Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA)

1 June 2017 - 28 February 2018

Lead Scientist: Jian Wang

Observatory: AAF, ENA

With their extensive coverage, low clouds greatly influence global climate, but they are poorly represented in global climate models (GCMs). The response of low clouds to changes in atmospheric greenhouse gases and aerosols remains the major source of uncertainty in climate simulations. The poor representations of low clouds in GCMs are partly due to inadequate observations of their microphysical and macrophysical structures, radiative effects, and the associated aerosol distribution and budget in regions where the aerosol impact is the greatest.

The Eastern North Atlantic (ENA) is a region with persistent but diverse subtropical marine boundary layer (MBL) clouds. Their albedo and precipitation are highly susceptible to perturbations in aerosol properties. Boundary layer aerosol in the ENA region is influenced by a variety of sources, leading to strong variations in cloud condensation nuclei (CCN) concentration and aerosol optical properties.

The ARM Climate Research Facility has a fixed ENA atmospheric observatory on Graciosa Island in the Azores, providing invaluable information on MBL aerosols and low clouds. At the same time, the vertical structures and horizontal variabilities of aerosols, trace gases, clouds, drizzle, and atmospheric thermodynamics are critically needed for understanding and quantifying the budget of MBL aerosols, the radiative properties, precipitation efficiency, and life cycle of MBL clouds, and the cloud response to aerosol perturbations. Much of this data can be obtained only through aircraft-based measurements. In addition, the interconnected aerosol and cloud processes are best investigated by a study involving simultaneous in situ aerosol, cloud, and thermodynamic measurements. In situ measurements are also necessary for validating and improving ground-based retrieval algorithms at the ENA observatory.

The Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) field campaign was motivated by the need for comprehensive in situ characterizations of boundary layer structure, and associated vertical distributions and horizontal variabilities of low clouds and aerosols over the Azores. The ARM Aerial Facility (AAF) Gulfstream-159 (G-1) research aircraft flew from Terceira Island in the Azores during two intensive operational periods: early summer 2017 (June to July) and winter 2018 (January to February). Deployments during both seasons allowed for examination of key aerosol and cloud processes under a variety of representative meteorological and cloud conditions.

The science themes for ACE-ENA included:

  • the budget of MBL CCN and its seasonal variation
  • effects of aerosols on clouds and precipitation
  • cloud microphysical and macrophysical structures, and entrainment mixing
  • advancing retrievals of turbulence, clouds, and drizzle
  • model evaluation and process studies.

A key advantage of the deployments is the strong synergy between the measurements aboard the G-1 and the routine measurements at the ENA observatory, including state-of-the-art profiling and scanning radars. The three-dimensional cloud structures provided by the scanning radars will put the detailed in situ measurements into mesoscale and cloud life cycle contexts. On the other hand, high-quality in situ measurements will enable validation and improvements of ground-based retrieval algorithms at the ENA observatory, leading to high-quality and statistically robust data sets from the routine measurements.

The deployments, combined with the routine measurements at the ENA site, will have a long-lasting impact on the research and modeling of low clouds and aerosols in the remote marine environment.

Operational Periods:



Eduardo Azevedo Mary Gilles Edward Luke
Christopher Bretherton Anne Jefferson Allison McComiskey
Duli Chand Michael Jensen Fan Mei
J.-Y. Christine Chiu Pavlos Kollias Mark Miller
Xiquan Dong Chongai Kuang Arthur Sedlacek
Jerome Fast Alexander Laskin Raymond Shaw
Andrew Gettelman Ernie Lewis Robert Wood
Steven Ghan Xiaohong Liu
Scott Giangrande Yangang Liu


Goldberger LA, F Mei, J Hubbe, and CD Kluzek. 2020. Navigation and Meteorological Data from Multiple Sensors on Airborne Platform (NAVMET-AIR) Value-Added Product Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-255.

Watson T, A Aiken, Q Zhang, P Croteau, T Onasch, L Williams, and C Flynn. 2020. Second ARM Aerosol Chemical Speciation Monitor Users’ Meeting Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-249.

Zheng G, A Sedlacek, A Aiken, Y Feng, T Watson, S Raveh-Rubin, J Uin, E Lewis, and J Wang. 2020. "Long-range transported North American wildfire aerosols observed in marine boundary layer of eastern North Atlantic." Environment International, 139, 10.1016/j.envint.2020.105680.

Gallo F, J Uin, S Springston, J Wang, G Zheng, C Kuang, R Wood, E Azevedo, A McComiskey, F Mei, A Theisen, J Kyrouac, and A Aiken. 2020. "Identifying a regional aerosol baseline in the eastern North Atlantic using collocated measurements and a mathematical algorithm to mask high-submicron-number-concentration aerosol events." Atmospheric Chemistry and Physics, 20(12), 10.5194/acp-20-7553-2020.
Research Highlight

kazemirad M and M Miller. 2020. "Summertime Post-Cold-Frontal Marine Stratocumulus Transition Processes over the Eastern North Atlantic." Journal of the Atmospheric Sciences, 77(6), 10.1175/JAS-D-19-0167.1.

