Dataset
STFC RAL methane retrievals from IASI on board MetOp-B, version 2.0
Update Frequency: Not Planned
Latest Data Update: 2022-01-16
Status: Completed
Online Status: ONLINE
Publication State: Citable
Publication Date: 2022-01-18
DOI Publication Date: 2022-01-20
Download Stats: last 12 months
Dataset Size: 242.32K Files | 748GB
Abstract
This Infrared Atmospheric Sounding Interferometer (IASI) methane dataset contains height-resolved and column-averaged volume mixing ratios of atmospheric methane (CH4) retrieved from the IASI instrument on the MetOp-B satellite. 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. This dataset was produced by Version 2.0 of the Rutherford Appleton Laboratory's (RAL's) IASI optimal estimation scheme to retrieve methane, which takes as input temperature and water vapour profiles and surface spectral emissivity pre-retrieved by RAL's Infrared and Microwave Scheme applied to IASI, MHS and AMSU-A on MetOp-B. 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.
Development of the Version 2.0 scheme and its application to MetOp-A (2007-2017, http://dx.doi.org/10.5285/f717a8ea622f495397f4e76f777349d1) was funded by the National Centre for Earth Observation (NCEO) under the UK Natural Environment Research Council (NERC) with additional funding from EUMETSAT. Adaptation to MetOp-B and production of the IASI MetOp-B methane dataset 01/2018-03/2021 were funded by NCEO and ESA Contract No. 4000129987/20/I-DT Methane+.
Data were produced by the United Kingdom Research and Innovation (UKRI) Science and Technology Facilities Council (STFC) Remote Sensing Group (RSG) at the Rutherford Appleton Laboratory (RAL).
Citable as: Knappett, D.; Siddans, R.; Ventress, L.; Kerridge, B.; Latter, B. (2022): STFC RAL methane retrievals from IASI on board MetOp-B, version 2.0. NERC EDS Centre for Environmental Data Analysis, 20 January 2022. doi:10.5285/4bbcb1722f2842c1b0a5ebc19160a863. https://dx.doi.org/10.5285/4bbcb1722f2842c1b0a5ebc19160a863
Abbreviation: Not defined
Keywords: methane, IASI, optimal estimation, retrieval, averaging kernels, assimilation
Details
| Previous Info: |
No news update for this record
|
|---|---|
| Previously used record identifiers: |
No related previous identifiers.
|
| Access rules: |
Access to these data is available to any registered CEDA user. Please Login or Register for an account to gain access.
Use of these data is covered by the following licence: 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 has been 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) and supplied to the Centre for Environmental Data Analysis for long term archiving. Development of the Version 2.0 Infrared Atmospheric Sounding Interferometer (IASI) offline thermal infrared methane retrieval scheme and its application to MetOp-A (2007-2017, http://dx.doi.org/10.5285/f717a8ea622f495397f4e76f777349d1) were funded by the National Centre for Earth Observation (NCEO) under the UK Natural Environment Research Council (NERC) with additional funding from EUMETSAT. Adaptation to MetOp-B and production of the IASI MetOp-B methane dataset (01/2018-03/2021) were funded by NCEO and ESA Contract No. 4000129987/20/I-DT Methane+. |
| Data Quality: |
Data are as provided by the data providers. See the user guide for further information
|
| File Format: |
Data are in NetCDF format
|
Related Documents
Process overview
This dataset was generated by a combination of instruments deployed on platforms
and computations as detailed below.
Mobile platform operations
| Mobile Platform Operation 1 | Mobile Platform Operation for: Metop-B |
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
- names: A priori column-averaged dry-air mole fraction of atmospheric methane (ppmv).
- units: 1e-6
- long_name: A priori dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ap_ch4_vmr
- names: A priori dry-air mole fraction of atmospheric methane (ppmv).
- units: 1
- long_name: A priori effective cloud fraction.
- var_id: ap_cloud_fraction
- names: A priori effective cloud fraction.
- units: hPa
- long_name: A priori effective cloud-top pressure (hPa)
- var_id: ap_cloud_pressure
- names: A priori effective cloud-top pressure (hPa)
- units: 1e-6
- var_id: ap_ch4_xvmr_err
- long_name: A priori error on retrieved column-averaged dry-air mole fraction of atmospheric methane (ppmv).
- names: A priori error on retrieved column-averaged dry-air mole fraction of atmospheric methane (ppmv).
- units: 1e-6
- long_name: A priori error on retrieved dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ap_ch4_vmr_err
- names: A priori error on retrieved dry-air mole fraction of atmospheric methane (ppmv).
- units: K
- long_name: A priori surface temperature (K).
- var_id: ap_surface_temperature
- names: A priori surface temperature (K).
- long_name: AVHRR L1 (tir) radiances in channels 3b, 4 and 5.
- units: W/(m^2*sr*m^-1)
- var_id: rad_avhrr_tir
- names: AVHRR L1 (tir) radiances in channels 3b, 4 and 5.
- long_name: AVHRR L1 (vis/nir/swir) radiances in channels 1, 2 and 3a.
