Wind velocity in different barometric pressure and characteristics of the flow field at the vent port of air knife, designed by Institute of Optics and Electronics, Chinese Academy of Sciences, driven by compressed gas were calibrated and analyzed by using a IFA-300 hot-wire anemometer. The results show that wind velocity has a good liner relation with barometric pressure; the larger the pressure is, the greater the velocity is; and the uniformity and stability of flow field at the vent port are related to the location of flow field. In the centre of the flow field, the velocity of flow field was the largest, and the instability was the lowest, its value was close to 2%. On the edge of the flow field, the velocity of flow field was the lowest, and the instability was the largest, its value approximately equaled 28%.

Thunderstorm clouds were identified and tracked by K-means clustering algorithm and forecasted through the kind of linear extrapolation prediction. Based on the statistical relationship of Z=AIb between radar reflectivity factor Z and precipitation intensity I, Z values measured by radar had been compared with those data of the corresponding ground actual rainfall intensity. By regression statistical analysis, the coefficients of A and b under different rainfull can be deduced respectively and the estimation equation was obtained. The identifying and tracking method about thunderstorm clouds was described in detail by selecting Nanjing radar data about the precipitation process on September 18, 2007 and the forecast result was also verified. The result indicated that thunderstorm clouds were able to be identified, tracked and estimated with extrapolation by this method and the short-time precipitation was accurate.

Based on the sonde data above the South Pole in 2008, using temperature and wind speed profiles, the vertical structures of boundary layer, the heights of the top of boundary layer and tropopause were decided. The air temperature, water vapor pressure, wind speed and direction in the surface were studied by statistical methods. The results showed that the vertical structures of boundary layer above the South Pole are stable in the most time. However, some are instable in summer, especially in January. The average height of the boundary layer in summer night is 389 m, bigger than in daytime, 304 m. It is 591 m in winter, bigger than in summer. The average height of the tropopause in the daytime is little bigger than in the nighttime of summer, they are respectively 6172 m and 5770 m. The inverse Richardson numbers of the high atmosphere above the South Pole are smaller than 4, the possibility of turbulence formation is very small.

Fourier transform infrared spectroscopy has advantages of high resolution, large flux, wide frequency band, and is widely used in the field of trace element analysis. In the online monitoring process of atmospheric pollution composition, accurate standard spectral database is the first condition and calculation basis of atmospheric composition detection. A set of calibration spectra database platform used in the online analysis by infrared spectrum is presented. The factors with affecting spectral instruments, including the instrument resolution, apodization functions and the solid angle of incident radiation, etc, are studied in the use of the Fourier infrared spectrometer by the process of actual measurement. On this basis, the instrument lineshape function of the Fourier transform infrared spectrometer is modeled. Then the true high resolution spectrum was degraded from high resolution to low resolution, which closely modeled the true measured spectra by a real spectrometer. A set of infrared quantitative calibration database based on HITRAN is established. The simulation of calibration spectra based on the database are given. The database can be used in the infrared spectral analysis of trace gas and trace element research.

Ring effect is defined as the phenomenon that the depth of solar Fraunhofer lines in scattered light is less than those observed in direct sunlight. And today it is commonly agreed that rotational Raman scattering on atmospheric molecules is the dominant source for the Ring effect. The Ring effect is affected by the optical properties of aerosol. And thus the aerosol information can be retrieved from the measured strength of the Ring effect. A novel method is presented to simulate Ring effect based on the Monte Carlo atmospheric radiative transfer model (McArtim). The average probability of photons that have undergone rotational Raman scattering (RRS) event is calculated under different atmospheric situations, which represents corresponding strength of Ring effect. A comparison of the results of Ring effect between simulation and measurement with MAX-DOAS shows a good agreement. The result indicates the Ring effect can be calculated rapidly with radiative transfer model. The simulation technique can be combined with the MAX-DOAS measurement to retrieve the properties of aerosols in the future.

A space-borne differential absorption spectrometer is a high precision aerospace optical remote sensor. It obtains hyperspectral, high spatial resolution spectral information by using CCD (charge coupled device) detectors. Since they are key detectors, the performance of the entire instrument is largely determined by CCDs. The temperature of CCD modules has a greater impact on the instrument measurement accuracy. It leads to severe temperature target. Due to the complex and compact structure, it gets harder to cool and control the CCD modules’ temperature. To meet the detector temperature requirement, a thermal control scheme is presented by comprehensively analyzing the structure and power distribution feature of CCD modules as well as the space heat flux at sun-synchronous orbit. Thermal analysis tool I-DEAS/TMG is utilized to compute temperature distribution and fluctuations in several typical operating conditions. The results show that the temperature of CCD in ultraviolet channel is below 22℃, in visible channel is below 15℃; the fluctuation of temperature in different circle is under 2℃. The design of heat conduction path is verified to be rational and efficient to transfer heat from CCDs. The temperature of CCD heating surface is under control and within the preferred range.

Active temperature control is adapted as an important mean for the spaceborne instruments to fit the harsh thermal environment. The way of active heating is used for the spaceborne instrument to control the temperature of its temperature sensitive component. The reliability of the temperature control module is directly related to the effects of the active temperature control measures, which may affect the instrument performance. Based on the temperature control circuit, the reliability comparison between two redundant design schemes is carried out, namely the system backup and the unit backup. The results showed that the backup system has higher reliability. According to the results of the reliability prediction, in combination with the on-board temperature control function module’s feature, the temperature control module was selected.

In the gas concentration measurement based on tunable diode laser absorption spectroscopy (TDLAS), higher temperature stability of laser is required. To meet this requirement, an automatic temperature control (ATC) proposal is put forward. A mathematical model of the thermoelectric cooler (TEC) is derived. The thermal inertia of TEC is tested and the proportional-integral-derivative (PID) control circuit parameters are determined. Finally, a temperature control circuit with high control performance is designed. The closed negative feedback loop was adopted for the circuit. PID circuit is used to generate control signal and drive the TEC. High accuracy controlling of VCSELs working temperature is realized. The results show that the temperature stability is up to ±0.03℃. The temperature control circuit could effectively keep the laser working stable.

A detecting circuit of an infrared thermopile is introduced. Then the output signal and noise of the detector are analyzed. With calculating the inherent noise of the analog signal chain, the amplifying and conditioning method of weak signal are studied and a new method of noise match is proposed. The circuit design of each step is also given out, which has been simulated with Pspice. The test result shows that the design has achieved a good result in noise suppression and offset compensation, which can detect minimal 3.5 μV weak DC signal. This design can be widely used in infrared spectrum detection and weak DC signal detection of μV class.

For corner detection of black white checkerboard, a new sub-pixel operator with high speed and high position accuracy was proposed. The principle of Hessian matrix, the execution procedure of the algorithm and basic ways of getting the sub-pixel coordinate in black white checkerboard were presented. All the corners needed in black white checkerboard were detected and all the coordinates of corners were calculated through experiments. Sub-pixel coordinates of corners were calculated with two order Taylor expansion. Finally, under different noise levels, compared with the Harris algorithm, extraction error and extraction time are calculated. The experimental results show that Hessian matrix is more accurate for corner detection of black white checkerboard. The result can be used in camera calibration.