CN103234877A - An inversion method for laser radar data of atmospheric particulate matter particle size spectrum spatial and temporal distribution - Google Patents

Abstract

The present invention discloses an inversion method for laser radar data of atmospheric particulate matter particle size spectrum spatial and temporal distribution. The method comprises: by measuring back scattered echo signal of atmospheric particulate matters via laser radar, accurately inverting to obtain extinction coefficients of atmospheric particulate matters in three wavelengths of infrared, visible and ultraviolet bands at different heights from the ground; building lognormal distribution spectral functions of four aerosol components and parameters thereof, for obtaining refractive indexes at different bands of different aerosols and the mixing ratio of the four aerosol components in different aerosol modes; obtaining the particle size spectrum normalized at 0.55 micron of the extinction coefficient of each aerosol basic component, and comparing with a standard spectrum for authentication; and finally performing iterative calculation to the extinction coefficient spectrums obtained by laser radar surveying to obtain the aerosol mixed volume ratio of each height, thus obtaining atmospheric particulate matter particle size distribution of different heights at different times. According to the inversion method of the invention, valid data are provided for analysis and study of particle properties and variation patterns, especially, an effective means for spatial and temporal change detection for the particle-size spectrum of the atmospheric particulate matters is provided, and active three-dimensional telemetry technology suitable for atmospheric particulate matter particle size distribution is established.

Description

A kind of Atmospheric particulates particle diameter spectrum spatial and temporal distributions laser radar data inversion method

Technical field

The present invention relates to environmental science, laser radar field, be specially a kind of Atmospheric particulates particle diameter spectrum spatial and temporal distributions laser radar data inversion method.

Background technology

Particle is on the rise to the influence of global atmosphere environment, clearly---and Atmospheric particulates aggravation atmospheric pollution level, the infringement people's is healthy, influences normal production and living, destroys the Nature ecologic equilibrium.Recent years, the global energy consumption increases year by year, though the global atmosphere pollution situation has obtained preliminary control, but China's atmosphere quality (especially city atmospheric environment quality) does not have fundamental turn for the better all the time, particularly the atmospheric pollution form that causes of sulphuric dioxide, flue dust and dust is still severe, the situation that urban air-quality exceeds standard is still serious, and particularly pellet pollutes generally and constantly worsens.Can suck particulate pollutant and become primary pollutant in China's atmosphere combined pollution.

At present, monitoring and research to the distribution of Atmospheric particulates particle diameter, the overwhelming majority utilizes the conventional port instrument to carry out at ground floor, to compose the process of spatial and temporal distributions and the conveying of pollutant zone owing to the near the ground middle particle particle diameter of human activity generation, traditional monitoring means is difficult to obtain active data and analysis result.Though the monitoring to high-altitude particle particle diameter is to utilize platforms such as sounding balloon, aircraft, dirigible or iron tower, carry traditional instrument and carry out monitoring, but these means are apparent to the drawback of high-altitude particle particle diameter monitoring, it can't realize the monitoring of high time resolution and the high spatial resolution of long-time continuous, and present stage, China lacked Atmospheric particulates particle diameter distribute permanently effective stereoscopic monitoring technology and method.Laser radar is by measuring the backscattering echo signal of particle in the atmosphere, obtain apart from the atmospheric extinction coefficient of ground differing heights, for analysis and research particle character and Changing Pattern valid data are provided, be the effective means of Atmospheric particulates spatial-temporal characteristics research.The present invention utilizes multi-wavelength laser radar technology and particle particle diameter spectrum spatial and temporal distributions inversion method, realizes that distribution is resolved to the particle particle diameter, sets up to be fit to the active solid method of telemetering that the Atmospheric particulates particle diameter distributes.

Summary of the invention

The purpose of this invention is to provide a kind of Atmospheric particulates particle diameter spectrum spatial and temporal distributions laser radar data inversion method, to solve the difficult problem of laser radar Atmospheric particulates particle diameter distribution spatial and temporal distributions inversion algorithm, expand the range of application of laser radar, realization is carried out rapidly, continuously, is efficiently monitored the Atmospheric particulates spatial-temporal characteristics, satisfies the needs of China's Study on environmental pollution and environmental monitoring.

In order to achieve the above object, the technical solution adopted in the present invention is:

Utilize Atmospheric particulates multi-wavelength Raman laser radar, accurately inverting obtains the extinction coefficient spatial and temporal distributions of Atmospheric particulates three wavelength in infrared, visible and ultraviolet band; Make up the spectral function of the lognormal distribution of four kinds of aerosol components, obtain the blending ratio of four kinds of aerosol components, four kinds of aerosol components in the complex index of refraction of different-waveband and different gasoloid patterns; Inverting obtains each single component aerosol component of normalization in the extinction coefficient spectrum of different wave length, so obtain each gasoloid basis extinction coefficient at the 0.55um place normalized particle diameter spectrum, and verify with standard spectrum; The laser radar extinction coefficient branch that to measure inverting at last carries out integral mean in time and space scale, and the extinction coefficient spectrogram is carried out each height gasoloid mixed volume ratio of iterative computation, Atmospheric particulates particle diameter spectrum spatial and temporal distributions.Described method step is:

(1), list laser radar equation, choosing the laser acquisition wavelength is 1064nm, 532nm and 355nm, corresponding laser radar equation is:

