LES (Large Eddy Simulation)

The parallelized LES model has been developed based on PALM (Univ. Hannover, Germany). Subgrid-scale turbulence is modeled according to Deardorff (1980). The numerical scheme is a standard, second order finite difference using the absolutely-conserving scheme of Piacsek and Williams (1970). The Poisson equation for pressure is solved by FFT method. The performance of a new parallized code shows an almost linear speed-up up to very large number of processors on SGI/Cray-T3E.

Fig. 1. LES of convection-driven PBL

Fig. 2. LES of shear-driven PBL

OGCM (Ocean General Circulation Model)

 The OGCM has been developed based on the Geophysical Fluid Dynamics Laboratory (GFDL), modular ocean model (MOM), version 2 OGCM (Pacanowski 1996), in collaboration with NIED (National Research Institute of Earth Science and Disaster Prevention) of Japan. Horizontal resolution is 1.125o in longitude and 0.5625o in latitude. There are 37 levels in the vertical, with 25 of these levels in the upper 400 m. The new vertical mixing scheme developed by Noh (Noh and Kim 1999, Noh et al. 2002) is embedded in the model.

Fig. 3. Obseved and simulated SST

Fig. 4. Annual mean volume transport streamfunction

Ocean Mixed Layer Model (Noh Scheme)

We developed a new ocean mixed layer model, taking into consideration the observational evidence of the near surface turbulence structure owing to wave breaking (Noh and Kim 1999). The model is a second-order turbulence closure model using eddy diffusivity, but it produces a well-mixed layer even under the stabilizing heat flux, contrary to the previous models. The model is now included various OGCMs (RIAM OM, COCO, MRI OGCM, OGCM of Kyoto Univ.).

[OML fortran program download]

Planetary Boundary Layer Model (YSU Scheme)

Based on the analysis of LES data, an improved PBL model has been developed which corrected inconsistency of Troen-Mahrt model (1986). The most important modification is the explicit treatment of the entrainment at the top of the boundary layer (Noh et al. 2002). The model is now included in WRF-NMM.

[PBL fortran program download]

          Department of Atmospheric Sciences, Yonsei University

                       Shinchon-dong 134, Seodaemun-ku, Seoul, 120-749, Korea.

                  (Tel) 82-2-2123-5680, (Fax) 82-2-365-5163