An altimetric based metric for Gulf Stream position in climate models
Event: 2015 Ocean Surface Topography Science Team Meeting
Session: Science III: Large scale and global change ocean processes: the ocean's role in climate
Presentation type: Type Poster
Contribution: not provided
Here we present model metrics for Gulf Stream position and strength, providing both their climatological mean and variance. For high-resolution models we fit the sea level across the Gulf Stream to an error function. In a comparison between and North Atlantic ocean-only and coupled simulations at high resolution (0.1°) we find qualitative agreement with observations in both mean and variance of position. We also develop a metric for low-resolution models based on the location of maximum zonal velocity and apply it to historical simulations of models in the CMIP5 archive. While the mean position of the Gulf Stream is qualitatively similar among the models, there are large differences in the spatial and temporal variance of its position.
Quantifying biases in Gulf Stream position and strength (both mean and variability) is vital to evaluating and improving the performance of climate models in the North Atlantic as Gulf Stream strength and position are closely related to sea surface temperature in the subpolar North Atlantic. In addition, understanding and predicting decadal-scale changes in the Gulf Stream can provide insight into the decadal variability of the North Atlantic processes to which it is closely linked.