- units: W/(m^2*sr)
- var_id: rad_avhrr_vis
- names: AVHRR L1 (vis/nir/swir) radiances in channels 1, 2 and 3a.
- long_name: Apriori 13CH4 scaling factor.
- var_id: ap_ch4iso_sf
- names: Apriori 13CH4 scaling factor.
- long_name: Apriori HDO scaling factor.
- var_id: ap_hdo_sf
- names: Apriori HDO scaling factor.
- long_name: Apriori error on 13CH4 scaling factor.
- var_id: ap_ch4iso_sf_err
- names: Apriori error on 13CH4 scaling factor.
- long_name: Apriori error on HDO scaling factor.
- var_id: ap_hdo_sf_err
- names: Apriori error on HDO scaling factor.
- var_id: ak_xvmr
- long_name: Averaging kernel for column-averaged mixing ratio.
- names: Averaging kernel for column-averaged mixing ratio.
- var_id: ak_vmr
- long_name: Averaging kernel for profile mixing ratios.
- names: Averaging kernel for profile mixing ratios.
- units: 1e-6
- long_name: Column-averaged equivalent CH4 (modelled).
- var_id: ch4_xvmr_eql
- names: Column-averaged equivalent CH4 (modelled).
- units: 1e-6
- long_name: Column-averaged equivalent N2O (modelled).
- var_id: n2o_xvmr_eql
- names: Column-averaged equivalent N2O (modelled).
- var_id: day
- long_name: Day of the month (1-31).
- names: Day of the month (1-31).
- long_name: Errors on residual scale factors.
- var_id: rsf_err
- names: Errors on residual scale factors.
- long_name: Estimated error on retrieved 13CH4 scaling factor.
- var_id: ch4iso_sf_err
- names: Estimated error on retrieved 13CH4 scaling factor.
- units: 1e-6
- long_name: Estimated error on retrieved methane profile (ppmv).
- var_id: ch4_vmr_err
- names: Estimated error on retrieved methane profile (ppmv).
- long_name: Estimated error on the retrieved HDO scaling factor.
- var_id: hdo_sf_err
- names: Estimated error on the retrieved HDO scaling factor.
- units: 1e-6
- long_name: Estimated error on the retrieved column-averaged mixing ratio (ppmv).
- var_id: ch4_xvmr_err
- names: Estimated error on the retrieved column-averaged mixing ratio (ppmv).
- long_name: Flag indicating retrieval convergence (1=fully converged). Results with other values should be used with more caution.
- var_id: conv
- names: Flag indicating retrieval convergence (1=fully converged). Results with other values should be used with more caution.
- var_id: pixel_number
- long_name: IASI detector pixel (0-3).
- names: IASI detector pixel (0-3).
- units: hPa
- long_name: IMS (pre-retrieval) cloud fraction.
- var_id: ims_cloud_fraction
- names: IMS (pre-retrieval) cloud fraction.
- units: hPa
- long_name: IMS (pre-retrieval) cloud top pressure (hPa).
- var_id: ims_cloud_pressure
- names: IMS (pre-retrieval) cloud top pressure (hPa).
- long_name: IMS (pre-retrieval) flag indicating IASI ascending (1) or descending (0) node.
- var_id: ims_iasc
- names: IMS (pre-retrieval) flag indicating IASI ascending (1) or descending (0) node.
- long_name: IMS (pre-retrieval) retrieval convergence.
- var_id: ims_conv
- names: IMS (pre-retrieval) retrieval convergence.
- long_name: IMS (pre-retrieval) retrieval cost function value (measurement vector component).
- var_id: ims_jy
- names: IMS (pre-retrieval) retrieval cost function value (measurement vector component).
- long_name: IMS (pre-retrieval) retrieval cost function value (state vector component).
- var_id: ims_jx
- names: IMS (pre-retrieval) retrieval cost function value (state vector component).
- units: K
- var_id: ims_dt1000
- long_name: IMS (pre-retrieval) surface - 1000m air temperature difference (K).
- names: IMS (pre-retrieval) surface - 1000m air temperature difference (K).
- units: K
- var_id: ims_dt2
- long_name: IMS (pre-retrieval) surface - 2m air temperature difference (K).
- names: IMS (pre-retrieval) surface - 2m air temperature difference (K).
- units: K
- long_name: IMS (pre-retrieval) surface temperature (K).
- var_id: ims_surface_temperature
- names: IMS (pre-retrieval) surface temperature (K).
- units: 1
- var_id: emis
- long_name: Modelled surface spectral emissivity at selected wavenumbers.
- names: Modelled surface spectral emissivity at selected wavenumbers.
- var_id: month
- long_name: Month of the year (1-12).
- names: Month of the year (1-12).
- long_name: Number of scan line (0=start of orbit).
- var_id: scan_line
- names: Number of scan line (0=start of orbit).
- long_name: Off-diagonals of the solution correlation matrix for a subset of retrieval levels (as used for averaging kernels).
