High Uptake Efficiency and Conductivity of Polycrystalline Ice: Implication to UT/LS Clouds and Contrails

The uptake of gases onto ice particles of upper tropospheric cirrus (UT) and lower polar stratosphere (LS) clouds depends on the efficiency and time of the reactive gas interaction that also determines the ice particle impact on heterogeneous chemistry. The HC1 vapor uptake by polycrystalline ice produced by water freezing is investigated under laboratory conditions relevant to UT/LS. The uptake efficiency and ice conductivity were measured simultaneously in a Knudsen cell reactor. Regions with HC1 water solutions in ice are likely to be formed during the HCl—ice interaction. This potentially defines a mechanism of effective and long HC1 uptake by ice particles of cirrus clouds, polar stratospheric clouds (PSCs), and contrails due to fast freezing of submicron water drops.