Abstract:
Global synoptic surface observations from the Air Weather Service for 1901-1973, called "Tape Deck 13" because it is the combination of multiple card decks (datasets), conversion to a standard format and transfer to tape. There are usually 1 to 4 records per station each day. Wind direction (dd), wind speed (ff), and station elevation
... (stnelev) are "standard" variables usually available in each deck; the rest of the variables are "supplemental fields" which are not in some decks (groups of stations). Sea level pressure (slp) "standard" format excludes the high order digits, retaining only tens, units and tenths mb; however, some decks provide the hundreds/thousands digit in the "supplemental fields". 
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