AWS TD13 Global Surface Observations, daily 1901-1973

There are usually 1 to 4 records per station each day. Wind direction, wind speed, and station elevation 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 "standard" format excludes the high order digits, retaining only tens, units and tenths of millibars; however, some decks provide the hundreds/thousands digit in the "supplemental fields".