Atmospheric Radiation Measurement Climate Research Facility US Department of Energy
 
 

MASRAD - Aerosol Optical Properties

29 June 2005 - 30 August 2005

Lead Scientist: Anthony Strawa

Observatory: amf, pye

Principal Investigators: J. Ogren, C. Berkowitz, R. Halthore, A. Laskin, A. Strawa, J. Wang, A. Wexler

As part of the ARM Mobile Facility (AMF) deployment to Point Reyes, CA in the spring and summer of 2005, a suite of instrumentation was installed to measure the chemical, physical and optical properties of aerosol particles at the site. This deployment took part in conjunction with the MArine Stratus Radiation Aerosol and Drizzle (MASRAD) study. Point Reyes has been called one of the foggiest places on earth, and while that may be hyperbole, the foggy nature of the locale provided an excellent opportunity to study the inter-relationship between aerosol particle and cloud droplet properties using a surface-based observing platform. In addition to the cloud/aerosol research, several other complementary aerosol projects took place at the site including (a) an intercomparison of the Cadenza cavity ring down technique (funded by NASA) and PSAP for measuring light absorption (b) coordinated ultrafine and chemistry aerosol particle measurements and (c) measurement of aerosol optical, physical and chemical properties during cloud free conditions at a marine site. The measurements and specific scientific questions addressed are described below:

Several of the participants were funded by DOE’s Aerosol Science Program (ASP). A major focus of the ASP research is the interaction between clouds and aerosol particles. To study this, a counter-flow virtual impactor (CVI) was used to selectively sample cloud drops. The CVI takes advantage of the higher inertia of the cloud drops to draw them through a slight counter-flow into the system while smaller particles are unable to overcome the counter-flow. Downstream of the CVI the cloud drops were evaporated and the resulting cloud condensation nuclei (CCN) was fed to aerosol instrumentation to characterize their optical, chemical, physical (size, number and shape) and cloud activation properties. In parallel with the CVI system, a second aerosol inlet with an upper cut-off size of 5 micrometers sampled the interstitial aerosol – i.e., the particles which have not activated to cloud droplets. Instrumentation downstream of this interstitial inlet was similar to that downstream of the CVI and also included an SMPS for sizing the particles and a humidograph for assessing hygroscopic growth of the aerosol. By running these two inlet systems in tandem the following scientific questions were addressed: • What are the differences in chemistry between interstitial and activated aerosol? • What role do organics play in aerosol formation and activation? • How do clouds change the optical properties of the aerosol? • How do the CCN spectra differ between interstitial and activated aerosol? • Can CCN closure be obtained?

While the research described above focused on aerosol-cloud relationships, many of the deployed instruments sampled continuously, thus providing characterization of cloud-free summertime aerosol at Point Reyes. This data set was used to address the following scientific questions: • How do light absorption measurement methods compare under a variety of sampling conditions (e.g., what is the influence of particle size on instrument performance?) • What are the chemical, optical, and physical properties of the aerosol at a marine site during fog- free conditions? • What can be learned about the chemical species and processes controlling homogeneous aerosol nucleation processes in the coastal marine boundary layer?

A number of different types of models, covering processes ranging from radiative transfer to marine aerosol microphysics to cloud droplet formation were used to interpret the measurements. Results from this study are relevant to improving the parameterization of aerosol forcing (direct and indirect effect) in climate models.

Timeline

  • Parent Campaign
  • Sibling Campaign

2011

Berkowitz CM, LK Berg, XY Yu, ML Alexander, A Laskin, RA Zaveri, BT Jobson, E Andrews, and JA Ogren. 2011. "The influence of fog and airmass history on aerosol optical, physical and chemical properties at Pt. Reyes National Seashore." Atmospheric Environment, 45(15), 10.1016/j.atmosenv.2011.02.016.

2008

Kim B, MA Miller, SE Schwartz, Y Liu, and Q Min. 2008. "The role of adiabaticity in the aerosol first indirect effect." Journal of Geophysical Research: Atmospheres, 113(D5), 10.1029/2007jd008961.

2007

Chiu JC, A Marshak, W Wiscombe, SC Valencia, and EJ Welton. 2007. "Cloud Optical Depth Retrievals from Solar Background "Signals" of Micropulse Lidars." IEEE Geoscience and Remote Sensing Letters, 4(3), 10.1109/lgrs.2007.896722.

2005

Miller MA, A Bucholtz, B Albrecht, and P Kollias. 2005. Marine Stratus Radiation, Aerosol, and Drizzle (MASRAD) Science Plan. Ed. by Carrothers, D, U.S. Department of Energy. DOE/ER-ARM-0501.


View All Related Publications

Campaign Data Sets

IOP Participant Data Source Name Final Data
Anthony Strawa CADENZA Order Data

PYE Data Sources

Name Full Name Browse Data
AERI Atmospheric Emitted Radiance Interferometer Browse Data
AERINF AERI Noise Filtered Browse Data
AIP Aerosol Intensive Properties Browse Data
AOD-MFRSR Aerosol Optical Depth (AOD) derived from MFRSR measurements Browse Data
AOS 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
ECMWFDIAG European Centre for Medium Range Weather Forecasts Diagnostic Analyses Browse Data
ECOR Eddy Correlation Flux Measurement System Browse Data
GNDRAD Ground Radiometers on Stand for Upwelling Radiation Browse Data
MERGESONDE Merged Sounding Browse Data
MET Surface Meteorological Instrumentation Browse Data
MFRSR Multifilter Rotating Shadowband Radiometer Browse Data
MFRSRCLDOD Cloud Optical Properties from MFRSR Using Min Algorithm Browse Data
MOLTS Model Output Location Time Series Browse Data
MPL Micropulse Lidar Browse Data
MWR Microwave Radiometer Browse Data
MWRP Microwave Radiometer Profiler Browse Data
MWRRET MWR Retrievals Browse Data
NCEPGFS National Centers for Environment Prediction Global Forecast System Browse Data
NFOV Narrow Field of View Zenith Radiometer Browse Data
PBLHT Planetary Boundary Layer Height 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
RUC Rapid Update Cycle Model Data Browse Data
SKYRAD Sky Radiometers on Stand for Downwelling Radiation Browse Data
SONDE Balloon-Borne Sounding System Browse Data
SONDEADJUST Sonde Adjust Browse Data
TSI Total Sky Imager Browse Data
VISST Minnis Cloud Products Using Visst Algorithm Browse Data