Fig. 4: Mean sea surface density (SSD), Ekman pumping, and their changes.
From: The role of mountains in shaping the global meridional overturning circulation
a–d Mean SSD (units: kg/m3) in Flat, Flat2Real, TP (Tibetan Plateau), and TP + AT (Antarctic), respectively, with black dots (crosses) denoting mean Ekman upwelling (downwelling) in each experiment. The Ekman pumping is calculated as \({\omega }_{E}={curl}(\frac{\tau }{\rho f})\), where \(\tau\) is the surface wind stress with units of \({dyn}/c{m}^{2}\), \(\rho\) is the density of sea water (\(1024{kg}/{m}^{3}\)), and \(f\) is Coriolis parameter with units of \(1/s\). e shows the equilibrium changes in SSD and Ekman pumping in Flat with respect to Real, while f–h show their equilibrium changes in Flat2Real (Year 5601–6000), TP, and TP + AT, respectively, with respect to Flat. Black dots (crosses) denoting region with anomalous Ekman upwelling (downwelling). i shows the equilibrium sea surface salinity (SSS) changes (units: psu) in Flat with respect to Real, while j–l show the equilibrium SSS changes in Flat2Real, TP, and TP + AT, respectively, with respect to Flat. Note that the patterns of e and f and those of i and j are nearly identical but with opposite signs. e and i are included for convenience of analysis. The mean SSD in experiments AT and AM is similar to that in Flat, and thus is not shown here.
