Investigation of variability of the North Atlantic Subtropical Mode Water using profiling float data and numerical model output

The values of the mean STMW temperature derived from both the float data and model output are roughly equal (18.1 °C for floats and 18.0 °C for the model). The model is found to capture well the observed annual cycle of the STMW volume. Given good agreement between float and model profiles, we use a longer MICOM simulation to investigate decadal variability of the STMW renewal rate in terms of the annual subduction rate and its relationship to the large-scale atmospheric circulation pattern changes measured by the North Atlantic Oscillation index. Good correlation is found between the model annual subduction rate anomaly at the Panulirus Station and the NAO winter index anomaly on decadal time scales with NAO leading by 2-3 years.