The subject of the PDF (Probability Density Function) of the irradiance fluctuations in a turbulent atmosphere is still unsettled.Theory reliably describes the behavior in the weak turbulence regime,but theoretical de...The subject of the PDF (Probability Density Function) of the irradiance fluctuations in a turbulent atmosphere is still unsettled.Theory reliably describes the behavior in the weak turbulence regime,but theoretical description in the strong and whole turbulence regimes are still controversial.Based on Born perturbation theory,the physical manifestations and correlations of three typical PDF models (Rice-Nakagami,exponential-Bessel and negative-exponential distribution) were theoretically analyzed.It is shown that these models can be derived by separately making circular-Gaussian,strong-turbulence and strong-turbulence-circular-Gaussian approximations in Born perturbation theory,which denies the viewpoint that the Rice-Nakagami model is only applicable in the extremely weak turbulence regime and provides theoretical arguments for choosing rational models in practical applications.In addition,a common shortcoming of the three models is that they are all approximations.A new model,called the Maclaurin-spread distribution,is proposed without any approximation except for assuming the correlation coefficient to be zero.So,it is considered that the new model can exactly reflect the Born perturbation theory.Simulated results prove the accuracy of this new model.展开更多
The functions of Bessel are used extensively in the various problems of the science and the technology. A laser offers practical remote sensing technologies for measuring environmental changes on both global and local...The functions of Bessel are used extensively in the various problems of the science and the technology. A laser offers practical remote sensing technologies for measuring environmental changes on both global and local scales. We describe a computer model that was developed to simulate the performance of three-dimensional (3D) laser radars (lidars). The principle of the problem consists in interpreting information on the absorption of the laser impulse in a spectral line assigned to the chemical body that one studied. Our purpose is to estimate the vertical variation of extinction and atmospheric transmission due to aerosol particles near the air-geographical surface interface. The feasibility and effectiveness of the proposed method is demonstrated by computer simulation.展开更多
The probability density function of irradiance fluctuations in a turbulent atmosphere remains an open topic of research.It is generally considered that the speckle field has an elliptical-Gaussian speckle distribution...The probability density function of irradiance fluctuations in a turbulent atmosphere remains an open topic of research.It is generally considered that the speckle field has an elliptical-Gaussian speckle distribution,but because of its complexity there is still no exact analytical solution.By introducing the concept of random fluctuation intensity and using an equiprobability density ellipse,exact models of the random fluctuation intensity and its phase are proposed.Through theoretical analysis and numerical simulation,it is concluded that the random fluctuation intensity and its corresponding phase are independent only under the circular-Gaussian approximation.展开更多
基金supported by the Special Foundation Program for Taishan Mountain Scholars
文摘The subject of the PDF (Probability Density Function) of the irradiance fluctuations in a turbulent atmosphere is still unsettled.Theory reliably describes the behavior in the weak turbulence regime,but theoretical description in the strong and whole turbulence regimes are still controversial.Based on Born perturbation theory,the physical manifestations and correlations of three typical PDF models (Rice-Nakagami,exponential-Bessel and negative-exponential distribution) were theoretically analyzed.It is shown that these models can be derived by separately making circular-Gaussian,strong-turbulence and strong-turbulence-circular-Gaussian approximations in Born perturbation theory,which denies the viewpoint that the Rice-Nakagami model is only applicable in the extremely weak turbulence regime and provides theoretical arguments for choosing rational models in practical applications.In addition,a common shortcoming of the three models is that they are all approximations.A new model,called the Maclaurin-spread distribution,is proposed without any approximation except for assuming the correlation coefficient to be zero.So,it is considered that the new model can exactly reflect the Born perturbation theory.Simulated results prove the accuracy of this new model.
文摘The functions of Bessel are used extensively in the various problems of the science and the technology. A laser offers practical remote sensing technologies for measuring environmental changes on both global and local scales. We describe a computer model that was developed to simulate the performance of three-dimensional (3D) laser radars (lidars). The principle of the problem consists in interpreting information on the absorption of the laser impulse in a spectral line assigned to the chemical body that one studied. Our purpose is to estimate the vertical variation of extinction and atmospheric transmission due to aerosol particles near the air-geographical surface interface. The feasibility and effectiveness of the proposed method is demonstrated by computer simulation.
基金supported by the Special Foundation Program for Taishan Mountain Scholars
文摘The probability density function of irradiance fluctuations in a turbulent atmosphere remains an open topic of research.It is generally considered that the speckle field has an elliptical-Gaussian speckle distribution,but because of its complexity there is still no exact analytical solution.By introducing the concept of random fluctuation intensity and using an equiprobability density ellipse,exact models of the random fluctuation intensity and its phase are proposed.Through theoretical analysis and numerical simulation,it is concluded that the random fluctuation intensity and its corresponding phase are independent only under the circular-Gaussian approximation.
