Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

Marine ARM GPCI Investigation of Clouds (MAGIC)

1 October 2012 - 30 September 2013

Lead Scientist: Ernie Lewis

Observatory: AMF, MAG

Magic_Image_v6-01 Clouds remain a major source of uncertainty in climate projections. In this context, subtropical marine boundary layer (MBL) clouds play a key role in cloud-climate feedbacks that are not well understood yet play a large role in biases both in seasonal coupled model forecasts and annual mean climate forecasts. In particular, current climate models do not accurately represent the transition from the stratocumulus (Sc) regime, with its high albedo and large impact on the global radiative balance of Earth, to shallow trade-wind cumulus (Cu), which play a fundamental role in global surface evaporation and also albedo. Climate models do not yet adequately parameterize the small-scale physical processes associated with turbulence, convection, and radiation in these clouds. Part of this inability results from lack of accurate data on these clouds and the conditions responsible for their properties, including aerosol properties, radiation, and atmospheric and oceanographic conditions.

In MAGIC, the Marine ARM (Atmospheric Radiation Measurement) GPCI Investigation of Clouds, the second ARM Mobile Facility (AMF2) was deployed on the Horizon Lines cargo ship Spirit traversing the route between Los Angeles, California, and Honolulu, Hawaii, for one full year, from October 2012 through September 2013. AMF2's unique capabilities were utilized to observe and characterize the properties of clouds and precipitation, aerosols, and atmospheric radiation; standard meteorological and oceanographic variables; and atmospheric structure. Additionally, two intensive observational periods were conducted in January and July 2013, during which more detailed measurements of the atmospheric structure were made.

This first marine deployment of AMF2 yielded an unparalleled and extremely rich data set that will greatly enhance the ability to understand and represent clouds and precipitation, aerosols, and radiation, and the interactions among them; the processes that determine their properties; and factors that control these processes. Deployment of AMF2 on a ship that routinely traverses this route provided an opportunity to collect a long-term data set over a vast cloud region which is of intense interest to climate modelers. Specifically, the transect lies closely along the cross section used for the GPCI, and the data collected provided constraint, validation, and support for this modeling effort, and for associated modeling efforts such as the CGILS and EUCLIPSE. The founders of ARM recognized the importance of these marine cloud regimes and the original document recommending locales for ARM sites explicitly called for sites in the eastern north Pacific or eastern north Atlantic Ocean. This deployment, at long last, met the identified requirement for ARM measurements in this region.

The C-9 class ship Horizon Spirit is a 268-meter (880-foot) steam-powered container ship that makes the Los Angeles-to-Hawaii run as part of the Horizon Lines fleet.
The C-9 class ship Horizon Spirit is a 268-meter (880-foot), steam-powered container ship that makes the Los Angeles-to-Hawaii run as part of the Horizon Lines fleet.


GPCI = GCSS Pacific Cross-section Intercomparison, a working group of GCSS

GCSS = GEWEX Cloud Systems Study

GEWEX = Global Energy and Water Cycle Experiment, a core project of the World Climate Research Programme.


Bruce Albrecht Pavlos Kollias Joao Teixeira
Geoffrey Bland Michael Reynolds Warren Wiscombe
Charles Flagg Stephen Schwartz Robert Wood
Stephen Klein A. Siebesma Minghua Zhang

Related Publications


Yang W, A Marshak, and G Wen. 2019. "Cloud edge properties measured by the ARM shortwave spectrometer over ocean and land." Journal of Geophysical Research: Atmospheres, , doi: 10.1029/2019JD030622. ONLINE.
Research Highlight

Smalley M, K Suselj, M Lebsock, and J Teixeira. 2019. "A novel framework for evaluating and improving parameterized subtropical marine boundary layer cloudiness." Monthly Weather Review, , 10.1175/MWR-D-18-0394.1.

Zheng Y. 2019. "Theoretical understanding of the linear relationship between convective updrafts and cloud-base height for shallow cumulus clouds. Part I: Maritime conditions." Journal of the Atmospheric Sciences, 76(8), 10.1175/JAS-D-18-0323.1.

Zheng Y, D Rosenfeld, Y Zhu, and Z Li. 2019. "Satellite‐Based Estimation of Cloud Top Radiative Cooling Rate for Marine Stratocumulus." Geophysical Research Letters, 46(8), 10.1029/2019GL082094.
Research Highlight

Yue Z, D Rosenfeld, G Liu, J Dai, X Yu, Y Zhu, E Hashimshoni, X Xu, Y Hui, and O Lauer. 2019. "Automated Mapping of Convective Clouds (AMCC) Thermodynamical, Microphysical, and CCN Properties from SNPP/VIIRS Satellite Data." Journal of Applied Meteorology and Climatology, 58(4), 10.1175/JAMC-D-18-0144.1.

Bretherton C, I Mccoy, J Mohrmann, R Wood, V Ghate, A Gettelman, C Bardeen, B Albrecht, and P Zuidema. 2019. "Cloud, Aerosol and Boundary Layer Structure across the Northeast Pacific Stratocumulus-Cumulus Transition as observed during CSET." Monthly Weather Review, 147(6), 10.1175/MWR-D-18-0281.1.

Ghate V, D Mechem, M Cadeddu, E Eloranta, M Jensen, M Nordeen, and W Smith. 2019. "Estimates of entrainment in closed cellular marine stratocumulus clouds from the MAGIC field campaign." Quarterly Journal of the Royal Meteorological Society, 145(721), 10.1002/qj.3514.

