Surface meteorology

Surface pressure is required to perform the level 2 retrievals, so it must be available when processing the EM27 interferograms. Temperature, relative humidity, wind speed, and wind direction are convenient to have, but not required. Since there is not a standard way of collecting surface meteorology data for EM27 observations, EGI must be flexible in how it accepts this data.

Note: users are discouraged from using surface pressure from reanalysis meteorology for their surface pressure unless absolutely necessary. Surface pressure is needed to accurately calculate the position of the EM27 relative to the atmosphere above it, so a good quality measured surface pressure will give better results.

Continuing with our tutorial, recall the directory structure:

/
└── data
    └── xx
        ├── 20240401
        │   ├── coords.json
        │   ├── interferograms/
        │   └── met_source.json
        └── 20240402
            ├── coords.json
            ├── interferograms/
            └── met_source.json

Now we are going to create the met_source.json files.