What is the primary source of atmospheric moisture?

The primary source of atmospheric moisture is evaporation from water bodies. This process occurs when sunlight warms the surface of oceans, lakes, rivers, and other water bodies, causing water molecules to transition from the liquid phase to the gaseous phase. This vapor then rises into the atmosphere, increasing humidity levels.

While condensation from clouds plays a crucial role in the water cycle by forming precipitation and is important for the distribution of existing moisture, it does not serve as a source of moisture itself. Similarly, transpiration from plants contributes to atmospheric moisture but is a smaller source compared to the vast amounts of water that evaporate from larger bodies of water. Geothermal springs, while they do release some moisture into the atmosphere, are not significant contributors compared to the extensive evaporation that happens globally from oceans and other water sources. This makes evaporation the most substantial process affecting atmospheric moisture levels.