Summary

Stable Isotopes in Cloud Tops flew the Sabreliner (Tail Number N307D) to determine the vertical transport of ice in clouds and the clouds' mechanism in controlling the concentration of water vapor in the upper troposphere. A stable isotope method was used, ice and vapor samples were collected simultaneously, and the project was supported by in situ thermodynamic, cloud physics, and satellite data. The project goal was 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.