The top panels show wind speed and direction measured at the buoy. When the sticks point down then the wind is blowing to the south, up is to the north. Southward blowing winds are upwelling favorable in that they force a layer of surface water to flow away from the coast causing subsurface water to replace this water near the coast. The subsurface water is colder.
The M2 mooring is further away from the coast, the relationship between wind and water temperature is not as strong here as it is at M1.