Gao S, C Lu, Y Liu, F Mei, J Wang, L Zhu, and S Yan. 2020. "Contrasting Scale Dependence of Entrainment‐Mixing Mechanisms in Stratocumulus Clouds." Geophysical Research Letters, 47(9), e2020GL086970, 10.1029/2020GL086970.

Wu P, X Dong, B Xi, J Tian, and D Ward. 2020. " Profiles of MBL cloud and drizzle microphysical properties retrieved from ground‐based observations and validated by aircraft measurements over the Azores ." Journal of Geophysical Research: Atmospheres, 125(9), e2019JD032205, 10.1029/2019JD032205.

Kazimirad M and M Miller. 2020. "Summertime Post-Cold-Frontal Marine Stratocumulus Transition Processes over the Eastern North Atlantic." Journal of the Atmospheric Sciences, 77(6), 10.1175/JAS-D-19-0167.1.
Research Highlight

Goss HB, KS Dorsey, CB Ireland, MR Wasem, RA Stafford, and R Jundt. 2020. 2019 Atmospheric Radiation Measurement (ARM) Annual Report. Ed. by Kathryn Dorsey, ARM user facility. DOE/SC-ARM-19-032.

Glienke S and F Mei. 2020. High-Volume Precipitation Spectrometer (HVPS) Instrument Handbook. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-239.

View All Related Publications

Campaign Data Sets

IOP Participant Data Source Name Final Data
Alexander Laskin Time Resolved Aerosol Collectors Order Data
Chuck Long SPN1-Radiometer Suite_Tilt Corrected Data Order Data
Alyssa Matthews 2DS Particle Imaging Probe Images Order Data
Alyssa Matthews Ambient Winds- AIMMS Order Data
Alyssa Matthews G-1 P1344 and P1347 Axis Video Cameras Order Data
Alyssa Matthews High Volume Precipitation Spectrometer - Images Order Data
Alyssa Matthews Water Content Monitor Order Data
Fan Mei 2DS Particle Imaging Probe Order Data
Fan Mei Condensation Particle Counters Order Data
Fan Mei Fast Cloud Droplet Probe (FCDP) Order Data
Fan Mei High Volume Precipitation Spectrometer Order Data
Fan Mei Merged-2dsfcdphvps Order Data
Fan Mei Meteorology/State/Position Parameters Order Data
Mikhail Pekour Aerodynamic Particle Sizer Order Data
Mikhail Pekour Open Path Tunable Diode Laser Hygrometer Order Data
Mikhail Pekour Optical Particle Counter - Counterflow Virtual Impactor Order Data
Mikhail Pekour Optical Particle Counter - Isokinetic Order Data
Raymond Shaw Holographic Detector for Clouds Order Data
John Shilling High- Resolution Time-of-Flight Aerosol Mass Spectrometer Order Data
John Shilling Proton Transfer Reaction Mass Spectrometer Order Data
Stephen Springston Carbon Monoxide Analyzer aboard Aircraft_IOPI Order Data
Stephen Springston Carbon Monoxide Analyzer aboard Aircraft_IOPII Order Data
Stephen Springston Ozone Monitor aboard Aircraft_IOPI Order Data
Stephen Springston Ozone Monitor aboard Aircraft_IOPII Order Data
Amy Sullivan Particle-Into-Liquid Sampler (PILS) Order Data
Jason Tomlinson Cloud Imaging Probe - G1 Aircraft Order Data
Jason Tomlinson Cloud, Aerosol and Precipitation Spectrometer Order Data
Jason Tomlinson Liquid Water Content (pvm-100a probe) Order Data
Jason Tomlinson Passive Cavity Aerosol Spectrometer Order Data
Janek Uin Meteorological Measurements associated with the Aerosol Observing System Order Data
Janek Uin Ultra-High Sensitivity Aerosol Spectrometer Order Data
Jian Wang Fast Integrated Mobility Spectrometer Order Data

