What should be used as the valid time for fields in the grb2d file?
[6/19/96] Fields in the grb2d file are either 6 hour averages or 6 hour forecasts. The GRIB reference time is used in the file name, BUT the valid time is actually 6 hours later for the forecast fields. The average fields are averages of the 6 hour period from the reference time to 6 hours later. The GRIB PDS information correctly specifies the time and the GrADS package will assign the proper time. • PRESmsl vs. PRMSLmsl: [6/19/96] These two variables are derived using slightly different algorithms for the same sea-level-pressure. Check this pres.msl for exact definitions. • Negative PWAT values: [6/19/96] This is a common phenomenon in numerical models. The negative values are to be flagged for special processing, or simply reset to zero. • According to BAMS paper, temperature tendency by physics, non-physics, and radiation (GRIB Table 2 #215-217) are available as reanalysis products. Where are they? [6/19/96] Since GRIB ID 215 through 217 can be computed from other heatings in reana
