التفاصيل البيبلوغرافية
| العنوان: |
Numerical Simulations on Day‐to‐Day Variations of Low‐Latitude Es Layers at Arecibo. |
| المؤلفون: |
Andoh, Satoshi1 (AUTHOR) andoh@kugi.kyoto-u.ac.jp, Saito, Akinori1 (AUTHOR), Shinagawa, Hiroyuki2 (AUTHOR) |
| المصدر: |
Geophysical Research Letters. 4/16/2022, Vol. 49 Issue 7, p1-11. 11p. |
| مصطلحات موضوعية: |
*RADIO wave propagation, *LATITUDE, *ATMOSPHERIC models, *PHASE velocity, *COMPUTER simulation, *DENSE plasmas, *ZONAL winds |
| مستخلص: |
To reveal mechanisms of day‐to‐day variations of the low‐latitude sporadic E (Es) layers, Es layer simulations were performed and compared to plasma layers observed by the Arecibo radar. Many studies have been conducted about the Es layers till now. However, few studies investigated the day‐to‐day variations of the Es layers especially at the low‐latitudes. Herein, for the first time, our numerical model generally succeeded in reproducing features of the day‐to‐day variations of the low‐latitude Es layers. We found that the day‐to‐day variations of the Es layers are created by a combination of day‐to‐day variations of zonal/meridional‐wind shears driven by the tides and the downward phase velocity of the tides. The wind‐driven mechanism generally explains the day‐to‐day variations of the low‐latitude Es layers. Plain Language Summary: The sporadic E (Es) layers are highly dense plasma layers appearing irregularly at altitudes 90–130 km. They cause unexpected reflections and abnormal propagations of radio waves used for broadcast communications and navigations. The Es layers exhibit day‐to‐day variations in their behaviors and structures, making it difficult to accurately predict their occurrence. In this study, our numerical ionospheric model, coupled with the neutral winds of a whole atmospheric model, reproduced day‐to‐day variations of the Es layers observed by the radar at Arecibo. This is the first time such a modeling has been performed at Arecibo after decades of research on Es layers. Our numerical model, which is based on the wind‐driven mechanism, can reproduce their daily behaviors. Day‐to‐day variations of the winds are crucial for behaviors of the low‐latitude Es layers. Key Points: Our numerical model generally reproduced day‐to‐day variations of the sporadic E (Es) layers observed at Arecibo for the first timeDay‐to‐day variations of the low‐latitude Es layers are generally created by those of the atmospheric diurnal/semi‐diurnal tidesBelow ∼100 km at the low‐latitudes, the zonal‐wind shears of the diurnal tides form the Es layers, and the vertical winds do not [ABSTRACT FROM AUTHOR] |
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