Forecast fields marked as (accum.) represent accumulated values, i.e. values integrated in time over the range of the forecast.Example: a forecast slhf field has reference time (1995,12,31,18,0) and time range (unit=1=hour,P1=6,P2=0,indic=0); from the definition of the time range indicator:
0 = Forecast product valid for reference time + P1 (P1>0),it follows that the field has been accumulated over [18:00,0:00] .