1. Summary of Current and Ongoing Cold Pool Modeling Research University of Utah/DAQ CAP John Horel, Erik Crosman, Erik Neemann University of Utah Department of Atmospheric Sciences Lance Avey Utah DAQ AMS Annual Meeting 18 th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA Atlanta, GA 4 February 2014

2. Summary of Current Problems Simulating Meteorology of CAPs Clouds Type (ice or liquid) Extent Duration Winds Too strong in surface layer Over- dispersive, mix- out and end of CAP too soon Stability profile Too weak/diffuse of capping inversion Improper depth of mixed layers Land surface Snow cover and albedo evolution often mispecified

3. Winds YSU PBL ΔX 1.33 kmLES ΔX 0.25 km

4. LES ΔX 250 m OBSERVATIONS COARSE ΔX 1335 m Stability profile Too weak/diffuse of capping inversion Improper depth of mixed layers Stability

5. Snow cover

6. NAM 12Z 1 Dec F000 GJT Clouds observed GFS

7. Summary of Uintah Basin WRF CAP Modifications 1. An “idealized” layer of snow and SWE was specified in the WRF initialization fields based on elevation in a manner similar to Alcott and Steenburgh (2013). 2. Albedo modified to observations; 3. WRF vegetation parameter changed to let less snow cover ground 4. Thompson Microphysics modified to produce more realistic ice clouds; turned off cloud ice sedimentation and the autoconversion of cloud ice in boundary-layer Summary of modifications and cold pool in Uintah Basin modeling results In manuscript about to be submitted: Simulations of a cold-air pool associated with elevated wintertime ozone in the Uintah Basin, Utah E. M. Neemann 1, E. T. Crosman 1, J. D. Horel 1, and L. Avey 2 [1]{Department of Atmospheric Sciences, University of Utah, Salt Lake City, Utah} [2]{Utah Division of Air Quality, Salt Lake City, Utah}

8. Future CAP Modeling Plans Further testing to determine best model parameterizations (PBL, microphysics, land surface) for CAP cases for spectrum of cold pool types Further edits to cloud microphysics code (e.g., testing WRF ice-fog scheme of Kim et al. (2014) in Uintah Basin ) Sensitivity to initialization time and initial conditions (starting at beginning or middle of CAP) Sensitivity to land use data set (USGS, MODIS, NLCD 2006) Possible edits to boundary-layer scheme or turn boundary-layer scheme off (LES) (J. Massey U of U) Sensitivity to model vertical and horizontal resolution for range of CAP types Incorporate snow physics model in addition to better initial snow fields like what Hopefully better understanding of what physical processes/aspects of CAPs that models are struggling with will be gained