Operations Updates
ARM Climate Research Facility Operations Update - January 31, 2005
This bimonthly report provides a brief summary of significant accomplishments and activities in the operations area of the ARM Climate Research Facility (ACRF).
Mobile Facility Beta Testing Complete; System Headed to California Seashore
A key addition to the ACRF scientific infrastructure is ready to roll...literally. In February, the ARM Mobile Facility (AMF) is being packed up and shipped from Richland, Washington, to the Point Reyes National Seashore north of San Francisco, California. There, it will be reassembled in preparation for its first deployment as part of a 6-month experiment to study the microphysical characteristics of marine stratus clouds, and in particular, marine stratus drizzle processes. Throughout the deployment, the AMF will accommodate aerosol observing equipment for National Oceanic and Atmospheric Administration (NOAA) researchers co-sponsored by ARM and the DOE Aerosol Science Program. Because similar equipment has been proposed as a future baseline AMF capability, this collaboration represents a prototype deployment with NOAA equipment.
The ARM Mobile Facility gets checked over prior to the start of beta testing in January 2004.
After a year of engineering design, procurement, and construction, beta testing of the AMF began on January 3, 2004, at DOE's Pacific Northwest National Laboratory. During the test period, ACRF operations staff monitored the station during normal work hours. They also launched one RS-92 radiosonde per day, requiring local notices to be in place with the Federal Aviation Administration one hour prior to each launch. The beta test allows ACRF operations and engineering staff to ensure proper operation of the full complement of instrumentation and to troubleshoot the data collection and transmission systems prior to the AMF's first deployment.
Meanwhile, preparations continued for the Pt. Reyes deployment. As part of the permit review, the AMF Site Scientist gave a well-received presentation of the AMF to National Park Service (NPS) officials in November 2004. All permits were subsequently granted and ACRF infrastructure staff began coordinating their work with the NPS personnel. In December, they worked with NPS personnel to clean a vacant building, complete with an operational well and septic system, for the deployment team to use while on site. They also made plans to install a fence around the deployment site to keep nearby cattle away from the instruments. In January, the electrical infrastructure was installed, and a schedule for site operations and communications was established.
New Shortwave Spectrometer Performs Well in Field Evaluation
These full spectrum plots show radiance data collected by the SWS at five time intervals over the course of four consecutive days. The scattering profiles indicate three cloudy days (Nov. 21-23) and one clear day (Nov. 24). Click for a larger version.
From November 19, 2004, to December 17, 2004, a new Shortwave Spectrometer (SWS) was deployed at the ACRF Southern Great Plains (SGP) site as part of the engineering design process. The instrument, a modified version of the National Aeronautic and Space Administration's airborne Solar Spectral Flux Radiometer, is configured in a zenith-viewing radiance mode with a 3° field-of-view. It is designed to collect measurements of wavelengths ranging from 350-1700nm, with a resolution of 8-12nm. These measurements will be used in a Quality Measurement Experiment to evaluate and improve models of shortwave spectral radiance. A similar evaluation was completed by ARM for longwave spectral radiance data from the Atmospheric Emitted Radiance Interferometer spectrometer.
Operating uninterrupted throughout the 29-day evaluation period, the SWS collected radiance spectra at a rate of 1 Hz. Approximately 36,000 spectra per day were obtained during daylight hours. To establish instrument offsets and noise levels, "dark signal"—the signal measured by the instrument when the optics are blocked and no light gets in—was obtained during business working days with the help of the SGP site personnel. All data were retrieved and monitored at NASA's Ames Laboratory via a high-speed network connection. Comparisons between SWS and ARM's Total Sky Imager qualitatively demonstrated good correlation between the measurements.
The late fall deployment provided a wide variety of weather conditions for operators to test the robustness of the SWS system. This month-long deployment will allow scientists and engineers to evaluate the proposed design and refine it, if necessary, prior to committing funds for the development/construction of the new instrument.
