What is atmospheric circulation?

Atmospheric circulation refers to the large-scale movement of air within the Earth’s atmosphere, driven primarily by the uneven heating of the Earth's surface by the Sun. This process is fundamental to understanding weather and climate patterns. When certain areas of the Earth receive more solar energy, the air above these regions warms up, expands, and becomes lighter, causing it to rise. Conversely, cooler areas experience denser air that sinks. This difference in temperature and pressure across the globe leads to the development of wind patterns as air moves from high-pressure to low-pressure regions.

The other options, while related to different aspects of atmospheric and environmental processes, do not accurately define atmospheric circulation. The cycle of water in the atmosphere pertains to the hydrological cycle, which involves the continuous movement of water through evaporation, condensation, and precipitation. Movements of ocean currents relate to the flow of water in the oceans and are influenced by factors such as wind, temperature, and salinity, rather than being part of the atmospheric circulation itself. Regular patterns of seasonal changes involve broader climatic shifts over time rather than the ongoing movement of air masses, which is what defines atmospheric circulation specifically.