Factors driving the seasonal and hourly variability of sea-spray aerosol number in the North Atlantic
Factors driving the seasonal and hourly variability of sea-spray aerosol number in the North Atlantic
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北大西洋海雾气溶胶数量季节性和每小时变化的驱动因素
DOI：
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发表时间：
2019
影响因子：
11.1
通讯作者：
M. Behrenfeld
中科院分区：
文献类型：
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作者：
G. Saliba;Chia‐Li Chen;S. Lewis;L. Russell;L. Rivellini;Alex K. Y. Lee;P. Quinn;T. Bates;N. Haëntjens;E. Boss;L. Karp‐Boss;Nicholas Baetge;C. Carlson;M. Behrenfeld
重要意义海洋喷雾气溶胶粒子是大气中天然气溶胶的最大来源，对海洋的直接和间接辐射效应有很大贡献。风速在驱动SSA产生方面的作用是众所周知的；然而，SSA产生受到其他参数影响的程度，如海表面温度(SST)和海水(来自浮游植物的)颗粒有机碳，仍然知之甚少。在这里，跨越北大西洋浮游植物水华整个年度周期的船载测量提供了SST和海洋生物量对SSA数量浓度和直径的影响的直接测量。我们的结果对于理解海洋边界层中SSA的产生及其辐射影响具有重要意义。从2015年冬季到2018年春季，北大西洋气溶胶和海洋生态系统研究(NAAMES)的四个实地活动在每年的浮游植物水华周期中采集了一组广泛的海洋和大气参数。这一独特的数据集提供了四季的公开海洋观测，包括风速、海表面温度(SST)、660纳米处的海水颗粒衰减(cp，660，海洋颗粒有机碳的量度)、细菌生产率以及海雾气溶胶的大小分布和数量浓度(NSSA)。NAAMES的测量显示，在每小时时间尺度上，NSSA和海洋边界层的当地风速之间有中等到很强的相关性(0.56<；R<；0.70)，但这种关系在代表每个季节的运动平均中有所减弱，部分原因是多天平均导致风速范围缩小。NSSA与海水cp，660的相关性较弱(R=0.36，P<；0.01)，但在低风速时段，与cp，660的相关性较好(R=0.51，P<；0.05)。此外，NAAMES的测量还提供了SSA模式直径(Dm)对SST的观测依赖关系，在每小时的时间尺度上，dm在较高的SST(R=0.60，P<；<；0.01)时变得更大。这些结果意味着，使用风速的双峰SSA参数化而不是随SST变化的单一SSA模式的气候模式可能会将SSA数浓度(因此云凝结核)高估4至7倍，并可能将SSA散射(因此直接辐射效应)低估2至5倍，此外还可能将风速对SSA散射的可变性高估5倍。
Significance Sea-spray aerosol (SSA) particles are the largest source of natural aerosol to the atmosphere on a mass basis and contribute significantly to the direct and indirect radiative effects over oceans. The role of wind speed in driving SSA production is well known; however, the degree to which SSA production is influenced by other parameters, such as sea-surface temperature (SST) and seawater (phytoplankton derived) particulate organic carbon, remain poorly understood. Here, shipborne measurements spanning the full annual cycle of the North Atlantic phytoplankton bloom provide direct measurements of the influence of SST and ocean biomass on SSA number concentrations and diameter. Our results have significant implications for understanding SSA production and their radiative impacts in the marine boundary layer. Four North Atlantic Aerosol and Marine Ecosystems Study (NAAMES) field campaigns from winter 2015 through spring 2018 sampled an extensive set of oceanographic and atmospheric parameters during the annual phytoplankton bloom cycle. This unique dataset provides four seasons of open-ocean observations of wind speed, sea surface temperature (SST), seawater particle attenuation at 660 nm (cp,660, a measure of ocean particulate organic carbon), bacterial production rates, and sea-spray aerosol size distributions and number concentrations (NSSA). The NAAMES measurements show moderate to strong correlations (0.56 < R < 0.70) between NSSA and local wind speeds in the marine boundary layer on hourly timescales, but this relationship weakens in the campaign averages that represent each season, in part because of the reduction in range of wind speed by multiday averaging. NSSA correlates weakly with seawater cp,660 (R = 0.36, P << 0.01), but the correlation with cp,660, is improved (R = 0.51, P < 0.05) for periods of low wind speeds. In addition, NAAMES measurements provide observational dependence of SSA mode diameter (dm) on SST, with dm increasing to larger sizes at higher SST (R = 0.60, P << 0.01) on hourly timescales. These results imply that climate models using bimodal SSA parameterizations to wind speed rather than a single SSA mode that varies with SST may overestimate SSA number concentrations (hence cloud condensation nuclei) by a factor of 4 to 7 and may underestimate SSA scattering (hence direct radiative effects) by a factor of 2 to 5, in addition to overpredicting variability in SSA scattering from wind speed by a factor of 5.
影响因子：
3.7
作者：
Engel, Anja;Bange, Hermann W.;Zaencker, Birthe
通讯作者：
Zaencker, Birthe