Earth observation

In Europe, Earth observation has often been used to refer to satellite-based remote sensing, 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.

In the US, the term remote sensing has been used since the 1960s to refer to satellite-based remote sensing. Remote sensing has also been used more broadly for observations utilizing any form of remote sensing technology, including airborne sensors and even ground-based sensors such as cameras. 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.

Earth observations may include:

• numerical measurements taken by a thermometer, wind gauge, ocean buoy, altimeter or seismometer
• photos and radar or sonar images taken from ground or ocean-based instruments
• photos and radar images taken from remote-sensing satellites
• decision-support tools based on processed information, such as maps and models

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:

• forecasting weather
• tracking biodiversity and wildlife trends
• measuring land-use change (such as deforestation)
• monitoring and responding to natural disasters, including fires, floods, earthquakes, landslides, land subsidence and tsunamis
• managing natural resources, such as energy, freshwater and agriculture
• addressing emerging diseases and other health risks
• predicting, adapting to and mitigating climate change

The ongoing launch of new remote-sensing satellites, in situ instruments located on the ground, as well as those on balloons and airplanes, and in rivers, lakes and oceans, have increased the availability and frequency of comprehensive and nearly real-time observations.

Starting from 2017, 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), along with the opportunities such observation provides to improve social and economic well-being.