Which phenomenon affects the direction of the earth's surface wind?

The correct answer highlights the impact of the Earth's rotation on wind direction, a phenomenon known as the Coriolis effect. As air moves from high to low pressure areas, the rotation of the Earth causes it to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This deflection is crucial in understanding global wind patterns and the circulation of the atmosphere.

The Coriolis effect arises because the Earth rotates on its axis, and different points on its surface move at different speeds. Points near the equator are moving faster than those closer to the poles due to the larger circumference. As air moves, it doesn't travel in a straight line but rather curves, leading to the prevailing wind patterns observed around the planet.

Other options, while they may influence weather and climate, do not directly affect the wind direction in the same fundamental way that the rotation of the Earth does. For instance, the gravitational pull of the Moon primarily influences tides rather than wind patterns. Seasonal temperature changes can affect wind speed and local weather conditions but do not establish the basic flow and direction of winds. Ocean currents are influenced by prevailing winds, but they are not the primary factor affecting wind direction itself.