Simultaneous PMC and PMSE observations with a ground-based lidar and SuperDARN HF radar at Syowa Station, Antarctica

H Suzuki,M K Ejiri,M Tsutsumi,M Abo,T Ogawa,N Sato,T D Kawahara,Y Tomikawa,T Nakamura,A S Yukimatu

doi:10.5194/angeo-31-1793-2013

H Suzuki, M K Ejiri + Show 8 more

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https://doi.org/10.5194/angeo-31-1793-2013

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Abstract. A Rayleigh–Raman lidar system was installed in January 2011 at Syowa Station, Antarctica (69.0° S, 39.6° E). Polar mesospheric clouds (PMCs) were detected by lidar at around 22:30 UTC (LT −3 h) on 4 February 2011, which was the first day of observation. This was the first detection of PMCs over Syowa Station by lidar. On the same day, a Super Dual Auroral Radar Network (SuperDARN) HF radar with oblique-incidence beams detected polar mesospheric summer echoes (PMSE) between 21:30 and 23:00 UTC. This event is regarded as the last PMC activity around Syowa Station during the austral summer season (2010–2011), since no other PMC signals were detected by lidar in February 2011. This is consistent with results of PMC and mesopause temperature observations by satellite-born instruments of AIM (Aeronomy of Ice in the Mesosphere)/CIPS (Cloud Imaging and Particle Size) and AURA/MLS (Microwave Limb Sounder) and horizontal wind measurements taken by a separate MF radar. Doppler velocity of PMSE observed by the HF radar showed motion toward Syowa Station (westward). This westward motion is consistent with the wind velocities obtained by the MF radar. However, the PMSE region showed horizontal motion from a north-to-south direction during the PMC event. This event indicates that the apparent horizontal motion of the PMSE region can deviate from neutral wind directions and observed Doppler velocities.

Highlights

Polar mesospheric clouds (PMCs), known as noctilucent clouds (NLCs), are the highest altitude clouds in the Earth’s atmosphere, and are produced at very low temperatures below the frost point (< 140 K) in the mesopause region
The horizontal neutral wind velocity at the PMC altitude obtained by MF radar is shown in the bottom-right corner of Fig. 8
The neutral winds measured by the MF radar (Fig. 7) show no large wind shear near the PMC altitude within such a range

Summary

Introduction

Polar mesospheric clouds (PMCs), known as noctilucent clouds (NLCs), are the highest altitude clouds in the Earth’s atmosphere, and are produced at very low temperatures below the frost point (< 140 K) in the mesopause region. The vertical solid our results of PMC occurrence and temperature trends of the lines in the lower panel correspond to centers of sampling mesopause over Syowa Station during the austral summer times.

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