Research On The Ultraviolet Spectral Radiation Characteristics Of Atmospheric Background

With the rapid development of Ultraviolet technology, the characteristics of the UV spectral radiation on the background of the earth’s atmosphere have become the research focus in some fields such as space-based target detection, satellite remote sensing, and so on. When spacebome ultraviolet photoelectric detection system observed the earth, the UV radiation from the background of the earth’s atmosphere is received in addition to UV radiation of observed target. In order to obtain the best detection results, the contrast between the background UV radiation and target UV radiation must be strictly distinguished. Therefore, it is an indispensable part of spacebome UV detection to make research on the UV spectral radiation characteristics of atmospheric background which also provides a basis for rational analysis and design the UV detection system.In this dissertation, the simulation study of the transmission characteristics of the UV radiation in the atmosphere was carried out based on the basic theory of atmospheric radiative transfer. The main research work involves the following aspects:1. The scattering effect of atmospheric constituents on UV radiation was elaborated, including Rayleigh scattering and Mie scattering. The scattering characteristics of particles whose size parameters are very small can be described with Rayleigh scattering theory. The scattering characteristics of large size parameter particles should be expounded by Mie theory.2. The methods for sloving the equation of radiative transfer for plane-parallel atmospheres were analyzed. Considering the whole atmospheric layer, upward radiance at the top of the atmosphere was calculated under different conditions in UV spectral region based on adding methods. In the case of no aerosol condition, the relative error of calculated integral radiance is less than10%in the spectral region of0.2-0.4μm. The computed results show that the intensity of radiation for atmospheric background is extremely weak in the region of0.2-0.28μm and it makes little interference on target signal. This spectral region is optimal working band of UV detection instruments.3. The effects of photochemical reaction on the radiative transfer properties of atmospheric background in UV spectral bands have been studied. The photodissociation coefficients of oxygen and ozone at different altitudes were quantificationally computed and the mechanism of the stratospheric ozone photochemistry was discussed in detail. The results indicated that photochemical reaction would change with the vertical distribution of ozone concentration, thus, make an impact on the UV spectral distribution.4. A software related to UV spectral radiative properties of atmospheric background has been developed. Based on Visual C++6.0, the software which could simulate the upward radiance distribution at the top of the atmosphere in UV spectral region was designed. After atmospheric parameters and geometry conditions are input, the data and images of transmittance of the entire atmospheric layer and the UV spectral radiance would be output.