中国4个地点地基与卫星臭氧总量长期观测比较

Long-term Total Ozone Comparisons Between Space-based and Ground-based Observations at 4 Sites in China

对我国河北香河、云南昆明、青海瓦里关及黑龙江龙凤山地基观测臭氧总量与不同时期、不同卫星反演的产品差别特点进行比较，评估地基和卫星观测臭氧总量数据的质量信息以及近30年来我国不同区域臭氧总量的变化趋势特征。结果表明：4个站点的地基与卫星观测臭氧总量的绝对和相对差别分别为-5～10DU和-5％～4％；日平均相对差别基本上呈现随机分布特征。TOMS算法反演的卫星臭氧总量与地基差别总体上要优于与DOAS算法反演的同期产品。地基与卫星臭氧总量差别呈明显的区域特点，可能反映了卫星反演计算中所需的臭氧、温度垂直分布等初始条件的纬度分布差异对卫星产品精度的影响。在过去30年，4个站点的臭氧总量在经历1993年前的显著降低后于1995-1996年逐渐回升，而瓦里关站在2001年前后的回升更为明显。

The observed total ozone differences between ground-based data and available satellite products over Xianghe, Kunming, Waliguan and Longfengshan are analyzed. The absolute differences of total ozone between space-based and ground-based observations are -5-10 DU. And the relatives differences （RD） is -5 %-4 %, fitting the normal distribution of 0.05 significance. Compared with the ground-based observation, the precision of TOMS （Total Ozone Mapping Spectrophotometer） version total ozone is better than that of DOAS （Differential Optical Absorption Spectroscopy）. Total ozone RDs are statistically similar at Xianghe and Longfengshan where total ozone is high, while the similarity of RDs are also detected at low total ozone region Kunming and Waliguan. The regional similarities also indicate in the sensitivity validations of total ozone RDs to the SZA （solar zenith angle） and total ozone references. The integrated total ozone dataset with the ground-based and TOMS as well as OMI observations in the 4 proxy sites also reflect the substantial depletion of global total ozone event around 1993. An eventual recover trend emerged in Xianghe, Kunming, and Longfengshan during 1995-1996, but the recover trend in Waliguan doesn＇t occur until 2001. The inter-comparisons also reveal the quality information of ground-based total ozone observations. For example, due to Brewer grating scratches in 2000-2006, total ozone observation from Longfengshan intends to be lower at high SZA conditions, which has been reflected in the RDs sensitivity validation to SZA. The increasing total ozone difference between Dobson # 075 and OMI or SCIAMACHY products since 2007 needs further investigation.