Details of Award
NERC Reference : NE/F000022/1
Reference Forward Model (RFM) Development
Grant Award
- Principal Investigator:
- Dr A Dudhia, University of Oxford, Oxford Physics
- Grant held at:
- University of Oxford, Oxford Physics
- Science Area:
- Terrestrial
- Marine
- Atmospheric
- Overall Classification:
- Atmospheric
- ENRIs:
- Pollution and Waste
- Global Change
- Environmental Risks and Hazards
- Science Topics:
- Water In The Atmosphere
- Radiative Processes & Effects
- Technol. for Environ. Appl.
- Climate & Climate Change
- Abstract:
- Almost all remote sensing instruments rely on sensing some type of electromagnetic radiation, and therefore require some mathematical model describing the emission and transmission of radiation from the target through the atmosphere to the instrument. Such models can either be 'reference' models, which tend to incorporate explicit physics and have maximum accuracy and flexibility, or 'optimised' models which are usually parameterised, fast, and applicable to specific instruments. For infrared instruments, probably the mostly widely used reference model within the NERC community is the Reference Forward Model (RFM), developed and maintained at the University of Oxford. The RFM is a 'line-by-line' model. Starting with a database (HITRAN) containing the spectroscopic parameters of several hundred thousand molecular lines, the RFM calculates the cumulative absorption of all significant lines at a specific frequency, modifified according to the local atmospheric conditions (pressure and temperature and molecular concentrations). A radiative transfer calculation is then performed for a series of path segments each characterised by different local conditions which, together, represent the complete passage of radiation through the atmosphere. This is then repeated for as many different frequencies as required. Such line-by-line calculations are computationally expensive but give maximum accuracy. In addition to simulating observations for past, present and future infrared (and microwave) instruments, the RFM has also been used in support of spectroscopic measurements at the NERC Molecular Spectroscopy Facility and for radiation budget studies to assess the impact of greenhouse gases. The RFM was originally developed under an ESA contract to provide accurate simulations of measurements for the MIPAS fourier transform spectrometer on the Envisat satellite. Since then it has evolved into a freely available, general purpose radiative transfer model having incorporated a number of additional features in response to user requests and suggestions. This subsequent code development, distribution and user support has been on an informal basis without any explicit funding from NERC or any other body. Outside the NERC community, the code has also been requested by overseas users and the surface-based infrared astronomers. The RFM is only one of several freely available line-by-line models, but its main advantages are its ease of use, robust coding and flexibility. This proposal is to seek funding for time to work on several major RFM developments which form too large a task to be performed on the previous informal basis. These are intended to exploit recent algorithmic and database developments, to update the coding language for improved usability, and to produce documentation on the algorithms used internally. Funding for a separate major RFM development - the incorporation of single scattering to simulate aerosol effects - has recently been approved under the NERC Directed Programme APPRAISE. The intention is to combine all these modifications into a single new software release. Given the already wide usage of the model as a research tool, particularly within the NERC Earth Observation community, the Earth Observation Mission Support scheme seems the appropriate funding source to approach for this work.
- NERC Reference:
- NE/F000022/1
- Grant Stage:
- Completed
- Scheme:
- Directed (Research Programmes)
- Grant Status:
- Closed
- Programme:
- EO Mission
This grant award has a total value of £22,734
FDAB - Financial Details (Award breakdown by headings)
| Indirect - Indirect Costs | DA - Estate Costs | DI - Staff |
|---|---|---|
| £8,718 | £2,949 | £11,066 |
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