Greg McFarquhar                                                               University of Illinois


The CIRPAS Twin Otter takes off from Guthrie, OK for a routine flight through low-level liquid clouds (photo courtesy of ARM archive, Some of the in-situ cloud microphysical probes used during RACORO to record images of cloud particles and data needed to determine the cloud droplet size distributions (two-dimensional stereo probe and cloud imaging probe depicted). Picture from window of Twin Otter during a routine cloud monitoring mission (photo courtesy of ARM archive,
RACORO: The Routine ARM Aerial Facility (AAF) Clouds with Low Liquid Water Depths (CLOWD) Optical Radiative Observations (RACORO) campaign was conducted out of Guthrie and Ponca City, Oklahoma between January and July 2009. The goal of RACORO was to conduct long-term routine flights in boundary layer (low-altitude) liquid water clouds over the Department of Energy Atmospheric Radiation Measurement (DOE ARM) Program's Southern Great Plains Site in Ponca City, Oklahoma. RACORO was different from previous field campaigns in that it aimed at obtaining representative statistics of cloud microphysical properties needed to evaluate retrieval algorithms and support process studies and model simulations; previous short-term field campaigns have focused more on analysis of a few case studies, about which the representativeness may be questioned. The three main objectives of RACORO were as follows: 1) obtain representative statistics of cloud optical and mcirophysical properties and of cloud radiative fluxes for cloud retreival validations; 2) observe the aerosol properties assocaited with cloud variability, such as aerosol amount, aerosol size distribution and the number of cloud condensation nuclei; and 3) to facilitate understanding of how meteorological factors influence cloud dynamics, microphysical properties, and aerosol-cloud interactions by making measurements of moisture and mass flux at cloud base.
Uof Illinois Role and Interests: In his capacity as Chief Scientist of the ARM Aerial Facility (AAF), Prof. McFarquhar played a major role in the design of the experiment, the development of the science and flight operations plan, and the selection of instruments/aircraft for the project. In addition, Prof. McFarquhar served on the Science Steering Committee for RACORO and was heavily involved in the flight planning. Graduate student Hee-Jung Yang spent 2 weeks in Ponca City, Oklahoma during a more intensive operations period of the project. She is planning to use some of the RACORO data in her thesis research.

Publications arising from RACORO:

To follow.

Thesis arising from RACORO:

Lots of opportunities available to use these data!