Combination of multiple laser beams provides an effective approach for achieving high power laser beam with high energy, so beam combination technologies have been widely investigated for the past years. Recently, with the development of practical application requirement such as free-space optical communication and laser propagation engineering, the propagation properties of combined beams through atmospheric turbulence gradually become hot issues in the field of light propagation. Firstly, the comparison of various techniques including extended Huygens-Fresnel principle, Rytov perturbation approximation and numerical simulation is conducted, according to various combined beams that are composed by multiple typical laser arrays. Secondly, some methods for estimating the beam quality of combined beams are listed, such as power in the bucket (PIB), β factor, M2 factor and beam propagation factor (BPF). Finally, some problems that should be further studied according to investigation actualities and main results of combined beams are presented.

The sun photometer was used to measure the diurnal atmospheric transmittance of autumn and winter in a mountainous area of South China. The results show that the transmittance of measurement location has distinctive characteristics of daily and monthly variation. The daily maximal transmittance appears around 12:00. The remaining bands show that the transmittance in October is greater than the other two months excluding water vapor band 936 nm. The band 936 nm has reverse characteristics. The vertical transmittance of the band 936 nm shows calmer variation than those of the remain bands whose vertical transmittance in October and November are obviously greater than the vertical transmittance in December. The vertical transmittance of the whole bands presents more variation before 10:00 and the results after 12:00 show calmer variation. The atmospheric transmittance or vertical transmittance of different months shows less fluctuation after 10:00, and the atmospheric transmittance or vertical transmittance of afternoon are currently greater than those of morning. The results can be used as references for the optical engineerings which are applied in the region.

Based on the data of daily mean temperature of Hefei from 1953 to 2011, the change characteristics of daily mean temperature from winter to spring (January to April) of Hefei in recent 60 years have been analyzed by using Mann-Kendal technique. The change trend of the daily mean temperature, the beginning points and the break points of the daily mean temperature raise have been shown. The calculation results are tested by Yamamoto Test. The frequencies of the dates have been analyzed. The results showed that the fluctuations of the beginning points were large, and the distribution of corresponding dates was scatted. The days between 30th January and 10th February were more than other months. The fluctuations of break points were small. The corresponding dates intensively occured between the 10th and 15th January. The frequencies of dates between the 10th and 20th January were more than 50%.

The turbulent data obtained at the Hefei 35 m meteorological tower from 28, February, 2012 to 1, March, 2012 have been analyzed. Turbulence spectra, local isotropy and normalized standard deviation of velocity are analyzed with the stability. A hail process happened during the experiment. Results show that inertial sub-range is corresponding to dimensionless frequency which ranges from 0.02 to 2; inertial sub-range and the turbulent spectral isotropy vary with stable condition; the inertial sub-range is smaller under stable condition than under unstable condition; the normalized standard deviation of vertical velocity obeys the well-known 1/3 law under stable and unstable condition, and the value of the dimensionless variance of vertical velocity is 1.12 near neutral condition; wind speed, momentum flux and heat flux changed dramatically occurred before and after the hail; and strong convection occurred during this process.

Aerosol optical and microphysical parameters of particles under severe haze polluted condition in the Pearl River Delta (PRD) in Southern China in November 2009 were observed by using Raman-Mie polarized lidar. It was found that the haze layer was distributed below 1.5 km, and the concentration of haze layer was comparatively thicker at the heigh of 600~1000 m, the characteristics of dust haze were analyzed and discussed. In the beginning, the depolarization ratio in 532 nm wavelength is 0.2, Angstrom exponent and lidar ratio of the haze were 1±0.4 and 40±8 sr, respectively. It meant that there was a large number of non-spherical particles and large size particles in the haze particles, it was in line with characteristics of anthropogenic emissions particles. After November 26, 2009, the depolarization ratio in 532 nm wavelength of haze particles gradually decreases to 0.07 ± 0.02, Angstrom exponent and lidar ratio also changed to 1.5±0.6 and 56±12 sr, respectively. It was proved that there was a larger proportion of fine particles in haze, and the particles were mostly spherical particles. It meant that a large number of the second particles were generated after November 25, which aggravated the haze pollution. The result indicated that at the beginning, some artificial particles resulted in the light haze, these artificial source provided the condition for compound air pollution, with the second particle generating, the haze pollution was further aggravated.

