We use eddy-permitting simulations of the Northeast Pacifc (1950-2007) to study a prominent deterministic salinity signal in the subsurface. The signal is dominated by anomalous geostrophic advection. We develop a simple theory for anomalous geostrophic advection, which can be represented by chaining together two autoregressive first-order (AR-1) Hasselmann climate models-the first for the wind stress curl forcing the baroclinic pressure held, and the second for the baroclinic pres-sure controlling anomalous advection of salinity-such that the spectrum of pressure shows the familiar -2 slope, and salinity shows a -4 slope.