Deliverables REFIR (Radiation Explorer in the Far InfraRed) - Small-size spaceborne Fourier spectrometer for new atmospheric measurements in the far IR - Definition, assessment of feasibility and required resource The study has demonstrated the feasibility of REFIR, a spaceborne Fourier-transform spectrometer in the thermal to far infrared (9-100 micrometers) suitable for vertical sounding of temperature and water vapour of the high troposphere and other scientific information, that may be derived from the measured spectra at 0.5 cm-1 resolution. An additional broad-band channel is provided for the measurement of total emitted radiation, while an embedded thermal imager and a multispectral pushbroom imager (both contained in the instrument envelope) are included for monitoring the cloud field simultaneously with the main spectral measurement. The REFIR scientific objectives are stated as follows: -Measuring the spectral radiance in the FIR (100 -1100 cm-1), a portion of the planetary emission to space that is not covered by any current or planned space mission. -Improving our knowledge on the distribution of the atmospheric constituents that modulate to a large extent the FIR emission to space (mid and upper tropospheric water vapour, using the strong spectral signature of water vapour in the FIR; mid and upper tropospheric clouds, such as cirrus). The REFIR instrument concept consists of: -A far infrared REFIR Fourier Transform Spectrometer (RFTS) as the primary spectrometer. -The REFIR Embedded Imager operating in an infrared �window� (REI), sharing the same bore-sight as RFTS, for scene/cloud identification. -The REFIR Total Energy Radiometer (RTER), a broadband channel operating in the range from 0.3 to 100 micrometers. -The REFIR Add-on Imager (RAI) to provide multi-channel imagery. The instrument has an overall mass of 70 kg, a power consumption of 82 W and a raw data rate of 170 kbit/s (reducible to 33 kbit/s by on-board compression), making it suitable for stand-alone missions on small satellites in LEO (low Earth orbit), or inclusion in larger missions as additional payload, with a nominal lifetime of 3 years or more. REFIR will provide observations in a spectral range that is not currently measured from space, nor will be with the planned ESA, NASA and NASDA missions. The availability of such novel spectral measurements from space will allow addressing several important issues in the field of climate and global change, and of applied meteorology as well, and among them: -The role of the FIR part of the planetary emission spectrum, which gives an important contribution to the cooling of the atmosphere, arising mainly from the mid and upper troposphere, while the bulk of the emission monitored by broadband radiometers comes from the underlying surface and lower troposphere. -The role of water vapour in modulating the planetary emission to space, made possible by inversion of RFTS spectral measurements taken in the rotational band of water vapour. -The role of clouds in modulating the planetary emission to space, made possible by using new and innovative techniques of spectral data analysis combined with the availability of imaging information (REI and RAI). -The quality of our knowledge regarding the absorption properties of water vapour, in particular of its continuum absorption, in a spectral range that is currently not measured in its entirety. All this added knowledge would certainly improve the quality of our simulations of radiance; fluxes and cooling rates, from a spectral resolution comparable to the REFIR observations down to the coarse resolutions used in GCM and climate models. Moreover the spectral outgoing radiance is an excellent tool for the assessment of general circulation model performance since it provides spectral signatures reflecting GCM processes that are simply not available from spectrally integrated results. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
