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.