WB57MIDCIX

In order to improve our understanding of the role clouds play in the climate system, NASA invested considerable effort in characterizing clouds with instruments ranging from passive remote sensors on board the EOS platforms, to active remote sensors on Cloudsat and Calipso. These missions, when taken together, had the capacity to advance our understanding of the coupling between various components of the hydrologic cycle and the atmospheric circulation, and held the additional potential of leading to significant improvements in the characterization of cloud feedbacks in global models. This was especially true considering that several of these platforms were flown in an identical orbit within several minutes of one another as a constellation of satellites known as the A-Train. The algorithms that were being implemented and developed to convert these data streams from radiance and reflectivity measurements into geophysical parameters invariably rely on some set of simplifying assumptions and empirical constants. Uncertainties in these relationships led to poorly understood random and systematic errors in the retrieved properties. This lack of understanding introduced ambiguity in interpreting the data and in using the global data sets for their intended purposes. In light of this, we proposed a series of flights with the WB57F to address certain specific issues related to the basic properties of mid latitude cirrus clouds.

The science questions we wished to address were, 1) Can cloud property retrieval algorithms developed for A-Train active and passive remote sensing measurements accurately characterize the microphysical properties of synoptic and convectively generated cirrus cloud systems? 2) What are the relationships between the cirrus particle mass, projected area, and particle size spectrum in various genre of cirrus clouds? 3) Does the complement of state of the art in situ cloud probes provide the level of precision and accuracy needed to develop and validate algorithms and to contribute to our understanding of the characteristics and microphysical processes operating in cirrus clouds?

The timeframe and location for this flight series werefrom mid April through mid May 2004 and the flights took place in the south-central United States in the vicinity of the Southern Great Plains Atmospheric Radiation Measurement Central Facility near Lamont, Oklahoma where a raft of active and passive remote sensors continuously operate. We requested flight hours sufficient for 8 research flights over a period of 3 weeks (~50 flight hours). We proposed that the WB57 be instrumented to measure the following quantities.

1) The cirrus cloud particle size distribution 2) The ice crystal particle habit 3) Several of the state-of-the-art instruments for measuring the ice mass concentration (or ice water content, IWC) 4) The volume extinction coefficient 5) Water Vapor at upper tropospheric temperatures

Timeline

Campaign Data Sets