$P_r\left(r\right)=P_{t}k{r}^{-2}\mathrm{\β}\left(r\right)\exp \{-2{\∫}_0^r\mathrm{\α}\left(r^{\′}\right)d{r}^{\′}\}$

P _r(r) be that laser radar receives the backscatter signal power (W) apart from the r place, P _tBe Laser emission power (W), k is laser radar system constant (Wkm ³S _r), be the function of time apart from r, β (r) is the backscattering coefficient (km apart from the r place ^-LS _r ^-1), β (r)=β wherein _a(r)+β _m(r), β _a(r) and β _m(r) be respectively gasoloid and atmospheric molecule at the backscattering coefficient at distance r place, α (r) is the total extinction coefficient (km apart from the r place ^-1), α (r)=α _a(r)+α _m(r), α _a(r) and α _m(r) extinction coefficient at distance r place of expression place atmospheric aerosol and air molecule respectively.

(2), described laser radar equation carried out distance revise, ground be multiply by simultaneously to square r of tested aerosol particle subgroup height in the equation both sides ²:

${\mathrm{<figure-callout\; id="2"\; label="P\; r\; r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">P</figure-callout>}}_r{r}^{}{}^2=k{P}_t[{\mathrm{\&beta;}}_a\left(r\right)+{\mathrm{\&beta;}}_m\left(r\right)]\exp \left\{12{\&Integral;}_0^r\right[{\mathrm{\&alpha;}}_a\left(r^{\&prime;}\right)+{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right)\left]{\mathrm{dr}}^{\&prime;}\right\}$

(3), determine (calibrated altitude) r _cPlace's atmospheric aerosol particle and air molecule extinction coefficient (calibration value), Fernald has provided r _cAtmospheric aerosol particle extinction coefficient under sentencing (back is to integration):

${\mathrm{\&alpha;}}_a\left(r\right)=-\frac{S_a}{S_m}\&CenterDot;{\mathrm{\&alpha;}}_m\left(r\right)+\frac{P\left(r\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2\&CenterDot;\exp \left[2(\frac{S_a}{S_m}-1){\&Integral;}_r^{r_c}{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right)d{r}^{\&prime;}\right]}{\frac{P\left(r_c\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{{\mathrm{\&alpha;}}_a\left(r_c\right)+\frac{S_a}{S_m}{\mathrm{\&alpha;}}_m\left(r_c\right)}+2{\&Integral;}_r^{r_c}P\left(r^{\&prime;}\right){r^{\&prime;}}^2\exp \left[2(\frac{S_a}{S_m}-1){\&Integral;}_r^{r_c}{\mathrm{\&alpha;}}_m\left(r^{\&prime;\&prime;}\right){\mathrm{dr}}^{\&prime;\&prime;}\right]{\mathrm{dr}}^{\&prime;}}---\left(1\right)$

And r _cThe above atmospheric aerosol particle body extinction coefficient (forward direction integration) in place is:

${\mathrm{\&alpha;}}_a\left(r\right)=-\frac{S_a}{S_m}\&CenterDot;{\mathrm{\&alpha;}}_m\left(r\right)+\frac{P\left(r\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2\&CenterDot;\exp [-2(\frac{S_a}{S_m}-1){\&Integral;}_{r_c}^r{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right){\mathrm{dr}}^{\&prime;}]}{\frac{P\left(r_c\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{{\mathrm{\&alpha;}}_a\left(r_c\right)+\frac{S_a}{S_m}{\mathrm{\&alpha;}}_m\left(r_c\right)}-2{\&Integral;}_{r_c}^{r}P\left(r^{\&prime;}\right){r^{\&prime;}}^2\exp [-2(\frac{S_a}{S_m}-1){\&Integral;}_{r_c}^r{\mathrm{\&alpha;}}_m(r^{\&prime;\&prime;}){\mathrm{dr}}^{\&prime;\&prime;}]d{r}^{\&prime;}}---\left(2\right)$

S _a=α _a(r)/β _a(r) be atmospheric aerosol delustring back scattering ratio, depend on the optical maser wavelength of incident, the distribution of yardstick spectrum and the refractive index of atmospheric aerosol particle, this value is a nondimensional numerical value, and numerical values recited is between 0 to 90.Here suppose that it is constant, this means the yardstick spectrum of atmospheric aerosol particle and chemical composition not with height change, the variation of atmospheric aerosol particle delustring and scattering properties only is the change owing to its number density.For 532nm wavelength, S _a=50, for the 1064nm wavelength, establish S _a=40.S is compared in the delustring back scattering of air molecule _m=α _m(r)/β _m(r)=8 π/3.The extinction coefficient α of air molecule _m(r) can or use temperature and humidity pressure normal atmosphere pattern by temperature and humidity pressure meteorological sounding data in the real atmosphere, obtain the density of air molecule, be calculated by molecule Rayleigh scattering theory again.Calibrated altitude r _cBe to determine by choosing the height that is close to the clean atmosphere layer place that does not contain atmospheric aerosol particle.P on this height (r) r ²/ β _mThe value minimum.The atmospheric aerosol extinction coefficient boundary value α of 532nm wavelength _a(r _c) by atmospheric aerosol scattering than 1+ β _a(r _c)/β _m(r _c)=1.01 determine, the atmospheric aerosol extinction coefficient boundary value of 1064nm wavelength is 1.08 to determine by the atmospheric aerosol scattering ratio.

