Hello,
I have an ECMWF Grib file containing the same set of variables on two
different time ranges. Is there any way to access a given variable on both
of the time ranges in NCL? It seems that NCL gives both of them the same
file variable name, and so is only able to access one.
An abbreviated version of the Grib inventory for this file, as output from
wgrib, is:
------------------------------------------------------------------------------------------------------------------
1:0:d=00091400:LNSP:kpds5=152:kpds6=109:kpds7=1:TR=1:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
2:33360:d=00091400:Z:kpds5=129:kpds6=109:kpds7=1:TR=1:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
3:66720:d=00091400:T:kpds5=130:kpds6=109:kpds7=1:TR=1:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
4:100080:d=00091400:Q:kpds5=133:kpds6=109:kpds7=1:TR=1:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
5:133440:d=00091400:U:kpds5=131:kpds6=109:kpds7=1:TR=1:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
6:166800:d=00091400:V:kpds5=132:kpds6=109:kpds7=1:TR=1:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
...
243:8073120:d=00091406:LNSP:kpds5=152:kpds6=109:kpds7=1:TR=0:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
244:8106480:d=00091406:Z:kpds5=129:kpds6=109:kpds7=1:TR=0:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
245:8139840:d=00091406:T:kpds5=130:kpds6=109:kpds7=1:TR=0:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
246:8173200:d=00091406:Q:kpds5=133:kpds6=109:kpds7=1:TR=0:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
247:8206560:d=00091406:U:kpds5=131:kpds6=109:kpds7=1:TR=0:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
248:8239920:d=00091406:V:kpds5=132:kpds6=109:kpds7=1:TR=0:P1=0:P2=0:TimeU=1:hybrid lev 1:anl:ECMWF stream?:NAve=0
...
------------------------------------------------------------------------------------------------------------------
The variables are each present for time ranges TR=0 and TR=1. (One has the 6Z
and 18Z data, and the other has the 0Z and 12Z data.)
NCL treats both sets of variables as having the same variable names. For
instance, getfilevarnames shows the following:
------------------------------------------------------------------------------------------------------------------
(0) initial_time0
(1) g0_lon_2
(2) g0_lat_1
(3) initial_time3
(4) lv_HYBL4
(5) lv_HYBL4_a
(6) lv_HYBL4_b
(7) LOGP_GDS0_HYBL
(8) LOGP_GDS0_HYBL
(9) SPF_H_GDS0_HYBL
(10) SPF_H_GDS0_HYBL
(11) V_GRD_GDS0_HYBL
(12) V_GRD_GDS0_HYBL
(13) U_GRD_GDS0_HYBL
(14) U_GRD_GDS0_HYBL
(15) TMP_GDS0_HYBL
(16) TMP_GDS0_HYBL
(17) GP_GDS0_HYBL
(18) GP_GDS0_HYBL
------------------------------------------------------------------------------------------------------------------
Is there any way to distinguish these identically-named file variables
in NCL? If not, as a last resort, I realize I could use wgrib to split
these Grib files into two, one containing the TR=0 data, and the other
the TR=1 data.
Thanks!!
--Larry
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Larry W. Horowitz phone: (609) 452-6520
GFDL/NOAA fax: (609) 987-5063
P.O. Box 308, Princeton Univ. home page: http://www.asp.ucar.edu/~larryh/
Princeton, NJ 08542-0308 email: larryh@ucar.edu or lwh@gfdl.noaa.gov
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