Numerical prediction of sporadic E layer occurrence using GAIA

AbstractA sporadic E layer has significant influence on radio communications and broadcasting, and predicting the occurrence of sporadic E layers is one of the most important issues in space weather forecast. While sporadic E layer occurrence and the magnitude of the critical sporadic E frequency (foEs) have clear seasonal variations, significant day-to-day variations as well as regional and temporal variations also occur. Because of the highly complex behavior of sporadic E layers, the prediction of sporadic E layer occurrence has been one of the most difficult issues in space weather forecast. To explore the possibility of numerically predicting sporadic E layer occurrence, we employed the whole atmosphere–ionosphere coupled model GAIA, examining parameters related to the formation of sporadic E layer such as vertical ions velocities and vertical ion convergences at different altitudes between 90 and 150 km. Those parameters in GAIA were compared with the observed foEs data obtained by ionosonde observations in Japan. Although the agreement is not very good in the present version of GAIA, the results suggest a possibility that sporadic E layer occurrence can be numerically predicted using the parameters derived from GAIA. We have recently developed a real-time GAIA simulation system that can predict atmosphere–ionosphere conditions for a few days ahead. We present an experimental prediction scheme and a preliminary result for predicting sporadic E layer occurrence.

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Numerical prediction of sporadic E layer occurrence using GAIA

10.21203/rs.3.rs-46157/v3 ◽

2020 ◽

Author(s):

Hiroyuki Shinagawa ◽

Chihiro Tao ◽

Hidekatsu Jin ◽

Yasunobu Miyoshi ◽

Hitoshi Fujiwara

Keyword(s):

Space Weather ◽

Coupled Model ◽

Weather Forecast ◽

Temporal Variations ◽

Radio Communications ◽

Prediction Scheme ◽

Experimental Prediction ◽

Sporadic E Layers ◽

Sporadic E Layer ◽

Sporadic E

Abstract A sporadic E layer has significant influence on radio communications and broadcasting, and predicting the occurrence of sporadic E layers is one of the most important issues in space weather forecast. While sporadic E layer occurrence and the magnitude of the critical sporadic E frequency ( foEs ) have clear seasonal variations, significant day-to-day variations as well as regional and temporal variations also occur. Because of the highly complex behavior of sporadic E layers, the prediction of sporadic E layer occurrence has been one of the most difficult issues in space weather forecast. To explore the possibility of numerically predicting sporadic E layer occurrence, we employed the whole atmosphere–ionosphere coupled model GAIA, examining parameters related to the formation of sporadic E layer such as vertical ions velocities and vertical ion convergences at different altitudes between 90 km and 150 km. By comparing those parameters in GAIA with observed foEs data obtained by ionosonde observations in Japan, we found that variations in the vertical ion convergence at 120 km altitude agree fairly well with variations in foEs . This result suggests that sporadic E layer occurrence can be numerically predicted using the parameters derived from GAIA. We have recently developed a real-time GAIA simulation system that can predict atmosphere–ionosphere conditions for a few days ahead. We present an experimental prediction scheme and a preliminary result for predicting sporadic E layer occurrence.

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Numerical prediction of sporadic E layer occurrence using GAIA

10.21203/rs.3.rs-46157/v1 ◽

2020 ◽

Author(s):

Hiroyuki Shinagawa ◽

Chihiro Tao ◽

Hidekatsu Jin ◽

Yasunobu Miyoshi ◽

Hitoshi Fujiwara

Keyword(s):

Space Weather ◽

Coupled Model ◽

Weather Forecast ◽

Temporal Variations ◽

Radio Communications ◽

Prediction Scheme ◽

Experimental Prediction ◽

Sporadic E Layers ◽

Sporadic E Layer ◽

Sporadic E

Abstract A sporadic E layer has significant influence on radio communications and broadcasting, and predicting the occurrence of sporadic E layers is one of the most important issues in space weather forecast. While sporadic E layer occurrence and the magnitude of the critical sporadic E frequency (foEs) have clear seasonal variations, significant day-to-day variations as well as regional and temporal variations also occur. Because of the highly complex behavior of sporadic E layers, the prediction of sporadic E layer occurrence has been one of the most difficult issues in space weather forecast. To explore the possibility of numerically predicting sporadic E layer occurrence, we have examined various parameters related to sporadic E layer formation using the whole atmosphere–ionosphere coupled model GAIA. By comparing the parameters in GAIA with observed foEs data obtained by ionosonde observations in Japan, we found that variations in the vertical ion convergence at 120 km altitude agree fairly well with variations in foEs. This result suggests that sporadic E layer occurrence can be numerically predicted using the parameters derived from GAIA. We have recently developed a real-time GAIA simulation system that can predict atmosphere–ionosphere conditions for a few days ahead. We present an experimental prediction scheme and a preliminary result for predicting sporadic E layer occurrence.

