Effects of sulfuric acid and ammonium sulfate coatings on the ice nucleation properties of kaolinite particles
Effects of sulfuric acid and ammonium sulfate coatings on the ice nucleation properties of kaolinite particles
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DOI：
10.1029/2008gl035997
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发表时间：
2009-01
影响因子：
5.2
通讯作者：
M. Eastwood;S. Cremel;Michael B. Wheeler;B. Murray;É. Girard;A. Bertram
中科院分区：
文献类型：
--
作者：
M. Eastwood;S. Cremel;Michael B. Wheeler;B. Murray;É. Girard;A. Bertram
研究了在233~246K温度范围内，包覆硫酸、包覆(NH4)2SO4和未包覆高岭石颗粒的成冰起始条件。我们将起始条件定义为观测到第一次冰核事件的相对湿度和温度。未包覆的颗粒是极好的冰核；在所研究的所有温度下，相对于冰的起始相对湿度(RHI)低于110%，与之前的测量结果一致。然而，硫酸涂层极大地改变了高岭石颗粒的成冰能力，使成冰所需的RHI增加了约30%，与Möhler等人最近的测量结果相似。[2008b]。(NH_4)_2SO_4包覆颗粒在245K是贫冰核，而在236K是有效冰核。(NH_4)_2SO_4包覆粒子的不同可能是由于(NH_4)_2SO_4的潮解和风化性质所致。这些结果支持SO2和NH3的排放可能影响矿物粉尘颗粒的成冰特性的观点。
The onset conditions for ice nucleation on H2SO4 coated, (NH4)2SO4 coated, and uncoated kaolinite particles at temperatures ranging from 233 to 246 K were studied. We define the onset conditions as the relative humidity and temperature at which the first ice nucleation event was observed. Uncoated particles were excellent ice nuclei; the onset relative humidity with respect to ice (RHi) was below 110% at all temperatures studied, consistent with previous measurements. H2SO4 coatings, however, drastically altered the ice nucleating ability of kaolinite particles, increasing the RHi required for ice nucleation by approximately 30%, similar to the recent measurements by Möhler et al. [2008b]. (NH4)2SO4 coated particles were poor ice nuclei at 245 K, but effective ice nuclei at 236 K. The differences between H2SO4 and (NH4)2SO4 coatings may be explained by the deliquescence and efflorescence properties of (NH4)2SO4. These results support the idea that emissions of SO2 and NH3 may influence the ice nucleating properties of mineral dust particles.