Saturday, 27 July 2013

Polar mesospheric summer echoes

This week, we've been supporting EISCAT observations of polar mesospheric summer echoes (PMSE). These are unusually strong VHF radar reflections ("echoes") that occur at around 80-85 km altitude (hence "mesospheric"). This is the altitude of what is called the "D-Region" of the ionosphere, and it is a similar altitude to that where noctilucent clouds are found. They are noted at high latitudes ("polar") from June to August in the north (thus "summer").

PMSE are not well understood and remain an area of active research. The campaign that is currently running is making use of multiple facilities in Norway, Sweden and Finland, and KAIRA is playing its role, observing the radar echoes from the EISCAT VHF using a multibeam experiment. In total 60 HBA beamlets (20 pointing directions x 3 subbands each) are being recorded, at raw signal levels using our local pipeline programme (KLP).

We hope that the additional spatial information provided by KAIRA will assist the scientists who are researching this phenomenon. Hopefully, we'll be able to report some successful results soon.

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