With the development of the research on climatic variation, environmental monitoring, remote sensing and other fields, the importance of atmospheric radiation transmission has become increasingly prominent. Radiative transfer simulation, atmospheric transmissivity and spectral radiance calculation, and the inversion of the meteorological elements are necessary. Therefore, it is urgent to develop a fast, accurate and widely used radiative transfer model. A highly modular and widely used radiative transfer simulation software- the atmospheric radiative transfer simulator(ARTS) is presented, including research background, the main function of the software, the calculation process, the application fields, and some simulation examples. At present, the radiative transfer model has been applied to the forward simulation system and inversion system of Odin/SMR, MASTER and SOPRANO detectors successfully.

An analysis of visibility in China from 1980 to 2008 was conducted based on 29 years’ data that was collected from over 350 meteorological observation stations. In order to find out the trends and influencing factors of visibility from different areas, grid-based population density was also used to classify different types of stations. Results show that visibility decreased steadily after 1980, especially in Eastern China. This kind of decrease usually happened in areas that have high population density and relative humidity (RH). The amplitude and frequency of visibility decline have a good relativity with the population that surrounded the observational station. However, results of Northwest China shows an increase in regional visibility, especially in the areas with a relatively low RH and low population, such as Inner Mongolia and Xinjiang. This might be caused by the decrease in frequency and intensity of sand storm in recent years. The decrease of visibility in South China is the most significant, which might be caused by economical production activities. The regional correlations of visibility between different observational sites showed an obvious increase in Northern and Eastern China, which reflects the aggravation of regional pollution in these areas.

Sellmeier dispersion formula and Lorentz-Lorenz function are two common formulas that describe the relationship between the refractive index of materials and the wavelength of the incoming light wave at different temperatures. To examine the differences between the calculation results based on these two formulas, two theoretical models are used to simulate the refractive index, group index, group velocity dispersion (GVD), and the third order dispersion (TOD) of distilled water within the wavelength range of 400～1100 nm at four different temperatures respectively. The differences between the calculated results are analyzed. It is shown that the difference between refractive index and group index is rather small, but the differences in GVD and TOD can be relatively large.

Spectral inversion method is used to simulate the distortions of phase screen. By setting the parameters of laser emission system, the peak Strehl ratio of far field spot of emitting light and spot of receiving light is calculated. According to the definition of the correlation of Pearson, the characteristic parameters of the change trend of calculated peak Strehl ratio, correlation coefficient with the transmission effect (turbulence effects characteristic parameter D/r0, thermal blooming heat distortion parameters Nd) are obtained. The relative deviation of Strehl of emitting light and receiving light is analyzed, and its rationality is validated. By analyzing the relative error and correlation coefficient, the Strehl ratio differences between the emitting light and receiving light far-field spot are researched.

The vertical distribution characteristics of a dust and fine particle pollution process of Nanjing were measured and studied by polarization lidar in March, 2015. The meteorological factors, particle concentration distribution, particle composition and optical properties of different kinds of particles were discussed, combining with ground meteorological data, PM2.5 and PM10 concentration data, PM2.5 component data and the result observed by MODIS satellite. The results indicate that the adverse weather conditions such as high humidity and weak wind are favorable for the formation and accumulation of the secondary particles, and the SNA (SO2－4, NO－3, NH+4) concentration of soluble components showed a significant increasing trend during the experimental period. At the same time, the settlements of sand particle from long distance significantly influenced the chemical composition of the ground PM2.5. The dust particles from 1.1 km to 2.5 km were transported to the ground during afternoon of March 21 to March 22, which caused Ca2+ iron concentration of PM2.5 increase to 3.2 μg/m3 suddenly. The PM2.5 spread to the west and the PM2.5 concentration was reduced efficiently under the influence of southeast current after afternoon in March 22. At the same time, dust transport and fugitive dust occurred, causing the concentration of coarse particles up to 347 μg/m3. Compared with the particle distribution of Wuxi, the particle distribution characteristics in Nanjing showed highly similar characteristics, it indicated the particles distribution was regional. Finally the backward trajectory analysis showed that the backward trajectories were largely consistent at the height of 500 m, 800 m and 1000 m, the air mass mainly originated from Mongolia, and passed Beijing, Shandong, then moved to the East China Sea, finally backed to Nanjing.

