json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "id": "http://schema.envirocar.org/phenomenon.json#",
      "type": "object",
      "additionalProperties": false,
      "required": [
          "name",
          "unit"
      ],
      "properties": {
          "name": {
              "type": "string"
          },
          "unit": {
              "type": "string"
          },
          "created": {
              "type": "string",
              "format": "date-time"
          },
          "modified": {
              "type": "string",
              "format": "date-time"
          }
      }
  }