Consider the following statements concerning the Thermocline:

1.The thermocline is the transition layer between the warmer mixed water at the surface and the cooler deep water below.

2.The thermocline is semi-permanent in the tropics and varies in temperate regions, often being deepest during the summer.

3.The depth of the thermocline plays no role in meteorological forecasting, such as predicting the risk of hurricane formation.

4.The thermocline is present in the polar regions, where the water column is cold from the surface to the bottom.

How many of the above statements are correct?