ENA Data Sources

Name Full Name Browse Data
2DS-AIR 2 Dimensional Stereo Probe aboard aircraft Browse Data
ACSM Aerosol Chemical Speciation Monitor Browse Data
AERI Atmospheric Emitted Radiance Interferometer Browse Data
AERINF AERI Noise Filtered 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
ARMBE ARM Best Estimate Data Products Browse Data
CAMSITE camera that monitors a site area Browse Data
CAPS-PMEX Cavity Attenuated Phase Shift Extinction Monitor Browse Data
CAS-AIR Cloud and Aerosol Spectrometer aboard aircraft Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CCN-AIR Cloud Condensation Nuclei Particle Counter aboard Aircraft Browse Data
CEIL Ceilometer Browse Data
CEILPBLHT Boundary-layer height data with CEIL Browse Data
CIP-AIR Cloud Imaging Probe aboard aircraft Browse Data
CMH-AIR Chilled Mirror Hygrometer aboard aircraft Browse Data
CO-AIR Carbon Monoxide- Airborne Browse Data
CO-ANALYZER Carbon Monoxide Analyzer Browse Data
CPC Condensation Particle Counter Browse Data
CPC-AIR Condensation particle counter aboard aircraft Browse Data
CSPHOT Cimel Sunphotometer Browse Data
DL Doppler Lidar Browse Data
DLPROF Doppler Lidar Profiles Browse Data
ECMWFDIAG European Centre for Medium Range Weather Forecasts Diagnostic Analyses Browse Data
ECOR Eddy Correlation Flux Measurement System Browse Data
FCDP-AIR Fast Cloud Droplet Probe aboard aircraft Browse Data
GHG Greenhouse Gas Monitor Browse Data
GNDRAD Ground Radiometers on Stand for Upwelling Radiation Browse Data
GUSTPROBE-AIR Gust Probe aboard aircraft Browse Data
HK-AIR House Keeping Instruments aboard Aircraft Browse Data
HTDMA Humidified Tandem Differential Mobility Analyzer Browse Data
HVPS-AIR High Volume Precipitation Spectrometer aboard aircraft Browse Data
INLETCVI-AIR Inlet for Counterflow Virtual Impactor aboard aircraft Browse Data
INLETISOK-AIR Isokinetic Inlet aboard aircraft Browse Data
INTERPSONDE Interpolated Sonde Browse Data
IRT Infrared Thermometer Browse Data
KASACR Ka-Band Scanning ARM Cloud Radar Browse Data
KAZR Ka ARM Zenith Radar Browse Data
KAZRARSCL Active Remote Sensing of CLouds (ARSCL) product using Ka-band ARM Zenith Radars Browse Data
KAZRCOR KAZR Corrected Data Browse Data
LDIS Laser Disdrometer Browse Data
LDQUANTS Laser Disdrometer Quantities Browse Data
MAWS Automatic Weather Station Browse Data
MET Surface Meteorological Instrumentation Browse Data
MET-AIR Meteorological Instrumentation aboard Aircraft Browse Data
MFR Multifilter Radiometer Browse Data
MFRSR Multifilter Rotating Shadowband Radiometer Browse Data
MFRSRAOD1MICH MFRSR: derived AOD using the first Michalsky algorithm Browse Data
MFRSRCLDOD Cloud Optical Properties from MFRSR Using Min Algorithm Browse Data
MPL Micropulse Lidar Browse Data
MPLCMASK Cloud mask from Micropulse Lidar Browse Data
MWR3C Microwave Radiometer, 3 Channel Browse Data
MWRP Microwave Radiometer Profiler Browse Data
MWRRETV2 MWR Retrievals with MWRRET Version 2 Browse Data
NAV-AIR Navigational Location, Motion, and Attitude for Airborne Platforms Browse Data
NAVMET-AIR Navigation and Met Data from multiple sensors on airborne platform Browse Data
NEPHELOMETER Nephelometer Browse Data
NEPHELOMETER-AIR 3-Wavelength integrating nephelometer aboard aircraft Browse Data
OZONE Ozone Monitor Browse Data
OZONE-AIR Ozone Monitor aboard Aircraft Browse Data
PBLHT Planetary Boundary Layer Height Browse Data
PCASP-AIR Passive cavity aerosol spectrometer aboard aircraft Browse Data
PSAP Particle Soot Absorption Photometer Browse Data
PSAP-AIR Particle soot absorption photometer aboard aircraft Browse Data
QCECOR Quality Controlled Eddy Correlation Flux Measurement Browse Data
QCRAD Data Quality Assessment for ARM Radiation Data Browse Data
RADFLUXANAL Radiative Flux Analysis Browse Data
RAIN Rain Gauge Browse Data
RL Raman Lidar Browse Data
RLPROF Raman LIDAR Vertical Profiles Browse Data
RLPROF-FEX Raman Lidar Vertical Profiles Feature Detection and Extinction Browse Data
RLPROFMR Raman Lidar Mixing Ratio Browse Data
RLPROFTEMP Raman Lidar Temperature VAP Browse Data
RWP Radar Wind Profiler Browse Data
SACRADVVAD SACR Advance Velocity Azimuth Display Browse Data
SEBS Surface Energy Balance System Browse Data
SKYRAD Sky Radiometers on Stand for Downwelling Radiation Browse Data
SONDE Balloon-Borne Sounding System Browse Data
SONDEGRID Gridded Sonde VAP Product Browse Data
SP2-AIR Single Particle Soot Photometer aboard aircraft Browse Data
SWS Shortwave Spectroradiometer Browse Data
TSI Total Sky Imager Browse Data
UHSAS Ultra-High Sensitivity Aerosol Spectrometer Browse Data
VARANAL Constrained Variational Analysis Browse Data
VDIS Video Disdrometer Browse Data
VISST Minnis Cloud Products Using Visst Algorithm Browse Data
WB Weighing Bucket Precipitation Gauge Browse Data
WSACR W-band Scanning ARM Cloud Radar Browse Data
XSAPR X-Band Scanning ARM Precipitation Radar Browse Data