page_title: Geostationary Earth Radiation Budget
hierarchical_section_title: Geostationary Earth Radiation Budget
caption_attribution_description: English: EOCF
context_page_description: The Geostationary Earth Radiation Budget is an instrument aboard EUMETSAT's Meteosat Second Generation geostationary satellites designed to make accurate measurements of the Earth Radiation Budget.
  It was produced by a European consortium consisting of the United Kingdom, Belgium and Italy. The first, known as GERB 2, was launched on 28 August 2002 on an Ariane 5 rocket. The second, GERB 1, was launched on 21 December 2005, and the third, GERB3, on 5 July 2012. The last GERB 4 device was launched 14 July 2015. The first launched GERB 2 on MSG 1 is currently situated over the Indian Ocean at 41.5°E, while GERBs 1 and 3 on MSG 2 and 3 are still located over the standard Africa EUMETSAT position. GERB 4 on MSG is yet to become operational.
  Unknowns of Measuring and Predicting Changes in Earth's climate
  The un-precedented rate of atmospheric CO
  2 increase occurring since the industrial revolution due to human activity is of much concern to scientists as it has occurred an order of magnitude faster than planet Earth has ever experienced.
context_section_description: The Geostationary Earth Radiation Budget (GERB) is an instrument aboard EUMETSAT's Meteosat Second Generation geostationary satellites designed to make accurate measurements of the Earth Radiation Budget. 
  It was produced by a European consortium consisting of the United Kingdom, Belgium and Italy. The first, known as GERB 2, was launched on 28 August 2002 on an Ariane 5 rocket. The second, GERB 1, was launched on 21 December 2005, and the third, GERB3, on 5 July 2012. The last GERB 4 device was launched 14 July 2015. The first launched GERB 2 on MSG 1 is currently situated over the Indian Ocean at 41.5°E, while GERBs 1 and 3 on MSG 2 and 3 are still located over the standard Africa EUMETSAT position. GERB 4 on MSG is yet to become operational.
  Unknowns of Measuring and Predicting Changes in Earth's climate
  
  The un-precedented rate of atmospheric CO
  2 increase occurring since the industrial revolution due to human activity is of much concern to scientists as it has occurred an order of magnitude faster than planet Earth has ever experienced. Climate models described as Global Circulation Models (GCMs) are currently avenue to investigate and try and predict how Earth climate will change in response such an un-precedented rate of change.
   Such computer models largely agree on many predictions of how climate will be 'forced' to a different state by such changes but there is still much disagreement, more specifically how such forcing will also results in 'feedbacks' to the system. For example, increased CO
  2 will increase the green house effect resulting in warmer atmosphere and more melting of Arctic ice. However it is known that a warmer atmosphere can for example contain a higher quantity of water vapor at the same relative humidity, and the melting of highly reflective white Arctic ice will expose open ocean to sunlight. Since water vapor is itself a very strong greenhouse gas and dark Arctic Ocean will absorb more sunlight than highly reflected floating ice, these are both reasonably well understood to be positive feedbacks that will act to accelerate the rate of global warming. Perhaps the least understood aspect of climate change involves clouds, and how they might change in-response to straight atmospheric warming from increased CO
  2. These effects collectively referred to as Cloud Forcing or Cloud Radiative Forcing (CRF) and Feedback are not yet understood to the level where it can be predicted with certainty whether their possible feedbacks will in total be positive and accelerate, or negative and slow down global warming. The actions of the Earth weather/climate system are essentially the work done from a global scale heat engine, the heat into which comes from all the absorbed solar energy while the heat out is from thermal infra-red emissions back to space. These two radiative fluxes are referred to as Short-Wave (SW for solar) and Long-Wave (LW for IR) components in what is known as the Earth Radiation Budget (ERB, naturally the heat in requires the reflected SW to be measured and subtracted from the also needed in incoming solar flux). Clouds hence naturally have a huge effect on the ERB due to their high solar SW reflectivity and their strong absorption of outgoing thermal LW. Globally ERB fluxes can only be measured from orbit and have been collected since the 1970s by missions from the US and Europe, most extensively since 1998 by the NASA Cloud and the Earth's Radiant Energy System (CERES) instruments in low Earth orbit. Such orbital platforms however at most see each point of Earth only twice per day, while cloud formation and modulation of the ERB occurs on the time scale of minutes (see Fig.1). Hence although vital for tracking global changes in the ERB such low orbital measurements cannot be directly used to validate computer simulations of changes to convective cloud formation and dissipation in direct response to the inevitable surface warming due to CO
  2 increases etc. To address this deficiency in the Earth observing system the European consortium between the UK, Belgium and Italy embarked on the G
caption: Fig.3 Earth Observation Characterisation Facility (EOCF)