电离层Es电波传播模型研究
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摘要
考虑大气折射的影响,对不同高度Es层条件下大圆路径传播距离与仰角的关系进行计算.基于电离层Es电子密度时空分布特点,建立高阶Es反射模型;运用高阶修正贝塞尔函数表示电离层Es电子密度扰动的自相关函数,综合考虑电离层Es各向异性结构的尺度关系,建立高阶Es散射模型.仿真计算Es层VHF斜入射传播衰减与频率、距离的关系.对于反射模型,Es层厚度越厚,电波衰减越大.对于散射模型,Es层不规则体水平尺度相同,垂直水平漂移的尺度越大,衰减越大;而垂直水平漂移的尺度相同,水平尺度越大,衰减越小.无论反射模型还是散射模型,f_0E_s越高,衰减越小;电波工作频率越高,衰减越大.对比建立的模型与VHF链路的测量结果,明确不同强度的电离层Es反射/散射机制,证明了建立模型的正确性.
Considering the influence of atmospheric refraction, the relationship between the greatcircle propagation distance and the elevation angle under different height Es layers is calculated.Based on the numerical model of ion density of the Es layer, and using an autocorrelation function of the fluctuation of electron density given by modified Bessel functions of the fifth, the reflection and scattering models are built considering the scale of irregularities. The relationships between the attenuation of the VHF oblique incident propagation of the Es layer and the frequency are simulated by the models. For the reflection model, the thicker the Es layer is, the greater the attenuation is. For the scattering model, the larger the vertical and horizontal drift scale are, the greater the attenuation is under the same horizontal scale of Es layer irregularities. However, if the vertical and horizontal drifts are same, the attenuation is inversely proportional to the horizontal scale. In reflection and scattering models, the higher the f_0E_s is, the smaller the attenuation is while the higher the operating frequency of radio waves is, the greater the attenuation is. The results also agree well with the observations of Es propagation path. Es reflection/scattering mechanism is clear for different intensity of ionosphere.
Considering the influence of atmospheric refraction, the relationship between the greatcircle propagation distance and the elevation angle under different height Es layers is calculated.Based on the numerical model of ion density of the Es layer, and using an autocorrelation function of the fluctuation of electron density given by modified Bessel functions of the fifth, the reflection and scattering models are built considering the scale of irregularities. The relationships between the attenuation of the VHF oblique incident propagation of the Es layer and the frequency are simulated by the models. For the reflection model, the thicker the Es layer is, the greater the attenuation is. For the scattering model, the larger the vertical and horizontal drift scale are, the greater the attenuation is under the same horizontal scale of Es layer irregularities. However, if the vertical and horizontal drifts are same, the attenuation is inversely proportional to the horizontal scale. In reflection and scattering models, the higher the f_0E_s is, the smaller the attenuation is while the higher the operating frequency of radio waves is, the greater the attenuation is. The results also agree well with the observations of Es propagation path. Es reflection/scattering mechanism is clear for different intensity of ionosphere.
引文
[1] MIYA K, SHIMIZU K, KOJIMA T. Oblique-incidence sporadic-E propagation and its ionospheric attenuation[J]. Radio Sci., 1978, 13(3):559-570
[2] KERB LAY T S. Trajectories of radio waves reflected from the large-scale inhomogeneous structure of the Es-layer[J].Geomagn. Aeron., 1979, 19:20
[3] ALTHOUSE E L, DAVIS J R. A practical evaluation of Earth-backscatter simulation and an estimate of the HF ground-scatter coefficient[J]. Radio Sci.,1972, 7(10):897-911
[4] MAKARENKO S F, KERBLAY T S. Coefficient of reflection of radio waves from a thin horizontally inhomogeneous Es-layer[J]. Geomagn. Aeron., 1980, 20:310
[5] SINNO K, KAN M, HIRUKAWA Y, On the reflection and transmission losses for ionospheric radio wave propagation via sporadic E[J]. Radio Res. Lab. Jpn., 1976,23(110):65
[6] KOBAYASHI T. Estimation of the strength of Es waves by foes at the mid-point[J]. Radio Res. Lab. Jpn., 1964,11(56):181
[7] SHERSTYUKOV O N, AKCHURIN A D, SHER-STYUKOV R O. Frequency dependences of reflection coefficient from Es layer at oblique incidence[C]. In Proceedings of 30th URSI General Assembly and Scientific Symposium(URSIGASS), Istanbul, Turkey, 2011
[8] SHERSTYUKOV O N, AKCHURIN A D, SHERSTYUKOV R O. Determination of sporadic E radio wave propagation parameters based on vertical and oblique sounding[J]. Adv. Space Res., 2015, 56(6):1169-1176
[9] LI Hui, CHE Haiqin, WU Jian, et al. Ionogram traces of Es layer based on partial reflection theory[J]. Chin. J.Radio Sci., 2011, 26(2):311-314
[10] CLARKE R H, TIBBLE D V. Measurement of the elevation angles of arrival of multi-component HF skywaves[J].Proc. Inst. Electr. Engrs., 1978, 125:17
[11] MINULLIN R G, MIKHAYLOV B K. Pulsed VHFsounding of the Es-layer on a 1620 km link[J]. Geomagn.Aeron., 1973, 13:233
