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ESA Greenhouse Gases Climate Change Initiative (GHG_cci): Column-averaged CH4 Merged Product generated with the EMMA algorithm (CH4_EMMA), version 1.2

Update Frequency: Not Planned
Latest Data Update: 2017-07-20
Status: Completed
Online Status: ONLINE
Publication State: Published
Publication Date: 2018-03-19
Download Stats: last 12 months
Dataset Size: 1.82K Files | 330MB


The CH4_EMMA dataset is comprised of level 2, column-averaged dry-air mole fractions (mixing ratios) for methane (XCH4). It has been produced using the ensemble median algorithm EMMA to several different versions of the Japanes Greenhouse gases Observing Satellite (GOSAT) XCH4 data, as part of the ESA Greenhouse Gases Climate Change Initiative (GHG_cci) project. This version of the product is v1.2, and forms part of the Climate Research Data Package 4.

The ensemble median algorithm EMMA has been applied to level 2 data of several different retrieval products from the Japanese Greenhouse gases Observing Satellite (GOSAT) This is therefore a merged GOSAT XCH4 Level 2 product, which is primarily used as a comparison tool to assess the level of agreement / disagreement of the various input products (for model-independent global comparison, i.e. for comparisons not restricted to TCCON validation sites and independent of global model data).

For further information on the product and the EMMA algorithm please see the EMMA website, the GHG-CCI Data Products webpage or the Product Validation and Intercomparison Report (PVIR).

Citable as:  ESA CCI GHG project team (2018): ESA Greenhouse Gases Climate Change Initiative (GHG_cci): Column-averaged CH4 Merged Product generated with the EMMA algorithm (CH4_EMMA), version 1.2. Centre for Environmental Data Analysis, date of citation.
Abbreviation: Not defined
Keywords: ESA, GHG, CCI, CH4, EMMA


Previous Info:
No news update for this record
Previously used record identifiers:
No related previous identifiers.
Access rules:
Public data: access to these data is available to both registered and non-registered users.
Use of these data is covered by the following licence: When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record.
Data lineage:

Data were processed by the ESA CCI GHG project team and supplied to CEDA as part of the ESA CCI Open Data Portal Project

File Format:
Data are in NetCDF format

Process overview

  • units: degree
  • long_name: Sensor zenith angle
  • standard_name: sensor_zenith_angle
  • var_id: sensor_zenith_angle
  • units: 1e-9
  • long_name: a priori dry-air mole fraction profile of atmospheric methane
  • var_id: ch4_profile_apriori
  • long_name: l2 processor id
  • var_id: median_processor_id
  • units: 1
  • long_name: normalized column averaging kernel
  • var_id: xch4_averaging_kernel
  • units: hPa
  • long_name: pressure levels
  • var_id: pressure_levels
  • units: 1
  • long_name: pressure weight
  • var_id: pressure_weight
  • var_id: xch4_quality_flag
  • long_name: quality flag
  • units: degree
  • long_name: solar zenith angle
  • var_id: solar_zenith_angle
  • standard_name: solar_zenith_angle
  • units: 1e-9
  • var_id: median_uncertainty
  • long_name: xch4 median uncertainty
  • units: 1e-9
  • var_id: median_uncertainty_ex
  • long_name: xch4 median uncertainty ex
  • units: 1e-9
  • var_id: median_uncertainty_se
  • long_name: xch4 median uncertainty se

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
  • long_name: time
  • standard_name: time
  • var_id: time
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