The Scripps Coupled Ocean–Atmosphere Regional (SCOAR) Model, with Applications in the Eastern Pacific Sector

Abstract

A regional coupled ocean–atmosphere model is introduced. It is designed to admit the air–sea feedbacks arising in the presence of an oceanic mesoscale eddy field. It consists of the Regional Ocean Modeling System (ROMS) and the Regional Spectral Model (RSM). Large-scale forcing is provided by NCEP/DOE reanalysis fields, which have physics consistent with the RSM. Coupling allows the sea surface temperature (SST) to influence the stability of the atmospheric boundary layer and, hence, the surface wind stress and heat flux fields. The system is denominated the Scripps Coupled Ocean–Atmosphere Regional (SCOAR) Model. The model is tested in three scenarios in the eastern Pacific Ocean sector: tropical instability waves of the eastern tropical Pacific, mesoscale eddies and fronts of the California Current System, and gap winds of the Central American coast. Recent observational evidence suggests air–sea interactions involving the oceanic mesoscale in these three regions. Evolving SST fronts are shown to drive an unambiguous response of the atmospheric boundary layer in the coupled model. This results in significant model anomalies of wind stress curl, wind stress divergence, surface heat flux, and precipitation that resemble the observations and substantiate the importance of ocean–atmosphere feedbacks involving the oceanic mesoscale.

Top marine predators track Lagrangian coherent structures

“…Indeed some investigators (33)(34)(35)(36) emphasize the role of local air-sea feedbacks arising from ocean mesoscale features. For example, Chelton et al (36) showed that an oceanatmosphere coupling is observed in the California Current System during summer.…”

A review on regional dynamical downscaling in intraseasonal to seasonal simulation/prediction and major factors that affect downscaling ability

“…Recently, fully coupled atmosphere-ocean RCMs have been used for dynamic downscaling studies (e.g., Aldrian et al, 2005;Ren and Qian, 2005;Seo et al, 2007;Artale, et al, 2010;Ratnam et al, 2013). In general, these studies reported an improvement in dynamic downscaling due to coupled models.…”

Predictability and Diagnosis of Low-Frequency Climate Processes in the Pacific

“…We also developed the Scripps Coupled Ocean-Atmosphere Regional (SCOAR) model (Seo, Miller and Roads, 2007a), which includes the Regional Spectral Model for the atmosphere (Juang and Kanamitsu, 1994) and the Regional Ocean Modeling System (ROMS) for the ocean (Haidvogel et al 2000;Shchepetkin and McWilliams 2005). SCOAR has been remarkably successful in simulating mesoscale ocean-atmosphere coupling for Pacific tropical instability waves (TIW's), mesoscale eddies in the California Current System (Figure 5), and gap winds along the Central American Coast (Seo et al, 2007a).…”

“…SCOAR has been remarkably successful in simulating mesoscale ocean-atmosphere coupling for Pacific tropical instability waves (TIW's), mesoscale eddies in the California Current System (Figure 5), and gap winds along the Central American Coast (Seo et al, 2007a). These phenomena were modeled for the first time using high resolution and full coupling, with key aspects of model variables compared favorably with observations.…”