{
    "source_type":{
        "gridded_insitu":"gridded product based on measurements collected from in-situ instruments",
        "reanalysis":"gridded product generated from a model reanalysis based on in-situ instruments and possibly satellite measurements",
        "satellite_blended":"gridded product based on both in-situ instruments and satellite measurements",
        "satellite_retrieval":"gridded product based on satellite measurements"
    }
}