Campaign : Marine ARM GPCI Investigation of Clouds (MAGIC)

2012.10.01 - 2013.09.30

Website :

Lead Scientist : Ernie Lewis

For data sets, see below.


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, CA and Honolulu, HI for one full year, from October, 2012, through September, 2013, during which the unique capabilities provided by AMF2 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 (IOPs) were conducted January and July of 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 parameterize 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.

Other Contacts

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

Campaign Data Sets

IOP ParticipantData Source DescriptionFinal Data
ReynoldsShip Leg Reports Order Data
SpringstonMentor Processed Ozone Order Data
ReynoldsBest Estimate 1-min Sea Surface Temperature Data Order Data
SenumMentor Processed Humidigraph Order Data
SenumMentor Processed Cloud Condensation Nuclei Counter Order Data
ReynoldsBest Estimate 1-min Downwelling Radiation Data Order Data
ReynoldsBest Estimate 1-min Meteorology Data Order Data
ReynoldsBulk Aerodynamic Fluxes Order Data
SenumMentor Processed Hydroscopic Tandem Diffentential Mobility Analyser Order Data
SenumMentor Processed Nephelometer Order Data
ReynoldsAir Temperature Measurements (Psychrometer) Order Data
LewisShip Leg Summaries Order Data
SpringstonMentor Processed Particle Soot Absorption Photometer Order Data
ReynoldsRaw Navigation/GPS Data Order Data
WagenerEuropean Centre for Medium Range Weather Forecasting Order Data
SpringstonMentor Processed Meteorological Data Order Data
MinnisVISST: Cloud Properties derived from Geostationary Satellite Data Order Data

Additional Data Sets

IOP ParticipantData Source DescriptionFinal Data
McBrideSolar Spectral Flux Radimeter Order Data
DeMottIce Spectrometer Order Data
ChiuCIMEL Sunphotometer Order Data
SenumUltra High Sensitivity Aerosol Spectrometer Order Data
BartholomewParcivel Disdrometer Order Data
ReynoldsAtmospheric Optical Depth Order Data
ReynoldsInfrared Seasurface Skin Temperature Autonomous Radiometer Order Data
ReynoldsBridge Display (Wind) Order Data
ReynoldsRH Quality Assurance (Psychrometer) Order Data
ReynoldsSunshine Pyranometer Order Data

ARM Mobile Facility Instruments

Data Source DescriptionBrowse DataBrowse Plots
Aerosol Observing System
 Browse Data
Meteorological Measurements associated with the Aerosol Observing System
 Browse Data Browse Plots
Atmospheric Sounder Spectrometer for Infrared Spectral Technology
 Browse Data
Cloud Condensation Nuclei Particle Counter
 Browse Data Browse Plots
 Browse Data
Condensation Particle Counter
 Browse Data Browse Plots
Cimel Sunphotometer
 Browse Data
High Spectral Resolution Lidar
 Browse Data
Humidified Tandem Differential Mobility Analyzer
 Browse Data
Infrared Thermometer
 Browse Data Browse Plots
Ka ARM Zenith Radar
 Browse Data
Laser Disdrometer
 Browse Data
Surface Meteorological Instrumentation
 Browse Data
Micropulse Lidar
 Browse Data Browse Plots
Marine W-Band (95 GHz) ARM Cloud Radar
 Browse Data
Microwave Radiometer
 Browse Data Browse Plots
Microwave Radiometer, 3 Channel
 Browse Data Browse Plots
Navigational Location and Attitude
 Browse Data
 Browse Data
Ozone Monitor
 Browse Data Browse Plots
Portable Radiation Package
 Browse Data Browse Plots
Particle Soot Absorption Photometer
 Browse Data Browse Plots
Radar Wind Profiler
 Browse Data
Shortwave Array Spectroradiometer-Zenith
 Browse Data
Balloon-Borne Sounding System
 Browse Data Browse Plots
Stabilized Platform
 Browse Data Browse Plots
Total Sky Imager
 Browse Data Browse Plots
Ultra-High Sensitivity Aerosol Spectrometer
 Browse Data