Ice nucleation processes in upper tropospheric wave‐clouds observed during SUCCESS
Ice nucleation processes in upper tropospheric wave‐clouds observed during SUCCESS
复制标题
成功期间观测到的对流层上层波云中的冰核过程
DOI：
10.1029/98gl00299
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发表时间：
1998
影响因子：
5.2
通讯作者：
B. Gary
中科院分区：
文献类型：
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作者：
Eric J. Jensen;O. B. Toon;A. Tabazadeh;G. Sachse;B. Anderson;K. R. Chan;C. W. Twohy;B. Gandrud;Steven M. Aulenbach;A. Heymsfield;John Hallett;B. Gary
我们将在SUCCESS实验期间观测到的波状云前沿附近的原位测量结果与数值模拟进行了比较。在一个非常寒冷的波状云前沿（温度<-60°C）附近观测到的相对于冰的高过饱和度（>50%）与近期的理论和实验室研究大致相符，这些研究表明均匀冻结硫酸盐气溶胶需要较高的过饱和度。此外，在这片云中观测到的冰晶数密度峰值（约4立方厘米⁻³）与我们模型中计算出的数密度相符。在较温暖的波状云（温度≃ -37°C）中，观测到相对较大的冰晶数密度（20 - 40立方厘米⁻³）。我们的模型计算表明，这些较大的数密度可能是由于硫酸盐气溶胶活化形成液滴，随后均匀冻结所致。如果在这两片云中存在适量的有效异质冻结核（0.5 - 1立方厘米⁻³），那么冰晶数密度和峰值相对湿度应该会低于观测值。
We have compared in situ measurements near the leading‐edges of wave‐clouds observed during the SUCCESS experiment with numerical simulations. Observations of high supersaturations with respect to ice (>50%) near the leading edge of a very cold wave cloud (T <−60°C) are approximately consistent with recent theoretical and laboratory studies suggesting that large supersaturations are required to homogeneously freeze sulfate aerosols. Also, the peak ice crystal number densities observed in this cloud (about 4 cm−3) are consistent with the number densities calculated in our model. In the warmer wave‐cloud (T ≃−37°C) relatively large ice number densities were observed (20–40 cm−3). Our model calculations suggest that these large number densities are probably caused by activation of sulfate aerosols into liquid droplets followed by subsequent homogeneous freezing. If moderate numbers of effective heterogeneous freezing nuclei (0.5–1 cm−3) had been present in either of these clouds, then the number densities of ice crystals and the peak relative humidities should have been lower than the observed values.