Dataset
STFC RAL methane retrievals from IASI on board MetOp-A, version 2.0
Abstract
This Infrared Atmospheric Sounding Interferometer (IASI) methane dataset contains height-resolved and column-averaged volume mixing ratios of atmospheric methane (CH4). It also includes column-averaged water vapour (H2O), a scale factor for the HDO (water vapour isotopologue) volume mixing ratio profile, surface temperature, effective cloud fraction, effective cloud-top pressure and scale factors for two systematic residual spectra which are jointly retrieved from the spectral range 1232.25-1290.00 cm-1 by the Rutherford Appleton Laboratory (RAL) IASI optimal estimation methane retrieval scheme. The dataset additionally contains selected a priori values and uncertainties adopted in the optimal estimation scheme and retrieval output diagnostics such as the retrieval cost and the averaging kernels.
This work was funded by the National Centre for Earth Observation (NCEO) under the UK Natural Environment Research Council (NERC) with additional funding from EUMETSAT.
Data were produced by the United Kingdom Research and Innnovation (UKRI) Science and Technology Facilities Council (STFC) Remote Sensing Group (RSG) at the Rutherford Appleton Laboratory (RAL).
This is version 2.0 of the dataset.
Details
| Previous Info: |
No news update for this record
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| Previously used record identifiers: |
No related previous identifiers.
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| Access rules: |
Access to these data is available to any registered CEDA user. Please Login or Register for a CEDA account to gain access.
Use of these data is covered by the following licence(s): http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record. |
| Data lineage: |
Data produced by the Rutherford Appleton Laboratory (RAL) Remote Sensing Group (RSG) at the United Kingdom Research and Innovation (UKRI) Science and Technology Facilities Council (STFC). The development of the Infrared Atmospheric Sounding Interferometer (IASI) offline thermal-IR methane retrieval was funded by the Natural Environment Research Council (NERC) through its National Centre for Earth Observation (NCEO) with additional funding from EUMETSAT. |
| Data Quality: |
Data are as provided by the data providers. See the user guide for further information
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| File Format: |
Data are in NetCDF format.
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Related Documents
| https://www.atmos-meas-tech.net/10/4135/2017/ |
| RAL IASI MetOp-A TIR Methane Dataset v2.0 Product User Guide |
Citations: 1
The following citations have been automatically harvested from external sources associated with this resource where DOI tracking is possible. As such some citations may be missing from this list whilst others may not be accurate. Please contact the helpdesk to raise any issues to help refine these citation trackings.
| Pimlott, M.A., Pope, R.J., Kerridge, B.J., Latter, B.G., Knappett, D.S., Heard, D.E., Ventress, L.J., Siddans, R., Feng, W. & Chipperfield, M.P. (2022) Investigating the global OH radical distribution using steady-state approximations and satellite data. Atmospheric Chemistry and Physics 22, 10467–10488. https://doi.org/10.5194/acp-22-10467-2022 https://doi.org/10.5194/acp-22-10467-2022 |
Process overview
Mobile platform operations
| Mobile Platform Operation 1 | Mobile Platform Operation for: Metop-A |
Computation Element: 1
| Title | STFC RAL IASI methane processor |
| Abstract | Retrieval of methane using the STFC RAL IASI methane processor. Full retrieval diagnostic information including averaging kernels, estimated error and retrieved cloud parameters is produced. |
| Input Description | None |
| Output Description | None |
| Software Reference | None |
| Output Description | None |
- units: 1e-6
- long_name: A priori column-averaged dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ap_ch4_xvmr
- units: 1e-6
- long_name: A priori dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ap_ch4_vmr
- units: 1
- long_name: A priori effective cloud fraction.
- var_id: ap_cloud_fraction
- units: hPa
- long_name: A priori effective cloud-top pressure (hPa)
- var_id: ap_cloud_pressure
- units: 1e-6
- long_name: A priori error on retrieved dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ap_ch4_vmr_err
- units: K
- long_name: A priori surface temperature (K).
- var_id: ap_surface_temperature
- long_name: AVHRR L1 (tir) radiances in channels 3b, 4 and 5.
- units: W/(m^2*sr*m^-1)
- var_id: rad_avhrr_tir
- long_name: AVHRR L1 (vis/nir/swir) radiances in channels 1, 2 and 3a.
- units: W/(m^2*sr)
- var_id: rad_avhrr_vis
- long_name: Apriori 13CH4 scaling factor.
- var_id: ap_ch4iso_sf
- long_name: Apriori HDO scaling factor.
- var_id: ap_hdo_sf
- long_name: Apriori error on 13CH4 scaling factor.
- var_id: ap_ch4iso_sf_err
- long_name: Apriori error on HDO scaling factor.
