Observations of mesospheric ice particles from the ALWIN radar and SOFIE

Ice particles near the polar summer mesopause are observed visually, by radar, and using various remote and in-situ techniques. This study investigates concurrent radar observations from the ALOMAR wind (ALWIN) radar and measurements from the Solar Occultation For Ice Experiment (SOFIE) onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite. Mesospheric ice observations from radar are known as polar mesosphere summer echoes (PMSE), while satellite observations of these particles are referred to as polar mesospheric clouds (PMC). Comparisons of concurrent SOFIE and ALWIN observations indicate that PMC and PMSE are different manifestations of the same ice layer. The vertical extent of the ice layer is similar in the ALWIN and SOFIE records, with the primary difference that the PMSE signal peaks about 2 km higher than the PMC signal. SOFIE observations of ice particle size and concentration are used to test simple empirical proxies for PMSE which have previously been suggested based on a small number of rocket observations and microphysical modeling.