With the help of Lowell Instruments (www.lowellinstruments.com) we installed a data buoy about a mile east of Nobska Point in Vineyard Sound. It transmits the following data every half hour: wind speed, highest wind gust, air temperature, barometric pressure and surface water temperature (1 meter depth).
One interesting thing we’ve found is that surface water temperature variations are caused by the tidal current in Vineyard Sound. On the ebb tide, warm water from Nantucket Sound flows past the mooring. During flood tide, cold water flows from the Gay Head area. Note how the amplitude varies with the phase of the moon. During spring tides, the amplitude is at its maximum (sometimes 4 degrees F). During half moons, the amplitude is a lot less because water is not coming from as far away (not as warm, and not as cold).
To view the data, click here.