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<br />APPENDIX C. TEMPORARY CODING TO REMOVE
<br />VIRGA FROM SAA PRODUCTS
<br />
<br />In an effort to remove virga from SAA products, RADAR11.FOR was modified with additional coding,
<br />presented below. (The line numbers are from the experimental version of the program, but enough
<br />neighboring statements are included for location to show the context so that such lines can be inserted in
<br />the correct locations. All extra lines are identified with a @ @ @ identifier. Some lines deal only with a
<br />simple range restriction.)
<br />
<br />(lines 52-60, main program comments section)
<br />
<br />C 98/12 Ed: Range limit added, reducing view from 230 to perhaps 200 km.
<br />C Look for @@@.
<br />C 98/12 Ed: Virga restrictions added to /RESTRICT/, also noted with @@@.
<br />C If there is enough precip within the "virga box" (shallow disc close to
<br />C ground and at relatively near range) then range correction is applied
<br />C beyond the box edge. Otherwise the echoes are not boosted out there and
<br />C their contributions are greatly reduced. That will let intense echoes
<br />C contribute somewhat to the precip accumulation, but virga contributions
<br />C should be minimized. A discontinuity may be seen where confidence drops.
<br />
<br />(SUBROUTINE STARTUP: lines 693-703)
<br />
<br />C
<br />C LIMITVUE
<br />C INSIDE
<br />C TOPIN
<br />C BOTIN
<br />C INSUM
<br />C INTOT
<br />C INFLAG
<br />C INQUALIF
<br />C DURATION
<br />C FRACTION
<br />
<br />/RESTRICT/ variables for virg~ reductions: @@@
<br />1*4 Maximum range for precip accumulations @@@
<br />1*4 Range within which significant echo must occur @@@
<br />R*4 Altitude (km) above r~dar for top of qualifying box @@@
<br />R*4 Altitude (km) above r~dar for bottom of qualif. box @@@
<br />1*4 Range bin count of echoes >=10 dBZ within box @@@
<br />1*4 Range bin count of all data within qualifying box @@@
<br />1*4 0, else 1 if enough bright echoes inside box @@@
<br />1*4 Last qualifying time, hhmmss @@@
<br />R*4 Duration, fracto hrs, allowed since last INFLAG=l @@@
<br />R*4 Qualifying fraction, INSUM/INTOT, to set INFLAG @@@
<br />
<br />(SUBROUTINE STARTUP: lines 710-711)
<br />
<br />COMMON/RESTRICT/LIMITVUE, INSIDE, TOPDl, BOTIN, INSUM, INTOT, INFLAG, @@@
<br />INQUALIF,DURATION,FRACTION @@@
<br />
<br />(SUBROUTINE STARTUP: lines 721-729)
<br />
<br />DATA LIMITVUE/200/ range, km, for limit of precip accumulation
<br />DATA INSIDE /125/ range, km, for edge of virga box
<br />DATA TOPIN 11. 51 altitude, km, f:)r top of virga box
<br />DATA BOTIN /0.5/ altitude, km, for bottom of virga box
<br />DATA DURATION/1.01 elapsed time from last qualifying virga in
<br />DATA FRACTION/.05/ qualifying fraction of precip bins in box
<br />DATA INFLAG /0/ qualifying flag, 0 or 1
<br />DATA INQUALIF/-200000/ ! fictitious clock time
<br />DATA INSUM,INTOT/2*01 ! initial sums
<br />
<br />@@@
<br />@@@
<br />@@@
<br />@@@
<br />box@@@
<br />@@@
<br />@@@
<br />@@@
<br />@@@
<br />
<br />(SUBROUTINE STARTUP: lines 805-822, note the new list of parameters)
<br />
<br />C read in SM adaptation data (only those '~sed by snow algorithm)
<br />READ(2,*, IOSTAT=IER) CZM !!Z-S multo coef. for snow, 150.
<br />IF (IER.NE.O) READ(2,*) CZM !! if was a column heading line
<br />READ(2,*) CZP !! Z-S power coef. for snow, 2.0
<br />READ(2, *) MAXSPEKL !! dBZ*2 nois,e tolerance, else 0
<br />READ(2,*) MAXNOISE !! percent pr,ecip noise tolerance, else 0
<br />WRITE(6, , (IS, "=MAXSPEKL,",I5,"=MAXNOISE") ') MAXSPEKL,MAXNOISE
<br />READ(2,*) DBZMIN !! trace snow threshold (dBZ) , 10.
<br />READ(2,*) DBZMAX !! outlier bin threshold (dBZ) , 40.
<br />READ (2, *) LIMITVUE !! range beyond which data are not trusted @@@
<br />READ(2,*) INSIDE !! range edge for virga box @@@
<br />READ (2, *) TOPIN !! altitude, km, of top of virga box @@@
<br />READ(2,*) BOTIN !! altitude, km, of bottom of virga box @@@
<br />READ(2,*) DURATION !! duration, frac.hr., after last qualify @@@
<br />READ(2,*) FRACTION !! fraction of range bins with precip in box@@@
<br />READ(2,*, IOSTAT=IER) KLEAIR
<br />C 1 (0) if (not) restricting accum. to VCP 11 & 21
<br />CLOSE (2)
<br />
<br />(SUBROUTINE HINDZERO: lines 947-948)
<br />
<br />27
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