Dataset
Retrieved sulfur dioxide column amounts and heights from the IASI instrument (9-30 April 2021) v1.0
Abstract
This dataset contains retrievals of sulfur dioxide (SO2) from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp platforms. This is a global dataset for 9-30th April 2021 which includes plumes from La Soufrière (St Vincent), Sabancaya (Peru) and Sangay (Ecuador).
Two retrieval schemes have been used: (1) Walker et al. (2011,2012) linear retrieval which flags pixels containing SO2 and (2) Carboni et al. (2012,2016) iterative retrieval which quantifies information about the SO2 including the column amount, height and the associated errors. The retrieved outputs are provided for individual IASI orbits.
This dataset was used to study the large plume of SO2 from the April 2021 eruption of La Soufrière on St Vincent in the Eastern Caribbean.
The data has been produced by the Earth Observation Data Group at the University of Oxford, as part of the NERC Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET).
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: |
Please contact the data centre for details on how to access these data.
For data use licensing information please contact: support@ceda.ac.uk |
| Data lineage: |
The dataset has been produced by the Earth Observation Data Group at the University of Oxford, as part of the NERC Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET). The Oxford linear and iterative SO2 retrievals have been applied to the IASI level 1c files available at CEDA. The results were then passed to CEDA to be archived. |
| Data Quality: |
A quality control has been applied to the iterative retrieval portion of this dataset. This requires that the column amounts retrieved are positive, that the retrieval pressures are between 0 and 1100 hPa and the heights in kilometres are positive. Additionally, the retrieval must coverage within 10 iterations and the output should have a normalised cost of less than 10. The iterative retrieval outputs (column amounts, heights and effective radiating temperatures) all have errors associated with them. The user can opt to apply a stricter quality control by further restricting the retrieval cost or by considering the retrieval errors.
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| File Format: |
netcdf
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Related Documents
Process overview
Independent Instruments
| IASI |
| Output Description | None |
- units: km
- var_id: ir_km_err
- long_name: Altitude error from the IASI SO2 iterative retrieval
- units: km
- var_id: ir_km
- long_name: Altitude from the IASI SO2 iterative retrieval
- units: DU
- var_id: ir_du_err
- long_name: Column amount error from the IASI SO2 iterative retrieval
- units: DU
- var_id: ir_du
- long_name: Column amount from the IASI SO2 iterative retrieval
- units: DU
- var_id: lin_ret
- long_name: Effective SO2 column amount from the linear SO2 retrieval for IASI using V3 absorption band assuming SO2 is evenly distributed between 0 and 20 km.
- units: K
- var_id: ir_k_err
- long_name: Effective radiating temperature error from the IASI SO2 iterative retrieval
- units: K
- var_id: ir_k
- long_name: Effective radiating temperature from the IASI SO2 iterative retrieval
- units: seconds
- var_id: pixel_time
- long_name: IASI time in seconds since 1st January 2000
- var_id: flagged_index
- long_name: Index for pixels which have an effective column amount from the linear retrieval that exceed the specified threshold (0.490904 DU)
- var_id: good_ret_index
- long_name: Index of pixels where the IASI SO2 iterative retrieval was applied and the results pass the quality control
- var_id: ir_cost
- long_name: Normalised cost from the IASI SO2 iterative retrieval
- units: hPa
- var_id: ir_hpa_err
- long_name: Pressure error from the IASI SO2 iterative retrieval
- units: hPa
- var_id: ir_hpa
- long_name: Pressure from the IASI SO2 iterative retrieval
- var_id: orbit_direction
- long_name: direction of the IASI orbit; ascending [0], descending [1]
- units: radians
- var_id: zenith_angle
- long_name: zenith angle
Co-ordinate Variables
- units: degrees_north
- standard_name: latitude
- var_id: latitude
- long_name: latitude
- units: degrees_east
- standard_name: longitude
- var_id: longitude
- long_name: longitude
Temporal Range
2021-04-09T00:00:00
2021-04-30T00:00:00
Geographic Extent
90.0000° |
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-180.0000° |
180.0000° |
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-90.0000° |