[12] EDWARDS K J, KERSLEY L, SHRUBSOLE L F.Sporadic-E propagation at frequencies around 70 MHz[J].Radio Elect. Engr., 1984, 54(5):231-237
[13] KERBLAY T S, NOSOVA G N, MINULLIN R G, et al.Periods of fluctuations of signals produced by ionospheric scattering and reflection from Es-layer on frequencies of27.8 and 40.3 MHz[J]. Geomugn. Aeron., 1977, 17:158
[14] WHITEHEAD J D. Recent work on mid-latitude and equatorial sporadic-E[J]. J. Atmos. Terr. Phys., 1989,51(5):401-424
[15] EBU. VHF propagation due to sporadic ionization or the E region of the ionosphere(Band 1)[R]. European Broadcasting Union, 32 avenue Albert Lancaster, B-1180 Brussels, Belgium, 1974
[16] TAGHOLM L F, BELL C P, KNIGHT P. Ionospheric propagation in VHF television band I[R]. Nasa Sti/recon Technical Report N, BBC RD, 1975:17
[17] RAVICHANDRAN V C, RAO M M. Transequatorial propagation of TV signals via sporadic-E[J]. IETE J.Res., 1992, 38:52-56. DOI:10.1080/03772063.1992.11437025
[18] REDDY C A. Physical significance of the Es parameters f_bE_s, fE_s, and f_0E_s 2. Causes of partial reflections from Es[J].J. Geophys. Res., 1968, 73(17):5627-5647
[19] REDDY C A, MATSUSHITA S, The variations of neutral wind shears in the E-region as deduced from blanketing Es[J]. J. Atmos. Terr. Phys., 1968, 30:747
[20] TAO K A. A theoretical study of sporadic—E structure in the light of radio measurement[J]. Ionosph. Spor.,1962:235-257
[21] BOOKER H G, GORDON W E. A theory of radio scattering in the troposphere[J]. Proc. IRE, 1950, 38:401
[22] BOOKER H G. The use of radio stars to study irregular refraction of radio waves in the ionosphere[J]. Proc. IRE,1958, 46:298
[2] KERB LAY T S. Trajectories of radio waves reflected from the large-scale inhomogeneous structure of the Es-layer[J].Geomagn. Aeron., 1979, 19:20
[3] ALTHOUSE E L, DAVIS J R. A practical evaluation of Earth-backscatter simulation and an estimate of the HF ground-scatter coefficient[J]. Radio Sci.,1972, 7(10):897-911
[4] MAKARENKO S F, KERBLAY T S. Coefficient of reflection of radio waves from a thin horizontally inhomogeneous Es-layer[J]. Geomagn. Aeron., 1980, 20:310
[5] SINNO K, KAN M, HIRUKAWA Y, On the reflection and transmission losses for ionospheric radio wave propagation via sporadic E[J]. Radio Res. Lab. Jpn., 1976,23(110):65
[6] KOBAYASHI T. Estimation of the strength of Es waves by foes at the mid-point[J]. Radio Res. Lab. Jpn., 1964,11(56):181
[7] SHERSTYUKOV O N, AKCHURIN A D, SHER-STYUKOV R O. Frequency dependences of reflection coefficient from Es layer at oblique incidence[C]. In Proceedings of 30th URSI General Assembly and Scientific Symposium(URSIGASS), Istanbul, Turkey, 2011
[8] SHERSTYUKOV O N, AKCHURIN A D, SHERSTYUKOV R O. Determination of sporadic E radio wave propagation parameters based on vertical and oblique sounding[J]. Adv. Space Res., 2015, 56(6):1169-1176
[9] LI Hui, CHE Haiqin, WU Jian, et al. Ionogram traces of Es layer based on partial reflection theory[J]. Chin. J.Radio Sci., 2011, 26(2):311-314
[10] CLARKE R H, TIBBLE D V. Measurement of the elevation angles of arrival of multi-component HF skywaves[J].Proc. Inst. Electr. Engrs., 1978, 125:17
[11] MINULLIN R G, MIKHAYLOV B K. Pulsed VHFsounding of the Es-layer on a 1620 km link[J]. Geomagn.Aeron., 1973, 13:233
[12] EDWARDS K J, KERSLEY L, SHRUBSOLE L F.Sporadic-E propagation at frequencies around 70 MHz[J].Radio Elect. Engr., 1984, 54(5):231-237
[13] KERBLAY T S, NOSOVA G N, MINULLIN R G, et al.Periods of fluctuations of signals produced by ionospheric scattering and reflection from Es-layer on frequencies of27.8 and 40.3 MHz[J]. Geomugn. Aeron., 1977, 17:158
[14] WHITEHEAD J D. Recent work on mid-latitude and equatorial sporadic-E[J]. J. Atmos. Terr. Phys., 1989,51(5):401-424
[15] EBU. VHF propagation due to sporadic ionization or the E region of the ionosphere(Band 1)[R]. European Broadcasting Union, 32 avenue Albert Lancaster, B-1180 Brussels, Belgium, 1974
[16] TAGHOLM L F, BELL C P, KNIGHT P. Ionospheric propagation in VHF television band I[R]. Nasa Sti/recon Technical Report N, BBC RD, 1975:17
[17] RAVICHANDRAN V C, RAO M M. Transequatorial propagation of TV signals via sporadic-E[J]. IETE J.Res., 1992, 38:52-56. DOI:10.1080/03772063.1992.11437025
[18] REDDY C A. Physical significance of the Es parameters f_bE_s, fE_s, and f_0E_s 2. Causes of partial reflections from Es[J].J. Geophys. Res., 1968, 73(17):5627-5647
[19] REDDY C A, MATSUSHITA S, The variations of neutral wind shears in the E-region as deduced from blanketing Es[J]. J. Atmos. Terr. Phys., 1968, 30:747
[20] TAO K A. A theoretical study of sporadic—E structure in the light of radio measurement[J]. Ionosph. Spor.,1962:235-257
[21] BOOKER H G, GORDON W E. A theory of radio scattering in the troposphere[J]. Proc. IRE, 1950, 38:401
[22] BOOKER H G. The use of radio stars to study irregular refraction of radio waves in the ionosphere[J]. Proc. IRE,1958, 46:298
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