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 Warren Wiscombe
Geoffrey Bland Stephen Schwartz Robert Wood
Charles Flagg A. Siebesma Minghua Zhang
Stephen Klein Joao Teixeira


  • Child Campaign


Nie Y, X Li, Q Paletta, M Aragon, A Scott, and A Brandt. 2024. "Open-source sky image datasets for solar forecasting with deep learning: A comprehensive survey." Renewable and Sustainable Energy Reviews, 189, 113977, 10.1016/j.rser.2023.113977.


Feingold G, VP Ghate, LM Russell, P Blossey, W Cantrell, MW Christensen, MS Diamond, A Gettelman, F Glassmeier, J Haywood, F Hoffmann, C Kaul, M Lebsock, AC McComiskey, DT McCoy, Y Ming, J Muelmenstaedt, A Possner, P Prabhakaran, PK Quinn, S Schmidt, RA Shaw, CE Singer, A Sorooshian, V Toll, J Wan, R Wood, F Yang, J Zhang, and X Zheng. 2022. 2022: DOE-NOAA Marine Cloud Brightening Workshop. U.S DOE Office of Science/NOAA. DOE/SC-0207. 10.2172/1902718.

Kalmus P, C Ao, K Wang, M Manzi, and J Teixeira. 2022. "A high-resolution planetary boundary layer height seasonal climatology from GNSS radio occultations." Remote Sensing of Environment, 276, 113037, 10.1016/j.rse.2022.113037.

ZHU Z, P Kollias, E Luke, and F Yang. 2022. "New insights on the prevalence of drizzle in marine stratocumulus clouds based on a machine learning algorithm applied to radar Doppler spectra." Atmospheric Chemistry and Physics, 22(11), 10.5194/acp-22-7405-2022.
Research Highlight

Feng X, R Anthes, and J Sjoberg. 2022. "Estimation of random error statistics in high-resolution radiosondes, ERA-Interim, and COSMIC radio occultation soundings in the northeast Pacific Ocean during the MAGIC campaign." Journal of Atmospheric and Oceanic Technology, 39(9), 10.1175/JTECH-D-21-0171.1.

Tang S, J Fast, K Zhang, J Hardin, A Varble, J Shilling, F Mei, M Zawadowicz, and P Ma. 2022. "Earth System Model Aerosol–Cloud Diagnostics (ESMAC Diags) package, version 1: assessing E3SM aerosol predictions using aircraft, ship, and surface measurements." Geoscientific Model Development, 15(10), 10.5194/gmd-15-4055-2022.
Research Highlight


Zheng Y, H Zhang, and Z Li. 2021. "Role of surface latent heat flux in shallow cloud transitions: A mechanism-denial LES study." Journal of the Atmospheric Sciences, 78(9), 10.1175/JAS-D-20-0381.1.
Research Highlight

Brendecke J, X Dong, B Xi, and P Wu. 2021. "Maritime Cloud and Drizzle Microphysical Properties Retrieved from Ship‐Based Observations during MAGIC." Earth and Space Science, 8(5), e2020EA001588, 10.1029/2020EA001588.

Dorsey KS, R Jundt, CB Ireland, MR Wasem, RA Stafford, and A Hunzinger. 2021. 2020 Atmospheric Radiation Measurement (ARM) Annual Report. Ed. by Kathryn Dorsey, U.S. Department of Energy. DOE/SC-ARM-20-020.


Johnson J, L Regayre, M Yoshioka, K Pringle, S Turnock, J Browse, D Sexton, J Rostron, N Schutgens, D Partridge, D Liu, J Allan, H Coe, A Ding, D Cohen, A Atanacio, V Vakkari, E Asmi, and K Carslaw. 2020. "Robust observational constraint of uncertain aerosol processes and emissions in a climate model and the effect on aerosol radiative forcing." Atmospheric Chemistry and Physics, 20(15), 10.5194/acp-20-9491-2020.

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Campaign Data Sets

IOP Participant Data Source Name Final Data
Mary Jane Bartholomew disdro 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 SSFR Order Data
Patrick Minnis visible infrared solar-infrared split window technique (visst) Order Data
R. Reynolds Atmospheric Optical Depth Order Data
R. Reynolds Best Estimate 1-min Sea Surface Temperature Data Order Data
R. Reynolds Bridge Display (Wind) Order Data
R. Reynolds Flux Data Order Data
R. Reynolds Infrared Seasurface Skin Temperature Autonomous Radiometer Order Data
R. Reynolds Met Order Data
R. Reynolds RH Quality Assurance (Psychrometer) 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 Shortwave Radiation Order Data
Gunnar Senum Humidified Tandem Differential Mobility Analyzer Order Data
Gunnar Senum Mentor Processed Cloud Condensation Nuclei Counter Order Data
Gunnar Senum Mentor Processed Humidigraph Order Data
Gunnar Senum Nephelometer Order Data
Gunnar Senum Ultra High Sensitivity Aerosol Spectrometer- G1 Aircraft Order Data
Stephen Springston Particle Soot Absorption Photometer - G-1 Aircraft 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
CEILPBLHT Boundary-layer height data with CEIL Browse Data
CEILSHIPCOR Ceilometer Corrected for Ship Motion Browse Data
CPC Condensation Particle Counter Browse Data
HSRL High Spectral Resolution Lidar Browse Data
HSRLSHIPCOR HSRL Corrected for Ship Motion Browse Data
HTDMA Humidified Tandem Differential Mobility Analyzer Browse Data
INTERPSONDE Interpolated Sonde Browse Data
IRT Infrared Thermometer Browse Data
KAZR Ka ARM Zenith Radar Browse Data
KAZRSHIPCOR KAZR Ship Motion Correction Browse Data
MARINEMET Marine Surface Meteorological Instrumentation Browse Data
MPL Micropulse Lidar Browse Data
MPLCMASK Cloud mask from Micropulse Lidar Browse Data
MPLPOLFSSHIPCOR MPL Corrected for Ship Motion Browse Data
MWACR Marine W-Band (95 GHz) ARM Cloud Radar Browse Data
MWACRSHIPCOR MWACR Ship Motion Correction Browse Data
MWR Microwave Radiometer Browse Data
MWR3C Microwave Radiometer, 3 Channel Browse Data
MWRRET MWR Retrievals Browse Data
NAV Navigational Location and Attitude Browse Data
NAVBE Navigational Location and Attitude Best Estimate 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
SONDEGRID Gridded Sonde VAP Product Browse Data
S-TABLE Stabilized Platform Browse Data
TSI Total Sky Imager Browse Data
UHSAS Ultra-High Sensitivity Aerosol Spectrometer Browse Data