(4), obtain gasoloid behind the extinction coefficient of 1064nm, 532nm and 355nm wavelength, draw the extinction coefficient profile.

(5), coal smoke type, thick dirt, ocean particle and four kinds of gasoloid bases of water soluble particle are proposed, set up the normal state logarithm energy spectrum function of four kinds of bases:

$\frac{\mathrm{dN}}{d\log r}=\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">N</figure-callout>}}{\sqrt{2\mathrm{\&pi;}}\log \mathrm{\&sigma;}}\exp [-\frac{{(\log r-\log r_m)}^2}{2\left(\log \mathrm{\&sigma;}\right)}]---\left(3\right)$

And calculating obtains four kinds of gasoloid basis spectrum parameters value r separately _mOneself and σ.

(6), the gasoloid pattern is divided into continent type gasoloid, ocean type gasoloid and aerosols from major cities model, by data four kinds of gasoloid bases of calculating proportion in three kinds of gasoloid patterns.

(7), for each gasoloid basis, introduce parameter particle average external volume V _j(um ³) and population concentration N _j(population/cm ³) two parameters, obtain four kinds of gasoloid basis particle average external volumes and particle concentration value by calculating.

(8), average external volume V _j(um ³) and population concentration N _j(population/cm ³) two parameters can be expressed as:

$V_j=\frac{4\mathrm{\&pi;}}{3N_j}\underset{0}{\overset{+\&infin;}{\&Integral;}}{r}^3\frac{d{N}_j\left(r\right)}{\mathrm{dr}}\mathrm{dr}---\left(4\right)$

The population that Nj is each composition when 0.55 micron is located extinction coefficient and is 1 (km-1).

v _j＝n _j×V _j （5）

v _jBe the cumulative volume of corresponding each composition, n _jBe the population concentration of each composition.Volume ratio C of every kind of aerosol component so _jFor:

$C_j=\frac{v_j}{v}---\left(6\right)$

By (4) and (5) formula, can obtain total population concentration:

$n=\underset{j}{\mathrm{\&Sigma;}}{n}_j=v\underset{j}{\mathrm{\&Sigma;}}\frac{C_j}{V_j}---\left(7\right)$

Population density number percent then:

$\frac{n_j}{n}=-\frac{\frac{C_j}{V_j}}{\underset{j}{\mathrm{\&Sigma;}}\frac{C_j}{V_j}}---\left(8\right)$

Total extinction coefficient:

$K^{\mathrm{ext}}=N\underset{j}{\mathrm{\&Sigma;}}\frac{n_j}{n}{K}_j^{\mathrm{ext}}\left(\mathrm{\&lambda;}\right)---\left(9\right)$

And to obtain each gasoloid basis delustring be 1 (km at the 550nm place ^-1) time particle spectra distribute; K wherein ^ExtRepresent total extinction coefficient, Represent that each basis is at the extinction coefficient of wavelength X.

(9), calculate the parameter that obtains according to step (4), step (6) and step (7), can to obtain continental gasoloid be 1 (km at the 550nm extinction coefficient to function (formula 9) and in the step (8) ^-1) grain spectrum distribution plan.

(10), the grain spectrum distribution plan that step (9) is obtained and the gasoloid transmitance in the United States standard atmosphere compare the validity that checking grain spectrum distributes.

(11), the extinction coefficient of the different wave length that step (4) inverting is obtained carries out integration with average, to obtain the extinction coefficient that satisfies the computing demand at room and time.

(12), the extinction coefficients of different detection wavelength that the particle spectra of each gasoloid basis in the step (8) and step (11) are obtained carry out interative computation, obtain the scale factor in differing heights and different time sections.By changing the concentration proportioning of basis, the spectrum extinction coefficient of calculating, extinction coefficient and the measured data of getting corresponding laser radar wavelength place compare, and obtain gasoloid basis concentration proportioning at the differing heights place by the method for least square method.

$S=\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}[\mathrm{Simu}\left({\mathrm{\&lambda;}}_i\right)-\mathrm{Lidar}\left({\mathrm{\&lambda;}}_i\right){]}^2$

λ: the i=1 of different wave length place, 2,3 corresponding 355nm, 532nm, 1064nm

Simu (λ): the Aerosol Extinction that the MIE scattering analogue calculates

Lidar (λ): the Aerosol Extinction of laser radar actual measurement.

(13), with the particle spectra of each gasoloid basis in the step (8) with the scale factor of step (12) is carried out computing obtain Atmospheric particulates particle diameter spectrum spatial and temporal distributions:

$\frac{\mathrm{dN}}{d\log r}=\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}\frac{N_i}{\sqrt{2\mathrm{\&pi;}}\log \mathrm{\&sigma;}}\exp [-\frac{{(\log r_i-\log r_{m,i})}^2}{2\left(\log \mathrm{\&sigma;}\right)}]$

I: corresponding gasoloid basis dust is water-soluble, the sea salt coal smoke;

N: the concentration value of each corresponding basis;

r _m, i: each basis particle diameter lognormal distribution intermediate value;

r _i: each basis particle diameter;

This invention can high time resolution and high spatial resolution obtain Atmospheric particulates particle diameter spectrum spatial and temporal distributions, its time resolution is up to every group of data of 5min, the highest 7.5m that can be of spatial resolution.

