The High Latitude Monitoring Station (HLMS) VHF auroral radar is located at Elmendorf Air Force base near Anchorage, Alaska. The radar operates at a frequency of 50 MHz and measures reflections from auroral structures in the E-region of the ionosphere over Fairbanks, Poker Flat, and Fort Yukon using a single beam, as shown above. The measurements cover a line-of-sight range of 200-1200 km from the radar, divided into 40 range gates of 25 km each.
To receive a reflection, the radar pulse must strike a reflective structure (e.g., field-aligned ionization) which is nearly perpendicular to the radar beam. The geometry of this magnetic aspect angle is as follows:
During active periods, the auroral region moves north and south due to geomagnetic substorms. A typical day of activity is shown in the following plot of the radar returns versus time:
You can view these summary plots of recent radar data using the visual data catalogs listed in the HLMS Auroral Radar index.
This page last updated Monday, November 04, 2002 at 06:01 PM by Ed Hoch.