Lidar as an active remote sensing technique has been widely applied in survey of the atmospheric and marine environment. Three dimensional scanning system enriches the special area for air pollution monitoring Lidar. The structure of the Lidar developed is introduced. And the hardware system of the scanning control system is also presented. Two common structures of LabVIEW are introduced for measurement and control program. The three dimensional scanning system for air pollution monitoring Lidar is developed with the mode of producer-consumer based on events and state machine structure with LabVIEW. Test results show that the developed system is stable and can be easily integrated with other systems.

Currently the characteristics of clear ocean areas aerosol can be obtained by the MODIS aerosol retrieval algorithm but the result of brighter coastal waters is not satisfactory. It is because the turbid waters are not dark target for the two aerosol retrieval channels centered near 0.553 μm, 0.646 μm, and they are not always dark target for the channel centered near 0.86 μm. An aerosol retrieval algorithm for remote sensing of aerosol properties over turbid coastal water is described. In this algorithm, channels centered near 0.86 μm, 1.24 μm, 1.64 μm and 2.13 μm are used, and the reflectance of 0.86 μm is corrected under certain circumstances. The proposed algorithm is applicable for MODIS data observed over turbid coastal water in the Southeast of China. The retrieval results agree quite well with the measurements obtained with sun photometers.

Based on the importance of water vapor in the atmosphere and the advantage of GPS in measuring atmospheric water vapor, several departments, including meteorological departments, institute of surveying and mapping, and astronomical observatory in East China, have established the GPS/MET network. Data is collected to analyze the accuracy of precipitable water vapor (PWV), zenith wet delay (ZWD) and zenith total delay (ZTD), which are derived by GPS/MET. It is compared with radiosonde data within 10 km from GPS stations. The result shows that: (1) The PWV data obtained by inversion of GPS/MET have high consistency with radionsonde result, the average error is less than 1 mm and the relative error is 11.54%. Moreover, the accuracy of GPS/ZTD is even higher and the relative error is less than 1%. (2)The correlation coefficients between inversion of each quantity and radionsonde result are high. Specifically, the coefficients of PWV and ZWD are more than 0.98, while the coefficient of ZTD is 0.977. Apart from that in summer, the coefficient of GPS/PWV is 0.927, and it is more than 0.96 in other seasons. (3)Based on the results of radiosonde data, the accuracy of GPS/PWV is better than results derived by NECP data. It has a broad application prospect in improving the severe weather monitoring, and prediction ability and the numerical weather forecast accuracy.

Water vapor is an important component of terrestrial atmosphere, which attenuates infrared radiance in the atmosphere and affects optical-electron engineering capability. The 940 nm channel of sun-photometer was calibrated by modified Langley method. According to the relationship between atmospheric transmittance and water vapor amount, the precipitable water vapor(PWV) was measured with ground-based microwave radiometer in Hefei, Anhui and Kashi, Xinjiang regions. The results showed that the PWV retrieved by these methods agrees with each other, the relative percent difference in the retrievals is less than 5.1%. The daily PWV retrievaled by microwave radiometer agreed well with the sun-photometer.

MCU or DSP is widely used for control in the data acquisition system. In the application of high accuracy linear CCD, it is important to sample and store data quickly. In view of these questions, a design method of spectrum data acquisition system based on SOPC is proposed. The CCD driving circuit and A/D controller circuit on Altera’s Cyclone III FPGA EP3C10E144C8N are realized, and the USB interface chip CY7C68013 is chosen to complete the high-speed data transmission together. Experimental results show that the system has high integration, high price/performance, and can be realized in a short time, the new technology brings a new spot to the design of spectrum instrument.