- var_id: ch4_vsx
- names: Off-diagonals of the solution correlation matrix for a subset of retrieval levels (as used for averaging kernels).
- long_name: Position within scan line (0-29).
- var_id: scan_position
- names: Position within scan line (0-29).
- units: hPa
- long_name: Pressure levels of true state in provided averaging kernels.
- var_id: mod_plev
- names: Pressure levels of true state in provided averaging kernels.
- units: hPa
- long_name: Pressures of retrieval levels (hPa) for which averaging kernels are provided.
- var_id: ret_plev_ak
- names: Pressures of retrieval levels (hPa) for which averaging kernels are provided.
- long_name: Retrieval cost function value.
- var_id: chim
- names: Retrieval cost function value.
- units: hPa
- long_name: Retrieval pressure levels (hPa).
- var_id: ret_plev
- names: Retrieval pressure levels (hPa).
- long_name: Retrieved 13CH4 scaling factor.
- var_id: ch4iso_sf
- names: Retrieved 13CH4 scaling factor.
- long_name: Retrieved HDO scaling factor (effective HDO amount compared to Hitran assumed ratio of HDO to main water vapour isotope).
- var_id: hdo_sf
- names: Retrieved HDO scaling factor (effective HDO amount compared to Hitran assumed ratio of HDO to main water vapour isotope).
- units: 1e-6
- long_name: Retrieved column-averaged dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ch4_xvmr
- names: Retrieved column-averaged dry-air mole fraction of atmospheric methane (ppmv).
- units: 1e-6
- long_name: Retrieved column-averaged mole fraction of atmospheric water vapour in air (ppmv).
- var_id: h2o_xvmr
- names: Retrieved column-averaged mole fraction of atmospheric water vapour in air (ppmv).
- units: 1e-6
- long_name: Retrieved dry-air mole fraction of atmospheric methane (ppmv).
- var_id: ch4_vmr
- names: Retrieved dry-air mole fraction of atmospheric methane (ppmv).
- units: 1
- var_id: cloud_fraction
- long_name: Retrieved effective cloud fraction.
- names: Retrieved effective cloud fraction.
- units: hPa
- long_name: Retrieved effective cloud-top pressure (hPa).
- var_id: cloud_pressure
- names: Retrieved effective cloud-top pressure (hPa).
- units: K
- standard_name: surface_temperature
- var_id: surface_temperature
- long_name: Retrieved surface temperature (K).
- names: surface_temperature, Retrieved surface temperature (K).
- long_name: Scale factors for the mean fit and across-track residual patterns.
- var_id: rsf
- names: Scale factors for the mean fit and across-track residual patterns.
- units: degree
- standard_name: sensor_zenith_angle
- long_name: Sensor zenith angle (degrees).
- var_id: vza
- names: sensor_zenith_angle, Sensor zenith angle (degrees).
- units: degree
- var_id: sza
- standard_name: solar_zenith_angle
- long_name: Solar zenith angle (degrees).
- names: solar_zenith_angle, Solar zenith angle (degrees).
- units: km
- long_name: Spatially interpolated ECMWF surface altitude (km).
- var_id: ecmwf_alt
- names: Spatially interpolated ECMWF surface altitude (km).
- units: km
- long_name: Surface altitude (km) corresponding to IASI measurement, based on averaging GTOPO30 to 12km resolution and sampling every 0.05 degrees.
- var_id: iasi_alt
- names: Surface altitude (km) corresponding to IASI measurement, based on averaging GTOPO30 to 12km resolution and sampling every 0.05 degrees.
- units: hPa
- standard_name: surface_air_pressure
- var_id: surface_pressure
- long_name: Surface pressure (hPa) used in the retrieval.
- names: surface_air_pressure, 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
- names: The average number of retrieval steps (number of calls to the forward model).
- units: K
- long_name: The brightness temperature difference (K) at 12 microns between observations and simulations (based on ECMWF data). Used to initially screen observations for cloud.
- var_id: bt_diff
- names: The brightness temperature difference (K) at 12 microns between observations and simulations (based on ECMWF data). Used to initially screen observations for cloud.
- units: ms
- long_name: Time of day in msec since midnight (UTC).
- var_id: time_in_msec
- names: Time of day in msec since midnight (UTC).
- units: cm-1
- long_name: Wavenumbers for which modelled surface spectral emissivity is provided.
- var_id: emis_wn
- names: Wavenumbers for which modelled surface spectral emissivity is provided.
- var_id: year
- long_name: Year.
- names: Year.
Co-ordinate Variables
- units: degree_north
- standard_name: latitude
- var_id: lat
- long_name: Latitude (degrees north).
- names: latitude, Latitude (degrees north).
- units: degree_east
- standard_name: longitude
- var_id: lon
- long_name: Longitude (degrees east).
- names: longitude, Longitude (degrees east).
Coverage
Temporal Range
Start time:
2018-01-01T00:00:00
End time:
2021-03-31T23:59:59
Geographic Extent
90.0000° |
||
-180.0000° |
180.0000° |
|
-90.0000° |
Related parties