Laser radar system apparatus for multi-wavelength measurement of atmospheric carbon dioxide concentration and vertical aerosol profile

Abstract

A laser radar system apparatus for the multi-wavelength measurement of the atmospheric carbon dioxide concentration and a vertical aerosol profile, including: a laser transmitting unit; a dual-pulse laser capable of simultaneously transmitting laser having three wavelengths, i.e., 1572 nm, 1064 nm, and 532 nm; a transmitting beam expander; a receiving telescope system; a visual axis monitoring module; a photoelectric detection unit; and a data acquisition and processing unit. The laser that simultaneously outputs laser having three wavelengths is used in a laser radar system, and an optical differential absorption method and a high spectral resolution detection method are used, such that the atmospheric carbon dioxide concentration and the vertical aerosol profile can be measured simultaneously and high-precision aerosol monitoring is implemented during the high-precision obtaining of the concentration of the greenhouse gas carbon dioxide.

Claims

1. A laser radar system apparatus for multi-wavelength measurement of atmospheric carbon dioxide concentration and vertical aerosol profile, wherein the apparatus comprises a 1064 nm seed laser (1), a 1572 nm seed laser (2), a three-wavelength laser (4), a transmitting beam expander (5), a receiving telescope system (6), a visual axis monitoring module (7), a relay optical unit (8), a photoelectric detection unit (9), an integral ball (10), a collimator (11), a first spectroscope (12), a second spectroscope (13), a third spectroscope (14), a data acquisition and processing unit (15), an reflective mirror (16); wherein the photoelectric detection unit (9) includes a fourth spectroscope (9-1), a fifth spectroscope (9-2), a sixth spectroscope (9-3), a 1572 nm detection optical unit (9-4), a 1064 nm detection optical unit (9-5), a 532 nm polarization detection optical unit (9-6), a 532 nm high spectral detection optical unit (9-7), a 532 nm parallel polarization detection optical unit (9-8), a polarization spectroscope (9-10), a high spectral filter (9-11), a 1572 nm detector (9-12), a 1064 nm detector (9-13), a 532 nm polarization receiving detector (9-14), a 532 nm high spectral receiving detector (9-15), a 532 nm parallel polarization receiving detector (9-16); wherein: the output ports of the 1064 nm seed laser (1), the 1572 nm seed laser (2) are connected to the input port of the three-wavelength laser (4) through optical fiber, and a 1572 nm beam emitted by the three-wavelength laser (4) passes through the first spectroscope (12) and is divided into two paths of beams, one path of which passes through the second spectroscope (13) and being divided into two beams, wherein one beam passes through the integral ball (10) and the collimator (11) and is incident on the photoelectric detection unit (9), while the other beam passes through the reflective mirror (16) and then is incident on the visual axis monitoring module (7); and the other path of which and the beams with wavelengths of 532 nm and 1064 nm emitted by the three-wavelength laser (4) simultaneously pass through the transmitting beam expander (5) and are incident into the atmosphere; and the echo signals of the three wavelengths 532/1064/1572 nm scattered by the atmosphere or ground are received by the receiving telescope system (6) and then divided into two paths of beams by the third spectroscope (14) divided by the field of view; wherein one path of which is incident into the visual axis monitoring module (7), and the other path of which passes through the relay optical unit (8) and is incident into the photoelectric detection unit (9); and the output port of the photoelectric detection unit (9) is connected to the input port of the data acquisition and processing unit (15); in the photoelectric detection unit (9), the 1572 nm light passes through the integral ball (10) and the collimator (11) and is incident on the fourth spectroscope (9-1), and after passing through the fourth spectroscope (9-1) and the 1572 nm detection optical unit (9-4), it is incident on the 1572 nm detector (9-12); and the three-wavelength beam passing through the relay optical unit (8) is incident on the fourth spectroscope (9-1) and is divided into two beams, wherein one beam has a wavelength of 1572 nm, and the other beam has wavelengths of 532 nm and 1064 nm; and the beam with the wavelength of 1572 nm beam passes through the 1572 nm detection optical unit (9-4) and is incident on the 1572 nm detector (9-12), and the other beam with the wavelengths of 532 nm and 1064 nm passes through the fifth spectroscope (9-2) and is divided into two beams, one of which has a wavelength of 532 nm and the other has a wavelength of 1064 nm; the 1064 nm beam passes through the 1064 nm detection optical unit (9-5) and is incident on the 1064 nm detector (9-13), and the 532 nm beam is incident on the polarization spectroscope (9-10), and then it is divided into 532 nm vertical light and parallel light beams; and the 532 nm vertical light passes through the 532 nm polarization detection optical unit (9-6) and is incident on the 532 nm polarization receiving detector (9-14), and the 532 nm parallel light passes the sixth spectroscope (9-3) and is divided into two paths of beams; one path of which sequentially passes through the high spectral filter (9-11), 532 nm high spectral detection optical unit (9-7) and is incident on the 532 nm high spectral receiving detector (9-15), and the other path of which passes through the 532 nm parallel polarization detecting optical unit (9-8) and is incident on the 532 nm parallel polarization receiving detector (9-16).

