Studies of the Earth's radiation budget have been carried out using satellite data for over three decades. A wealth of climatological information has been archived and a number of important results obtained, notably from the Earth Radiation Budget Experiment (ERBE). GERB data is expected to contribute to this field in several important areas:
- Radiation budget climatology over the region covered by MSG, including climatological means and temporal and spatial variability.
- Impact of clouds on the radiation budget, including cloud feedbacks. This will require the separate archiving of clear-sky fluxes to enable calculation of the cloud radiative forcing diagnostic.
- Water vapour greenhouse effect and the water vapour feedback.
- Diurnal cycle of convection and land surface temperatures.
- Retrieval of the surface radiation budget and comparisons with other satellite retrievals and with surface observations (e.g. from BSRN).
- Combining 1). and 5), it will be possible to study the atmospheric flux divergences.
- Impact of aerosols on the radiation budget. Of particular interest in this region are wind-blown dust from the Sahara and other arid regions, aerosols from biomass burning over tropical Africa and sulphate and other pollution aerosols from populated areas, notably Europe.
Planned Science - Evaluation of Numerical Models
An important application for GERB data will be in the evaluation of numerical models, in particular the three-dimensional models used in climate simulations and numerical weather prediction (NWP). Since climate models are themselves being used in many of the applications identified above, that list of applications is also appropriate here. In testing the model simulations, two broad categories are also worth highlighting:
- Determination of the overall climatology of the model over the area covered by GERB data.
- Using GERB data to test the performance in particular regions, giving insight into the physical realism of the parametrization schemes and the interactions between them. This is expected to be a particularly fruitful application, since the excellent temporal resolution of GERB (15 minutes) and the close match with the timestep of a typical global model means that processes such as surface heating and convection can be studied on a timestep to timestep basis.
- A further application involves the testing of forward models which are used for simulating the radiation budget from operational or other products (e.g. ISCCP, re-analyses).
Follow this link to see the latest comparison between GERB data and the Met Office Unified Model carried out at the University of Reading.
Planned Science - Meteorological and Other Exploitation
Plans to exploit GERB data by the national meteorological agencies are still at an early stage of development. One application which is at a mature stage of planning, however, is the proposal by RMIB to merge the GERB and SEVIRI data streams in near real-time and to produce radiation budget products for limited geographical regions at the high spatial resolution provided by SEVIRI. Details of this proposal are available elsewhere. Other broad categories of potential applications include:
- operational use by national/international Met. services
- commercial: agriculture, solar energy (with regard to surface fluxes)
- use by EUMETSAT to add value to SEVIRI data and products.
Planned Science - Earth Observation Science
This application is listed separately because it is expected that the GERB data will be widely used for research into the science of satellite remote sensing, as opposed to the climate and meteorological studies listed in other sections. Strong interactions between the communities is expected, however. Applications that are planned include:
- Analysis of GERB radiance data on their own (including calibration/validation activities)
- Analysis of GERB radiance data in conjunction with data from SEVIRI
- Analysis of GERB radiance data in conjunction with co-located data from other satellite instruments (e.g. Advanced Along Track Scanning Radiometer)
- Studies of the angular reflectance characteristics of clouds and surfaces
- Observing system applications, including merging the GERB data with data from polar orbiting satellites (e.g. ScaRaB and CERES) to create well-sampled high level products.
Education and Public Understanding
Apart from the research applications identified above, the data will be used in public awareness projects.