DOE-2 Reference Manual Version 2.1 - DOE2.com

7. General CommentsOne of the major problems of weather tapes is the amount of missing data.As mentioned before while discussing the interpolation interval, the DOE-2Weather Processor attempts to supply values for the missing data according toa linear interpolation process. This makes sense when the number of consecutivemissing values is relatively small. The purpose of the interpolationinterval is to allow the user to specify what "relatively small" means. Thenext question is how should the user evaluate "relative smallness." It issuggested that, before attempting to create a packed file, the user LIST amonth of the unpacked tape to obtain an idea of how much data is missing.This will be indicated by the value -999 or -999. in the data columns of theprint-out.1440 and CD144 tapes come in two varieties: tapes with measurements every'hour and those with measurements every third hour. Listing the tape is thebest way of discovering which kind of tape the user is dealing with. If thetape turns out to have data every third hour, the user should use the code-word1440-3 or CD1443 in the PACK input. This will speed up the packing and cutdown the number of warning messages.After the tape has been listed, the appropriate interpolation warninginterval may be chosen. For 1440-3 and CD1443 tapes not many consecutivevalues need to be missing before the number of hours of missing data becomeslarge. An interpolation warning interval of 9 is recommended for these tapes.Other tapes, such as TRY, WYEC and TMY, have little missing data and an interpolationwarning interval of 4 can be used.Once the file is packed, it should again be listed (or as in Example 1,listed along with the packing). The user should examine the days that wereflagged with warning messages to see whether it is desirable to replace someof the hourly values using the EDIT option. The EDIT option cannot be used inthe same run as PACK. Both EDIT and STAT can be used only with packed files,whereas PACK can only be used with unpacked files. The EDIT feature cannot beused to change file types; that is, to change an OLD file to a NORMAL file.When changing dry-bulb temperatures through the EDIT option, the usershould also make changes in the dew-point temperatures, so that the humidityratio will be recalculated appropriately.VIII.43 (Revised 5/81)