1993年中山站地区“臭氧洞”和UV┐B的特征分析

GROUND BASED MEASUREMENTS OF COLUMN AMOUNTS OF OZONE AND UV B OVER ZHONGSHAN STATION, ANTARCTICA,IN THE 93 “OZONE HOLE”

本文给出了１９９３年在东南极中山站（６９．３８°Ｓ，７６．３７°Ｅ）地区首次运用ＷＭＯ（世界气象组织）认可的Ｂｒｅｗｅｒ臭氧分光光谱仪，进行臭氧和ＵＶ－Ｂ地面的同步观测结果。观测表明中山站地区在１９９３年８月初到１１月底频繁出现臭氧低于２００ＤＵ的值；１２月初臭氧值恢复正常。在整个“臭氧洞”期间，臭氧值起伏变化很大，并且和７０ｈＰａ到５０ｈＰａ上空的温度变化密切相关，臭氧的日变化不很明显。中午时刻有生物效应的ＵＶ－Ｂ辐射通量与臭氧斜程柱总量呈负指数关系；云和太阳高度角控制着ＵＶ－Ｂ辐射通量日变化过程。ＵＶ－Ｂ光谱扫描的结果表明２９５－３２５ｎｍ波段内的光谱强度比３１５－３２５ｎｍ的光谱强度更受臭氧变化的影响。消除云和气溶胶对ＵＶ－Ｂ辐射过程的部分影响，对每天中午时刻３００．５ｎｍ和３２３．５ｎｍ光谱强度比值计算，反映出了“臭氧洞”期间臭氧值降低是ＵＶ－Ｂ辐射增强的重要因子。

The Brewer ozone spectrophotometer ,which is recommended by the World Meteorological Organization(WMO), at Zhongshan station(69.37°S,76.38°E),Antarctica first provides hourly ground based measurements of O 3,UV B at the earth surface in the 93 “Ozone Hole”.These measurements define the column ozone abundance and the UV B radiation environment of the region and ,in conjunction with a daily record of sky conditions and the upper atmospheric temperature, permit a general understanding of the close relationship between the ozone and stratospheric temperature and the role of ozone and cloud cover in regulating UV B radiation levels at the Antarctica surface in the period of the ozone depletion. The processes of low column ozone abundance (near or below 220DU) have been detected from August to the end of November,and a normal abundance (near or above 260DU)recovers at the beginning of December.High coherent variations between the ozone column abundance and the temperature from 70hPa to 50hPa altitude are very obivious.Daily variations of UV B radiation are greatly controlled by the solar zenith angle(SZA),ozone and the sky conditions.Preliminary statistical analyses tell us that noontime biologically weighted damaging UV B(damaging UV B,DUV B) flux is a negative exponential function of slant ozone column abundance. Spectra scanning presents that in the range of UV B, ground surface irradiance of shorter wavelength is more easily influenced by the changes of the above ozone column abundance. Avoiding from the variability associated with cloud cover aerosols,and albedo etc., the ratio of noontime irradiance for 300.5nm to that for 323.5nm shows that ozone is one of the most important factors for UV B enhancing during the ozone depletion period.