The present invention's beneficial effect compared with prior art:

(1) the present invention can long-time online high time resolution and high spatial resolution Atmospheric particulates particle diameter spectrum is distributed carry out main remote sensing survey, this be traditional instrument can't realize.

(2) the present invention can obtain the optical property of particle when carrying out Atmospheric particulates particle diameter spectrum distribution stereoscopic monitoring, realizes the Atmospheric particulates multiparameter is extracted simultaneously.

(3) the present invention also can usefully carry out horizontal scanning to Atmospheric particulates particle diameter spectrum and measure except can the Atmospheric particulates particle diameter spectrum distribution vertical features in high-altitude being carried out the remote sensing survey analysis.

(4) the present invention calculates and is convenient to sequencing, can be that unattended automatic inversion is measured.

Description of drawings

The process flow diagram that Fig. 1 realizes for the inventive method;

The extinction coefficient profile figure of the 1064nm that Fig. 2 obtains for the laser radar inverting, 532nm and 355nm wavelength;

Fig. 3 is that gasoloid basis is at the extinction coefficient performance plot of different wave length;

Fig. 4 is that continental aerosol particle spectrum distributes;

Fig. 5 is Atmospheric particulates particle diameter spectrum distribution plan.

Embodiment

A kind of Atmospheric particulates particle diameter spectrum spatial and temporal distributions laser radar data inversion method that proposes in according to the present invention is that example is analyzed with certain experimental data.Lognormality particle diameter distributed model by known atmospheric aerosol basis, and gasoloid basic granules thing particle is at the complex index of refraction index at different-waveband place, by MIE scattering calculation procedure, obtain the spectrum extinction coefficient under given concentration and mutual proportioning situation.And multi-wavelength laser radar can be in ultraviolet, visible, Aerosol Extinction that three wavelength points places of near infrared provide the different spaces place.By setting initial gasoloid mode parameter (continent type gasoloid), change the wherein concentration proportioning relation of each basis, calculating is at the extinction coefficient at corresponding wavelength place, pass through fitting method, the final CONCENTRATION DISTRIBUTION that obtains only aerosol model, on this basis by known basis particle diameter distributed model, calculate the total particle diameter distribution profile of particle corresponding under the current extinction coefficient situation again.

Laser radar not only can obtain subaerial extinction coefficient, and can obtain extinction coefficient spatial and temporal distributions on the differing heights, by get the method for average according to certain altitude, can obtain distribution and the corresponding basis proportioning of particle on the differing heights.

As shown in Figure 1, the inventive method performing step is as follows:

(1), list laser radar equation, choosing the laser acquisition wavelength is 1064nm, 532nm and 355nm, corresponding laser radar equation is:

$P_r\left(r\right)=P_{t}k{r}^{-2}\mathrm{\&beta;}\left(r\right)\exp \{-2{\&Integral;}_0^r\mathrm{\&alpha;}\left(r^{\&prime;}\right){\mathrm{dr}}^{\&prime;}\}$

P _r(r) be that laser radar receives the backscatter signal power (W) apart from the r place, P _tBe Laser emission power (W), k is laser radar system constant (Wkm ³S _r), be the function of time apart from r, β (r) is the backscattering coefficient (km apart from the r place ^-1S _r ^-1), β (r)=β wherein _a(r)+β _m(r), β _a(r) and β _m(r) be respectively gasoloid and atmospheric molecule at the backscattering coefficient at distance r place, α (r) is the total extinction coefficient (km apart from the r place ^-1), α (r)=α _a(r)+α _m(r), α _a(r) and α _m(r) extinction coefficient at distance r place of expression place atmospheric aerosol and air molecule respectively.

(2), described laser radar equation carried out distance revise, ground be multiply by simultaneously to square r of tested aerosol particle subgroup height in the equation both sides ²:

${\mathrm{<figure-callout\; id="2"\; label="P\; r\; r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">P</figure-callout>}}_r{r}^{}{}^2=k{P}_t[{\mathrm{\&beta;}}_a\left(r\right)+{\mathrm{\&beta;}}_m\left(r\right)]\exp \left\{12{\&Integral;}_0^r\right[{\mathrm{\&alpha;}}_a\left(r^{\&prime;}\right)+{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right)\left]{\mathrm{dr}}^{\&prime;}\right\}$

(3), determine (calibrated altitude) r _cPlace's atmospheric aerosol particle and air molecule extinction coefficient (calibration value), Fernald has provided r _cAtmospheric aerosol particle extinction coefficient under sentencing (back is to integration):

${\mathrm{\&alpha;}}_a\left(r\right)=-\frac{S_a}{S_m}\&CenterDot;{\mathrm{\&alpha;}}_m\left(r\right)+\frac{P\left(r\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2\&CenterDot;\exp \left[2(\frac{S_a}{S_m}-1){\&Integral;}_r^{r_c}{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right){\mathrm{dr}}^{\&prime;}\right]}{\frac{P\left(r_c\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{{\mathrm{\&alpha;}}_a\left(r_c\right)+\frac{S_a}{S_m}{\mathrm{\&alpha;}}_m\left(r_c\right)}+2{\&Integral;}_r^{r_c}P\left(r^{\&prime;}\right){r^{\&prime;}}^2\exp [2(\frac{S_a}{S_m}-1){\&Integral;}_r^{r_c}-{\mathrm{\&alpha;}}_m\left(r^{\&prime;\&prime;}\right)d{r}^{\&prime;\&prime;}]d{r}^{\&prime;}}---\left(1\right)$

