The Cloud Layer EXperiment (CLEX-10) – November 2006 to January 2007

Updated, January 25, 2007

Overview

The Cloud Layer EXperiment (CLEX) is a program funded by the US Department of Defense's Center for Geosciences/Atmospheric Research intended to study microphysical, morphological and dynamical properties of mid-level clouds (altocumulus, altostratus, etc). These clouds (which reside at ~2 to 7 km) provide a testbed for studying how ice forms in the presence of liquid water and how liquid water and ice interact in these clouds.

This project is the first CLEX that has not taken place over the Great Plains in the US. The 10th CLEX is being conducted in conjunction with the Canadian CloudSat and CALIPSO Validation Project (C3VP). For more information regarding the project overview, please visit the official CLEX-10 site. This is also the first CLEX in which the Colorado State University Continuous Flow Diffusion Chamber (CFDC) has flown. The CFDC is ideal for these studies as it measures ice nuclei (IN) concentrations. IN are thought to initiate ice formation in mid-altitude clouds. The CFDC will characterize IN concentrations as a function of temperature and water saturation ratio. Analysis will focus on determining the relation between the presence or absence of ice in cloud and IN concentrations.

The CLEX-10 Project web page documents the field study based in Ottawa, Ontario, Canada, while a CFDC web page including preliminary data is maintained by our Ph.D. student Matt Richardson to document his participation in this field study.