Although models, theoretical studies and laboratory work play a major role in the atmospheric sciences, ultimately new theories and model simulations must be tested and evaluate through observations of the state of the atmosphere. The work of Prof. McFarquhar's group at the University of Illinois has concentrated on using observations and multi-scale models in combination so as to ultimately improve the representation of clouds in weather models. As our work concentrates on improving our knowledge of the basic properties of clouds and improving their representation in weather and climate models, we need to make measurements of clouds. We do this using aircraft that fly through clouds, measuring the microphysical properties of clouds in-situ. Because cloud properties vary considerably depending upon formation mechanism, height and geographic location, field experiments have been conducted in a wide variety of locations (illustrated above) so as to better understand the variability of cloud and associated properties. Click on the project name below to see some highlights of the project and the group members in action (topics, sponsors and aircrafts reflect the McFarquhar group effort and may represent a subset of the funding agencies and aircraft involved in the project).