Impact of atmospheric transport on the evolution of microphysical and optical properties of Saharan dust
Impact of atmospheric transport on the evolution of microphysical and optical properties of Saharan dust
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DOI：
10.1002/grl.50482
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发表时间：
2013-05
影响因子：
5.2
通讯作者：
C. Ryder;E. Highwood;Michele Lai;H. Sodemann;J. H. Marsham
中科院分区：
文献类型：
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作者：
C. Ryder;E. Highwood;Michele Lai;H. Sodemann;J. H. Marsham
撒哈拉沙尘通过改变辐射平衡和将矿物质沉积到大西洋来影响气候。两者都取决于颗粒大小。我们提出了飞机测量，包括42个配置文件的大小分布（0.1-300微米），代表新鲜上升的灰尘，区域老化的灰尘，并在撒哈拉空气层（SAL）在加那利群岛的灰尘。SAL剖面中尘埃的平均有效直径比新上升的尘埃小4.5 µm，而垂直结构从低浅层（0-1.5 km）变为混合良好的撒哈拉尘埃深层（0-5 km）。粒径分布显示，在抬升后12小时，大于30 µm的颗粒损失了60%至90%。在新鲜、老化和SAL曲线之间，单次散射系数（SSA）从0.92增加到0.94再增加到0.95：这足以使加热速率改变26%。一些接近地表的新鲜尘埃显示SSA低至0.85。
Saharan dust affects the climate by altering the radiation balance and by depositing minerals to the Atlantic Ocean. Both are dependent on particle size. We present aircraft measurements comprising 42 profiles of size distribution (0.1–300 µm), representing freshly uplifted dust, regional aged dust, and dust in the Saharan Air Layer (SAL) over the Canary Islands. The mean effective diameter of dust in SAL profiles is 4.5 µm smaller than that in freshly uplifted dust, while the vertical structure changes from a low shallow layer (0–1.5 km) to a well‐mixed deep Saharan dust layer (0–5 km). Size distributions show a loss of 60 to 90% of particles larger than 30 µm 12 h after uplift. The single scattering albedo (SSA) increases from 0.92 to 0.94 to 0.95 between fresh, aged, and SAL profiles: this is enough to alter heating rates by 26%. Some fresh dust close to the surface shows SSA as low as 0.85.