The PIs wish to determine the vertical transport of ice in clouds and the clouds' mechanism in controlling the concentration of water vapor in the upper troposphere. They will use a stable isotope method, and propose to simultaneously collect ice and vapor samples, as well as to gather supporting in situ thermodynamic, cloud physics, and satellite data. The project goal is to determine the formation altitude of ice in the tops of winter frontal and summer convective clouds and the relative role of cloud ice and vapor as a supplier of water vapor in the upper troposphere.
