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In 2019, 39 million km 2 (15 million sq mi) of Earth's land surface consisted of forest and woodlands, 12 million km 2 (4.6 million sq mi) was shrub and grassland, 40 million km 2 (15 million sq mi) were used for animal feed production and grazing, and 11 million km 2 (4.2 million sq mi) were cultivated as croplands. [271]
Global surface temperature (GST) is the average temperature of Earth's surface. More precisely, it is the weighted average of the temperatures over the ocean and land. The former is also called sea surface temperature and the latter is called surface air temperature. Temperature data comes mainly from weather stations and satellites.
The preliminary reference Earth model (PREM) plots the average of Earth's properties by depth. [1] It includes a table of Earth properties, including elastic properties, attenuation, density, pressure, and gravity. PREM has been widely used as the basis for seismic tomography and related global geophysical models. [2]
The transition between the inner core and outer core is located approximately 5,150 km (3,200 mi) beneath Earth's surface. Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 19% of Earth's radius [0.7% of volume] or 70% of the Moon's radius.
A data set which describes the global average of the Earth's surface curvature is called the mean Earth Ellipsoid. It refers to a theoretical coherence between the geographic latitude and the meridional curvature of the geoid. The latter is close to the mean sea level, and therefore an ideal Earth ellipsoid has the same volume as the geoid.
The Earth's magnetic field protects the Earth from the deadly solar wind and has long been used for navigation. It originates in the fluid motions of the outer core. [24] The magnetic field in the upper atmosphere gives rise to the auroras. [26] Earth's dipole axis (pink line) is tilted away from the rotational axis (blue line).
The geologic temperature record are changes in Earth's environment as determined from geologic evidence on multi-million to billion (10 9) year time scales. The study of past temperatures provides an important paleoenvironmental insight because it is a component of the climate and oceanography of the time.
A hybrid topological data model has the option of storing topological relationship information as a separate layer built on top of a spaghetti data set. An example is the network dataset within the Esri geodatabase. [23] Vector data are commonly used to represent conceptual objects (e.g., trees, buildings, counties), but they can also represent ...