Five phases ozone monitoring instrument(OMI) NO2 column density data and Back Trajectory Model (HYSPLIT4) were used to simulate and analyze an NO2 pollution event around the APEC meeting, Beijing, November, 2014. The results show that the spatial distribution of NO2 vertical column density was extremely uneven before APEC. The high-value were distributed in surrounding of Beijing and Tianjin, the mid-value were distributed in its south areas, north and northwest is the low value area. The high value concentration in Beijing, Tianjin and the southern region showed a decreasing trend from south to north during APEC; the range of high value area expanded northward to the central and southern areas of Beijing and Tianjin after APEC. Compared with concentration a week ago, density of NO2 in Xingtai and Handan, which are in south of Beijing-Tianjin-Hebei region, had showed a trend of rising, and concentration in another places had fallen 42% during the APEC. According to back trajectory analysis based on HYSPLIT, the import of NO2 pollution comes from Tangshan, Tianjin before APEC. During the period of APEC, the pollution comes from Russia, Mongolia region. After the APEC, Beijing, Tianjin, Taiyuan and the Southwest are the main NO2 sources areas.

The gridding distribution of Ozone Monitoring Instrument (OMI) NO2 tropospheric column concentration is obtained by using the OMI NO2 Level2 products through an area weight factor, and the spatial and temporal variation of NO2 column concentration is analyzed from 2007 to 2014 over three typical areas (the industry area, the area along Yellow River, the farming area) in the central region of China. The results show that the minimum annual average value of NO2 tropospheric column concentration of all areas occurs in 2009, the maximum occurs in 2013. And compared with 2013, the value in 2014 decreases more than 25%. At the same time, the variation characteristics of NO2 column concentration in the typical time periods (Chinese New Year period (almost in February) and the biomass burning period(in June)) are analyzed. The results show that the column concentrations over three areas all have a decrease during February, and during June the increase percent in farming area is about 80%. The relative variance ratio of NO2 column concentration shows the variation characteristics of NO2 column during the recent 8 years, which indicates that the two factories areas have an over 15% decrease from mid of 2008 to mid of 2009 when compared with the same period in the former year, but the farming area doesn’t have such changes. However, all of the areas have an obvious decrease in 2014 with a ratio over 20%.

The sulfur dioxide (SO2) concentration during 2005～2012 over China was monitored from the planetary boundary layer (PBL) SO2 column density retrieved from Aura Ozone Monitoring Instrument (OMI) data and land use types of China from MODIS. Spatial analysis was adopted to analyze PBL SO2 column density’s spatial characteristics with time and land use type respectively over China. From the perspective of spatiotemporal variations, the result shows that the high SO2 density in China is mainly concentrated in the area of Urumqi, Beijing-Tianjin-Hebei, Yangtze River Delta, Sichuan Basin and Pearl River Delta region. Besides, the SO2 value in northern China is high in winter and low in summer, and has a rising trend in recent years. The SO2 value in South China is low in winter and high in summer, and the peak value has decreased during 2005～2012. In terms of land use, the high value of SO2 was found in urban and crop land, while the low value of SO2 was found in forest, lawn and bare land. Those results reflect that human activities play a key role in the distribution and variation of PBL SO2.

An acquisition system of infrared spectrum signal based on field-programmable gate array(FPGA) is introduced. It is designed to implement data acquisition of 64-channel infrared spectrum signal. Altera’s EP2C35 family chip is used as the control unit to realize the analog multiplexers switching, A/D conversion, data access. For weak DC signal of infrared spectrometer, a signal conditioning circuit is designed to restrain noise. Finally, the data is transmitted to upper computer by serial port. A brief introduction is given about every sub modules. By testing, the system has been validated to be reliability, which can detect minimal 0.23 μV weak DC signal and the actual signal to noise ratio can reach 45 dB.