Total ozone ΩT is the amount of ozone in a column, extending from the bottom to the top of the atmosphere. It consists of the integrated column of ozone from the sounding ΩS, plus an estimated residual ozone column above burst altitude ΩR. Ozone columns are expressed in Dobson Units (DU).
DigiCORA calculates total ozone according to E-3-18 of GAW Report 268.