From a few hundred feet beneath the Earth's surface down to the geocenter, the temperature of the Earth increases with depth. The rate at which the temperature increases per unit distance is the geothermal gradient. The geothermal gradient varies from place to place, depending on how the rocks in the area react to heat. Other factors, such as the presence of rising magma, also influence the geothermal gradient. A low geothermal gradient of 0.6 degrees Fahrenheit per 100 feet occurs underneath parts of Japan. A high temperature gradient of 11 degrees Fahrenheit per 100 feet occurs under the Atlantic Ocean along the mid-Atlantic Ridge, according to the World of Earth Science.
The tropics receive direct rays from the sun all year around. The regions north and south of the tropics do not receive such direct sunlight. As the latitude increases, the solar rays strike the Earth at increasingly oblique angles, so the air is hotter at the equator and gets gradually cooler toward the poles. The latitudinal temperature gradient measures the rate at which atmospheric temperature decreases going north or south from the equator. The temperature readings used to compute the gradient must all be taken at the same height above sea level. The magnitude of the gradient varies seasonally; it is higher in winter than in summer.
The troposphere is the lowest portion of the Earth's atmosphere. Proceeding up from the ground, the temperature of the air continuously decreases up to the tropopause, the boundary of the troposphere. The vertical temperature gradient measures the rate at which the temperature decreases while proceeding directly up from any given spot on the surface of the Earth.
Cold water weighs more than an equal volume of warm water, so warmer water tends to stay at the top of an ocean, while colder water remains below. An ocean depth temperature gradient measures the rate at which the temperature of ocean water decreases while going down from the surface. The greatest depth gradient values occur in a region called the thermocline. The depth of the thermocline varies, ranging from 164 feet deep in the tropical waters of the eastern Pacific Ocean down to 3,281 feet in cooler parts of the globe, according to Earth and Space research. A low temperature gradient exists below the thermocline. The temperature gradient is irregular in the surface waters of the Arctic and Antarctic.