Atmospheric Radiation Measurement Climate Research Facility US Department of Energy
 
 

MASRAD: Cloud Study from the 2NFOV at Pt. Reyes Field Campaign

2 June 2005 - 30 September 2005

Lead Scientist: Warren Wiscombe

Observatory: amf, pye

Cloud optical depth is one of the most important cloud optical properties, and vital for any cloud-radiation parameterization. Our ARM Science Team project has pioneered an algorithm to retrieve cloud optical depth in a fully three-dimensional cloud situation using zenith radiances from the ARM ground-based passive two-channel (673 and 870nm) Narrow Field-Of-View radiometer, called the 2NFOV. The underlying principle of this algorithm is that clouds have nearly identical optical properties in these two channels while there is a strong spectral contrast in vegetated surface reflectance between the two channels. Based on the resulting very different surface-cloud reflection interactions in these two channels, this algorithm retrieves not only cloud optical depth, but also a “radiation-effective cloud fraction” that is valuable for the climate modeling community.

Due to the one-second time resolution of 2NFOV measurements, for the first time we are able to capture local, rapid changes in 3D cloud structures at the natural time scale of clouds. We have applied this algorithm to one month of 2NFOV measurements at the ARM Southern Great Plains site, and compared retrievals with those estimated from other instruments. This algorithm shows an excellent ability to retrieve cloud properties in various cloud situations, while retrievals based on solar flux and on microwaves have serious limitations. We expect to have extensive comparisons with a larger data set from the Pt. Reyes field campaign to further validate this algorithm, and to advance our understanding of cloud property statistics. Pt. Reyes was ideal for our work because of the high abundance of clouds and because competing retrieval algorithms work best for low stratocumulus clouds and thus are most able to furnish comparison data for our method.

Timeline

  • Parent Campaign
  • Sibling Campaign

2010

Ching J, N Riemer, M Dunn, and M Miller. 2010. In-cloud turbulence structure of marine stratocumulus.

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.

Voyles J. 2005. 2005 Annual Report. Ed. by Roeder, L, DOE ARM Climate Research Facility. DOE/SC-ARM-0507. 10.2172/876681.


View All Related Publications

Campaign Data Sets

IOP Participant Data Source Name Final Data
Warren Wiscombe Narrow Field of View Sensor 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