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Analyses of Aircraft Measurements and LES Modeling for Improved Physical Parameterization for Seasonal Prediction

As part of the Unified Physical Parameterizations for Extended Forecast (UPPEF) Departmental Research Initiative (DRI), we conducted aircraft measurements of the marine stratocumulus-topped boundary layers off the coast of central California in September 2012. The intensive observation is referred to as UPPEF2012. The measurements of UPPEF2012 included 12 flights, 10 of which focused on the cloud covered marine boundary layers. This dataset has been quality controlled and made available to other UPPEF researchers together with a flight summary documenting the cloud conditions and the measurement legs for each flight. Preliminary analyses of the dataset also revealed important characteristics related to surface forcing and cloud breaks. This previous work laid the foundation for further in-depth analyses, modeling, and parameterization development, which is to be proposed under the current proposal. In phase II of this project, our emphases will on in-depth analyses of the measurements, parameterization validation and development, and collaboration with other UPPEF PIs on joint data analyses and modeling efforts. We intend to 1) extend the previous analyses on surface flux and processes related to cloud breaks to a wider range of data obtained during UPPEF 2012 and relate these analyses to parameterizations under investigations of the modeling groups in UPPEF; 2) Analyses of the probability distribution function (pdf) of thermodynamic and cloud variability and the physical parameters controlling the forms of pdf; 3) LES modeling study on breaking cloud mechanisms; 4) extensive collaborative analyses particularly with the modeling groups of UPPEF for development and testing of improved physical parameterizations for a broad range of cloud conditions.
Office of Naval Research