Monthly Averages ---------------- This is an R2 issue. When the R2 system was moved from the DOE machine to NCEP's IBMs, most of the codes had to be ported. However the code that made the monthly averages was not ported and code that already ran on the IBMs was used. For most fields, the was no numerical change. However, RUNOF was much different. Jan 1979-Dec 2000: Run ff is the aveage runoff in units of mm/6 hours Jan 2001-present: Runoff is the accumulated runoff for the month.