Aerosol climatology using a tunable spectral variability cloud screening of AERONET data
Aerosol climatology using a tunable spectral variability cloud screening of AERONET data
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DOI：
10.1029/2005gl025478
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发表时间：
2006-04
影响因子：
5.2
通讯作者：
Y. Kaufman;G. Gobbi;I. Koren
中科院分区：
文献类型：
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作者：
Y. Kaufman;G. Gobbi;I. Koren
气溶胶、湿度和云通常是相互关联的。因此，严格的云筛选可以系统地偏向于多云和干燥的条件，低估了平均气溶胶光学厚度（AOT）。在这里，使用AERONET数据，我们表明，可变的大气光学条件的系统拒绝可以产生这样的偏差，在平均AOT。因此，我们建议两种方法来处理云污染：（1）引入更强大的光谱变率云屏蔽和（2）保留大部分的数据，尽管云污染，估计平均云污染，并纠正它。这两种方法被应用到气溶胶的longström指数> 0.3，并与AERONET云屏蔽水平1.5的数据进行了比较。新方法不适用于纯粉尘。对10个AERONET台站204年数据的分析表明，罗马（意大利）的AOT几乎没有变化，但北京（中国）的AOT变化高达0.12或+30%。
Aerosols, humidity and clouds are often correlated. Therefore, rigorous cloud screening can systematically bias toward less cloudy and drier conditions, underestimating the average aerosol optical thickness (AOT). Here, using AERONET data we show that systematic rejection of variable atmospheric optical conditions can generate such bias in the average AOT. Therefore we recommend two approaches to deal with cloud contamination: (1) to introduce more powerful spectral variability cloud screening and (2) to retain most of the data despite cloud contamination, estimate average cloud contamination and to correct for it. Both methods are applied to aerosol with Ångström exponent > 0.3 and compared with the AERONET cloud screened level 1.5 data. The new methods do not apply for pure dust. Analysis for 10 AERONET stations with ∼4 years of data, shows almost no change for Rome (Italy), but up to a change in AOT of 0.12 or +30% in Beijing (PRC).