Anomalies of the GS position (a), speed (b), width (c), and cross-front SSH difference (d). Anomalies are computed by removing the annual cycle and performing a low-pass filter. (e–h) Linear trends during 1993–2016 at each longitude grid for the GS position, speed, width, and cross-front SSH difference, respectively. Gray shading indicates the 95% significance interval. (i–l) are similar to (e–h) but for the period 1993–2011. Units are degree latitude for GS position, cm/s for GS speed, km for GS width, and cm for cross-front SSH difference.