Simultaneous observations of noctilucent clouds and polar mesosphere summer echoes at Syowa Station, Antarctica

Abstract

This paper reports simultaneous observations of visible noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE) at Syowa Station (69°01′S, 38°61′E) in Antarctica. During a 1.5 h interval from 2000 to 2130 UT (2300 to 0030 LT) on Feb. 11, 2009, visible NLC were observed south of Syowa Station. The oblique sounding HF radar of SuperDARN at Syowa Station simultaneously observed peculiar echoes in the closest two range gates. The echoes had a small Doppler velocity and a narrow spectral width, which are consistent with the characteristics of PMSE in the SuperDARN data. The simultaneous appearance of the visible NLC and peculiar near-range echoes observed by the HF radar suggests that the echoes were actually a signature of PMSE in the HF band. In addition, the data from the simultaneous measurements show that the spatial distributions of NLC and PMSE in the HF band were collocated with each other, which implies that oblique sounding HF radar is a useful tool for estimating the two-dimensional horizontal distribution of PMSE.