A method to reflect the MSNA anomaly of the ionosphere over a single point using altimetry satellites

Abstract

The present invention belongs to the technical field of ionospheric physics, and specifically relates to a method for using an altimetry satellite to reflect the MSNA anomaly of the ionosphere above a single point, the steps of which include determining the observation point, the time range and the observation range of the observation; obtaining the solar activity data F10.7 within the time range and the Jason‑TEC data within the observation range, and converting the world time into the local time; processing the Jason‑TEC data of the same orbit in the adjacent time through the observation range; separating the Jason‑TEC data of different years by month, then separating them by 0‑23h, matching them with the F10.7 of the day, and finally mapping them to the condition that F10.7 is N; calculating the average value of Jason‑TEC at 0‑23h for each month, and projecting the average value data to one day; and drawing a Jason‑TEC diagram. The present invention can reflect the MSNA phenomenon above a single point through measured data.

Description

Technical Field

[0001] The invention belongs to the technical field of ionospheric physics, and in particular relates to a method for reflecting the MSNA anomaly of the ionosphere above a single point by using an altimetry satellite. Background Art

[0002] The midlatitude summer nighttime anomaly (MSNA) is an ionospheric anomaly, which is characterized by the peak of the daily electron density (or TEC) in summer occurring at night (LT: 02:00-04:00) rather than in the afternoon. Currently, there are two main methods to use TEC to reflect the MSNA phenomenon. One is to reflect the MSNA region based on the Global Ionospheric Map (GIM) data, and the other is to reflect it through GPS measured TEC data. Among them, the global total electron content TEC is one of the important parameters in ionospheric physics.

[0003] However, the MSNA area is mainly distributed in the ocean area. GIM data is model data established based on measured data, and GPS is obtained by actual measurements at land stations. The measured data in the MSNA area mainly comes from satellite observations. However, due to factors such as short satellite observation time and long observation cycle, it is impossible to use measured data to better reflect the MSNA phenomenon.

[0004] Therefore, in order to reflect the MSNA phenomenon through measured data, a new method needs to be studied. Summary of the invention

[0005] In view of the above deficiencies in the prior art, the present invention provides a method for reflecting the MSNA anomaly of the ionosphere above a single point by using an altimetry satellite, which can reflect the MSNA phenomenon above a single point through measured data.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is a method for using an altimetry satellite to reflect the MSNA anomaly of the ionosphere above a single point, comprising the following steps:

[0007] S1. Determine the observation point A. The coordinates of the observation point A are (x, y), where x and y represent latitude and longitude respectively.

[0008] S2. Based on the observation point A, determine the observation time range T, T∈[t1, t2], t1 and t2 represent different years, and t1 is earlier than t2;

[0009] S3. Determine the observation range. The observation range is an area that extends outward from the observation point A as the center. The size of the area is determined by the radius R.

[0010] S4, obtaining solar activity data F10.7 within the time range T and Jason-TEC data within the observation range (here, data within the time range T and within the observation range), wherein Jason-TEC data refers to TEC data provided by the Jason satellite, and F10.7 represents the solar 10.7 cm wavelength radio radiation flow;

[0011] S5, convert Jason-TEC data from universal time UT to local time LT;

[0012] S6. Process the Jason-TEC data of the same orbit passing through the observation range at adjacent times as the TEC observation value at the observation point A at this time, wherein adjacent times refer to the time range from when the satellite (here, Jason satellite) enters the observation range to when it leaves the observation range, and the same orbit refers to an orbit passing through the observation range; the Jason-TEC data of the same orbit passing through the observation range at adjacent times are all TEC data acquired by the Jason satellite on an orbit within the observation range;

[0013] S7, for the processed Jason-TEC data, separate the Jason-TEC data of different years by month, and then separate the Jason-TEC data of different months by 0-23h;

[0014] S8, match the Jason-TEC data to the F10.7 of the day;

[0015] S9, map the Jason-TEC data to the condition of F10.7 as N, where N represents the level of solar activity in sfu;

[0016] S10, calculate the average value of Jason-TEC data (here refers to the mapped data) in 0-23h each month, and project the average value data to one day;

[0017] S11. Based on the average value data, the Jason-TEC diagram from 0 to 23 h in S10 is drawn to reflect the anomaly of ionospheric MSNA above observation point A.

