Interaction of HNO3 with water‐ice surfaces at temperatures of the free troposphere
Interaction of HNO3 with water‐ice surfaces at temperatures of the free troposphere
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DOI：
10.1029/97gl01403
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发表时间：
1997-06
影响因子：
5.2
通讯作者：
J. Abbatt
中科院分区：
文献类型：
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作者：
J. Abbatt
在水-冰而不是硝酸水合物具有化学稳定性的条件下，在低温涂壁流管中测量了水-冰膜对气相HNO 3的吸收。据观察，在短时间尺度上，HNO 3的吸收量约为1 → 3 ×1014分子/cm²冰膜，而在10分钟的长得多的时间尺度上，吸收量稍小。短时间尺度的吸收对硝酸分压不敏感，在HNO 3分压从1.3 × 10−7到3.1 × 10−6 Ω的20倍变化中，变化不超过2倍。这意味着冰表面在这些分压下被HNO 3饱和。此外，摄取量在一定程度上取决于温度在208至248 K的范围内，在最低温度下的最大摄取量。吸收在很大程度上是不可逆的，当停止暴露于气相HNO 3时，只有20 → 25%的吸附的HNO 3从膜解吸。这些实验表明，吸附卷云表面可能是一个重要的清除过程中的HNO 3在对流层。
The uptake of gas‐phase HNO3 by water‐ice films has been measured in a low‐temperature, coated‐wall flow tube under conditions where water‐ice, and not a hydrate of nitric acid, is thermodynamically stable. It is observed that there is uptake of HNO3 on the order of 1 → 3 ×1014 molecules per cm² of ice film on a short timescale, and a somewhat smaller uptake on a much longer timescale of 10's of minutes. The short timescale uptake is insensitive to the nitric acid partial pressure, varying by not more than a factor of two over a 20‐fold variation in the partial pressure of HNO3 from 1.3 × 10−7 to 3.1 × 10−6 torr. This implies that the ice surface is saturated with HNO3 at these partial pressures. Also, the uptake is somewhat dependent on temperature over the range 208 to 248 K, with the largest uptake at the lowest temperatures. The uptake is largely irreversible, with only 20 → 25% of the adsorbed HNO3 desorbing from the film when the exposure to gas‐phase HNO3 is stopped. These experiments suggest that adsorption to cirrus cloud surfaces may be an important scavenging process of HNO3 in the troposphere.