CW3E Publication Notice

SKRIPS v1.0: A Regional Coupled Ocean–Atmosphere Modeling Framework (MITgcm–WRF) Using ESMF/NUOPC, Description and Preliminary Results for the Red Sea

October 15, 2019

CW3E postdoc Rui Sun, along with co-authors Aneesh Subramanian, Bruce Cornuelle, Art Miller, Matt Mazloff, and Ibrahim Hoteit of KAUST (King Abdullah University of Science and Technology), published a paper in Geoscientific Model Development entitled “SKRIPS v1.0: A regional coupled ocean–atmosphere modeling framework (MITgcm–WRF) using ESMF/NUOPC, description and preliminary results for the Red Sea”

In this study, a new regional coupled ocean–atmosphere model is developed and its implementation is presented. The coupled model is based on two open-source community model components: (1) MITgcm ocean model and (2) Weather Research and Forecasting (WRF) atmosphere model. The coupling between these components is performed using ESMF (Earth System Modeling Framework) and implemented according to National United Operational Prediction Capability (NUOPC) protocols. The coupled model is named the Scripps–KAUST Regional Integrated Prediction System (SKRIPS). In the paper, the SKRIPS is demonstrated with a real-world example by simulating a 30-day period including a series of extreme heat events occurring on the eastern shore of the Red Sea region in June 2012. The results obtained by using the coupled model, along with those in forced stand-alone oceanic or atmospheric simulations, are compared with observational data and reanalysis products. It is shown that the coupled model is capable of performing coupled ocean–atmosphere simulation. In addition, a scalability test is performed to investigate the parallelization of the coupled model. The results indicate that the coupled model code scales well and the ESMF/NUOPC coupler accounts for less than 5% of the total computational resources in the Red Sea test case. The coupled model and documentation are available at UCSD library (, and the source code is maintained at Github (

Figure 1: The schematic description of the coupled ocean–atmosphere model. The yellow block is the ESMF/NUOPC coupler; the red blocks are the implemented MITgcm–ESMF and WRF–ESMF interfaces; the white blocks are the oceanic and atmospheric components. From WRF to MITgcm, the coupler collects the atmospheric surface variables and updates the surface forcing to drive MITgcm. From MITgcm to WRF, the coupler collects oceanic surface variables and updates them in WRF as the bottom boundary condition.

Figure 2: The parallel efficiency test of the coupled model in the Red Sea region, employing up to 512 CPU cores. The simulation using 32 CPU cores is regarded as the baseline case when computing the speed-up. Tests are performed on the Shaheen-II cluster at KAUST.

Sun, R., A.C. Subramanian, A.J. Miller, M.R. Mazloff, I. Hoteit, and B.D. Cornuelle (2019): SKRIPS v1.0: a regional coupled ocean–atmosphere modeling framework (MITgcm–WRF) using ESMF/NUOPC, description and preliminary results for the Red Sea. Geosci. Model Dev., 12, 4221–4244,