[0018] As a preferred embodiment of the present invention, in S3, R is set to 2°. The value of R can be set according to specific needs. In geographical and astronomical observations, it is common to use angles as a unit of measure for distance because these fields often involve the measurement of spherical or curved surfaces. For example, the surface of the earth is imagined as a large sphere, so it is intuitive and convenient to use angles to describe distance; on the surface of the earth, 1° is approximately equal to 111 kilometers (this value is approximate, and the actual distance will vary with latitude). Therefore, a radius of 2° covers a circumferential distance of approximately 222 kilometers.

[0019] In S4, F10.7 is an index of solar radio flux, which represents the intensity of the sun's radio radiation at a wavelength of 10.7 cm, usually expressed in solar flux units (sfu). The F10.7 index is an important indicator of solar activity because it has a strong correlation with other solar activity indicators such as sunspot numbers and solar flares. Common methods for obtaining F10.7 data include ground observations, satellite observations, scientific databases (such as NOAA, SWPC), online services, etc. For example, you can download F10.7 within the time range through NASA's website.

[0020] The Jason satellite is a series of satellites jointly developed by NASA, CNES, ESA and some other institutions. It is a type of altimeter satellite that can obtain global total electron content (TEC) data (especially TEC data in the ocean). Jason-TEC data can be downloaded through the Radar Altimeter Database System (RADS) and other channels.

[0021] As a preferred embodiment of the present invention, in S3 and S4, by formula Determine the data within the observation range, where R is the radius of the observation range, (x i ,y i ) is the coordinate of the measuring point i, x i ,y i Represent latitude and longitude respectively, the observation point A (x, y) is the center point, i (x i ,y i ) represents a measurement point distributed around the observation point A (that is, the measurement point i is distributed around the center point and is within the observation range).

[0022] Since the MSNA phenomenon occurs at a specific local time (LT), the acquired Universal Time (UT) data needs to be converted to local time to ensure that the data is associated with the local time.

[0023] As a preferred embodiment of the present invention, in S5, the conversion formula is:

[0024] (1);

[0025] In the formula, lon represents longitude, It is the difference between local time and universal time.

[0026] As a preferred solution of the present invention, in S6, the formula for processing Jason-TEC data is:

[0027] (2);

[0028] In the formula, represents the processed TEC data; P i is the intermediate variable; d i is the distance between the measurement point i and the observation point A corresponding to the TEC data; is the TEC data obtained at measurement point i.

[0029] For the adjacent time and the same orbit involved in S6, more specifically, the same orbit refers to the path taken by the Jason satellite when passing through a specific area of ​​the earth. Adjacent time refers to the continuous observations made by the Jason satellite on the same orbit from the time the satellite enters the observation range to the time it leaves the observation range.

[0030] As a preferred solution of the present invention, in the above S9, N is set to 70sfu, and the Jason-TEC data is mapped to the condition that F10.7 is 70sfu, that is, the TEC data is standardized, and the TEC data observed at different times are adjusted to the level assuming that the solar activity level is always at 70sfu. The mapping process allows the data obtained at different times and different solar activity levels to be compared with each other, and 70sfu is equivalent to the middle level of solar activity.

[0031] As a preferred solution of the present invention, in S9, the mapping formula is:

[0032] (3);

[0033] In the formula, is the actual value (i.e. the actual value of the obtained solar activity data F10.7); Indicates the degree of solar activity mapped to, that is, mapped to 70sfu; It represents the TEC value after being processed by formula (2), which is The corresponding TEC value; is the TEC value after mapping.

[0034] The algorithm involved in the present invention can be executed by an electronic device. The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The algorithm is implemented by executing the program by the processor.

