The main parameters in detecting raindrop size distribution are overviewed, and the traditional measuring methods are discussed separately. Most of them possess the shortcomings of low measurement precision, big error, workload and poor real-time response. New type measurement raindrops spectrum tool-laser disdropmeter are developed, and the measurement principle of disdropmeter are analyzed in detail. Compared to traditional measurements, the virtues of disdropmeter in detecting raindrop size distribution are pointed out. The applications of disdropmeter, such as raindrop size distribution, rainfall measurement and the correction of weather radar et al are given. The developments of laser disdrometer technology at home and abroad are displayed. The research work progress on laser disdrometer of the Key Laboratory of Atmospheric Composition and Optical Radiation, CAS, is introduced. The experiments carried out with laser disdrometer in recent years are simply discussed.

From June 20 to July 20, 2009, mobile Doppler wind lidar of Ocean University of China was operated in Zhuhai National Climate Observatory (N22°4′54″， E113°12′50″) for atmospheric observation. The lidar system, observation experiment, principle and application of atmospheric boundary layer height detection were introduced. In order to obtain the information of atmospheric boundary layer height, the measured data were processed and analyzed, using the first order derivative method. And the problem of how to detect atmospheric boundary layer height when existing clouds was also discussed. The results show that the height of atmospheric boundary layer is between 0.3 km and 1.2km, and the average height is 0.66 km in Zhuhai from June to July of 2009.

Raindrop identification is important in automated weather observations, weather radar calibration and other related research areas. As to measurement of raindrop shape, two-dimensional video disdrometer’s principle, main technical parameter, function and application are concluded firstly, then a precipitation slit photography based on linear CCD is put forwarded, the process of linear scanning and the reconstruction process of precipitation are analyzed, the measuring optical system with telecentric optical system as imaging system and Cora illumination as lighting system are designed, which can realize uniform lighting and high precision measurement, and prospective problems were analyzed at last.

It is obtained the relation functions between particle diameter, terminal velocity and drop size distribution based on the data of particle diameter, terminal velocity and particle number detected by laser raindrop monitor. The rainfall intensity is calculated and compared with meteorological data to build error functions. According to measurement error, a precipitation inversion algorithm is developed to calibrate rainfall intensity and amount of precipitation, resulting in reducing 10% error of corrected precipitation amount. At last, precipitation type is distinguished by calculated relative data.

C2H2 and C2H6 are continuously monitored with multi-reflected White cell Fourier transform infrared(FTIR) spectrometer in Zhejiang region in December 2010. The concentration of component information is obtained by measuring gas atmospheric absorption spectra and the correlation between C2 H2 and C2 H6 concentration is also analyzed. The results show that the non-contact measurement system can realize online monitoring a variety of gases in the air and reveal the concentration information of measured region in time.

Absorption of water vapor distributes in the whole mid-infrared bands, and it interferes with the quantitative analysis of infrared spectra. Impact of spectral absorption of water vapor on measurement precision is analyzed. The gas without dryness and after dryness are measured by Fourier transform infrared spectroscopy(FTIR), and the precision and detection limits of CO, CO2 , N2 O and CH4 are compared in the different measurements. The results show that the precision and detection limits were improved after drying of the sample gas.

Microcystic aeruginosa was cultivated in laboratory condition with nature water for about 95 days. Three dimensional excitation-emission (3DEEM) fluorescence spectroscopy and synchronous scan fluorescence spectroscopy of the culture water at different growth stages were measured, simultaneously the chlorophyll-a and extracellular MC-LR concentration were analyzed. The results show that fluorescence signal A, signal X and signal C could be observed obviously from 3DEEM fluorescence spectroscopy and synchronous scan fluorescence spectroscopy, which represent protein-like substance, marine humic-like acid and fulvic-like substance respectively. All the three fluorescence signals intensity and MC-LR concentration were normalized by chlorophyll-a concentration. In the decline phase, the normalized fluorescence signals(A, X, C) and normalized MC-LR concentration show the same dynamic laws and good linear correlation. The maximum values appeared at the same time. Therefore, MC-LR concentration can be estimated by the feature fluorescence signal (A, X, C) and chlorophyll-a concentration. Comparing to 3DEEM fluorescence spectroscopy, synchronous scans fluorescence spectroscopy (Δλ=80 nm) is less time-consuming and can give out the entire feature fluorescence signal (A, X, C). It is suitable for real-time analysis of water fluorescent spectroscopy which can be used to rapidly estimate the MC-LR concentration.

Organic carbon (OC) and elemental carbon (EC) in atmospheric aerosols play a major role in environment, climate and human health effects. At present, thermal-optical method is acknowledged to be a more mature method for measuring the OC and EC, which can be divided into two methods, thermal-optical transmission (TOT) method and thermal-optical reflectance (TOR) by the optical correction way. Theory of the two methods is almost the same, but the measuring results are different obviously. Therefore, a thermal-optical transmission and reflection simulating experiment platform are developed by deeply understanding the theory of thermal-optical method. Through contrast experiment, it is indicated that the reason leading to the obvious difference between the two methods is that TOR laser split come more early than TOT.

Sunshine duration is one of the observation elements in ground observatory. For a long time, sunshine duration is observed by Jordan sunshine recorders in China, which having poor precision, poor data comparability and low automatic level. With the development of modern techniques, some kinds of sunshine duration detectors and sensors are developed abroad, whereas there are few relative researches in China. In order to develop operational sunshine detector with independent intellectual property rights, current development and key techniques of sunshine detector based on direct radiation measurement are discussed. The sunshine detector based on direct radiation measurement has the widely prospect of application, radiation response of photoelectric sensor, design and encapsulation of radiation sensor, automatic solar tracking and structure optimization of equipment should be emphatically investigated, and the condition adaptability, stability and reliability should be promoted.

According to the characteristics of ceilometer return noise, an effective denoising method of wavelet adaptive threshold is presented to reduce ceilometer return noise. To verify the feasibility of the denoising method, some numerical simulations are carried out to reduce the Gauss white noise of the simulated signal, and also, the laser diode ceilometer returns contaminated by noise are denoised by the method. Moreover, the comparisons among the wavelet adaptive threshold, wavelet modulus maxima, wavelet decomposing and recomposing, and the wavelet default threshold are performed. Experiment results show that the method of the wavelet adaptive threshold is capable of effectively reducing laser diode ceilometer return noise and the denoising effect is better than other three methods.

OTSU is one of the most commonly used image-threshold methods, which based on one-dimension histogram of image’s gray level. The two-dimension OTSU takes the gray level of pixel point, as well as the spatial information between the pixel point and its field into consideration. Because of infrared image, different from the general characteristics of gray image, the two-dimensional OTSU segmentation is targeted adopted. According to the comparison with one-dimension OTSU, it is indicated that the two-dimension OTSU can segment the near-infrared image better and get the furnace image more effectively. By monitoring its temperature in the late period and alarming through sound and light, it greatly enhances the security of high- heat furnace.