Regional inversions of TROPOMI observations with CHIMERE

The TROPOspheric Monitoring Instrument (TROPOMI), an imaging spectrometer on board Sentinel 5-P, provides dry-air total-column methane mole fraction (XCH4) with daily coverage and a relatively high resolution (5.5×7km²). It provides valuable data that can be assimilated in atmospheric inversions to estimate CH4 emissions and thus to build robust top-down budgets of these emissions. It is particularly valuable at regional scale, because of its denser coverage than previous reference satellite mappers (GOSAT, ISAI…), and in regions with few surface stations. This is the case for the domains studied in the framework of SMART-CH4 (South America, India/Southeast Asia).

These few pages are intended to serve as a tutorial to start a new regional configuration to run forward and inverse simulations. It is a basis to process the required inputs and run first simulations, to help adapt the existing configurations to new domains. Most of the examples use with the regional configuration in South America.

• Pre-processing of the inputs
  • 1. Building a new domain
  • 2. TROPOMI XCH4 observations
  • 3. Processing of other input data
    • a. Meteorological inputs
    • b. CAMS background
    • c. Prior CH4 emissions
    • d. Country/region mask [optional]
• Running a forward simulation
• Running an inverse simulation
• Basic plots and analyses of the simulations
  • 1. Forward simulation
  • 2. Inverse simulation