Previous studies have shown that wind-forced baroclinic Rossby waves can capture a large portion of lowfrequency steric sea surface height(SSH)variations in the North Atlantic.In this paper,the classical wind-driven R...Previous studies have shown that wind-forced baroclinic Rossby waves can capture a large portion of lowfrequency steric sea surface height(SSH)variations in the North Atlantic.In this paper,the classical wind-driven Rossby wave model derived in a 1.5-layer ocean is extended to include surface buoyancy forcing,and the new model is then used to assess the contribution from buoyancy-forced Rossby waves to low-frequency North Atlantic steric SSH variations.Buoyancy forcing is determined from surface heating as freshwater fluxes are negligible.It is found that buoyancy-forced Rossby waves are important in only a few regions belonging to the subtropicaltomidlatitude and eastern subpolar North Atlantic.In these regions,the new Rossby wave model accounts for 25%-70% of low-frequency steric SSH variations.Furthermore,as part of the analysis it is also shown that a simple static model driven by local surface heat fluxes captures 60%-75% of low-frequency steric SSH variations in the Labrador Sea,which is a region where Rossby waves are found to have no influence on the steric SSH.展开更多
文摘Previous studies have shown that wind-forced baroclinic Rossby waves can capture a large portion of lowfrequency steric sea surface height(SSH)variations in the North Atlantic.In this paper,the classical wind-driven Rossby wave model derived in a 1.5-layer ocean is extended to include surface buoyancy forcing,and the new model is then used to assess the contribution from buoyancy-forced Rossby waves to low-frequency North Atlantic steric SSH variations.Buoyancy forcing is determined from surface heating as freshwater fluxes are negligible.It is found that buoyancy-forced Rossby waves are important in only a few regions belonging to the subtropicaltomidlatitude and eastern subpolar North Atlantic.In these regions,the new Rossby wave model accounts for 25%-70% of low-frequency steric SSH variations.Furthermore,as part of the analysis it is also shown that a simple static model driven by local surface heat fluxes captures 60%-75% of low-frequency steric SSH variations in the Labrador Sea,which is a region where Rossby waves are found to have no influence on the steric SSH.
