A method for solving the occurrence time of maximum value of equatorial ionospheric anomaly crest

Abstract

The application provides a method for solving the average occurrence time of the maximum value of EIA wave peak. The technical scheme comprises the following steps: calculating the average local time of the maximum value of the equatorial ionospheric anomaly wave peak in the yth year by using the following formula: wherein y=2015 represents 2015, which is the solar activity index of the yth year; A, B and C are coefficients of the previous three items; D is a deviation item; f is a frequency; and phi is a phase. Due to the difference between the earth magnetic field configurations of the northern and southern hemispheres, the values of A, B and C are different when the EIA wave peak is in the northern or southern hemisphere. The application realizes the calculation of the average occurrence time of the maximum value of the equatorial ionospheric anomaly wave peak structure based on the solar activity number provided by OMNIWeb. The application is simple to calculate and convenient to use.

Description

Technical Field

[0001] This invention belongs to the field of space exploration technology, specifically relating to a method for determining the occurrence time of the maximum value of an anomaly peak in the equatorial ionosphere by utilizing the characteristics of solar cycle variations. Background Technology

[0002] Influenced by solar radiation and cosmic rays, the Earth's atmosphere ionizes at altitudes of 60–1000 km, forming the ionosphere. The EIA (Equatorial Ionization Anomaly) refers to the unique distribution of electron concentration in the ionosphere near the Earth's equator compared to the regions on either side. This ionization anomaly is one of the main phenomena caused by electromagnetic field variations in low latitudes, often attributed to the daytime E×B (electric field × magnetic field) drift and top diffusion of plasma near the magnetic equator. The typical shape of the EIA is characterized by an electron density peak forming in both the Northern and Southern Hemispheres on either side of the magnetic equator, known as EIA crests. These crests typically form around 09:00 local time, then spread towards the poles to approximately ±15° of magnetic latitude, forming EIA crest regions, reaching their peak around 14:00 local time. Since the EIA peak region in the Northern Hemisphere covers southern China (south of Wuhan), studying the characteristics of the ionosphere in this peak region can quickly reveal the model features of the Chinese ionosphere, providing relevant parameters for space satellite communications and other applications. For example, research has shown that L-band satellite signals are significantly affected by ionospheric variations in the EIA peak region. Therefore, understanding EIA variations is of great importance for satellite communications, positioning, and navigation applications in my country. Summary of the Invention

[0003] This invention proposes a method for determining the annual average occurrence time of the maximum value of EIA peaks, which can provide guidance for satellite applications.

[0004] The technical solution of the present invention includes the following steps:

[0005] The mean local time LT(y) of the maximum value of the equatorial ionospheric anomaly peak in year y is calculated using the following formula:

[0006]

[0007] For example, y = 2015 represents the year 2015. Let be the solar activity index for year y; A, B, and C are the coefficients of the first three terms, D is the offset term, f is the frequency, and φ is the phase. Due to the difference in the configuration of the Earth's magnetic field in the Northern and Southern Hemispheres, when the EIA peak is in the Northern Hemisphere, A = 0.017039, B = 0.006621, C = -0.0000014, D = 14.146179, f = 0.013423, and φ = -3.104273; when the EIA peak is in the Southern Hemisphere, A = 0.697202, B = 0.094484, C = -0.000445, D = 10.000755, f = 0.005744, and φ = 1.150494.

[0008] The above formula was obtained from the total electron content (TEC) information of the ionosphere from 2003 to 2022, acquired by the European Orbit Determination Centre, and derived through the inventor's research.

[0009] This invention uses solar activity data provided by OMNIWeb to calculate the time when the annual average equatorial ionospheric anomaly peak structure reaches its maximum value. This invention is simple to calculate and easy to use. Attached Figure Description

[0010] Figure 1 This is a comparison chart of the calculated values ​​obtained using this invention in the Northern Hemisphere with the actual values ​​and verification values.

[0011] Figure 2 This is a comparison chart of the calculated values, actual values, and verification values ​​obtained using this invention in the Southern Hemisphere. Detailed Implementation

[0012] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with the inventor's research process.

[0013] Obtain the solar activity index F with a time resolution of 1 day for year y from the OMNIWeb website. 10.7 Check and eliminate outlier data (outlier value 999), and complete the index data for the error day by averaging the data for the 27 days before and after the error day. After completion, calculate the solar radiation flux. Let y be the solar activity index for year y.

[0014] Total electron content (TEC) data for the ionosphere from 2003 to 2022 was obtained from the European Orbit Determination Centre. The data has a spatial resolution of 5° latitude × 5° longitude and a temporal resolution of 2 hours, covering the entire globe and spanning more than one solar cycle (approximately 11 years). TEC data from 2003 to 2020 was used for model building, while data from 2021 to 2022 was used for independent validation. The TEC data was divided into Northern and Southern Hemisphere data based on geomagnetic latitude. The local time corresponding to the maximum TEC value in each hemisphere at any given moment was identified, and its annual average was calculated, yielding the annual average local time (LT) of the maximum equatorial ionospheric anomaly peak. The formula for calculating the annual average local time of the maximum equatorial ionospheric anomaly peak was then derived. Figure 1 This is a comparison chart of the calculated values, actual values, and verification values ​​obtained using this invention in the Northern Hemisphere. Figure 2 This is a comparison chart of the calculated values, actual values, and verification values ​​obtained using the model obtained by this invention in the Southern Hemisphere. The technical solution of this invention is obtained by fitting the data from the two charts.

Claims

1. A method for determining the annual average occurrence time of the maximum value of EIA peaks, characterized in that, Includes the following steps: The mean local time LT(y) of the maximum value of the equatorial ionospheric anomaly peak in year y is calculated using the following formula: in, Let f be the solar activity index for year y; A, B, and C are the coefficients of the first three terms, D is the offset term, f is the frequency, and φ is the phase; when the EIA peak is in the Northern Hemisphere, A = 0.017039, B = 0.006621, C = -0.0000014, D = 14.146179, f = 0.013423, and φ = -3.104273; when the EIA peak is in the Southern Hemisphere, A = 0.697202, B = 0.094484, C = -0.000445, D = 10.000755, f = 0.005744, and φ = 1.150494; EIA refers to the equatorial ionosphere.

2. A method for determining the annual average occurrence time of the maximum value of EIA peaks, characterized in that, Obtain the solar activity index F with a time resolution of 1 day for year y from the OMNIWeb website. 10.7 Check and eliminate outlier data, and supplement the index data for the error day by averaging the data for the 27 days before and after the error day; after supplementation, calculate the solar radiation flux. Let y be the solar activity index for year y.

3. A method for determining the annual average occurrence time of the maximum value of EIA peaks, characterized in that, Check and eliminate the abnormal data value 999.

4. A method for determining the annual average occurrence time of the maximum value of EIA peaks, characterized in that, The total electron content information of the ionosphere obtained from the European Orbit Determination Centre has a spatial resolution of 5° latitude × 5° longitude and a temporal resolution of 2 hours. The data covers the globe and spans more than one solar cycle.

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