As reported in July 2005, the W-band ARM Cloud Radar (WACR) is a 95-GHz system designed for a unique purpose – monitoring the radar returns of insects in the lowest 5 km of the atmosphere. This data is used to remove “noise” from the millimeter wavelength cloud radar (MMCR) return signals at the ARM Southern Great Plains (SGP) site. Soon after the WACR began collected data at SGP site in December 2005, its radio frequency (RF) unit was removed for use in the new ARM Mobile Facility. With a new RF unit installed and a subsequent calibration problem solved, the radar is once again in action at the SGP site.
Several months after installing the new RF unit in the WACR, calibration issues presented an obstacle to operations until the source of the problem was identified: the proximity of trees to the calibration tower, located across the road to the north of the SGP Central Facility. To address this issue, a new, larger corner reflector was acquired and installed on the tower, and the RF unit was sent back to the manufacturer (ProSensing) in late August 2006 for additional software work to permit successful calibration. In the meantime, part of the tower was raised to further reduce ground clutter.
The WACR was successfully reinstalled in October 2006, with the detailed radar display featuring multiple screen modes for various health and status readings, and for the standard 1-hour scrolling display of atmospheric response. ARM operations staff reported fine atmospheric detail clearly visible on the computer screen, displaying rain signals before drops even reached the ground. Data comparisons between the WACR and MMCR are underway to ensure proper alignment of the WACR transmitter and MMCR beam.