Using new satellite observations, the response of surface wind and clouds to SST changes is investigated over cold oceans, where the planetary boundary layer (PBL) is often capped by a temperature inversion. In contrast to the negative correlation often observed on the basin-scale that is indicative of one-way atmospheric forcing, clear wind response is detected with zero to positive correlation with the causal SST anomalies, depending on the dominant wind-adjustment mechanism. In particular, SST modulation of vertical momentum mixing is a ubiquitous mechanism for surface wind variability near oceanic fronts around the world. Several types of boundary-layer cloud response are found, whose correlation with SST varies from positive to negative, depending on the role of surface moisture convergence. Noting that the surface moisture convergence is strongly scale-dependent, we propose that the horizontal scale is important for setting the sign of this SST-cloud correlation.
Finally, the processes by which local shallow PBL response might lead to a deep, tropospheric-scale response and the implications for the study of extratropical air-sea interaction are discussed.