In Europe, Earth observation has often been used to refer to satellite-based remote sensing,[1] but the term is also used to refer to any form of observations of the Earth system, including in situ and airborne observations, for example. The GEO, which has over 100 member countries and over 100 participating organizations, uses EO in this broader sense.[4]
In the US, the term remote sensing was used since the 1960s[5] to refer to satellite-based remote sensing. Remote sensing has also been used more broadly for observations using any form of remote sensing technology, including airborne sensors and even ground-based sensors such as cameras.[5] Perhaps the least ambiguous term to use for satellite-based sensors is satellite remote sensing (SRS), an acronym which is gradually starting to appear in the literature.[5][6]
Just as Earth observations consist of a wide variety of possible elements, they can be applied to a wide variety of uses. Some of the specific applications of Earth observations are:[6]
The quality and quantity of Earth observations continue to mount rapidly. In addition to the ongoing launch of new remote-sensing satellites, increasingly sophisticated in situ instruments located on the ground, on balloons and airplanes, and in rivers, lakes and oceans, are generating increasingly comprehensive, nearly real-time observations.
In 2017 [8] Earth observation have become increasingly technologically sophisticated. It has also become more important due to the dramatic impact that modern human civilization is having on the world and the need to minimize negative effects (e.g. geohazards),[8] along with the opportunities such observation provides to improve social and economic well-being.
