Propagation analysis of mesospheric gravity waves on OH and OI-557.7 nm airglow layers over King Sejong Station, Antarctic Peninsula Hosik Kam 1 , Yong Ha Kim 1 , Takuji Nakamura 2,3 , Masaki Tsutsumi 2,3 , Yoshihiro Tomikawa 2,3 , Masaru Kogure 3,2 , Septi Perwitasari 2 , Jeong-Han Kim 4 1 Department of Astronomy, Space, and Geology, Chungnam National University, Daejeon, South Korea 2 National Institute of Polar Research, Tachikawa, Japan 3 Department of Polar Science, SOKENDAI (The Graduate University for Advanced Studies), Tachikawa, Japan 4 Division of Polar Climate Sciences, Korea Polar Research Institute, Incheon, South Korea 2018. 4. 24. Instituto Nacional de Pesquisas Espaciais, INPE, Contacts: São José dos Campos, SP, Brasil. Hosik Kam: kamhosik@cnu.ac.kr
King Sejong Station (KSS) Geographical Location: 62 ° S, 58 ° W All-Sky Meteor Radar All-sky camera New observatory (Feb 2017) GPS/TEC FPI SATI monitor
Observation All-Sky Camera has been operating since May 2008. multi-wavelength filter wheel to capture airglow at different altitudes. Constituent of Airglow Central Wavelength (nm) Exposure Time (sec) Altitude (km) OH Meinel 720.0 – 820.0 20 87 OI 5577 557.7 150 96 OI 6300 630.0 150 250 Images of Wave feature observed by KSS ASC on 29 April, 2012 All-Sky Meteor Radar has been operating since March 2007. 12 kW Transmit power / 33 MHz frequency Daily detection of 12000 – 40000 meteors Horizontal Wind profiles in 80 – 100 km were derived Sky map of 34884 meteors detected by KSS MR on 8 April, 2016
ASC Observation Duration of KSS ASC observation: March ~ October, 2008~ Criteria for clear condition image sequence ① Duration time of clear condition: Over 1 hour Observed ② Valid region of clear condition: Over 100 pix x 100 pix (~100 km x 100 km) days 2008 92 2009 33 2010 146 2011 171 2012 216 2013 195 2014 210 2015 197 2016 187 2017 X 2018 Observing Total windows of image sequence for analysis in 2013 Total 1,455 + Observed days Clear nights Windows 195 29 31
ASC Data Analysis - Horizontal phase speed PSD distribution 𝐽 ′ /𝐽 0 (= 𝜍 ′ /𝜍 0 ) 𝐽 ′ 𝐽−𝐽 𝐽 0 = 𝐽 Input data : 𝐽 : Temporal mean of image sequence M-transform [Matsuda et al., 2014] 3D-FFT Horizontal wavelength range: 5-100 km Raw OH Raw OI-557.7 ~ 87 km ~ 96km Power Spectrum Density of I’/I 0 (logarithmic scale) Simultaneous analysis for OH & OI-5577 observed on same time & same spatial grid of 31 - image sequence windows Utilizing Matsuda_fft program from NIPR
Results_ Seasonal variation of total PSD 𝑄𝑇𝐸 in each PSD distribution Proxy of Wave activity OH PSD OI-557.7 PSD 𝑄𝑇𝐸 variation over Syowa & Davis station (Contributed from Masaru Kogure (NIPR)) 𝑄𝑇𝐸 variation over KSS Characteristics of seasonal variation of wave activity ( 𝑸𝑻𝑬 ) over KSS 1. Seasonal variation with strong wave activities during winter time. 2. Larger wave activities at KSS than Syowa & Davis station 3. Larger wave activities on OH layer(*) than those of OI-557.7 layer (*)
𝑄𝑇𝐸 in each PSD distribution Results_ 1. Strong activities during winter Proxy of Wave activity OH PSD OI-557.7 PSD • Also shown in Syowa & Davis station. • As various studies, strong activities in winter time at Antarctica. ( Yoshiki and Sato [2000], Venkat Ratnam et al. [2004], Whiteway et al. [1997], Baumgaertner and McDonald [2007], Jiang et al. [2005] … ) • From ASC airglow raw images (OH) over KSS, 𝑄𝑇𝐸 variation over KSS 2013.6.11 2013.3.7 ASC images in winter show non-monochromatic 𝑄𝑇𝐸 variation over Syowa & Davis station waves rather than fall and spring, relatively. (Contributed from Masaru Kogure (NIPR))
𝑄𝑇𝐸 in each PSD distribution Results_ 1. Strong activities during winter Proxy of Wave activity OH PSD OI-557.7 PSD • Also shown in Syowa & Davis station. • As various studies, strong activities in winter time at Antarctica. ( Yoshiki and Sato [2000], Venkat Ratnam et al. [2004], Whiteway et al. [1997], Baumgaertner and McDonald [2007], Jiang et al. [2005] … ) • From PSD analysis from ASC images over KSS, 𝑄𝑇𝐸 variation over KSS 2013.6.11 2013.3.7 As a result, expanded or homogeneous distribution from non-monochromatic waves in winter images 𝑄𝑇𝐸 variation over Syowa & Davis station Might be Secondary GWs or breaking GWs (Contributed from Masaru Kogure (NIPR))
Results_ 1. Strong activities during winter 2013.6.11 2013.4.17 2013.3.13 2013.5.15 2013.7.10 2013.8.8 2013.9.6 2013.10.5 OH PSD distribution near monthly 15th Tendency of non-monochromatic waves on ASC images during winter. Expanded or homogeneous features in PSD distribution during winter time contributed to enhance the wave activities ( 𝑄𝑇𝐸 ). If these features were induced by secondary GWs, the strong activities during winter in seasonal variation of 𝑄𝑇𝐸 indicated that the secondary GWs were captured on ASC over Antarctic peninsula winter MLT region. Around 60S at winter, secondary GWs are generated in the stratosphere and lower mesosphere ( Becker at al. [2017]).