And r _cThe above atmospheric aerosol particle body extinction coefficient (forward direction integration) in place is:

${\mathrm{\&alpha;}}_a\left(r\right)=-\frac{S_a}{S_m}\&CenterDot;{\mathrm{\&alpha;}}_m\left(r\right)+\frac{P\left(r\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2\&CenterDot;\exp [-2(\frac{S_a}{S_m}-1){\&Integral;}_{r_c}^r{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right){\mathrm{dr}}^{\&prime;}]}{\frac{P\left(r_c\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{{\mathrm{\&alpha;}}_a\left(r_c\right)+\frac{S_a}{S_m}{\mathrm{\&alpha;}}_m\left(r_c\right)}-2{\&Integral;}_{r_c}^{r}P\left(r^{\&prime;}\right){r^{\&prime;}}^2\exp [-2(\frac{S_a}{S_m}-1){\&Integral;}_{r_c}^r{\mathrm{\&alpha;}}_m\left(r^{\&prime;\&prime;}\right){\mathrm{dr}}^{\&prime;\&prime;}]{\mathrm{dr}}^{\&prime;}}---\left(2\right)$

S _a=α _a(r)/β _a(r) be atmospheric aerosol delustring back scattering ratio, it depends on the optical maser wavelength of incident, the yardstick spectrum of atmospheric aerosol particle distributes and refractive index, and numerical value is generally between 0 to 90.Here suppose that it is constant, this means the yardstick spectrum of atmospheric aerosol particle and chemical composition not with height change, the variation of atmospheric aerosol particle delustring and scattering properties only is the change owing to its number density.For 532nm wavelength, S _a=50, for the 1064nm wavelength, establish S _a=40.S is compared in the delustring back scattering of air molecule _m=α _m(r)/β _m(r)=8 π/3.The extinction coefficient α of air molecule _m(r) can resemble the sounding data or use the wet normal atmosphere pattern of temperature and pressure by temperature and pressure moisture in the real atmosphere, obtain the density of air molecule, be calculated by molecule Rayleigh scattering theory again.Calibrated altitude r _cBe to determine by choosing the height that is close to the clean atmosphere layer place that does not contain atmospheric aerosol particle.P on this height (r) r ²/ β _mThe value minimum.The atmospheric aerosol extinction coefficient boundary value α of 532nm wavelength _a(r _c) by atmospheric aerosol scattering than 1+ β _a(r _c)/β _m(r _c)=1.01 determine, the atmospheric aerosol extinction coefficient boundary value of 1064nm wavelength is 1.08 to determine by the atmospheric aerosol scattering ratio.

(4), obtain gasoloid behind the extinction coefficient of 1064nm, 532nm and 355nm wavelength, draw the extinction coefficient profile, as shown in Figure 2, be respectively gasoloid and survey wavelength at the extinction coefficient of differing heights in difference;

(5), coal smoke type, thick dirt, ocean particle and four kinds of gasoloid bases of water soluble particle are proposed, set up the normal state logarithm energy spectrum function of four kinds of bases:

$\frac{\mathrm{dN}}{d\log r}=\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">N</figure-callout>}}{\sqrt{2\mathrm{\&pi;}}\log \mathrm{\&sigma;}}\exp [-\frac{{(\log r-\log r_m)}^2}{2\left(\log \mathrm{\&sigma;}\right)}]---\left(3\right)$

And calculating obtains four kinds of gasoloid basis spectrum parameters value r separately _mAnd σ, as shown in table 1.

Table 1, lognormal distribution parameter

Type	r m	σ
			The coal smoke class	0.0118	2.000
Thick dirt	0.500	2.99
			The ocean particle	0.30	2.51
Water soluble particle	0.0050	2.99

(6), the gasoloid pattern is divided into continent type gasoloid, ocean type gasoloid and aerosols from major cities model, calculate four kinds of gasoloid bases proportion in three kinds of gasoloid patterns by data, as shown in table 2.Select to use different aerosol types to calculate according to different observation conditions.

Table 2, gasoloid basis proportion in different gasoloid patterns

Type	Thick dirt	Water soluble particle	The ocean particle	Coal smoke type
					Continental	0.70	0.29		0.01
The ocean		0.05	0.95
					The city	0.17	0.61		0.22

(7), for each gasoloid basis composition, introduce parameter particle average external volume V _j(um ³) and population concentration N _j(population/cm ³) two parameters, obtain four kinds of gasoloid basis particle average external volumes and particle concentration value by calculating, as shown in table 3.

