- support the calibration of the ARM millimeter cloud radar and evaluate the spatial versus temporal variability of cloud properties as seen by cloud radars,
- obtain in-situ measurements of cloud properties to validate retrieval algorithms, and
- obtain in-situ measurements of aerosol properties during clear-sky conditions.
The ETL Radar Meteorology and Oceanography Division will field their NOAA/K scanning cloud radar near the new ARM millimeter cloud profiling radar (mmCR) at the ARM SGP Central Facility. At times, both cloud radars will operate in the vertically-pointing mode for purposes of evaluating and perfecting the performance of the ARM mmCR. At other times, the excellent scanning capabilities of the NOAA/K will be employed to examine how well the temporal variability of cloudiness measured by the ARM mmCR, which is vertically-pointing only, is related to the horizontal variability of cloudiness and cloud geometry. In-situ measurements of hydrometeor sizes and concentrations will be made by the University of North Dakota Citation aircraft , which is capable of sampling both low and high altitude clouds. The PNNL Gulfstream-1 aircraft will concurrently sample low clouds whenever low and high clouds are present over the Central Facility. Spiral and stair-step flight paths through the cloud layers directly over or near (within 10 to 50 km of) the Central Facility in a variety of cloud conditions will be necessary for validating microphysical retrievals. The Gulfstream aircraft will also fly aerosol missions over the site in clear-sky conditions, as more fully described in the Aerosol IOP home page.