These graphs plot ocean temperature (deg C, top graph) and salinity (psu, bottom graph) as a function of day of the year (Day 110 is April 20, Day 121 is May 1). The data are from sensors located 1 meter (blue line) and 17 meters (green line) beneath the surface at mooring site 2 [56.9 deg N, 164.0 deg W]. The accuracy of the temperature sensor is about 0.01 deg C; the accuracy of the salinity estimate is about 0.01 psu. Given this sensor accuracy information, when is the water at 1 m significantly cooler or warmer than that at 17 m? Is the water at 1 m significantly saltier or fresher than the water at 17 m? When?