Ulloa's ring

{
  "id": "MLC-T-MET-009866",
  "term": "Ulloa's ring",
  "field": "Meteorology and atmospheric science",
  "definition": "A rare optical phenomenon observed from an aircraft or high mountain, appearing as a bright, white, circular halo around the shadow of the observer's head projected onto a cloud or fog layer below. It is caused by the backscattering of sunlight by water droplets in the cloud. This effect is distinct from a glory, which exhibits colored rings.",
  "synonyms": [
    "Bouguer’s halo"
  ],
  "url": "https://mlchart.com/terminology/meteorology/ulloa-s-ring/"
}