Method for correcting instrument attenuation by using relative proportion of mercury lamp spectral lines

Abstract

The invention relates to a method for correcting instrument attenuation by using relative proportion of mercury lamp spectral lines, and belongs to the technical field of correction methods. The problems of tedious operation, high cost and the like of an on-orbit instrument attenuation correction method in the prior art are solved. The method comprises the following steps of: irradiating an instrument by using a mercury lamp in a dark environment under the conditions that the temperature, the voltage and the mercury vapor pressure are not changed to obtain mercury lamp characteristic radiation spectrums under various wavelengths; performing normalization processing on the mercury lamp characteristic radiation spectrum under each wavelength by taking the mercury lamp characteristic radiation spectrum under the longest wavelength as a reference to obtain a radiation relative proportion of the mercury lamp characteristic radiation spectrum under each wavelength; and finally, regarding the attenuation of the radiation relative proportion of the mercury lamp characteristic radiation spectrum under each wavelength as the attenuation of the instrument, and completing attenuation correction of the instrument. The method is low in cost and high in efficiency, the attenuation correction method can be expanded, and more thoughts are provided for attenuation correction.

Description

Technical Field

[0001] The invention belongs to the technical field of correction methods, and in particular relates to a method for correcting instrument attenuation by utilizing the relative proportion of mercury lamp spectral lines. Background Art

[0002] When calibrating the attenuation of an on-orbit radiation instrument, a standard source can be used to calibrate the system to measure the attenuation of the instrument. However, when using a standard light source for calibration, it is usually necessary to compare the standard radiation intensity of the standard source under the external conditions of the light source at that time to determine the attenuation of the instrument, so as to correct the attenuation. However, due to the actual conditions of the on-orbit instrument, it is not easy to know the actual conditions of the external environment. Therefore, it is not easy to measure the attenuation of the instrument by comparing with the standard value.

[0003] Therefore, when correcting attenuation of on-orbit instruments, two sets of equipment with the same structure are usually set up to correct the attenuation of the instrument. For example, the spectral irradiance monitor SIM (Spectral Irradiance Monitor) launched by the Solar Radiation and Climate Experiment (SORCE) satellite sets up two channels, one for measuring solar spectral irradiance and the other for correcting attenuation.

[0004] However, measuring attenuation by comparing the standard value of a standard source requires clear external conditions. The comparison process is usually cumbersome and is limited by actual observation conditions, and it is often impossible to directly know the actual external conditions.

[0005] Attenuation correction solutions that use spare channels or spare instruments are often costly. Summary of the invention

[0006] In order to solve the problems of on-orbit instrument attenuation correction methods in the prior art, such as cumbersome operation and high cost, the present invention provides a method for correcting instrument attenuation by using the relative proportion of mercury lamp spectral lines, expands the attenuation correction method, and provides more ideas for attenuation correction.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows.

[0008] The method of the present invention for correcting instrument attenuation by using the relative ratio of mercury lamp spectral lines comprises the following steps:

[0009] Step 1: In a dark environment, with constant temperature, voltage, and mercury vapor pressure, use a mercury lamp to irradiate the instrument to obtain the characteristic radiation spectrum of the mercury lamp at each wavelength;

[0010] Step 2: Taking the characteristic radiation spectrum of the mercury lamp at the longest wavelength as a reference, normalizing the characteristic radiation spectrum of the mercury lamp at each wavelength to obtain the relative radiation proportion of the characteristic radiation spectrum of the mercury lamp at each wavelength;

[0011] Step 3: The attenuation of the relative proportion of the characteristic radiation spectrum of the mercury lamp at each wavelength is regarded as the attenuation of the instrument to complete the attenuation correction of the instrument.

[0012] Preferably, in step 1, the wavelength range is 253-578 nm.

[0013] The principle of the present invention is:

[0014] Under the conditions of constant temperature, voltage, and mercury vapor pressure, there is a relative proportional relationship between the characteristic spectral lines of the mercury lamp, and the spectral irradiance measured by the instrument should always meet this proportional relationship. However, the attenuation of the instrument corresponding to each band is different, and the part that is more biased towards the ultraviolet is attenuated more, which will cause this proportional relationship to change. When correcting the attenuation, since the infrared basically does not attenuate and the visible band attenuates very little, the spectral line with the longest wavelength is used as the benchmark, and the changes in the relative proportions of the remaining spectral lines are regarded as changes in their attenuation.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] Mercury lamps are not commonly used for radiation calibration. When used for attenuation correction, they need to be compared with the standard value of the mercury lamp in the current environment to perform attenuation correction. This process requires accurate determination of the current environmental state and detailed comparison, but the current environmental state is not easy to determine in the on-orbit state and the comparison process is cumbersome. The method of correcting attenuation using the relative proportional relationship of the mercury lamp spectral line in the present invention is simple to operate, and attenuation correction can be performed without confirming the environmental conditions or comparing with the standard value, which greatly facilitates the attenuation correction process.