Albrecht B, V Ghate, J Mohrmann, R Wood, P Zuidema, C Bretherton, C Schwartz, E Eloranta, S Glienke, S Donaher, M Sarkar, J McGibbon, A Nugent, R Shaw, J Fugal, P Minnis, R Paliknoda, L Lussier, J Jensen, J Vivekanandan, S Ellis, P Tsai, R Rilling, J Haggerty, T Campos, M Stell, M Reeves, S Beaton, J Allison, G Stossmeister, S Hall, and S Schmidt. 2019. "Cloud System Evolution in the Trades (CSET): Following the Evolution of Boundary Layer Cloud Systems with the NSF–NCAR GV." Bulletin of the American Meteorological Society, 100(1), 10.1175/BAMS-D-17-0180.1.


Ahlgrimm M, R Forbes, R Hogan, and I Sandu. 2018. "Understanding Global Model Systematic Shortwave Radiation Errors in Subtropical Marine Boundary Layer Cloud Regimes." Journal of Advances in Modeling Earth Systems, 10(8), 10.1029/2018MS001346.
Research Highlight

Mohrmann J, R Wood, J McGibbon, R Eastman, and E Luke. 2018. "Drivers of Seasonal Variability in Marine Boundary Layer Aerosol Number Concentration Investigated Using a Steady State Approach." Journal of Geophysical Research: Atmospheres, 123(2), 10.1002/2017JD027443.

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Campaign Data Sets

IOP Participant Data Source Name Final Data
Mary Jane Bartholomew Parcivel Disdrometer Order Data
J.-Y. Christine Chiu CIMEL Sunphotometer Order Data
Paul DeMott Ice Spectrometer Order Data
Ernie Lewis Ship Leg Summaries Order Data
Patrick McBride Solar Spectral Flux Radimeter Order Data
Patrick Minnis VISST: Cloud Properties derived from Geostationary Satellite Data Order Data
R. Reynolds Air Temperature Measurements (Psychrometer) Order Data
R. Reynolds Atmospheric Optical Depth Order Data
R. Reynolds Best Estimate 1-min Downwelling Radiation Data Order Data
R. Reynolds Best Estimate 1-min Meteorology Data Order Data
R. Reynolds Best Estimate 1-min Sea Surface Temperature Data Order Data
R. Reynolds Bridge Display (Wind) Order Data
R. Reynolds Bulk Aerodynamic Fluxes Order Data
R. Reynolds Infrared Seasurface Skin Temperature Autonomous Radiometer Order Data
R. Reynolds RH Quality Assurance (Psychrometer) Order Data
R. Reynolds Raw Navigation/GPS Data Order Data
R. Reynolds Ship Leg Reports Order Data
R. Reynolds Sunshine Pyranometer Order Data
Gunnar Senum Mentor Processed Cloud Condensation Nuclei Counter Order Data
Gunnar Senum Mentor Processed Humidigraph Order Data
Gunnar Senum Mentor Processed Hydroscopic Tandem Diffentential Mobility Analyser Order Data
Gunnar Senum Mentor Processed Nephelometer Order Data
Gunnar Senum Ultra High Sensitivity Aerosol Spectrometer Order Data
Stephen Springston Mentor Processed Meteorological Data Order Data
Stephen Springston Mentor Processed Ozone Order Data
Stephen Springston Mentor Processed Particle Soot Absorption Photometer Order Data
Richard Wagener European Centre for Medium Range Weather Forecasting Order Data

MAG Data Sources

Name Full Name Browse Data
AOS Aerosol Observing System Browse Data
AOSMET Meteorological Measurements associated with the Aerosol Observing System Browse Data
ASSIST Atmospheric Sounder Spectrometer for Infrared Spectral Technology Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CEIL Ceilometer Browse Data
CPC Condensation Particle Counter Browse Data
HSRL High Spectral Resolution Lidar Browse Data
HTDMA Humidified Tandem Differential Mobility Analyzer Browse Data
IRT Infrared Thermometer Browse Data
KAZR Ka ARM Zenith Radar Browse Data
LDIS Laser Disdrometer Browse Data
MET Surface Meteorological Instrumentation Browse Data
MPL Micropulse Lidar Browse Data
MPLCMASK Cloud mask from Micropulse Lidar Browse Data
MWACR Marine W-Band (95 GHz) ARM Cloud Radar Browse Data
MWR Microwave Radiometer Browse Data
MWR3C Microwave Radiometer, 3 Channel Browse Data
NAV Navigational Location and Attitude Browse Data
NEPHELOMETER Nephelometer Browse Data
OZONE Ozone Monitor Browse Data
PBLHT Planetary Boundary Layer Height Browse Data
PRP Portable Radiation Package Browse Data
PSAP Particle Soot Absorption Photometer Browse Data
RWP Radar Wind Profiler Browse Data
SASZE Shortwave Array Spectroradiometer-Zenith Browse Data
SONDE Balloon-Borne Sounding System Browse Data
S-TABLE Stabilized Platform Browse Data
TSI Total Sky Imager Browse Data
UHSAS Ultra-High Sensitivity Aerosol Spectrometer Browse Data
VISST Minnis Cloud Products Using Visst Algorithm Browse Data