- var_id: ap_hdo_sf_err
- long_name: Averaging kernel for column-averaged mixing ratio (ppmv).
- var_id: ak_xvmr
- long_name: Averaging kernel for profile mixing ratios (ppmv).
- var_id: ak_vmr
- units: 1e-6
- long_name: Column-averaged equivalent CH4 (modelled).
- var_id: ch4_xvmr_eql
- units: 1e-6
- long_name: Column-averaged equivalent N2O (modelled).
- var_id: n2o_xvmr_eql
- var_id: day
- long_name: Day of the month (1-31).
- long_name: Errors on residual scale factors.
- var_id: rsf_err
- long_name: Estimated error on retrieved 13CH4 scaling factor.
- var_id: ch4iso_sf_err
- units:
- units: 1e-6
- long_name: Estimated error on retrieved methane profile (ppmv).
- var_id: ch4_vmr_err
- long_name: Estimated error on the retrieved HDO scaling factor.
- var_id: hdo_sf_err
- units:
- units: 1e-6
- long_name: Estimated error on the retrieved column-averaged mixing ratio (ppmv).
- var_id: ch4_xvmr_err
- var_id: pixel_number
- long_name: IASI detector pixel (0-3).
- units: hPa
- long_name: IMS (pre-retrieval) cloud fraction.
- var_id: ims_cloud_fraction
- units: hPa
- long_name: IMS (pre-retrieval) cloud top pressure (hPa).
- var_id: ims_cloud_pressure
- long_name: IMS (pre-retrieval) retrieval convergence.
- var_id: ims_conv
- long_name: IMS (pre-retrieval) retrieval cost function value (measurement vector component).
- var_id: ims_jy
- long_name: IMS (pre-retrieval) retrieval cost function value (state vector component).
- var_id: ims_jx
- units: K
- long_name: IMS (pre-retrieval) surface temperature (K).
- var_id: ims_surface_temperature
- units: degree_north
- var_id: lat
- long_name: Latitude (degrees north).
- units: degree_east
- var_id: lon
- long_name: Longitude (degrees east).
- units: 1
- var_id: emis
- long_name: Modelled surface spectral emissivity at selected wavenumbers.
- var_id: month
- long_name: Month of the year (1-12).
- long_name: Number of scan line (0=start of orbit).
- var_id: scan_line
- long_name: Position within scan line (0-29).
- var_id: scan_position
- units: hPa
- long_name: Pressure levels of true state in provided averaging kernels.
- var_id: mod_plev
- units: hPa
- long_name: Pressures of retrieval levels (hPa) for which averaging kernels are provided.
- var_id: ret_plev_ak
- long_name: Retrieval cost function value.
- var_id: chim
- units: hPa
- long_name: Retrieval pressure levels (hPa).
- var_id: ret_plev
- long_name: Retrieved 13CH4 scaling factor.
- var_id: ch4iso_sf
- units:
- units: 1e-6
- long_name: Retrieved column-averaged dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ch4_xvmr
- units: 1e-6
- long_name: Retrieved column-averaged mole fraction of atmospheric water vapour in air (ppmv).
- var_id: h2o_xvmr
- units: 1e-6
- long_name: Retrieved dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ch4_vmr
- units: 1
- var_id: cloud_fraction
- long_name: Retrieved effective cloud fraction.
- units: hPa
- long_name: Retrieved effective cloud-top pressure (hPa).
- var_id: cloud_pressure
- units: K
- var_id: surface_temperature
- long_name: Retrieved surface temperature (K).
- long_name: Scale factors for the mean fit and across-track residual patterns.
- var_id: rsf
- units:
- units: degree
- long_name: Sensor zenith angle (degrees).
- var_id: vza
- units: degree
- var_id: sza
- long_name: Solar zenith angle (degrees).
- units: km
- long_name: Spatially interpolated ECMWF surface altitude (km).
- var_id: ecmwf_alt
- units: K
- long_name: Surface - 1000m air temperature difference
- var_id: ims_dt1000
- units: K
- long_name: Surface - 2m air temperature difference
- var_id: ims_dt2
- units: hPa
- var_id: surface_pressure
- long_name: Surface pressure (hPa) used in the retrieval.
- long_name: The average number of retrieval steps (number of calls to the forward model).
- var_id: nstep
- units: ms
- long_name: Time of day in msec since midnight (UTC).
- var_id: time_in_msec
- units: cm-1
- long_name: Wavenumbers for which modelled surface spectral emissivity is provided.
- var_id: emis_wn
- var_id: year
- long_name: Year.
Co-ordinate Variables
Temporal Range
2007-05-31T23:00:00
2017-12-31T23:59:59
Geographic Extent
90.0000° |
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-180.0000° |
180.0000° |
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-90.0000° |