Results_ 2. Stronger wave activities over KSS than Syowa & Davis station KSS Magnitude range of 𝑄𝑇𝐸 : 10 -4 to 10 -2 • Syowa Magnitude range of 𝑄𝑇𝐸 : 10 -4 to 10 -3 • Davis Magnitude range of 𝑄𝑇𝐸 : 10 -5 to 10 -3 • • Antarctic Peninsula is widely known as GW hot spot. • As various studies, strong wave activities over Antarctic Peninsula. ( Baumgaertner and McDonald [2007] ; Alexander et al. [2007] ; Hertzog et al. [2008] ; Plougonven et al. [2008] … ) 𝑄𝑇𝐸 variation over KSS Six major SH GW hot spots [Becker et al. (2017)] 𝑄𝑇𝐸 variation over Syowa & Davis station Sub-tropical Andes / Antarctic Peninsula / Southern Andes / (Contributed from Masaru Kogure (NIPR)) Tasmania / Ross ice Shelf / Southern edge of Africa
Results_ 3. Stronger OH PSD than OI-557.7 PSD logarithmic scale OH PSD OI-557.7 PSD 𝑄𝑇𝐸 variation over KSS (top) and Difference 𝑄𝑇𝐸 between OH PSD and OI-557.7 PSD (bottom) Generally, 𝑄𝑇𝐸 of OH has a larger power than 𝑄𝑇𝐸 of OI-557.7. If GWs have upward propagation from OH airglow layer (~87 km) to OI-557.7 nm airglow layer (~96 km), it means that the PSD of the waves are weakened. Difference PSD between OH PSD and OI-557.7 PSD In other word, the 𝑄𝑇𝐸 of waves loses the power when waves (OH PSD minus OI-557.7 PSD) nonlogarithmic scale propagate through MLT region.
Results_ 3. Stronger OH PSD than OI-557.7 PSD Critical level filtering case Critical level filtering Inference from Blocking Diagram using horizontal winds Blocking diagram = 𝑑 ℎ − (𝑣𝑑𝑝𝑡𝜄 + 𝑤𝑡𝑗𝑜𝜄) 𝑑 ℎ 𝑣 : zonal wind 𝑤 : meridional wind 𝜄 : propagation direction (0 ° ~360 ° ) OH PSD logarithmic scale OI-557.7 PSD 2013.4.12 nonlogarithmic scale Blocking diagram from 86 km to 96 km with 2 km of height bin from KSS MR winds with 15 min of time resolution Difference PSD between OH PSD and OI-557.7 PSD which is corresponding to clear image sequence window time. (OH PSD minus OI-557.7 PSD)
Results_ 3. Stronger OH PSD than OI-557.7 PSD Critical level filtering case nonlogarithmic scale OH PSD OI-557.7 PSD logarithmic scale 2013.3.24 Blocking diagram from KSS MR Difference PSD (OH PSD – OI PSD) Main difference PSD Northwest with 10-20m/s 88-96 km of blocking diagram
Results_ 3. Stronger OH PSD than OI-557.7 PSD Critical level filtering case nonlogarithmic scale OH PSD OI-557.7 PSD logarithmic scale 2013.4.17 Blocking diagram from KSS MR Difference PSD (OH PSD – OI PSD) Main difference region of PSD Northwest with 10-20m/s 88-96 km of blocking diagram
Results_ 3. Stronger OH PSD than OI-557.7 PSD Critical level filtering case nonlogarithmic scale OH PSD OI-557.7 PSD logarithmic scale 2013.5.15 Blocking diagram from KSS MR Difference PSD (OH PSD – OI PSD) Main difference region of PSD 1) Northeast with 10-50m/s & 2) Southeast with 20-40m/s 1) 88-90km of blocking diagram & 2) 94-96km of blocking diagram
Results_ 3. Stronger OH PSD than OI-557.7 PSD Critical level filtering case nonlogarithmic scale OH PSD OI-557.7 PSD logarithmic scale 2013.10.5 Blocking diagram from KSS MR Difference PSD (OH PSD – OI PSD) Main difference region of PSD Southwest with 30-50m/s 90-96 km of blocking diagram
Results_ 3. Stronger OH PSD than OI-557.7 PSD logarithmic scale OH PSD OI-557.7 PSD 𝑄𝑇𝐸 variation over KSS (top) and Difference 𝑄𝑇𝐸 between OH PSD and OI-557.7 PSD (bottom) Total clear windows: 31 Number of larger 𝑄𝑇𝐸 of OH than 𝑄𝑇𝐸 of OI-557.7: 27 Number of Difference PSD similar with wind blocking diagram: 16 About half of event windows show attenuated power of waves in Difference PSD between OH PSD and OI-557.7 PSD (OH PSD minus OI-557.7 PSD) OI-557.7 nm images probably due to wind filtering when waves nonlogarithmic scale propagated through MLT region.
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