2. The apparatus according to claim 1, wherein the three-wavelength laser (4) is a multi-wavelength laser which simultaneously outputs three wavelengths of 532 nm, 1064 nm, and 1572 nm, and the wavelength of 1572 nm pulsed light is locked with the wavelength of 1572 nm seed laser (2), and the wavelength of 1064 nm pulsed light is locked with the wavelength of 1064 nm seed laser.

3. The apparatus according to claim 1, wherein the apparatus further comprises a 1572 nm laser frequency lock unit (3).

4. The apparatus according to claim 1, wherein the photoelectric detection unit (9) further comprises a narrow band filter (9-9).

5. The apparatus according to claim 1, wherein the apparatus adopts both a method of optical differential absorption and a method of high-spectral resolution detection technology, and finally achieves the atmospheric carbon dioxide concentration and the vertical aerosol profile can be measured simultaneously.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a block diagram of the overall structure of a laser radar system apparatus based on multi-wavelength measurement of carbon dioxide concentration and vertical aerosol profile of the present invention. In the figure: 1—1064 nm seed laser, 2—1572 nm seed laser, 3—1572 nm laser frequency lock unit, 4—three-wavelength laser, 5—transmitting beam expander, 6—receiving telescope system, 7—visual axis monitoring module, 8—relay optical unit, 9—photoelectric detection unit, 10—integral ball, 11—collimator, 12—first spectroscope, 13—second spectroscope, 14—third spectroscope, 15—data acquisition and processing unit, 16—reflective mirror.

(2) FIG. 2 is a structural block diagram of the photoelectric detection unit of the present invention. In the figure: 9-1—fourth spectroscope, 9-2—fifth spectroscope, 9-3—sixth spectroscope, 9-4—1572 nm detection optical unit, 9-5—1064 nm detection optical unit, 9-6—532 nm polarization detection optical unit, 9-7—532 nm high spectral detection optical unit, 9-8—532 nm parallel polarization detection optical unit, 9-9—narrow band filter, 9-10—polarization spectroscope, 9-11—high spectral filter, 9-12—1572 nm detector, 9-13—1064 nm detector, 9-14—532 nm polarization receiving detector, 9-15—532 nm high spectral receiving detector, 9-16—532 nm parallel polarization receiving detector.