[0035] The beneficial effects of the present invention are:

[0036] The present invention uses Jason satellite data, which can accurately describe the changes in the ionosphere in the ocean and provide accurate TEC measured values. Based on the satellite data, the present invention can map the TEC values ​​of different solar activity levels to the same solar activity level, so that the ionospheric MSNA anomaly phenomenon over a single point (observation point) can be described by the measured data, making up for the deficiency that the Jason data cannot be used to describe the MSNA phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the process of the present invention;

[0038] Figure 2 It is the Jason-TEC diagram of Ohi3 station in November during the verification process of the present invention;

[0039] Figure 3 It is the Jason-TEC diagram of Ohi3 station in December during the verification process of the present invention;

[0040] Figure 4 This is the Jason-TEC diagram of Ohi3 station in January during the verification process of the present invention. DETAILED DESCRIPTION

[0041] The embodiments of the present invention are further described below in conjunction with the accompanying drawings:

[0042] like Figure 1 As shown in FIG. 1 , the method for reflecting the MSNA anomaly of the ionosphere above a single point by using an altimetry satellite comprises the following steps:

[0043] S1. Determine the observation point A. The coordinates of the observation point A are (x, y), where x and y represent latitude and longitude respectively.

[0044] S2. Based on the observation point A, determine the observation time range T, T∈[t1, t2], t1 and t2 represent different years, and t1 is earlier than t2;

[0045] S3. Determine the observation range. The observation range is an area that extends outward from the observation point A as the center. The size of the area is determined by the radius R.

[0046] S4, obtaining solar activity data F10.7 within the time range T and Jason-TEC data within the observation range, wherein Jason-TEC data refers to TEC data provided by the Jason satellite, and F10.7 represents the solar 10.7 cm wavelength radio radiation flow;

[0047] S5, convert Jason-TEC data from universal time UT to local time LT;

[0048] S6. Process the Jason-TEC data of the same orbit passing through the observation range at adjacent times as the TEC observation value at the observation point A at this time, wherein the adjacent time refers to the time range from the satellite entering the observation range to leaving the observation range, and the same orbit refers to an orbit passing through the observation range;

[0049] S7, for the processed Jason-TEC data, separate the Jason-TEC data of different years by month, and then separate the Jason-TEC data of different months by 0-23h;

[0050] S8, match the Jason-TEC data to the F10.7 of the day;

[0051] S9, map the Jason-TEC data to the condition of F10.7 as N, where N represents the level of solar activity in sfu;

[0052] S10, calculate the average value of Jason-TEC data in 0-23h each month, and project the average value data to one day;

[0053] S11. Based on the average value data, the Jason-TEC diagram from 0 to 23 h in S10 is drawn to reflect the anomaly of ionospheric MSNA above observation point A.

[0054] In S3 and S4, the formula Determine the data within the observation range, where R is the radius of the observation range, (x i ,y i ) is the coordinate of the measuring point i, x i ,y i Represent latitude and longitude respectively, the observation point A (x, y) is the center point, i (x i ,y i ) represents a measurement point distributed around the observation point A.

[0055] In S5, the conversion formula is:

[0056] (1);

[0057] In the formula, lon represents longitude, It is the difference between local time and universal time.

[0058] In S6, the formula for processing Jason-TEC data is:

[0059] (2);

[0060] In the formula, represents the processed TEC data; Pi is the intermediate variable; d i is the distance between the measurement point i and the observation point A corresponding to the TEC data; is the TEC data obtained at measurement point i.

[0061] In S9, the Jason-TEC data are mapped to the condition of F10.7 being 70 sfu, that is, the TEC data are standardized and the TEC data observed at different times are adjusted to the level assuming that the solar activity level is always at 70 sfu.

[0062] The mapping formula is:

[0063] (3);

[0064] In the formula, is the actual value; Indicates the degree of solar activity mapped to, that is, mapped to 70sfu; It represents the TEC value after being processed by formula (2), which is The corresponding TEC value; is the TEC value after mapping.

[0065] The verification process is:

[0066] During the verification process, R was taken as 2°, N was taken as 70sfu, and the observation point A was determined to be Ohi3. Ohi3 is the Ohi3 station on the Antarctic Peninsula, which is the main distribution area of ​​the MSNA phenomenon.

