Final answer:
Cotidal lines in the Northern Hemisphere rotate in a counterclockwise direction due to the Coriolis effect and the influence of Earth's rotation.
Step-by-step explanation:
In the Northern Hemisphere, cotidal lines, which represent points where high tide occurs simultaneously, rotate in a counterclockwise direction. This rotation is influenced by the Earth's rotation and the Coriolis effect.
This effect is a result of the Earth's rotation, which also causes hurricanes to rotate counterclockwise in the Northern Hemisphere, as demonstrated by the Coriolis force. Similarly, celestial observations, like those made by Hipparchus concerning the rotation of the sky around the north celestial pole, confirm that natural rotational movements in the Northern Hemisphere tend to follow a counterclockwise pattern.