Model Change Bulletin MCB#3 5/20/93 MPRM (dated 93140) This Model Change Bulletin is to notify users of changes made to correct problems and provide enhancements to the Meteorological Processor for Regulatory Models, MPRM (dated 90045). The revisions are summarized in the following. These revisions constitute MPRM (dated 93140) and completely replace MPRM (dated 90045). With this bulletin, the source codes and executables for MPRM (dated 93140) are being made available for downloading from the File Transfer Section of SCRAM. MPRM (dated 90045) is obsolete and, with this bulletin, will no longer be available on SCRAM. All copies of such should be discarded. Users of MPRM are referred to a companion WordPerfect 5.1 document (MPRMSUP.WPF) which provides supplemental information and necessary revisions to the MPRM User's Guide. For tracking purposes, modifications have been assigned identifying labels (B001, B002, etc. for 'bugs', and E001, E002, etc. for enhancements). This labeling convention is retained in the following. 1. Calms Processing - B001 - In MPRM (dated 90045), the last valid wind direction (LWD) in subroutines WS10S and WS1NWS (in MP4XFOR.FOR) was set too early resulting in erroneous data in the output file. Necessary corrections were made in subroutines WS1OS and WS1NWS. 2. Missing Data - B002 and B003 - In processing on-site data with MPRM (dated 90045), missing wind directions are erroneously treated as calms (i.e., the wind speed is set to 1 m/s and the wind direction is set to the last valid wind direction value). This is correct only if the wind speed is less than the threshold (OSCALM). Otherwise, the missing value indicator for wind direction (default value 999) should be retained through stage 3 processing. In the latter case (problem B003), the wind speed is set correctly, but the wind direction and flow vectors are not. These problems required an extensive re-write of subroutine WS1OS. Also, several variable names were changed to improve clarity. In particular, WDIR was changed to WFDIR, since it is really the flow direction, not the wind direction; and LWD was changed to LFD, since once again, it is the last flow direction that is saved, not the last wind direction. 3. Stability Classification - B004 - With MPRM (dated 90045), stability class estimates using on-site wind speed and sigma theta do not verify with hand calculation for some cases. This problem was traced to an incorrect assignment of the array elements for albedo and roughness in subroutine ROUGH. The code was corrected by changing OSSFC( , , 1) to OSSFC( , , 3), since roughness is the 3rd element of the array, not the 1st. 4. Conversion of on-site ceiling height - B005 - MPRM (dated 90045) does not correctly convert on-site ceiling height to the nearest 100's of feet. This problem was traced to subroutine OS1PGT in MP4XFOR.FOR. The statement 'CLHT = SFOBS(HR0124,33)' was corrected to read 'CLHT = OSSOBS(HR0124,33)'. 5. Extraction of upper air data -B006 - With MPRM (dated 90045), extraction of upper air data from a TD5600 file, may result in a SUBSCRIPT OUT OF RANGE error. This problem was traced to an error in subroutine GETSDG. The statement 'IF(SDGPOS .GT. NCHB1) THEN ...' was corrected to read 'IF(SDGPOS + NCHLEV .GE. NCHB1) THEN...'. 6. Decoding overpunch characters -B007 - In MPRM (dated 90045), an invalid blank overpunch is incorrectly treated as a valid blank - this affects processing of temperature (wet-bulb, dry-bulb, and dew-point), wind speed, and cloud cover. This problem was traced to subroutine SFLEVS. Necessary changes were made such that invalid blank overpunches retain the initial assignment for overpunch variables (-99999) and, thus, are reported as missing. 7. QA procedure for wind shear -B009 - In MPRM (dated 90045) there was some uncertainty that the QA of directional wind shear would accommodate traverses through 360 degrees. This required review of the code in subroutine UAQASM. It was concluded that this would not be a problem so long as the wind directions lie in the range of 0 to 360 degrees. New code was added to ensure that this is the case. 8. Action item for PG Stability - B011 - In MPRM (dated 90045), the action item for estimating the PG stability using on- site wind speed and NWS observations of cloud amount and ceiling height 'WNDNWS' does not match what is specified in the user's guide (TABLE 4-1) and output in stage 3 'WNDWXX'. This required changes to the MASTER and MP1 INCLUDE files. All references to WNDNWS in these files were replaced by WNDWXX to conform to the user's guide. 9. Need for upper air data in STAGE 3 - B014 - In MPRM (dated 90045), STAGE 3 processing for climatological models (e.g., STAR), which do not require mixing height data, proceeds normally without the UA pathway if the surface data are provided via the OS pathway. However, processing is terminated if these data are provided via the SF pathway. To get around this, users of MPRM (dated 90045) had to provide a "dummy" UA file in order to use SF pathway data in climatological models. This problem was traced to subroutine MRPATH. Necessary corrections were made to accommodate situations in which no UA pathway data are used, regardless of the source of surface meteorological data. 10. INCLUDE Files - E001 - All INCLUDE files were given a '.INC' extension. This facilitates compile operations by allowing use of a wildcard. 11. Leading blanks - E002 - MPRM (dated 90045) incorrectly interprets leading blank fields as missing. For example '_20' in the three column ceiling height field is interpreted as missing because the leading column is blank instead of zero. This problem was traced to the interpretation of overpunch fields in the CD144 format for NWS surface data. The default interpretation of leading blanks as missing was changed for NWS ceiling height, temperature, and wind speed. Leading blanks for these variables are now processed correctly as leading zeros. (see also item 6 - B007). 12. Missing Data Reports -E003 - Audit reports from MPRM (dated 90045) do not include the date and time for missing data - thus, users were forced to conduct a manual search for records with missing data. The MPRM code was revised such that the date and time associated with each missing data item are included in the QA audit report file. This fix is similar to the "trace" option available on the MP pathway. 13. SCRAM Data - E009 - With MPRM (dated 90045), NWS surface data downloaded from SCRAM must be processed through the on- site (OS) pathway. This is because SCRAM files, which are shortened versions of the standard CD144 file, have a different format than the CD144 format required by the surface (SF) pathway. A new option 'SCRAMFB' was added to subroutine IN2CRD and a new section was added to subroutine SFEXT to enable direct processing of SCRAM data through the SF pathway. 14. ASCII Data for ISCST2 -E011 - Code was added to provide a formatted (ASCII) meteorological data file for use with ISCST2. The format of this file is described on page 3-53 of the ISC2 users guide. A new label 'ISC2STA' was added to the list of dispersion models supported by MPRM to accommodate this new output file. 15. Direct input of stability -E012 - Code was added to STAGE 3 to bypass stability class processing and allow use of input stability class. To invoke this enhancement, a new option 'USERIN' was included in the MP pathway under the keyword VBL.