水平能见度经验公式在青岛沿海地区的应用

Studies on the Application of Empirical Formulae to the Calculation of Horizontal Visibility in Qingdao Coastal Area

利用青岛4 a的能见度观测资料和大气气溶胶光学参数反演资料检验了4种能见度经验计算公式的适用性。发现Koschmieder公式和乘幂公式能更好地刻画能见度和气溶胶光学厚度间变化趋势上的相关性,但是由于能见度观测的不确定性和气溶胶光学参数反演的不准确性导致的数据离散性,需要确定更有代表性的经验参数。利用最大发生频率原则确定不同光学厚度对应的能见度值,据此确定适合青岛的各经验公式的经验参数,最后利用MODIS光学厚度资料将乘幂经验公式应用到青岛附近沿海地区能见度的计算,发现春季和夏季的能见度低于其他季节。

The applicability of four empirical formulae to calculate horizontal visibility are tested with four years data of aerosol optical parameters and horizontal visibility observed in Qingdao. It is shown that the correlation between the general variation tendencies of horizontal visibility and the aerosol optical depth can be better described by scale height formula and exponent formula than other formulae. But the locally reprezentative empirical constents should be determined because of the data discrepancy caused by the uncertainties in visibility observations and inversions of the aerosol optical parameters. The empirical constants fited for Qingdao observational data are calculated based on the horizontal visibility values mostly observed under different aerosol optical depths conditions. The modified exponent empirical are then applied to calculate the visibility in Qingdao surrouding coastal area. The results show that visibilities in the months of spring and summer are lower than that in other months.