I did a search for this topic, but the relevant postings did not specify ATIS, ASOS/AWOS, METAR, etc. Based on my particular experience related below, I'd like to ask this question anyway.
Sample ATIS recording: "Denver International Airport Information India, 1753 Zulu. Visibility 10. Temperature 10. Dewpoint -4. Altimeter 3018. Light rain, mist. Ceiling 7000 broken...."
Does the "seven thousand" in the ATIS broadcast refer to altitude AGL or MSL? I used to think it was MSL, but DEN has a field elevation of 5431, and I could swear I once heard something like "ceiling three thousand broken." This doesn't make sense because the cloud ceiling can't be below the field elevation. I only heard it once though, on a particularly bad weather day. Can someone please clarify this for me?