Operations Updates
ARM Climate Research Facility Operations Update - February 29, 2008
This bimonthly report provides a brief summary of significant accomplishments and activities in the operations area of the ARM Climate Research Facility (ACRF).
Scout Team Scopes Out Sites for 2009 Field Campaign in Chile
At an elevation of 5320 meters, this location on Toco Mountain is one of the preferred sites identified by the scout team. Click for a larger version.
In February, a four-person scout team spent two weeks in Chile conducting initial site surveys and meeting with local contacts in preparation for phase two of the Radiative Heating in Underexplored Bands Campaign, or RHUBC-II. Planned to take place on the Chajnantor plateau between August and October 2009, this offsite field campaign will use spare ARM instruments, as well as guest instruments, to retrieve infrared radiation measurements across a broad portion of in the electromagnetic spectrum, including the elusive 17-100 µm and 6.7 µm regions. Combined with data from RHUBC in 2007, these hard-to-obtain measurements will be used to refine radiative calculations used in global climate models.
After their arrival in Santiago, the team spent two days meeting with Chilean government and administrators for the primary observatory on the Chajnantor plateau and talking with professors at the University of Chile. These contacts provided useful info about protocol, safety, and environmental conditions on the plateau. They then traveled to San Pedro de Atacama—the nearest town to the plateau—where they spent one day acclimating to the 2500-meter altitude and four days touring sites on the plateau and associated mountains at 5000-5650 meters. The team identified and prioritized potential sites based on scientific interest and operations feasibility, resulting in several very promising options.
The team also met with local technicians associated with the existing plateau observatories that will likely provide valuable assistance leading up to and during the deployment. The group then traveled to Valparaiso (an hours drive from Santiago) to meet with researchers associated with the plateau observatories before returning home. Based on their findings during this trip, the team will decide on a final deployment location and proceed with the necessary logistics arrangements.
Radar Focus Group Zeroes in on Data Quality
On the roof of the radar instrument shelter at the ACRF Southern Great Plains site, antennas for the W-band ARM Cloud Radar (rectangular white box) and millimeter wavelength cloud radar (conical cylinder) send data to their respective computer systems inside the shelter. Click for a larger version.
In 2007, the ACRF established a Radar Focus Group to address strategic needs related to the use of radars as a key component of the ACRF instrument suite. Based on needs identified by this group, a smaller team of science, engineering, and data quality staff met in early February in Santa Barbara, California, to determine methods that the Data Quality (DQ) Office can use to routinely monitor operation of the user facility's current cloud radars—namely, the millimeter wavelength cloud radar (MMCR) and W-band ARM Cloud Radar (WACR). The team's goal is to develop additional tools that automatically notify operations and engineering staff when problems with the radar occur, or ideally, recognize trends that allow engineering staff to address problems prior to data compromise.
In preparation for the meeting, ACRF engineering staff independently processed all of the existing MMCR data—about 2 terabytes—to try and identify known periods of problems with specific parameters recorded in the radar data. Some of the data analyses showed problems, but other problems were not easily identifiable. The team plans to establish procedures to routinely monitoring a selection of these parameters and train the DQ Office analysts in the identification of problems associated with the radar's hardware or software.
During the meeting, the group also identified the need to combine data in the operations databases along with handwritten notes recorded by engineering staff. These will be matched by date to the specific parameters that will be plotted on a graph to help show trends. One idea discussed was to overlay labels on the data, with a companion "popup" table that explains the various labels. The group is hoping to implement the ideas discussed during the meeting over the next few years. In particular, they plan to apply any advancements in this area to the MMCRs located at Manus and Nauru Island, which, due to their remoteness, are visited less often by technical personnel.
