Auxiliary thermometer

{
  "id": "MLC-T-MET-010389",
  "term": "Auxiliary thermometer",
  "field": "Meteorology and atmospheric science",
  "definition": "A secondary thermometer included in certain meteorological instruments, such as mercury-in-glass barometers, to measure the temperature of the instrument itself. This measurement is necessary to apply corrections to the primary reading, compensating for the thermal expansion or contraction of the instrument's components. For barometers, the auxiliary thermometer reading is used to correct for the density of the mercury column.",
  "url": "https://mlchart.com/terminology/meteorology/auxiliary-thermometer/"
}