with application to atmospheric turbulence. Bound.-Layer Meteor., 119, 339374, https://doi.org/10.1007/s10546-005-9011-y.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cuijpers, J. W. M., and P. G. Duynkerke, 1993: Large eddy simulation of trade wind cumulus clouds. J. Atmos. Sci., 50, 38943908, https://doi.org/10.1175/1520-0469(1993)050<3894:LESOTW>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Elsaesser, G. S., C. W. O’Dell, M. D. Lebsock, R. Bennartz, T. J. Greenwald, and F. J. Wentz, 2017: The Multisensor Advanced Climatology of Liquid Water Path (MAC-LWP). J. Climate, 30, 10 19310 210, https://doi.org/10.1175/JCLI-D-16-0902.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Garratt, J. R., 1992: The Atmospheric Boundary Layer. Cambridge University Press, 316 pp.

  • Gelaro, R., and Coauthors, 2017: The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2). J. Climate, 30, 54195454, https://doi.org/10.1175/JCLI-D-16-0758.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Heffter, J. L., 1980: Transport layer depth calculations. Proc. Second Joint Conf. on Applications of Air Pollution Meteorology, New Orleans, LA, Amer. Meteor. Soc., 787–791.

  • Jones, C. R., C. S. Bretherton, and D. Leon, 2011: Coupled vs. decoupled boundary layers in VOCALS-REx. Atmos. Chem. Phys., 11, 71437153, https://doi.org/10.5194/acp-11-7143-2011.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kalmus, P., M. Lebsock, and J. Teixeira, 2014: Observational boundary layer energy and water budgets of the stratocumulus-to-cumulus transition. J. Climate, 27, 91559170, https://doi.org/10.1175/JCLI-D-14-00242.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kalmus, P., S. Wong, and J. Teixeira, 2015: The Pacific subtropical cloud transition: A MAGIC assessment of AIRS and ECMWF thermodynamic structure. IEEE Geosci. Remote Sens. Lett., 12, 15861590, https://doi.org/10.1109/LGRS.2015.2413771.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Klein, S. A., and D. L. Hartmann, 1993: The seasonal cycle of low stratiform clouds. J. Climate, 6, 15871606, https://doi.org/10.1175/1520-0442(1993)006<1587:TSCOLS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Krueger, S. K., G. T. McLean, and Q. Fu, 1995a: Numerical simulations of the stratus to cumulus transition in the subtropical marine boundary layer. Part I: Boundary-layer structure. J. Atmos. Sci., 52, 28392850, https://doi.org/10.1175/1520-0469(1995)052<2839:NSOTST>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Krueger, S. K., G. T. McLean, and Q. Fu, 1995b: Numerical simulation of the stratus-to-cumulus transition in the subtropical marine boundary layer. Part II: Boundary-layer circulation. J. Atmos. Sci., 52, 28512868, https://doi.org/10.1175/1520-0469(1995)052<2851:NSOTST>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lothon, M., D. H. Lenschow, D. Leon, and G. Vali, 2005: Turbulence measurements in marine stratocumulus with airborne Doppler radar. Quart. J. Roy. Meteor. Soc., 131, 20632080, https://doi.org/10.1256/qj.04.131.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McGibbon, J., and C. S. Bretherton, 2017: Skill of ship-following large-eddy simulations in reproducing MAGIC observations across the Northeast Pacific stratocumulus to cumulus transition region. J. Adv. Model. Earth Syst., 9, 810831, https://doi.org/10.1002/2017MS000924.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Minnis, P., and Coauthors, 2008: Near-real time cloud retrievals from operational and research meteorological satellites. Proc. SPIE, 7107, 710703, https://doi.org/10.1117/12.800344.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • O, K.-T., R. Wood, and C. S. Bretherton, 2018: Ultraclean layers and optically thin clouds in the stratocumulus-tocumulus transition. Part II: Depletion of cloud droplets and cloud condensation nuclei through collision–coalescence. J. Atmos. Sci., 75, 16531673, https://doi.org/10.1175/JAS-D-17-0218.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Painemal, D., and P. Zuidema, 2011: Assessment of MODIS cloud effective radius and optical thickness retrievals over the Southeast Pacific with VOCALS-REx in-situ measurements. J. Geophys. Res., 116, D24206, https://doi.org/10.1029/2011JD016155.

