Do diurnal aerosol changes affect daily average radiative forcing?
Do diurnal aerosol changes affect daily average radiative forcing?
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DOI：
10.1002/grl.50567
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发表时间：
2013-06-28
影响因子：
5.2
通讯作者：
Hodges, Gary
中科院分区：
文献类型：
--
作者：
Kassianov, Evgueni;Barnard, James;Hodges, Gary
在许多城市/工业区经常观测到气溶胶的强日变化。然而，这种变化如何可能改变直接气溶胶辐射强迫（DARF），在很大程度上是未知的。为了量化的时间平均的DARF的变化，我们进行了29天的高时间分辨率的地面数据收集在科德角，这是顺风的大都市地区的双柱气溶胶项目的评估。我们表明，强的气溶胶负载的日变化（平均约20%）有一个可以忽略不计的影响，24小时的平均DARF时，每天平均的光学特性来找到这个量。然而，当存在气溶胶特性的稀疏时间采样时，这可能妨碍每日平均光学特性的计算，在计算的DARF中可能发生大的误差（高达100%）。我们描述了一个简单的方法来减少这些错误，这表明需要准确地找到强迫的最小时间采样。
Strong diurnal variability of aerosol has been observed frequently for many urban/industrial regions. How this variability may alter the direct aerosol radiative forcing (DARF), however, is largely unknown. To quantify changes in the time-averaged DARF, we perform an assessment of 29days of high temporal resolution ground-based data collected during the Two-Column Aerosol Project on Cape Cod, which is downwind of metropolitan areas. We demonstrate that strong diurnal changes of aerosol loading (about 20% on average) have a negligible impact on the 24-h average DARF when daily averaged optical properties are used to find this quantity. However, when there is a sparse temporal sampling of aerosol properties, which may preclude the calculation of daily averaged optical properties, large errors (up to 100%) in the computed DARF may occur. We describe a simple way of reducing these errors, which suggests the minimal temporal sampling needed to accurately find the forcing.