[0017] The method of using the relative ratio of mercury lamp spectrum lines to correct instrument attenuation of the present invention uses the mercury lamp commonly provided in the spectral instrument, and the mercury lamp is used as a common calibration light source for the instrument, and the cost is much lower than that of the backup instrument. The proportional relationship of the mercury lamp's own spectrum is used to perform attenuation correction through the change of its proportional relationship, which can achieve the purpose of attenuation correction at low cost and high efficiency. After testing, the method was used to perform attenuation correction on the remote sensing measurement data of the Fengyun-3 solar irradiance spectrometer, and the attenuation of the instrument was successfully corrected by up to about 65% in two and a half years, indicating that the method of the present invention can effectively correct the instrument attenuation, and the corrected data is better than the results before correction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are only some specific implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A flow chart of a method for correcting instrument attenuation using the relative ratio of mercury lamp spectral lines according to the present invention;

[0020] Figure 2 The attenuation of each band of the instrument in the two and a half years before the attenuation correction of the existing Fengyun-3 solar irradiance spectrometer in Example 1;

[0021] Figure 3 This is the result obtained by calibrating the Fengyun-3 solar irradiance spectrometer using the method of correcting instrument attenuation using the relative proportion of the mercury lamp spectral line in Example 1. DETAILED DESCRIPTION

[0022] In order to further understand the present invention, preferred embodiments of the present invention are described below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0023] like Figure 1 As shown, the method of correcting instrument attenuation using the relative proportion of mercury lamp spectrum lines of the present invention is to first irradiate the instrument with a mercury lamp in a dark environment under the conditions of constant temperature, voltage, and mercury vapor pressure to obtain the characteristic radiation spectrum of the mercury lamp at each wavelength; then, the characteristic radiation spectrum of the mercury lamp at the longest wavelength is used as a reference to normalize the characteristic radiation spectrum of the mercury lamp at each wavelength to obtain the relative radiation proportion of the characteristic radiation spectrum of the mercury lamp at each wavelength; finally, the attenuation of the relative radiation proportion of the characteristic radiation spectrum of the mercury lamp at each wavelength is regarded as the attenuation of the instrument to complete the attenuation correction of the instrument. The measurement range of the wavelength is determined according to actual needs. In this embodiment, the wavelength range used is 253-578nm, and the longest wavelength is 578nm.

[0024] The terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art, unless otherwise specified.

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with embodiments and comparative examples.

[0026] Example 1

[0027] Taking the remote sensing measurement data of the Fengyun-3 solar irradiance spectrometer as an example, the attenuation of each band of the instrument was recorded two and a half years before the attenuation correction. The results are as follows: Figure 2 As shown. Figure 2 It can be seen that during the two and a half years before the attenuation correction, as time went on, each wavelength attenuated to varying degrees, with short waves attenuating faster and long waves attenuating slower.

[0028] Take the solar irradiance measurement data corresponding to the mercury lamp spectrum line in the Fengyun-3 solar irradiance spectrometer remote sensing measurement data as an example.

[0029] After using mercury lamp to calibrate attenuation, the attenuation of each band of the instrument in the two and a half years is as follows Figure 3 As shown, it can be seen that the attenuation is well suppressed, especially in the shortwave part; Figure 3 There is still some attenuation that is not completely suppressed. This is because in the structure of the instrument, there are two glass sheets in front of the instrument that can be illuminated by the mercury lamp. These two glass sheets still have attenuation, and this part cannot be illuminated by the mercury lamp, so attenuation correction cannot be performed. From the results, it can be seen that this method successfully corrected the attenuation of the instrument for up to about 65% in two and a half years. The results show that this method can effectively correct the instrument attenuation.

[0030] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the embodiments. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A method for correcting instrument attenuation using the relative ratio of mercury lamp spectral lines, characterized in that: Here are the steps: Step 1: In a dark environment, with constant temperature, voltage, and mercury vapor pressure, use a mercury lamp to irradiate the instrument to obtain the characteristic radiation spectrum of the mercury lamp at each wavelength; Step 2: Taking the characteristic radiation spectrum of the mercury lamp at the longest wavelength as a reference, normalizing the characteristic radiation spectrum of the mercury lamp at each wavelength to obtain the relative radiation proportion of the characteristic radiation spectrum of the mercury lamp at each wavelength; Step 3: The attenuation of the relative proportion of the characteristic radiation spectrum of the mercury lamp at each wavelength is regarded as the attenuation of the instrument to complete the attenuation correction of the instrument.

2. The method for correcting instrument attenuation by using the relative ratio of mercury lamp spectral lines according to claim 1, characterized in that: In step 1, the wavelength range is 253-578nm.

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