Surface cooling predictions of the coupled NMM/WRF PBL and Noah land surface schemes

The Mellor-Yamada-Janjic (MYJ) turbulence scheme has been used in the NCEP operational meso-ETA model for close to 10 years. It is currently the TKE scheme used in the new mesoscale WRF-NMM and WRF-ARW models. Results of GABLS-II simulations using the MYJ scheme coupled to the ETA/NMM-WRF surface layer scheme will be presented. Improvements to the scheme resulting from these simulations will be reported on. Additional simulation results for stable boundary layers will be presented involving all or a subset of the following (1) coupling to the Noah land surface module, (2) coupling to a simple long-wave radiation scheme, (3) runs with varying manners of specifying length scale, (4) runs with varying manners of specifying surface layer stability functions. Based on the results of these simulations, issues relating to the general predictions and avenues for improvement of second-order closure based TKE schemes for stable boundary layers will be discussed.