Determining Highest Air Temperature Time

The near-surface air temperature is influenced by the continuous exchange of energy between the Earth's surface and the atmosphere. This exchange involves incoming solar radiation and outgoing longwave radiation.

Energy Balance and Air Temperature

The air temperature's progression throughout the day follows the net energy balance:

• Morning: After sunrise, incoming solar radiation begins to heat the surface and air. Temperature starts rising.
• Around Noon: Solar radiation is at its maximum intensity as the sun is highest. However, the ground and air are still accumulating heat.
• Mid-Afternoon: The air temperature reaches its peak. This occurs when the amount of incoming solar radiation effectively equals the amount of outgoing longwave radiation emitted by the surface. This balance point signifies that the rate of heating equals the rate of cooling, marking the maximum temperature achieved.
• Late Afternoon/Evening: As the sun lowers, incoming solar radiation decreases. Outgoing longwave radiation continues, leading to a net energy loss and falling air temperatures.

The condition described in option C, "When the incoming solar and outgoing longwave radiation balance each other," accurately represents the moment the air temperature reaches its highest point due to the cessation of net heating.