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Numerical prediction of sporadic E layer occurrence using GAIA

10.21203/rs.3.rs-46157/v2 ◽

2020 ◽

Author(s):

Hiroyuki Shinagawa ◽

Chihiro Tao ◽

Hidekatsu Jin ◽

Yasunobu Miyoshi ◽

Hitoshi Fujiwara

Keyword(s):

Space Weather ◽

Coupled Model ◽

Weather Forecast ◽

Temporal Variations ◽

Radio Communications ◽

Prediction Scheme ◽

Experimental Prediction ◽

Sporadic E Layers ◽

Sporadic E Layer ◽

Sporadic E

Abstract A sporadic E layer has significant influence on radio communications and broadcasting, and predicting the occurrence of sporadic E layers is one of the most important issues in space weather forecast. While sporadic E layer occurrence and the magnitude of the critical sporadic E frequency ( foEs ) have clear seasonal variations, significant day-to-day variations as well as regional and temporal variations also occur. Because of the highly complex behavior of sporadic E layers, the prediction of sporadic E layer occurrence has been one of the most difficult issues in space weather forecast. To explore the possibility of numerically predicting sporadic E layer occurrence, we employed the whole atmosphere–ionosphere coupled model GAIA, examining parameters related to the formation of sporadic E layer such as vertical ions velocities and vertical ion convergences at different altitudes between 90 km and 150 km. By comparing those parameters in GAIA with observed foEs data obtained by ionosonde observations in Japan, we found that variations in the vertical ion convergence at 120 km altitude agree fairly well with variations in foEs . This result suggests that sporadic E layer occurrence can be numerically predicted using the parameters derived from GAIA. We have recently developed a real-time GAIA simulation system that can predict atmosphere–ionosphere conditions for a few days ahead. We present an experimental prediction scheme and a preliminary result for predicting sporadic E layer occurrence.

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Seasonal variability and descent of mid-latitude sporadic E layers at Arecibo

Annales Geophysicae ◽

10.5194/angeo-27-923-2009 ◽

2009 ◽

Vol 27 (3) ◽

pp. 923-931 ◽

Cited By ~ 25

Author(s):

N. Christakis ◽

C. Haldoupis ◽

Q. Zhou ◽

C. Meek

Keyword(s):

Lower Thermosphere ◽

Time Base ◽

Large Set ◽

Seasonal Behavior ◽

Incoherent Scatter ◽

Electron Density Gradient ◽

Sporadic E Layers ◽

Sporadic E Layer ◽

Sporadic E ◽

Wind Shears

Abstract. Sporadic E layers (Es) follow regular daily patterns in variability and altitude descent, which are determined primarily by the vertical tidal wind shears in the lower thermosphere. In the present study a large set of sporadic E layer incoherent scatter radar (ISR) measurements are analyzed. These were made at Arecibo (Geog. Lat. ~18° N; Magnetic Dip ~50°) over many years with ISR runs lasting from several hours to several days, covering evenly all seasons. A new methodology is applied, in which both weak and strong layers are clearly traced by using the vertical electron density gradient as a function of altitude and time. Taking a time base equal to the 24-h local day, statistics were obtained on the seasonal behavior of the diurnal and semidiurnal tidal variability and altitude descent patterns of sporadic E at Arecibo. The diurnal tide, most likely the S(1,1) tide with a vertical wavelength around 25 km, controls fully the formation and descent of the metallic Es layers at low altitudes below 110 km. At higher altitudes, there are two prevailing layers formed presumably by vertical wind shears associated mainly with semidiurnal tides. These include: 1) a daytime layer starting at ~130 km around midday and descending down to 105 km by local midnight, and 2) a less frequent and weaker nighttime layer which starts prior to midnight at ~130 km, descending downwards at somewhat faster rate to reach 110 km by sunrise. The diurnal and semidiurnal-like pattern prevails, with some differences, in all seasons. The differences in occurrence, strength and descending speeds between the daytime and nighttime upper layers are not well understood from the present data alone and require further study.