    • Search Google Scholar
    • Export Citation
  • Painemal, D., P. Minnis, and M. Nordeen, 2015: Aerosol variability, synoptic-scale processes, and their link to the cloud microphysics over the northeast Pacific during MAGIC. J. Geophys. Res. Atmos., 120, 51225139, https://doi.org/10.1002/2015JD023175.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rogers, R. R., and M. K. Yau, 1989: A Short Course in Cloud Physics. 3rd ed. Pergamon Press, 290 pp.

  • Schwartz, M. C., and Coauthors, 2019: Merged cloud and precipitation dataset from the HIAPER-GV for the Cloud System Evolution in the Trades (CSET) Campaign. J. Atmos. Oceanic Technol., https://doi.org/10.1175/JTECH-D-18-0111.1, in press.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Smalley, M., and T. L’Ecuyer, 2015: A global assessment of the spatial distribution of precipitation occurrence. J. Appl. Meteor. Climatol., 54, 21792197, https://doi.org/10.1175/JAMC-D-15-0019.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Teixeira, J., and Coauthors, 2011: Tropical and subtropical cloud transitions in weather and climate prediction models: The GCSS/WGNE Pacific Cross-Section Intercomparison (GPCI). J. Climate, 24, 52235256, https://doi.org/10.1175/2011JCLI3672.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • van der Dussen, J. J., and Coauthors, 2013: The GASS/EUCLIPSE model intercomparison of the stratocumulus transition as observed during ASTEX: LES results. J. Adv. Model. Earth Syst., 5, 483499, https://doi.org/10.1002/jame.20033.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wood, R., and C. S. Bretherton, 2006: On the relationship between stratiform low cloud cover and lower tropospheric stability. J. Climate, 19, 64256432, https://doi.org/10.1175/JCLI3988.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wood, R., and Coauthors, 2018: Ultraclean layers and optically thin clouds in the stratocumulus-to-cumulus transition. Part I: Observations. J. Atmos. Sci., 75, 16311652, https://doi.org/10.1175/JAS-D-17-0213.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, C., X. Liu, M. Diao, K. Zhang, A. Gettelman, Z. Lu, J. E. Penner, and Z. Lin, 2017: Direct comparisons of ice cloud macro- and microphysical properties simulated by the Community Atmosphere Model version 5 with HIPPO aircraft observations. Atmos. Chem. Phys., 17, 47314749, https://doi.org/10.5194/acp-17-4731-2017.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wyant, M. C., C. S. Bretherton, H. A. Rand, and D. E. Stevens, 1997: Numerical simulations and a conceptual model of the stratocumulus to trade cumulus transition. J. Atmos. Sci., 54, 168192, https://doi.org/10.1175/1520-0469(1997)054<0168:NSAACM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xiao, H., and Coauthors, 2014: Diagnosis of the marine low cloud simulation in the NCAR Community Earth System Model (CESM) and the NCEP Global Forecast System (GFS)-Modular Ocean Model v4 (MOM4) coupled model. Climate Dyn., 43, 737752, https://doi.org/10.1007/s00382-014-2067-y

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yamaguchi, T., G. Feingold, and J. Kazil, 2017: Stratocumulus to cumulus transition by drizzle. J. Adv. Model. Earth Syst., 9, 23332349, https://doi.org/10.1002/2017MS001104.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhou, X., P. Kollias, and E. R. Lewis, 2016: Clouds, precipitation, and marine boundary layer structure during the MAGIC field campaign. J. Climate, 28, 24202442, https://doi.org/10.1175/JCLI-D-14-00320.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 2849 1105 211
PDF Downloads 824 232 25