BY AN ALL-SKY IMAGER AT COMANDATE FERRAZ ANTACTICA STATION (62 S) - - PowerPoint PPT Presentation

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BY AN ALL-SKY IMAGER AT COMANDATE FERRAZ ANTACTICA STATION (62 S) - - PowerPoint PPT Presentation

Sep 17, 2023 271 likes •544 views

THERMOSPHERIC NIGHTIME MSTIDS OBSERVED BY AN ALL-SKY IMAGER AT COMANDATE FERRAZ ANTACTICA STATION (62 S) [1] Wrasse, Cristiano Max; [1] Figueiredo, Cosme Alexandre Barros; [1] Takahashi, Hisao; [1] Bageston, Jos Valentin; [1] Barros, Diego;

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THERMOSPHERIC NIGHTIME MSTIDS OBSERVED BY AN ALL-SKY IMAGER AT COMANDATE FERRAZ ANTACTICA STATION (62 S)

[1] Wrasse, Cristiano Max; [1] Figueiredo, Cosme Alexandre Barros; [1] Takahashi, Hisao; [1] Bageston, José Valentin; [1] Barros, Diego; [1] Gobbi, Delano; [2] Paulino, Igo [1] Instituto Nacional de Pesquisas Espaciais, São José dos Campos, Brazil [2] Universidade Federal de Campina Grande, Campina Grande, PB – Brazil

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Outline

  • Ferraz station at King George Island
  • All-Sky airglow imager
  • Wave Activity over Ferraz Station
  • Summary

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(62.1°S, 58.4°W)

Partial view of King George Island, that is located about 200 km North

  • f the Antarctic Peninsula

Source: 1º Helicopter Squadron for General Employment (Esqd HU-1), Brazilian Navy

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Source: 1º Helicopter Squadron for General Employment (Esqd HU-1), Brazilian Navy

Punta Plaza facility (meteor radar and All-Sky camera)

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Ferraz Station - Punta Plaza Site

Source: J. V. Bageston

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A new all-sky airglow imager with three filters (OH NIR, OI 557.7 and 630.0 nm) was installed at Ferraz Antarctic Station in 2014.

Observing Gravity Waves at Ferraz

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Wave Activity in Mesophere Region

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Wave Activity in Mesophere Region

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Wave Activity in Ionosphere Region

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Wave Activity in Ionosphere Region

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Are these waves related to OH emission?

OH(9-3)

OI Filter used has a Band Wide of 20 Å

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How to ruled out OH Contamination?

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So, no wave was propagating at the mesosphere to NW direction!

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h ~ 100 km obs ~ 30 min Cobs ~ 50 m/s  ~ NW

We used the well know Cross Spectrum Analysis

Horizontal Wavelength Observed Phase Velocity Observed Period

  • Prop. Direction

How to obtained OI 6300 wave parameters?

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Now we applied the method to all observed cases!

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Over all Results

16 h ~75-200 km obs ~ 10-50 min cobs ~ 75-175 m/s NW S

27 waves

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So, what kind of waves are they?

Type Period (min) Wavelength (km) Phase Velocity (m/s) SSTID Few minutes   100 km c  200 m/s MSTID 5    60 minutes   1500 km 100  c  700 m/s LSTID 30 min    ~hours  > 1000 km 300  c  1200 m/s

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When wave structures are observed in the ionospheric parameters, they are called traveling ionospheric disturbances (TIDs). Depending on the size of the TID, they can be called small scale (SSTID), medium scale (MSTID) or large scale (LSTID).

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Comparison with other OI 630 nm observations

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Paulino et al., 2016

7oS

(98 waves) Figueiredo et al, 2018 (submited JGR)

22oS

(48 waves) Present Results

19 h ~ 75-200 km

ch ~ 75-175 m/s

obs ~ 10-50 min h ~ 100-200 km

ch ~ 30-180 m/s

obs ~ 10-35 min

ch ~ 80-150 m/s

obs ~ 10-30 min h ~ 90-140 km

62oS (27 waves)

2 years 2.5 years 10 years

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7oS

(98 waves)

22oS

(48 waves)

62oS (27 waves) One of the most important mechanisms that has been pointed out as being effective for generation of MSTIDs is the Perkins instability (Perkins, 1973).

Propagation Direction

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TID’s Propagation Direction

NH SH

SW NW

Equator

Perkins instability Mechanism

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Looking closely in the wave Propagation Directions

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7oS

(98 waves)

(FRITTS et al., 2009)

  • Not related with the Perkins instability process.
  • Not directed linked by waves generated in the

troposphere.

  • Waves may be generated at the bottom site of the

ionosphere region

Paulino et al., 2016

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22oS

(48 waves) Cloud Top Brightness Temperature (CTBT) with temperatures below -45°C. Cold front and tropospheric jet stream

Winter

Figueiredo et al., 2018 (Submitted to JGR)

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62oS (27 waves)

SSGW MSGW

NH SH

SW NW

Equator

Perkins Instability Mechanism

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Summary

  • Around 27 MSTIDs were observed in 2 years (2015 e 2016) at

the Brazilian Antarctic Station;

  • The main MSTID’ s characteristics:
  •  h ~ 75 - 200 km
  • obs ~ 10 - 50 min
  • cobs ~ 75 - 175 m/s
  • Similar wave parameters were found at S.J. Cariri (7oS) and

Cachoeira Paulista (22oS);

  • According to MSTID’s propagation direction they seem be

generated by the Perkins Instability Mechanism, however more investigation should be done.

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Obrigado! Perguntas?