The PFISR IPY Observations of Ionospheric Climate and Weather

Abstract

The recently commissioned Poker Flat Incoherent Scatter Radar (PFISR) began a continuous operation measurement program for the duration of the International Polar Year (IPY). The IPY began on 1 March 2007 and is an 18-month period of intense polar study. PFISR began its IPY campaign on 1 March 2007 and this paper describes the first 10 months of observations. The PFISR IPY science goals revolve around distinguishing between ionospheric climate and weather variability, and to determine the relative role of geomagnetic weather from the magnetosphere versus that driven from the atmosphere below. This latter goal may well be aided by the fact that the IPY period is at solar minimum, a time when major geomagnetic activity occurrence should be minimized. However, as nature would have it once the IPY observations began it was found that geomagnetic activity was a recurrent feature lasting the entire 10 months being discussed here. The PFISR IPY database will also be used as a long-term fiducial data set against which ionospheric models are to be compared. Hence, this paper provides a documentation of the contents of the database. Case studies as well as statistical studies of how the ionospheric climate and weather can be separated are presented. A particular emphasis is placed upon the F-region ion temperature observations. These appear to provide a very direct measure of geomagnetic energy input to the ionosphere–thermosphere system. Examples are shown in which 150 K F-region ion temperature increases are associated with very moderate geomagnetic disturbances in which the daily average 3-h Kp is only 2.5.