4.1 Shallow cumulus evaluated with the LASSO (ensemble LES) framework

Angevine, Wayne M., Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, and National Oceanic and Atmospheric Administration/Earth Systems Research Laboratory (NOAA/ESRL)/Chemical Sciences Division, Joseph Olson and Jaymes Kenyon, CIRES and NOAA/ESRL/Global Sciences Division

Shallow cumulus present an ongoing challenge to WRF. A variety of

physics options intend to represent these clouds, but finding a good

configuration has been complicated by the lack of good observations. The DOE ARM project LASSO now provides several cases with shallow cumulus. For each case, an ensemble of large eddy simulations were run using different initial conditions and advection terms. We report on WRF single-column tests using the LASSO framework. The new MYNN PBL with EDMF, and the older TEMF PBL scheme, are both exercised. A major advantage of LASSO is that we can distinguish between differences that are due to uncertainties in the case setup, versus those that are unambiguously caused by the WRF schemes themselves.