DETAILED DESCRIPTION

(3) The present invention will be further described below combined with examples and drawings, but the protection scope of the present invention should not be limited by this. FIG. 1 is a block diagram of the overall structure of the laser radar system apparatus based on multi-wavelength measurement of carbon dioxide concentration and vertical aerosol profile of the present invention. As shown in FIG. 1, the laser radar system for multi-wavelength measurement of atmospheric carbon dioxide concentration and vertical aerosol profile includes 1064 nm seed laser 1, 1572 nm seed laser 2, 1572 nm laser frequency lock unit 3, three-wavelength laser (532/1064/1572 nm) 4, transmitting beam expander 5, receiving telescope system 6, visual axis monitoring module 7, relay optical unit 8, photoelectric detection unit 9, integral ball 10, collimator 11, a first spectroscope 12, a second spectroscope 13, a third spectroscope 14, data acquisition and processing unit 15, reflective mirror 16. The photoelectric detection unit comprises a fourth spectroscope 9-1, a fifth spectroscope 9-2, a sixth spectroscope 9-3, 1572 nm detection optical unit 9-4, 1064 nm detection optical unit 9-5, 532 nm polarization detection optical unit 9-6, 532 nm high spectral detection optical unit 9-7, 532 nm parallel polarization detection optical unit 9-8, narrow band filter 9-9, polarization spectroscope 9-10, high pectral filter 9-11, 1572 nm detector 9-12, 1064 nm detector 9-13, 532 nm polarization receiving detector 9-14, 532 nm high spectral receiving detector 9-15, 532 nm parallel polarization receiving detector 9-16. The positional relationship of the above components is as follows:

(4) The output ports of the 1064 nm seed laser 1, the 1572 nm seed laser 2, the 1782 nm laser frequency lock unit 3 are connected to the input port of the three-wavelength laser 4 through the optical fiber, and the 1572 nm beam emitted by the three-wavelength laser 4 passes through the first spectroscope 12 and is divided into two paths of beams, One path of which passes through the second spectroscope 13 and is divided into two beams, wherein one beam passes through the integral ball 10 and the collimator 11 and is incident on the photoelectric detection unit 9, while the other beam passes through the reflective mirror 16 and then is incident on the visual axis monitoring module 7, and the other path of which and the beams with wavelengths of 532 nm and 1064 nm emitted by the three-wavelength laser 4 simultaneously pass through the transmitting beam expander 5 and are incident into the atmosphere. The echo signals of the three wavelengths 532/1064/1572 nm scattered by the atmosphere or the ground is received by the receiving telescope system 6 and then divided into two paths of beams by the third spectroscope 14 divided by the field of view, wherein one path of which is incident into the visual axis monitoring module 7, and the other path of which passes through the relay optical unit 8 and is incident into the photoelectric detection unit 9. The output port of the photoelectric detection unit 9 is connected to the input port of the data acquisition and processing unit 15.

(5) In the photoelectric detection unit 9, the 1572 nm beam passes through the integral ball 10 and the collimator 11 and is incident on the fourth spectroscope 9-1. After passing through the fourth spectroscope 9-1 and the 1572 nm detection optical unit 9-4, it is incident on the 1572 nm detector 9-12. The three-wavelength beam passing through the relay optical unit 8 is incident on the fourth spectroscope 9-1 and is divided into two beams, wherein one beam has a wavelength of 1572 nm, and the other beam has wavelengths of 532 nm and 1064 nm. One beam with the wavelength of 1572 nm passes through the 1572 nm detection optical unit 9-4 and is incident on the 1572 nm detector 9-12, and the other beam with the wavelengths of 532 nm and 1064 nm passes through the fifth spectroscope 9-2 and is divided into two beams, one of which has a wavelength of 532 nm and the other has a wavelength of 1064 nm. The 1064 nm beam passes through the 1064 nm detection optical unit 9-5 and is incident on the 1064 nm detector 9-13, and the 532 nm beam is incident on the polarization spectroscope, and then it is divided into 532 nm vertical light and parallel light beams. passes through the narrow band filter 9-9 and is incident on the polarization spectroscope 9-10, and then it is further divided into two beams, 532 nm vertical light and parallel light beams. The 532 nm vertical light passes through the 532 nm polarization detection optical unit 9-6 and is incident on the 532 nm polarization receiving detector 9-14, and the 532 nm parallel light passes the sixth spectroscope 9-3 and is divided into two paths of beams, one path of which sequentially passes through the high spectral filter 9-11, 532 nm high spectral detection optical unit 9-7 and is incident on the 532 nm high spectral receiving detector 9-15, and the other path of which passes through the 532 nm parallel polarization detecting optical unit 9-8 and is incident on the 532 nm parallel polarization receiving detector 9-16.

