In our study of the atmosphere of planet Earth, we need to have global observations of atmospheric parameters such as temperature, pressure, and the concentration of key chemically or radiatively active constituents, and radiative fluxes. We turn to observations made by sophisticated instruments on orbiting spacecraft to obtain these measurements.
The group is currently heavily involved in the analysis of the infrared emission spectrum of the Earth, measured at different times from a variety of spacecraft instruments. The idea is to search for small changes in these spectra, indicating changes in the radiative forcing of the Earth's climate. Currently, we are working with new, high resolution spectra from the European IASI experiment, and the US TES experiment. Comparisons with spectra measured in 1970 by IRIS are being undertaken, to show the growth of greenhouse forcing from 1970 to the present.
We are also the lead group for the Geostationary Earth Radiation Budget (GERB) experiment which is flying on all four of the Meteosat Second Generation (MSG) geostationary spacecraft, to make measurements of the Earth's radiation budget, for the first time from this orbit. Imperial is teamed with the Rutherford Appleton Laboratory, Leicester University, and with colleagues in Belgium and Italy, and many other centres in the UK and the rest of Europe, and the USA. Studies are being undertaken of the cloud-radiative feedback; the effects of desert dust on the radiation balance; the diurnal cycle; the net radiative balance at the top of the atmosphere; and many other problems using this truly unique experiment.
The Far Infrared is a relatively unused part of the spectrum for EO studies of the Earth, and with Italian and US colleagues we are studying the design of a future satellite Far Infared spectrometer. Much of this work is based on the design and the utilization of the TAFTS instrument (Tropospheric Airborne Fourier Transform Spectrometer), developed at Imperial College for measurements from aircraft of the heating rates within the Earth's atmosphere.
Current research topics include:
- Observed and simulated changes in the IR spectrum of the Earth
- The time variability of the Earth's Outgoing Longwave Radiation
- The radiative energy budget of the Earth, its variability and magnitude
- Net flux and ocean heat storage
- The role of dust in the Earth system
- The radiative effects of ice clouds
- The operation, data processing and scientific exploitation of the GERB experiment
- The water vapour and cloud feedbacks
- Spectroscopy of the Earth and its atmosphere
Spectral Signatures of Climate Change:
John Harries - Helen Brindley - Richard Bantges - Claudine Chen - Jenny Griggs
Find out more
View the Earth Observation Group website