Uncertainty in the magnitude of aerosol‐cloud radiative forcing over recent decades
Uncertainty in the magnitude of aerosol‐cloud radiative forcing over recent decades
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DOI：
10.1002/2014gl062029
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发表时间：
2014-12
影响因子：
5.2
通讯作者：
L. Regayre;K. Pringle;B. Booth;Lindsay A. Lee;G. Mann;J. Browse;M. Woodhouse;A. Rap;C. Reddington;K. Carslaw
中科院分区：
文献类型：
--
作者：
L. Regayre;K. Pringle;B. Booth;Lindsay A. Lee;G. Mann;J. Browse;M. Woodhouse;A. Rap;C. Reddington;K. Carslaw
气溶胶及其对云辐射特性的影响是地球能量收支计算中最大的不确定性来源之一。本文量化了气溶胶-云反照率效应强迫对31个气溶胶参数的敏感性。灵敏度在三个时期内进行比较；1850-2008, 1978-2008, 1998-2008。尽管1978-2008年期间全球人为二氧化硫排放量下降，但区域正强迫和负强迫的抵消导致全球平均云反照率强迫接近于零。与现有的负估计相反，我们的结果表明，在最近十年中，气溶胶-云反照率效应可能是正的（0.006至0.028Wm−2），这使得将温度中断解释为强迫响应变得更加困难。发现气溶胶过程以及自然和人为排放对强迫变化的比例贡献依赖于周期。为了更好地约束强迫估计，必须更好地理解在感兴趣的时间尺度上支配不确定性的过程。
Aerosols and their effect on the radiative properties of clouds are one of the largest sources of uncertainty in calculations of the Earth's energy budget. Here the sensitivity of aerosol‐cloud albedo effect forcing to 31 aerosol parameters is quantified. Sensitivities are compared over three periods; 1850–2008, 1978–2008, and 1998–2008. Despite declining global anthropogenic SO2 emissions during 1978–2008, a cancelation of regional positive and negative forcings leads to a near‐zero global mean cloud albedo effect forcing. In contrast to existing negative estimates, our results suggest that the aerosol‐cloud albedo effect was likely positive (0.006 to 0.028Wm−2) in the recent decade, making it harder to explain the temperature hiatus as a forced response. Proportional contributions to forcing variance from aerosol processes and natural and anthropogenic emissions are found to be period dependent. To better constrain forcing estimates, the processes that dominate uncertainty on the timescale of interest must be better understood.