关键词: 太阳光度计, 沙尘天气, 气溶胶光学厚度, Angstrom浑浊度系数β, 波长指数α

Abstract: Two sets of sun photometer CE318 were separately located in Tazhong meteorological station in the middle of Tarim basin and Hetian station in the south of the basin, they were used to monitor aerosol from Jun., 2002 to Nov., 2003. Based on the retrieval principles of aerosol optical property and combination with surface observational data, some interesting results and elementary classification criteria of different dusty weather according to aerosol optical depth (AOD) had been obtained and were presented as the following.The AOD at Hetian and Tazhong mainly decreased inversely with the growth of wavelength throughout the year except for Tazhong in spring, autumn and winter. At the same time, the diurnal variation curve of AOD at the two stations showed a symmetry parabola in each season, especially obvious in spring and summer. The values of AOD at Tazhong and Hetian were relatively high during summer half-year and low in Oct. and Dec. The simulated curve of Angstrom turbidity parameter β varying with visibility indicated that they varied in a contrary way and concentration of aerosol particles was high under heavy dusty weather condition. It was proved by the relation between wavelength index α and visibility that radius of large number of particles under heavy dusty weather was bigger than that of the light. The classification standard of different dusty weather was suggested as below: when AOD was higher than or equal to1.1206, it implied that dusty weather was likely to occur; if AOD≥3.0, sandstorm will take place. The aforementioned classification standards are suitable for desert areas while unsuitable for city such as Beijing where the air pollution is very severe. The two threshold values in Beijing are 0.3174 and 1.9982, respectively. In addition, the authors considered that the ratio of AOD to visibility could roundly reflect the factor change in both horizontal and vertical directions, so it was reasonable to measure the intensity of dusty weather.

Key words: sun photometer, dusty weather, aerosol optical depth (AOD), Angstrom turbidity parameter β, wavelength indicator α