Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

Measurements of Aerosols, Radiation, and Clouds over the Southern Ocean (MARCUS: Ice Nucleating Particle Measurements)

1 September 2017 - 30 April 2018

Lead Scientist: Paul DeMott

Observatory: amf, mar

Evidence exists that sea spray-sourced ice nucleating particles (INPs) result from biological and biochemical processes in seawater and the sea surface microlayer, and represent a distinctly different and variable, but oftentimes much less effective INP population in comparison to long-range transported desert dust. Over the Southern Ocean, far from land sources, these INPs may dominate in the marine boundary layer. Thereby, marine INPs may affect cloud phase and lifetime in this region where pervasive supercooled and mixed‐phase boundary layer clouds appear underrepresented in climate models. This project supports daily aerosol filter collections that will be made during the Measurements of Aerosols, Radiation, and Clouds over the Southern Ocean (MARCUS). The second ARM Mobile Facility's (AMF2) deployment on the Aurora Australis, for subsequent processing to determine the temperature spectrum of the concentrations of INPs active via the immersion freezing mechanism across the temperature regime from 0 to -27°C. Additional analyses (thermal, chemical) will be used to discern the biogenic versus inorganic contributions to INP populations. Portions of frozen samples of aerosols in liquid will be archived for future analyses, such as genetic analyses of biological community diversity in aerosols. The INP measurements collected for the MARCUS cruises will supplement and complement other aerosol and remote sensing measurements from the AMF2 suite, as well as other measurements over the region that may occur as part of the international multiagency effort called the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES). The MARCUS INP collections may provide the only such data in the region south of 60 degrees south latitude during SOCRATES. The database developed will provide comparison and contrast versus other widespread marine INP samples collected during U.S. Department of Energy-funded (MAGIC and ACAPEX) and other studies. Measurements will assist development of parameterizations of marine INP sources for use in regional and global scale modeling of the impacts of marine boundary layer aerosols on clouds and climate.


Thomas Hill
Greg McFarquhar


  • Parent Campaign
  • Sibling Campaign


Niu Q, G McFarquhar, R Marchand, A Theisen, S Cavallo, C Flynn, P DeMott, C McCluskey, R Humphries, and T Hill. 2024. "62°S Witnesses the Transition of Boundary Layer Marine Aerosol Pattern over the Southern Ocean (50°S–68°S, 63°E–150°E) during the Spring and Summer: Results from MARCUS (I)." Journal of Geophysical Research: Atmospheres, 129(9), e2023JD040396, 10.1029/2023JD040396.
Research Highlight


Steinke I, P DeMott, G Deane, T Hill, M Maltrud, A Raman, and S Burrows. 2022. "A numerical framework for simulating the atmospheric variability of supermicron marine biogenic ice nucleating particles." Atmospheric Chemistry and Physics, 22(2), 10.5194/acp-22-847-2022.
Research Highlight


Alexander S. 2019. Precipitation over Land and the Southern Ocean (PLATO) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-19-007.


DeMott PJ, TC Hill, and G McFarquhar. 2018. Measurements of Aerosols, Radiation, and Clouds over the Southern Ocean (MARCUS) Ice Nucleating Particle Measurements Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-18-031.

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MAR Data Sources

Name Full Name Browse Data
AERI Atmospheric Emitted Radiance Interferometer Browse Data
AERINF AERI Noise Filtered Browse Data
AERIOE AERIoe Thermodynamic Profile and Cloud Retrieval Browse Data
AOP Aerosol Optical Properties Browse Data
AOS Aerosol Observing System Browse Data
AOSMET Meteorological Measurements associated with the Aerosol Observing System Browse Data
CAMSITE camera that monitors a site area Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CEIL Ceilometer Browse Data
CEILPBLHT Boundary-layer height data with CEIL Browse Data
CO-ANALYZER Carbon Monoxide Analyzer Browse Data
CPC Condensation Particle Counter Browse Data
HTDMA Humidified Tandem Differential Mobility Analyzer Browse Data
INTERPSONDE Interpolated Sonde Browse Data
IRT Infrared Thermometer Browse Data
MARINEMET Marine Surface Meteorological Instrumentation Browse Data
MARINEPRECIP Marine Precipitation 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
MWACRARSCL Marine W-band ARM Cloud Radar, Active Remote Sensing of Clouds 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
SONDE Balloon-Borne Sounding System Browse Data
SONDEGRID Gridded Sonde VAP Product Browse Data
S-TABLE Stabilized Platform Browse Data
THERMOCLOUDPHASE Thermodynamic cloud phase 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
WACRARSCL W-band Cloud Radar Active Remote Sensing of Cloud Browse Data