Model Coupling IRENE

div class="title">Hurricane Irene (IRENE)

Introduction

Hurricane Irene was a the first hurricane and major hurricane of the 2011 Atlantic hurricane season. This coupled simulation is only run for 42 hours as it approaches the U.S. east coast on August 27, 2011. The WRF and ROMS grids are incongruent so the DATA model provides the SST values to WRF at locations not covered by the the ROMS grid. This test case uses ESMF/NUOPC coupling to create a DATA-WRF-ROMS coupling application.

Grid Setup and Melding

The WRF and ROMS grids are incongruent. That is, the WRF grid is larger than the ROMS grid. Therefore, the DATA model provides SST values at the WRF grid locations not covered by the ROMS grid. Thus, both DATA and ROMS SST values are exported to WRF and must be melded to create a smooth transition at the ROMS domain boundaries. The melding is computed as:

$$SST^{ATM}(:,:)=W^{ROMS}(:,:)*SST^{ROMS}(:,:)+W^{DATA}(:,:)*SST^{DATA}(:,:)$$

where $W^{ROMS}(:,:)+W^{DATA}(:,:)=1$ are the weight coefficients that guarantee a smooth transition between the ROMS and DATA values, as illustrated below.

These wights are computed and plotted using the script coupling/wrf_weights.m from the ROMS Matlab repository.