Table 3, aerosol component particle average external volume and particle concentration

	Thick dirt	Water soluble particle	The ocean particle	The coal smoke class
					V j(μm 3)	113.98352	113.98352×10 -6	5.14441	59.777553×10 -6
N j(/cm 3)	54.73400	1.86850×10 6	276.0500010	1.805820×10 6

(8), average external volume V _j(um ³) and population concentration N _j(population/cm ³) two parameters can be expressed as:

$V_j=\frac{4\mathrm{\&pi;}}{3N_j}\underset{0}{\overset{+\&infin;}{\&Integral;}}{r}^3\frac{d{N}_j\left(r\right)}{\mathrm{dr}}\mathrm{dr}---\left(4\right)$

The population that Nj is each composition when 0.55 micron is located extinction coefficient and is 1 (km-1).

v _j＝n _j×V _j （5）

v _jBe the cumulative volume of corresponding each composition, n _jBe the population concentration of each composition.Volume ratio C of every kind of aerosol component so _jFor:

$C_j=\frac{v_j}{v}---\left(6\right)$

By (4) and (5) formula, can obtain total population concentration:

$n=\underset{j}{\mathrm{\&Sigma;}}{n}_j=v\underset{j}{\mathrm{\&Sigma;}}\frac{C_j}{V_j}---\left(7\right)$

Population density number percent then

$\frac{n_j}{n}=-\frac{\frac{C_j}{V_j}}{\underset{j}{\mathrm{\&Sigma;}}\frac{C_j}{V_j}}---\left(8\right)$

Total extinction coefficient:

$K^{\mathrm{ext}}=N\underset{j}{\mathrm{\&Sigma;}}\frac{n_j}{n}{K}_j^{\mathrm{ext}}\left(\mathrm{\&lambda;}\right)---\left(9\right)$

K wherein ^ExtRepresent total extinction coefficient,

Represent that each basis is at the extinction coefficient of wavelength X.

The thick dirt of table 5, coal smoke, the complex refractive index of water soluble particle

In conjunction with each gasoloid basis complex index of refraction, each gasoloid basis extinction coefficient that obtains as shown in Figure 3 is 1 (km at the 550nm place ^-1) time different wave length the extinction coefficient characteristic pattern, as shown in Table 2, be zero for type gasoloid ocean, continent particle, so the extinction coefficient characteristic at different wave length of thick dirt, water soluble particle and coal smoke type gasoloid basis is only arranged among Fig. 3.

(9), calculate the parameter that obtains according to step (4), step (6) and step (7), and function (formula 9) can obtain as shown in Figure 3 in the step (8), and continental gasoloid is 1 (km at the 550nm extinction coefficient ^-1) grain spectrum distribution plan, obtain under continental gasoloid pattern the population concentration of the different-grain diameter of thick dirt, water soluble particle and coal smoke type gasoloid basis.

(10), the grain spectrum distribution plan that step (9) is obtained and the gasoloid transmitance in the United States standard atmosphere compare the validity that checking grain spectrum distributes.

(11), the extinction coefficient of the different wave length that step (4) inverting is obtained carries out integration with average, to obtain the extinction coefficient that satisfies the computing demand at room and time.

(12), the extinction coefficients of different detection wavelength that the particle spectra of each gasoloid basis in the step (8) and step (11) are obtained carry out interative computation, obtain the scale factor in differing heights and different time sections.By changing the concentration proportioning of basis, the spectrum extinction coefficient of calculating, extinction coefficient and the measured data of getting corresponding laser radar wavelength place compare, and obtain gasoloid basis concentration proportioning at the differing heights place by the method for least square method.

$S=\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}{[\mathrm{Simu}\left({\mathrm{\&lambda;}}_i\right)-\mathrm{Lidar}\left({\mathrm{\&lambda;}}_i\right)]}^2$

λ: the i=1 of different wave length place, 2,3 corresponding 355nm, 532nm, 1064nm

Simu (λ): the Aerosol Extinction that the MIE scattering analogue calculates

Lidar (λ): the Aerosol Extinction of laser radar actual measurement

(13) with the particle spectra of each gasoloid basis in the step (8) with the scale factor of step (8) is carried out computing obtain Atmospheric particulates particle diameter spectrum spatial and temporal distributions.Concentration is carried out computing and is obtained Atmospheric particulates particle diameter spectrum space-time branch:

$\frac{\mathrm{dN}}{d\log r}=\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}\frac{{\mathrm{<figure-callout\; id="2"\; label="N\; i"\; filenames="HDA00003032799200021.png,HDA00003032799200032.png"\; state="\{\{state\}\}">N</figure-callout>}}_i}{\sqrt{2\mathrm{\&pi;}}\log \mathrm{\&sigma;}}\exp [-\frac{{(\log r_i-\log r_{m,i})}^2}{2\left(\log \mathrm{\&sigma;}\right)}]$

I: corresponding gasoloid basis dust is water-soluble, the sea salt coal smoke;

N: the concentration value of each corresponding basis;

r _m, i: each basis particle diameter lognormal distribution intermediate value;

r _i: each basis particle diameter;

As shown in Figure 5, in aerosol particle spectrum near the ground, proportion water-soluble and that coal smoke class small-particle accounts for is relatively large.And dust type gasoloid proportion is less.Along with the dust-type gasoloid that highly raises accounts for to such an extent that proportion increases relatively, and the water-soluble and shared proportion of coal smoke class gasoloid elementary particle reduces relatively.The present invention can high time resolution and high spatial resolution obtain Atmospheric particulates particle diameter spectrum spatial and temporal distributions, its time resolution is up to every group of data of 5min, the highest 7.5m that can be of spatial resolution.

The non-elaborated part of the present invention belongs to those skilled in the art's common practise.