Wildlife Challenges Lead to Wireless Solutions
As reported in late 2006, a total precipitation sensor (TPS) was installed near the ACRF North Slope of Alaska (NSA) site in Barrow, to provide measurements of boundary layer (surface to 1000-m altitude) environmental conditions. After falling victim to curious and possibly hungry lemmings and other wildlife in the area, the fiber optic cable used to transfer data from the sensor to the Great White instrument shelter was recently replaced with a wireless data acquisition system and virtual access port. This not only negates the possibility of further cable damage from our furry friends, but reduces the potential for water-related damage during peak melting season and allows remote access for monitoring the data.
ACRF operations staff Walter Brower (standing) and Jimmy Ivanoff (kneeling) reinstall the TPS sensor near the Great White Facility in Barrow. Photo by Jessica Cherry. Click for a larger version.
Though covered by snow during the winter, exposure of the 1-km length of fiber optic cable during the summer months clearly presented a temptation to the local animal population. "Lemmings apparently don't respect the fact that this is mil-spec armored cable," said Mark Ivey, ACRF Site Manager for the NSA locale. Enclosing the cable within buried conduit was considered, but operations and engineering staff proposed another solution: a point-to-multipoint weblink to enhance the existing wireless system for the Great White towercam. Because the towercam and the TPS are in nearly opposite directions from the Great White, the devices required reprogramming of the wireless bridge at the Great White for relocation near the TPS, and the purchase of a more sophisticated wireless bridge to support an omni-directional antenna. Not only was this solution more cost effective and less disruptive to the environment than the buried conduit option, it allows for easier relocation or addition of other sensors.
An Ethernet control device now provides a virtual port from which the software acquires data from the TPS. Operations staff are updating the sensor's installation manual to reflect the recent upgrades, and data ingest using the new wireless data acquisition system has begun. A short run of metal conduit to protect exposed wires at the sensor is planned for spring, when temperatures warm up enough to keep the cables flexible during handling.
Final Preparations Underway for Arctic Aerosol Field Campaign
In this flight pattern, the Convair-580 takes off from Barrow (BR) after refueling, flies several legs within clouds between 1-2 km high, then returns to base at Fairbanks. Click for a larger image.
With just one month before the start of the Indirect and Semi-direct Aerosol Campaign (ISDAC), the ARM Aerial Vehicles Program (AVP) is finalizing the necessary contract arrangements, instrumentation integration activities, and flight planning scenarios. More than 80 scientists and logistics personnel will gather in Fairbanks, Alaska, to participate in the April campaign, which will obtain airborne and ground-based measurements of aerosol and cloud properties in the vicinity of the ACRF site in Barrow, Alaska. These data will be used to improve models that simulate Arctic cloud processes.
A Convair-580 provided by the National Research Council (NRC) of Canada will carry more than 40 instruments for measuring cloud and aerosol properties during ISDAC. The AVP team worked with NRC to establish the precise weight of the payload and adjust the final instrument package to stay within the combined fuel/payload weights limits. Some of the instruments have never been deployed on an aircraft science mission before. One such instrument is the Single Particle Laser Ablation Time-of-flight mass spectrometer, or SPLAT, which obtains size-resolved aerosol composition data. A successful maiden voyage on Battelle's Gulfstream-1 with the instrument in early February was welcome news to the ISDAC science team. Dozens of other instruments in addition to the SPLAT will be installed on the Convair at its home base in Ottawa, Canada, before it makes the transit flight to Fairbanks in late March.
Related NOAA and NASA aircraft studies based out of Fairbanks at the same time as ISDAC required additional coordination for both logistics and flight planning. Negotiations and agreements for accommodations, hangar and office space were completed in February, and nearly a dozen coordinated flights plans were developed among the agencies to balance their respective science objectives with weather conditions and safety. These plans are a requirement for approval of the flight safety plan required by DOE, and were used February 28-29 during a flight planning meeting in Ottawa, Canada. This meeting provided the ISDAC science team an opportunity for to simulate the forecasting and mission selection process that will occur daily during the month-long campaign. Final instrument integration activities and test flights were also discussed.
