Evaluations of WRF New Features with an Operational Army Ensemble Prediction System

The impacts of new updates in WRF V3.7 and V3.8 are investigated with ATEC (US Army test and evaluation command) multi-model, multi-physics and multi-perturbation ensemble-RTFDDA (ensemble real-time four dimensional data assimilation) four-dimensional (E-4DWX) foresting system. The following new updates are tested with the ATEC ensemble system: 1) new Cumulus parameterization features (e.g., New Tiedtke scheme, Multi-scale Kain-Fritche scheme, Kain-Fritsch cumulus potential scheme);  2) Planetary Boundary Layer scheme updates (e.g., Shin-Hong PBL,  top-down mixing option in YSU driven by radiative cooling); 3) Radiation and cloud effect (e.g.,  compute-performance optimized option for RRTMG radiation,  a new cloud fraction option); 4) new set Geogrid data (e.g., 9 sec, NLCD 2006/2011 landuse data, 9 sec impervious surface and canopy fraction datasets derived from NLCD2011 landuse dataset.). This work upgrades the ATEC operational ensemble system from WRF V3.5 to WRF V3.8, adds new members to system based on the evaluation of the new features in WRF V3.7 and V3.8, and also extends E-RTFDDA to include NCAR DART EnKF members, and two GSI data assimilation members. These new members are compared to the previous 32 members in the ATEC ensemble to study their impacts on the ensemble forecasts and a subset is chosen for the real-time ensemble upgrade. The comparison results will be reported at the meeting.