Land vs. Sea Convection Currents
Large bodies of water boast greater heat capacity than their neighboring land masses, meaning that as they warm up during the day, it creates a high pressure area which stirs the air above it. The cooler land surface has a lower pressure area, drawing in the sea air as a sea convection current, or a sea breeze. At night the reverse is true, causing the warmer land air to push out to sea as a land convection current, or land breeze.
Amospheric Convection Currents
Hot air climbs on convection currents from the Earth's surface through the levels of the atmosphere. This convection generates rain-producing clouds and cooling winds, which fall back to Earth's surface as cooler, denser air currents.
Forced Convection Currents
Pumps and other devices---such as ovens, refrigerators and air conditioning units---move heated air or water to generate forced convection. The human body also cools itself by means of forced convection, forcing heated sweat through the skin which is cooled by breezes passing over it.