Ice nucleation of bare and sulfuric acid-coated mineral dust particles and implication for cloud properties
Ice nucleation of bare and sulfuric acid-coated mineral dust particles and implication for cloud properties
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DOI：
10.1002/2014jd021567
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发表时间：
2014-08-27
影响因子：
4.4
通讯作者：
Zhao, Chun
中科院分区：
文献类型：
--
作者：
Kulkarni, Gourihar;Sanders, Cassandra;Zhao, Chun
与大气相关的粉尘矿物与可溶性材料涂层的冰成核性能还没有得到很好的理解。我们确定了五种不同矿尘类型的裸矿尘和硫酸涂层矿尘颗粒的冰成核能力，作为温度（-25 ℃至-35 ℃）和相对于水的相对湿度（RHw; 75%至110%）的函数：（1）亚利桑那州试验尘，（2）伊利石，（3）蒙脱石，（4）钾长石，和（5）石英。颗粒干分散和大小选择在200 nm，我们确定了在不同温度和RHw的尘埃粒子成核冰的分数。在水不饱和条件下，与裸尘埃颗粒相比，我们发现涂层颗粒的冰核能力有所降低。然而，在水过饱和条件下，我们没有观察到显著的涂覆效果（即，裸露的和涂覆的粉尘颗粒具有几乎相似的成核性能）。涂层颗粒的X-射线衍射图表明，酸处理改变了表面的结晶性质，并引起结构紊乱;因此，我们得出结论，缺乏这种结构化的顺序降低了沉积冰成核模式中的涂层颗粒的冰成核效率。此外，我们的单柱模型的结果表明，涂层颗粒显着修改云的性质，如冰晶数浓度和冰水含量相比，裸露的颗粒在水亚饱和条件。然而，在水过饱和的条件下，云的性质只在较温暖的温度下有所不同。这些模拟结果意味着，未来的老化尘埃粒子模拟应实现涂层参数化，以准确地预测云的属性。
Ice nucleation properties of atmospherically relevant dust minerals coated with soluble materials are not yet well understood. We determined ice nucleation ability of bare and sulfuric acid-coated mineral dust particles as a function of temperature (-25 to -35 degrees C) and relative humidity with respect to water (RHw; 75 to 110%) for five different mineral dust types: (1) Arizona test dust, (2) illite, (3) montmorillonite, (4) K-feldspar, and (5) quartz. The particles were dry dispersed and size selected at 200 nm, and we determined the fraction of dust particles nucleating ice at various temperatures and RHw. Under water-subsaturated conditions, compared to bare dust particles, we found that coated particles showed a reduction in their ice nucleation ability. Under water-supersaturated conditions, however, we did not observe a significant coating effect (i.e., the bare and coated dust particles had nearly similar nucleating properties). X-ray diffraction patterns of the coated particles indicated that acid treatment altered the crystalline nature of the surface and caused structural disorder; thus, we concluded that the lack of such structured order reduced the ice nucleation efficiency of the coated particles in deposition ice nucleation mode. In addition, our single column model results show that coated particles significantly modify cloud properties such as ice crystal number concentration and ice water content compared to bare particles in water-subsaturated conditions. However, in water-supersaturated conditions, cloud properties differ only at warmer temperatures. These modeling results imply that future aged dust particle simulations should implement coating parameterizations to accurately predict cloud properties.