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Modulation of sporadic E layers by small-scale atmospheric waves in Earth’s high-latitude ionosphere

Solnechno-Zemnaya Fizika ◽

10.12737/szf-53201912 ◽

2019 ◽

Vol 5 (3) ◽

pp. 116-129

Author(s):

Владимир Губенко ◽

Vladimir Gubenko ◽

Иван Кириллович ◽

Ivan Kirillovich

Keyword(s):

High Latitude ◽

Radio Occultation ◽

Small Scale ◽

Polar Cap ◽

Atmospheric Waves ◽

Sporadic E Layers ◽

High Latitude Ionosphere ◽

Sporadic E Layer ◽

Sporadic E ◽

Good Agreement

We have used radio occultation measurements of the satellite CHAMP (Challenging Minisatellite Payload) to examine sporadic E layers (altitudes 90–130 km) in Earth’s high-latitude ionosphere. We have developed a new method for determining characteristics of internal atmospheric waves based on the use of inclined sporadic E layers of Earth’s ionosphere as a detector. The method relies on the fact that an internal wave propagating through the initially horizontal sporadic E layer causes the plasma density gradient to rotate in the direction of the wave vector, which leads to the fact that the layer ionization plane is set parallel to the phase wave front. The developed method enables us to study the interrelations between small-scale internal waves and sporadic E layers in Earth’s ionosphere and significantly expands the capabilities of traditional radio occultation monitoring of the atmosphere. We have found that the internal atmospheric waves under study have periods from 35 to 46 min and vertical phase speeds from 1.2 to 2.0 m/s, which are in good agreement with the results of independent experiments and simulation data on sporadic E layers at a height of ~100 km in Earth’s polar cap.

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Observation of electron biteout regions below sporadic E layers at polar latitudes

Annales Geophysicae ◽

10.5194/angeo-33-371-2015 ◽

2015 ◽

Vol 33 (3) ◽

pp. 371-380 ◽

Cited By ~ 5

Author(s):

G. A. Lehmacher ◽

M. F. Larsen ◽

C. L. Croskey

Keyword(s):

Electric Fields ◽

Sounding Rockets ◽

Ion Drift ◽

Sporadic E Layers ◽

New Process ◽

Combined Action ◽

Sporadic E Layer ◽

Sporadic E ◽

Chemical Releases ◽

Trimethyl Aluminum

Abstract. The descent of a narrow sporadic E layer near 95 km altitude over Poker Flat Research Range in Alaska was observed with electron probes on two consecutive sounding rockets and with incoherent scatter radar during a 2 h period near magnetic midnight. A series of four trimethyl aluminum chemical releases demonstrated that the Es layer remained just slightly above the zonal wind node, which was slowly descending due to propagating long-period gravity waves. The location of the layer is consistent with the equilibrium position due to combined action of the wind shear and electric fields. Although the horizontal electric field could not be measured directly, we estimate that it was ~ 2 mV m−1 southward, consistent with modeling the vertical ion drift, and compatible with extremely quiet conditions. Both electron probes observed deep biteout regions just below the Es enhancements, which also descended with the sporadic layers. We discuss several possibilities for the cause of these depletions; one possibility is the presence of negatively charged, nanometer-sized mesospheric smoke particles. Such particles have recently been detected in the upper mesosphere, but not yet in immediate connection with sporadic E. Our observations of electron depletions suggest a new process associated with sporadic E.

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Sounding of sporadic E layers from CSES radio occultation and comparing with ionosonde measurements

10.5194/angeo-2022-1 ◽

2022 ◽

Author(s):

Chengkun Gan ◽

Jiayu Hu ◽

Xiaomin Luo ◽

Chao Xiong ◽

Shengfeng Gu

Keyword(s):

Standard Deviation ◽

Radio Occultation ◽

Density Ratio ◽

Mean Value ◽

Middle Latitudes ◽

Sporadic E Layers ◽

Sporadic E Layer ◽

The Difference ◽

Sporadic E ◽

New Criterion

Abstract. GNSS radio occultation (RO) plays an important role in ionospheric electron density inversion and sounding of sporadic E layers. As the China's first electromagnetic satellite, China Seismo Electromagnetic Satellite (CSES) has collected the RO data from both GPS and BDS-2 satellites since March 2018. In this study, we extracted the carrier to noise density ratio (CNR) data of CSES and calculated the standard deviation of normalized CNR. A new criterion is developed to determine the Es events, that is when the mean value of the absolute value of the difference between the normalized CNR is greater than 3 times of the standard deviation. The statistics show that sporadic E layers have strong seasonal variations with highest occurrence rates in summer season at middle latitudes. It is also found that the occurrence height of Es is mainly located at 90–110 km, and the period of local time 15:00–18:00 is the high incidence period of Es. In addition, the geometric altitudes of a sporadic E layer detected in CSES radio occultation profiles and the virtual heights of a sporadic E layer obtained by the Wuhan Zuo Ling Tai (ZLT) ionosonde show four different space-time matching criterions. Our results reveal that there is a good agreement between both parameters which is reflected in the significant correlation.

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