Operations Updates
ARM Climate Research Facility Operations Update - December 15, 2007
This bimonthly report provides a brief summary of significant accomplishments and activities in the operations area of the ARM Climate Research Facility (ACRF).
Radar Antenna Replacement Effort Begins at Barrow
On November 28, 2007, ACRF operations and engineering staff braved -15°F weather to install the new radar antenna at Barrow. After lifting the antenna via crane onto the roof of the skydeck, the gloves had to come off to securely fasten all the tiny connecting screws and bolts—brrrrr!
For estimates of cloud boundaries, there is no better capability than the millimeter wave cloud radar (MMCR). This sophisticated radar is part of the standard instrument suite at all of the permanent ACRF sites except for Atqasuk, Alaska. With the 3-meter antenna at the ACF Southern Great Plains (SGP) site more than 11 years old, and the 2-meter antennas in the Arctic and tropics ranging from 8 to 10 years old, all have begun showing signs of wear and tear. In late November, ACRF engineering staff replaced the MMCR antenna at the North Slope of Alaska site in Barrow, beginning a complex-wide effort to replace all the radar antennas throughout the user facility.
The MMCR antenna transmits pulses of millimeter-wave energy into the atmosphere, and receives the return signals that bounce back from cloud particles, bugs, or other objects in the atmosphere. These "retrievals" are used to determine cloud tops, bottoms, reflectivity, and vertical velocities. In the past few years, signs of wear began to appear on the antenna's reflector surface, as well as corrosion on the radar antenna's support struts. And finally, the water repellent coatings for the radomes began to lose their effectiveness. Because refitting, recalibrating, and shipping the old antenna would cost almost as much as installing new equipment, the ACRF sites will all receive new antennas in the coming two years. The new antennas include improved technology for radar echo measurements that help to remove return signals from insects and are useful for precipitation studies. The replacement effort also includes upgrading the radar's data acquisition systems at SGP and Barrow from analog to digital processors for increased sensitivity and efficiency.
External Data Center Completes Storage Expansion
When the XDC began operation in October 1996, it processed 26 datastreams based on 11 external data product collections and transferred an average of 12 GB/month to the ARM Archive. Today, the XDC handles 250 data streams based on 31 external data product collections with an average volume of 473 GB/month, and daily operations continue to require more storage. Click for a larger image.
The ARM External Data Center, or XDC, routinely acquires, processes, and transmits data sets which are scientifically relevant and complementary to ARM data, but originate from external agencies. External data often include large data sets such as model and satellite data, which consume tremendous amounts of storage space, especially when batch processing is required. For example, the XDC recently processed derived satellite data from May 1998 to October 2007; nearly 2 TB data storage capacity was required to complete the processing. In November, the XDC completed a storage system upgrade to support ever-growing file storage needs and increase the speed of large batch processing. The new system consists of the newest mainstream disk technology called SATA disk arrays. This disk system provides fault tolerance (data will not be affected in case of a disk failure) and 9 TB of backup storage capacity.
The new system was put into place in phases, beginning with replacing old Sun systems with new rack-mounted servers that provide database, data transfer, and backup functions. Then the backup system was upgraded to provide both disk-to-disk and disk-to-tape backups. The disk-to-tape backup capacity is now 25 TB, and can be expanded to 33 TB. Four servers were added to the rack to handle increased web services and satellite data processing. And finally, the old disk storage arrays were replaced with new SATA arrays.
ACRF Exhibit Draws Diverse Crowd at American Geophysical Union Meeting
Jennifer Delamere talks about her research experiences using the ARM Climate Research Facility with an interested researcher at the fall meeting of the American Geophysical Union.
With an updated display and new informational materials, the ACRF joined more than 160 exhibitors at the annual fall meeting of the American Geophysical Union in San Francisco. About 15,000 researchers, teachers, students, and consultants from all over the world attended the weeklong event, held December 10-14, to discuss and learn about the latest issues in all areas of Earth and space sciences. This is the fourth year that ACRF has sponsored an exhibit during the meeting.
Visitors from as far away as Tibet, Korea, and Tasmania visited the ACRF booth. Most visitors were interested in learning about the scope of the user facility, the kind of measurements obtained by the instruments, recent field campaigns, and how to access data from the ARM Archive. When not presenting their research, ARM scientists spent time at the booth throughout the meeting to assist in answering questions. In the poster sessions and oral presentations, research results based on data from the ACRF covered science in areas such as cloud and radiation interactions, aerosol properties and effects, land surface flux, modeling, and research capabilities. Data from ACRF field campaigns in Alaska, Australia, Oklahoma, and Africa were also featured in several posters and presentations.
