Calibrated measurements of PMSE strengths at three different locations observed with SKiYMET radars and narrow beam VHF radars

While PMSE are a well recognized summer phenomenon in the polar regions, debate still exists on their relative strengths as function of latitude and longitude. Different radar design and noise calibration procedures complicate comparison between sites. Here, we use radars at multiple sites, some with a common design, to better determine the radar backscatter cross-section, and hence compare PMSE strengths. Five radars at Yellowknife (62.5∘N62.5∘N, 114.3∘W114.3∘W), Andenes (69.3∘N69.3∘N, 16.0∘E16.0∘E) and Resolute Bay (75.0∘N75.0∘N, 95.0∘W95.0∘W) in the northern hemisphere were used to observe PMSE during July 2005. At Yellowknife, data were collected for thirteen days. In other two locations data were collected continuously for the full month of July. The radars were independently calibrated using the same method, and absolute backscatter cross-sections were determined. Resolute Bay is close to both the magnetic and geomagnetic north poles, and inside the auroral oval, while the other two sites are under the auroral oval on some occasions. Inter-comparison of the calibrated observations indicates that the strength of the PMSE at Yellowknife and Andenes are comparable, and both are significantly stronger than at Resolute Bay.