Claims (2)

1. an Atmospheric particulates particle diameter is composed spatial and temporal distributions laser radar data inversion method, it is characterized in that performing step is:

(1) list laser radar equation, choosing the laser acquisition wavelength is 1064nm, 532nm and 355nm, and corresponding laser radar equation is:

$P_r\left(r\right)=P_{t}k{r}^{-2}\mathrm{\&beta;}\left(r\right)\exp \{-2{\&Integral;}_0^r\mathrm{\&alpha;}\left(r^{\&prime;}\right){\mathrm{dr}}^{\&prime;}\}$

P _r(r) be that laser radar receives the backscatter signal power (W) apart from the r place, P _tBe Laser emission power (W), k is laser radar system constant (Wkm ³S _r), be the function of time apart from r, β (r) is the backscattering coefficient (km apart from the r place ^-1S _r ^-1), β (r)=β wherein _a(r)+β _m(r), β _a(r) and β _m(r) be respectively gasoloid and atmospheric molecule at the backscattering coefficient at distance r place, α (r) is the total extinction coefficient (km apart from the r place ^-1), α (r)=α _a(r)+α _m(r), α _a(r) and α _m(r) extinction coefficient at distance r place of expression place atmospheric aerosol and air molecule respectively;

(2) described laser radar equation is carried out distance correction, ground be multiply by simultaneously to square r of tested aerosol particle subgroup height in the equation both sides ²

$P_r{r}^2=k{P}_t[{\mathrm{\&beta;}}_a\left(r\right)+{\mathrm{\&beta;}}_m\left(r\right)]\exp \left\{12{\&Integral;}_0^r\right[{\mathrm{\&alpha;}}_a\left(r^{\&prime;}\right)+{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right)]{\mathrm{dr}}^{\&prime;}\};$

(3) determine calibrated altitude r _cPlace atmospheric aerosol particle and air molecule extinction coefficient, i.e. calibration value, Fernald has provided r _cBehind the atmospheric aerosol particle under sentencing to the integration extinction coefficient:

${\mathrm{\&alpha;}}_a\left(r\right)=-\frac{S_a}{S_m}\&CenterDot;{\mathrm{\&alpha;}}_m\left(r\right)+\frac{P\left(r\right)r^2\&CenterDot;\exp \left[2(\frac{S_a}{S_m}-1){\&Integral;}_r^{r_c}{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right){\mathrm{dr}}^{\&prime;}\right]}{\frac{P\left(r_c\right)r^2}{{\mathrm{\&alpha;}}_a\left(r_c\right)+\frac{S_a}{S_m}{\mathrm{\&alpha;}}_m\left(r_c\right)}+2{\&Integral;}_r^{r_c}P\left(r^{\&prime;}\right){r^{\&prime;}}^2\exp [2(\frac{S_a}{S_m}-1){\&Integral;}_r^{r_c}-{\mathrm{\&alpha;}}_m\left(r^{\&prime;\&prime;}\right){\mathrm{dr}}^{\&prime;\&prime;}]{\mathrm{dr}}^{\&prime;}}---\left(1\right)$

And r _cThe above atmospheric aerosol particle forward direction integration extinction coefficient in place is:

${\mathrm{\&alpha;}}_a\left(r\right)=-\frac{S_a}{S_m}\&CenterDot;{\mathrm{\&alpha;}}_m\left(r\right)+\frac{P\left(r\right)r^2\&CenterDot;\exp [-2(\frac{S_a}{S_m}-1){\&Integral;}_{r_c}^r{\mathrm{\&alpha;}}_m\left(r^{\&prime;}\right){\mathrm{dr}}^{\&prime;}]}{\frac{P\left(r_c\right)r^2}{{\mathrm{\&alpha;}}_a\left(r_c\right)+\frac{S_a}{S_m}{\mathrm{\&alpha;}}_m\left(r_c\right)}-2{\&Integral;}_{r_c}^{r}P\left(r^{\&prime;}\right){r^{\&prime;}}^2\exp [-2(\frac{S_a}{S_m}-1){\&Integral;}_{r_c}^r{\mathrm{\&alpha;}}_m\left(r^{\&prime;\&prime;}\right){\mathrm{dr}}^{\&prime;\&prime;}]{\mathrm{dr}}^{\&prime;}}---\left(2\right)$

S _a=α _a(r)/β _a(r) be atmospheric aerosol delustring back scattering ratio, it depends on the optical maser wavelength of incident, the yardstick spectrum of atmospheric aerosol particle distributes and refractive index, for 532nm wavelength, S _a=50, for 1064nm wavelength, S _a=40; S is compared in the delustring back scattering of air molecule _m=α _m(r)/β _m(r)=8 π/3; The extinction coefficient α of air molecule _m(r) by temperature and humidity pressure meteorological sounding data in the real atmosphere or use temperature and humidity pressure normal atmosphere pattern, obtain the density of air molecule, calculated by molecule Rayleigh scattering theory again; Calibrated altitude r _cDetermine P on this height (r) r by choosing the height that is close to the clean atmosphere layer place that does not contain atmospheric aerosol particle ²/ β _mThe value minimum; The atmospheric aerosol extinction coefficient boundary value α of 532nm wavelength _a(r _c) by atmospheric aerosol scattering than 1+ β _a(r _c)/β _m(r _c)=1.01 determine, the atmospheric aerosol extinction coefficient boundary value of 1064nm wavelength is 1.08 to determine by the atmospheric aerosol scattering ratio;

(4) obtain gasoloid behind the extinction coefficient of 1064nm, 532nm and 355nm wavelength, draw the extinction coefficient profile;