(6) The specific process of the laser radar system based on multi-wavelength measurement of carbon dioxide and aerosol concentration implemented in the present invention is:

(7) {circle around (1)} Through the fourth spectroscope 9-1, the 1572 nm echo signal received by the receiving telescope system 6 and the 1572 nm monitoring signal output by the integral ball 10 and collimator 11 simultaneously pass through the 1572 nm detection optical unit 9-4 and are incident on the 1572 nm detector 9-12. The light energy of the obtained echo signal 1572 nm online and 1572 nm offline is E.sub.1 and E.sub.2, respectively, and the light energy of the monitoring signal 1572 nm online and 1572 nm offline is E.sub.3 and E.sub.4, respectively. Consequently, the atmospheric carbon dioxide column concentration is X.sub.CO.sub.2=log ((E.sub.2.Math.E.sub.3)/(E.sub.1.Math.E.sub.4))/2IWF, wherein IWF is the weight function related to the absorption cross section of carbon dioxide molecule and is related to temperature, humidity, pressure of the atmospheric and laser light working wavelength.

(8) {circle around (2)} Split 532 nm beam and 1064 nm beam through the fifth spectroscope 9-2. The backscattering power of the vertical polarization channel can be obtained when the 532 nm beam passes through the narrow band filter 9-9, the polarization spectroscope 9-10 and the 532 nm polarization detection optical unit 9-6 and then is incident on the 532 nm polarization receiving detector 9-14. The backscattering power of the high spectral channel P.sub.M.sup.∥ can be obtained when passing through the narrow band filter 9-9, the polarization spectroscope 9-10, the high spectral filter 9-11 and the 532 nm high spectral detection optical unit 9-7 and then is incident on the 532 nm high spectral receiving detector 9-15. The backscattering power of the horizontal polarization channel P.sub.C.sup.∥ can be obtained when passing through the narrow band filter 9-9, the polarization spectroscope 9-10 and the 532 nm parallel polarization detection optical unit 9-8 and then is incident on the 532 nm parallel polarization receiving detector 9-16. The vertical profile of the aerosol backscattering coefficient, extinction coefficient, and depolarization ratio can be obtained with the radar equation P.sub.C.sup.⊥(R)=K.sub.1(β.sub.m.sup.⊥+β.sub.a.sup.⊥) exp [−2∫.sub.0.sup.R(α.sub.m+α.sub.a)dr]/R.sup.2, P.sub.M.sup.∥(R)=K.sub.2(T.sub.mβ.sub.m.sup.∥+T.sub.aβ.sub.a.sup.∥) exp [−2∫.sub.0.sup.R(α.sub.m+α.sub.a)dr]/R.sup.2 and P.sub.C.sup.∥(R)=K.sub.3(β.sub.m.sup.∥+β.sub.a.sup.∥) exp [−2∫.sub.0.sup.R(α.sub.m+α.sub.a)dr]/R.sup.2, wherein K.sub.1, K.sub.2 and K.sub.3 are constants of the three channel systems, respectively, β.sub.m.sup.⊥ and β.sub.a.sup.⊥ are the backscattering coefficients of molecules and aerosols in vertical channels, respectively, and β.sub.m.sup.∥ and β.sub.a.sup.∥ are the backscattering coefficients of molecules and aerosols in parallel channels, respectively, and α.sub.m and α.sub.a are the extinction coefficients of molecules and aerosols, respectively, and T.sub.m and T.sub.a are transmittance of the molecules and aerosols when passing through high spectral filter, respectively.