[0067] The time range is set to 2016 to 2022. After obtaining relevant data, processing and mapping according to the method of the present invention, the Jason-TEC diagrams of the Ohi3 station in November, December and January are obtained as follows: Figure 2 , Figure 3 and Figure 4 As shown in the figure, the unit of TEC is TECU (Total Electron Content Unit), 1TECU is equal to 10 per square meter. 16 Since Ohi3 is located in the southern hemisphere, November, December and January are the local summer months. Figures 2 to 4 It can be clearly found that the TEC value of Ohi3 station at night is significantly higher than that during the day, which proves that the method of using Jason-TEC to describe the MSNA phenomenon above the observation point is feasible.

Claims

1. A method for using an altimetry satellite to reflect the MSNA anomaly of the ionosphere above a single point, characterized in that The following steps are involved: S1. Determine the observation point A. The coordinates of the observation point A are (x, y), where x and y represent latitude and longitude respectively. S2. Based on the observation point A, determine the observation time range T, T∈[t1, t2], t1 and t2 represent different years, and t1 is earlier than t2; S3. Determine the observation range. The observation range is an area that extends outward from the observation point A as the center. The size of the area is determined by the radius R. S4, obtaining solar activity data F10.7 within the time range T and Jason-TEC data within the observation range, wherein Jason-TEC data refers to TEC data provided by the Jason satellite, and F10.7 represents the solar 10.7 cm wavelength radio radiation flow; S5, convert Jason-TEC data from universal time UT to local time LT; S6. Process the Jason-TEC data of the same orbit passing through the observation range at adjacent times as the TEC observation value at the observation point A at this time, wherein the adjacent time refers to the time range from the satellite entering the observation range to leaving the observation range, and the same orbit refers to an orbit passing through the observation range; S7, for the processed Jason-TEC data, separate the Jason-TEC data of different years by month, and then separate the Jason-TEC data of different months by 0-23h; S8, match the Jason-TEC data to the F10.7 of the day; S9, map the Jason-TEC data to the condition of F10.7 as N, where N represents the level of solar activity in sfu; S10, calculate the average value of Jason-TEC data in 0-23h each month, and project the average value data to one day; S11. Based on the average value data, the Jason-TEC diagram from 0 to 23 h in S10 is drawn to reflect the anomaly of ionospheric MSNA over observation point A. In S6, the formula for processing Jason-TEC data is: （2）； In the formula, represents the processed TEC data; P i is the intermediate variable; d i is the distance between the measurement point i and the observation point A corresponding to the TEC data; is the TEC data of the measurement point i obtained; In the above-mentioned S9, the mapping formula is: （3）； In the formula, is the actual value; Represents the degree of solar activity mapped; It represents the TEC value after being processed by formula (2), which is The corresponding TEC value; is the TEC value after mapping.

2. The method for reflecting the MSNA anomaly of the ionosphere above a single point by using an altimetry satellite according to claim 1, characterized in that: In the above-mentioned S3, the value of R is 2°.

3. The method for reflecting the MSNA anomaly of the ionosphere above a single point by using an altimetry satellite according to claim 1, characterized in that: In S3 and S4, the formula Determine the data within the observation range, where R is the radius of the observation range, (x i ,y i ) is the coordinate of the measuring point i, x i ,y i Represent latitude and longitude respectively, the observation point A (x, y) is the center point, i (x i ,y i ) represents a measurement point distributed around the observation point A.

4. The method for using an altimetry satellite to reflect the MSNA anomaly of the ionosphere above a single point according to claim 1, characterized in that: In the above-mentioned S5, the conversion formula is: （1）； In the formula, lon represents longitude, It is the difference between local time and universal time.

5. The method for using an altimetry satellite to reflect the MSNA anomaly of the ionosphere above a single point according to claim 1, characterized in that: In the above S9, N is taken as 70sfu, and the Jason-TEC data is mapped to the condition that F10.7 is 70sfu, that is, the TEC data is standardized, and the TEC data observed at different times are adjusted to the level assuming that the solar activity level is always at 70sfu.

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