(5) propose coal smoke type, thick dirt, ocean particle and four kinds of gasoloid bases of water soluble particle, set up the normal state logarithm energy spectrum function of basis, N represents population, and r represents aerodynamic size:

$\frac{\mathrm{dN}}{d\log r}=\frac{N}{\sqrt{2\mathrm{\&pi;}}\log \mathrm{\&sigma;}}\exp [-\frac{{(\log r-\log r_m)}^2}{2\left(\log \mathrm{\&sigma;}\right)}]---\left(3\right)$

And calculating obtains four kinds of gasoloid basis spectrum parameters value r separately _mAnd σ, pass through r _mThe particle diameter that calculates basis with the σ value distributes, and particle concentration distributes under the type gasoloid pattern of continent;

(6) the gasoloid pattern is divided into continent type gasoloid, ocean type gasoloid and aerosols from major cities model, calculates four kinds of gasoloid bases proportion in three kinds of gasoloid patterns by data;

(7) for each gasoloid basis, introduce parameter particle average external volume V _j(um ³) and population concentration N _j(population/cm ³) two parameters, obtain four kinds of gasoloid basis particle average external volumes and particle concentration value by calculating;

(8) average external volume V _jWith population concentration N _jTwo parameters are expressed as:

$V_j=\frac{4\mathrm{\&pi;}}{3N_j}\underset{0}{\overset{+\&infin;}{\&Integral;}}{r}^3\frac{d{N}_j\left(r\right)}{\mathrm{dr}}\mathrm{dr}---\left(4\right)$

N _jThe population that is each composition when 0.55 micron is located extinction coefficient and is 1 (km-1);

v _j＝n _j×V _j （5）

v _jBe the cumulative volume of corresponding each composition, n _jBe the population concentration of each composition, the volume ratio C of every kind of aerosol component _jFor:

$C_j=\frac{v_j}{v}---\left(6\right)$

By (5) and (6) formula, obtain total population concentration:

$n=\underset{j}{\mathrm{\&Sigma;}}{n}_j=v\underset{j}{\mathrm{\&Sigma;}}\frac{C_j}{V_j}---\left(7\right)$

Population density number percent then:

$\frac{n_j}{n}=-\frac{\frac{C_j}{V_j}}{\underset{j}{\mathrm{\&Sigma;}}\frac{C_j}{V_j}}---\left(8\right)$

Total extinction coefficient,

$K^{\mathrm{ext}}=N\underset{j}{\mathrm{\&Sigma;}}\frac{n_j}{n}{K}_j^{\mathrm{ext}}\left(\mathrm{\&lambda;}\right)---\left(9\right)$

And to obtain each gasoloid basis delustring be 1 (km at the 550nm place ^-1) time particle spectra distribute; K wherein ^ExtRepresent total extinction coefficient,

Represent that each basis is at the extinction coefficient of wavelength X;

(9) it is 1 (km at 550n m extinction coefficient that the middle function (formula 9) of the parameter that obtains according to step (4), step (6) and step (7) calculating, and step (8) obtains continental gasoloid ^-1) grain spectrum distribution plan;

(10) the grain spectrum distribution plan that step (9) is obtained and the gasoloid transmitance in the United States standard atmosphere compare, the validity that checking grain spectrum distributes;

(11) extinction coefficient of the different wave length that step (4) inverting is obtained carries out integration and average at room and time, to obtain the extinction coefficient that satisfies the computing demand;

(12) particle spectra with each gasoloid basis in the step (8) carries out interative computation with the different extinction coefficients of surveying wavelength that step (11) obtains, obtain the scale factor in differing heights and different time sections, by changing the concentration proportioning of basis, the spectrum extinction coefficient that calculates, extinction coefficient and the measured data of getting corresponding laser radar wavelength place compare, obtain gasoloid basis concentration proportioning at the differing heights place by the method for least square method

$S=\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}[\mathrm{Simu}\left({\mathrm{\&lambda;}}_i\right)-\mathrm{Lidar}\left({\mathrm{\&lambda;}}_i\right){]}^2$

λ: the i=1 of different wave length place, 2,3 corresponding 355nm, 532nm, 1064nm

Simu (λ): the Aerosol Extinction that the MIE scattering analogue calculates

Lidar (λ): the Aerosol Extinction of laser radar actual measurement

S: ask for the S value hour, corresponding concentration proportioning value;

(13) with the particle spectra of each gasoloid basis in the step (8) with the scale factor of step (12) is carried out computing obtain Atmospheric particulates particle diameter spectrum spatial and temporal distributions:

$\frac{\mathrm{dN}}{d\log r}=\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}\frac{N_i}{\sqrt{2\mathrm{\&pi;}}\log \mathrm{\&sigma;}}\exp [-\frac{{(\log r_i-\log r_{m,i})}^2}{2\left(\log \mathrm{\&sigma;}\right)}]$

I: corresponding gasoloid basis: coal smoke type, thick dirt, ocean particle and water soluble particle;

N: the concentration value of each corresponding basis;

r _m, i: each basis particle diameter lognormal distribution intermediate value

r _i: each basis particle diameter.

2. a kind of Atmospheric particulates particle diameter according to claim 1 is composed spatial and temporal distributions laser radar data inversion method, it is characterized in that: in the described step (13), the Atmospheric particulates particle diameter that obtains of high time resolution and high spatial resolution is composed spatial and temporal distributions, its high time resolution is 5min, and high spatial resolution is 7.5m.

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