A one-dimensional sectional model to simulate multicomponent aerosol dynamics in the marine boundary layer 1. Model description
A one-dimensional sectional model to simulate multicomponent aerosol dynamics in the marine boundary layer 1. Model description
复制标题
模拟海洋边界层多组分气溶胶动力学的一维截面模型 1. 模型说明
DOI：
10.1029/98jd01019
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发表时间：
1998
影响因子：
--
通讯作者：
F. Gelbard
中科院分区：
文献类型：
--
作者：
J. W. Fitzgerald;W. Hoppel;F. Gelbard
海洋边界层气溶胶模式（MARBLES）是一种一维、多组分截面气溶胶模式[Fitzgerald et al., this issue；Gelbard等人，这期]。首先，为了说明各种气溶胶过程是如何影响粒径分布的，在同一初始粒径分布上运行了一个或两个过程。由于目前对气溶胶的云处理和气溶胶与自由对流层（FT）交换对海洋气溶胶大小分布的影响感兴趣，因此对这两个过程进行了相当详细的研究。模拟表明，假设典型的交换速度为0.6 cm s−1，云处理在MBL上部的影响（特征双峰尺寸分布）在地表的时间尺度上表现得比与FT交换引起的变化快得多。该模型预测，在云处理最小值的大小范围内，在未激活的间隙颗粒和云凝结核（CCN）之间，FT可能是MBL的重要颗粒来源，CCN是由于溶解的SO2在云滴中转化为硫酸盐而生长的。该模式还用于模拟从美国东海岸向外的海洋平流的气团中气溶胶大小分布的演变长达10天。大陆气溶胶大小分布的改变，在一个遥远的海洋特征发生在6-8天的时间尺度上。在假定相当典型气象条件的10天平流模拟的基本情况中没有观察到成核。然而，在更有利的（尽管不是典型的）条件组合下，预测了显著的成核，包括显著的降水清除（12小时5 mm h−1的降雨），较低的温度10°C（表面283 K， 1000 m降低到278 K）和高DMS通量（40 μmol m−2 d−1）。在模式自初始化试验中，发现长期（8-10天）海洋气溶胶大小分布的预测基本上与初始条件无关。
The dynamics of aerosols in the marine boundary layer (MBL) are simulated with the marine boundary layer aerosol model (MARBLES), a one-dimensional, multicomponent sectional aerosol model [Fitzgerald et al., this issue; Gelbard et al., this issue]. First, to illustrate how the various aerosol processes influence the particle size distribution, the model was run with one or two processes operating on the same initial size distribution. Because of current interest in the effects of cloud processing of aerosols and exchange of aerosols with the free troposphere (FT) on marine aerosol size distributions, these two processes are examined in considerable detail. The simulations show that the effect of cloud processing (characteristic double-peaked size distribution) in the upper part of the MBL is manifested at the surface on a timescale that is much faster than changes due to exchange with the FT, assuming a typical exchange velocity of 0.6 cm s−1. The model predicts that the FT can be a significant source of particles for the MBL in the size range of the cloud-processing minimum, between the unactivated interstitial particles and the cloud condensation nuclei (CCN) which have grown as a result of conversion of dissolved SO2 to sulfate in cloud droplets. The model was also used to simulate the evolution of the aerosol size distribution in an air mass advecting from the east coast of the United States out over the ocean for up to 10 days. The modification of a continental aerosol size distribution to one that is remote marine in character occurs on a timescale of 6–8 days. Nucleation was not observed in the base case 10-day advection simulation which assumed rather typical meteorological conditions. However, significant nucleation was predicted under a more favorable (albeit, atypical) combination of conditions which included significant precipitation scavenging (5 mm h−1 of rain for 12 hours), colder temperatures by 10°C (283 K at the surface decreasing to 278 K at 1000 m) and a high DMS flux (40 μmol m−2 d−1). In a test of model self initialization, long-term (8–10 days) predictions of marine aerosol size distributions were found to be essentially independent of initial conditions.