Latitudinal Differences Of Medium-Scale Traveling Ionospheric - - PowerPoint PPT Presentation

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Latitudinal Differences Of Medium-Scale Traveling Ionospheric Disturbances Observed Over Andes Mountains

Cosme Alexandre FIGUEIREDO1, Hisao TAKAHASHI1, Cristiano WRASSE1, Yuichi OTSUKA2, Kazuo SHIOKAWA2, Diego BARROS1

Contact: cosme.figueiredo@inpe.br

1 – National Institute for Space Research, (INPE), Brazil. 2 – ISEE, Nagoya University, Japan.

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• 1. What are traveling ionospheric disturbances?
• 2. How to calculate the detrended total electronic content

(dTEC)?

• 3. Observation methodology and dTEC keogram analysis
• 4. Results of MSTID in different latitudes over Andes
• 5. Summary

Outline

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What are Traveling Ionospheric Disturbances?

Traveling ionospheric disturbances (TIDs) are wave-like perturbations that occur in ionospheric plasma, with wavelengths in the range of hundreds to thousands of kilometers and phase velocities of the order of hundreds of meters per second (HUNSUCKER, 1982; KELLEY, 2011).

MacDou gall et al. (2011) Otsuka et al. (2013) Paulino et al. (2016)

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Methodology Total Electron Content

satellite e recevier

TEC N ds  

TECU = 1016 electrons/m2

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Methodology Detrended TEC (dTEC)

After calculate the TEC, we calculate the perturbation components of TEC (dTEC) from TEC(t) subtracting the TEC trend obtained from a 1 hr. running average for each couple of a ground receiver and GNSS satellite.

     

     dTEC t TEC t TEC t 30 min .

~40 receivers

LISN

CAP ANDES (NICT Server)

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GPS ground based receiver

Area of

• bservation

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MSTIDs over Andes

What is the better way to observe MSTIDs?

Dusk Solar Terminator Night Dawn Solar Terminator

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Keograms

Keogram is made by taking latitudinal and longitudinal cut section of each processed dTEC map image, and, then, taking them to make a time series (time resolution of 1 min)

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Criteria used to identify MSTIDs

Established by Kotake et al. (2007), Otsuka et al. (2011, 2013), and Figueiredo et al. (2018)

• 1. The amplitude of oscillation of dTEC is exceeding

0.2 TECU;

• 2. The horizontal wavelength is shorter than 1,500 km;
• 3. The period is less than ~60 min;
• 4. The oscillation has more than two wavefronts and

propagates on the maps or keograms; we assume that the propagation direction is perpendicular to the wavefront of MSTIDs;

• 5. We have selected wavefront greater than 3° in latitude

and longitude in the keograms.

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Keograms Analysis Methodology

How to extract MSTIDs parameters?

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Keograms Analysis Methodology

Analysis of MSTIDs using 1D-FFT cross-spectrum

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Results: Low/middle latitude

Low Latitude (10-30°) Observation period: January/2013 MSTIDs Events: 6 Time occurrence: 18:00 – 23:00 UT Middle Latitude (30-50°) Observation period: January/2013 MSTIDs Events: 48 Time occurrence: All Day

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Results: Parameters in Low/middle

latitudes

Low Latitude Middle Latitude

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Results: Propagation Direction

Low Latitudes Middle Latitudes

Southeast- Southwest Northwest North, Northeast, and Southeast

Nighttime

Daytime Daytime

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Figueiredo et al. (2018)

Discussions Low Latitude : Time and

• ccurrence rate

Southeast – South of Brazil (826 MSTIDs)

Similar results

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Discussions Low Latitude: Propagation direction

Is it generated by deep convection in the amazon region or secondary waves or in situ ?

Southeast – South of Brazil

Figueiredo et al. (2018)

Andes

Cloud top Temperature

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Discussions Middle latitude: Occurrence

Martinis et al. (2010)

We do not find any paper about daytime MSTIDs over the Andes.

Nighttime MSTIDs in El Leocinto – Argentina

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Discussions Middle latitude: Propagation direction

Nighttime

Well Known Perkins Stability

Daytime MSTIDs sources Orography ??? Cold front???

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Summary

• 1. A total of 54 MSTIDs were observed in different latitudes.
• 4. Why the MSTIDs originated in middle latitudes do not propagate to low

latitudes?

• 2. Low Latitude MSTIDs are similar with Figueiredo et al. (2018) results.
• 3. Nighttime MSTIDs are generated by Perkins stability and daytime

MSTIDs need more studies.

• 5. why nighttime MSTIDs were not observed at low latitudes?

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Acknowledgments

Thank you very much!!! Muito Obrigado!!!

Contact: cosme.figueiredo@inpe.br

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Bibliography

PAULINO, I.; MEDEIROS, A. F.; VADAS, S. L.; WRASSE, C. M.; TAKAHASHI, H.; BURITI, R. A.; LEITE, D.; FILGUEIRA, S.; BAGESTON, J. V.; SOBRAL, J. H. A.; GOBBI,

• D. Periodic waves in the lower thermosphere observed by oi630 nm airglow images.

Annales Geophysicae, v. 34, n. 2, p. 293–301, 2016. FIGUEIREDO, C. A. O. B.; TAKAHASHI, H.; WRASSE, C. M.; OTSUKA, Y.; SHIOKAWA, K.; BARROS, D., Medium‐scale traveling ionospheric disturbances observed by detrended total electron content maps over Brazil, Journal of Geophysical Research, 123, 2215– 2227, 2018. MARTINIS, C.; BAUMGARDNER, J.; WROTEN, J.; MENDILLO, M. Seasonal dependence

• f mstids obtained from 630.0 nm airglow imaging at arecibo. Geophysical Research

Letters, v. 37, n. 11, p. n/a–n/a, 2010. ISSN 1944-8007.L11103. MacDougall, J., M. A. Abdu, I. Batista, R. Buriti, A. F. Medeiros, P. T. Jayachandran, and G. Borba (2011), Spaced transmitter measurements of medium scale traveling ionospheric disturbances near the equator, Geophys. Res. Lett., 38, L16806, doi: 10.1029/2011GL048598. OTSUKA, Y.; SUZUKI, K.; NAKAGAWA, S.; NISHIOKA, M.; SHIOKAWA, K.; TSUGAWA, T. GNSS observations of medium-scale traveling ionospheric disturbances

• ver Europe, Ann. Geophysicae, Volume 31, Issue 2, 2013, pp.163-172, doi:

10.5194/angeo-31-163-2013, 2013.