Upgrade to Millimeter Wave Cloud Radar Increases Volume of Data Collection

 
Published: 15 May 2004

In mid-April, hardware and software upgrades to the millimeter wave cloud radar (MMCR) at the ARM Climate Research Facility’s North Slope of Alaska (NSA) were completed. Hardware upgrades included replacing the OS/2 and Solaris computers with two Windows 2000 computers. One of these computers is for the MMCR radar. It now has a new digital signal processing board that allows much more efficient processing of the radar return signals, resulting in higher temporal resolution. The receiver was also upgraded from a 12 bit to 14 bit analog-to-digital converter. Software on the MMCR radar computer was upgraded to run a modified version of Vaisala’s LAP-XM software for controlling and acquiring the radar data. The other computer, for managing the MMCR data, monitors the system, controls calibration, and makes the processed radar “moments” data available to the site data system.

The MMCR probes the extent and composition of clouds at millimeter wavelengths. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). It also reports radar reflectivity of the atmosphere up to 20 km, and possesses a doppler capability that allows the measurement of cloud constituent vertical velocities. As a result of the MMCR upgrade, NSA operations staff are collecting 4 to 5 times the moments data compared to the old system, and are now recording radar spectra data continuously on a separate Firewire hard drive.