grib2.doc

计算线性趋势 回归系数 主要用于气象站点值的线性趋势计算

!                       of entries in Data Representation Template 5.N 
!                       ( N=gfld%idrtnum ).
!        gfld%unpacked = logical value indicating whether the bitmap and
!                        data values were unpacked.  If false, 
!                        gfld%bmap and gfld%fld pointers are nullified.
!        gfld%expanded = Logical value indicating whether the data field
!                         was expanded to the grid in the case where a
!                         bit-map is present.  If true, the data points in
!                         gfld%fld match the grid points and zeros were
!                         inserted at grid points where data was bit-mapped
!                         out.  If false, the data values in gfld%fld were
!                         not expanded to the grid and are just a consecutive
!                         array of data points corresponding to each value of
!                         "1" in gfld%bmap.
!        gfld%ibmap = Bitmap indicator ( see Code Table 6.0 )
!                     0 = bitmap applies and is included in Section 6.
!                     1-253 = Predefined bitmap applies
!                     254 = Previously defined bitmap applies to this field
!                     255 = Bit map does not apply to this product.
!        gfld%bmap() = Logical*1 array containing decoded bitmap, 
!                      if ibmap=0 or ibap=254.  Otherwise nullified.
!                      This element is actually a pointer to an array
!                      that holds the data.
!        gfld%fld() = Array of gfld%ndpts unpacked data points.
!                     This element is actually a pointer to an array
!                     that holds the data.
!     ierr     - Error return code.
!                0 = no error
!                1 = Beginning characters "GRIB" not found.
!                2 = GRIB message is not Edition 2.
!                3 = The data field request number was not positive.
!                4 = End string "7777" found, but not where expected.
!                6 = GRIB message did not contain the requested number of
!                    data fields.
!                7 = End string "7777" not found at end of message.
!                8 = Unrecognized Section encountered.
!                9 = Data Representation Template 5.NN not yet implemented.
!               15 = Error unpacking Section 1.
!               10 = Error unpacking Section 3.
!               11 = Error unpacking Section 4.
!               12 = Error unpacking Section 5.
!               13 = Error unpacking Section 6.
!               14 = Error unpacking Section 7.
!
! REMARKS: Note that derived type gribfield contains pointers to many
!          arrays of data.  The memory for these arrays is allocated
!          when the values in the arrays are set, to help minimize
!          problems with array overloading.  Because of this users
!          are encouraged to free up this memory, when it is no longer
!          needed, by an explicit call to subroutine gf_free.
!          ( i.e.   CALL GF_FREE(GFLD) )
!
!          Subroutine gb_info can be used to first determine
!          how many data fields exist in a given GRIB message.
!
! REMARKS2: It may not always be possible to expand a bit-mapped data field.
!           If a pre-defined bit-map is used and not included in the GRIB2
!           message itself, this routine would not have the necessary
!           information to expand the data.  In this case, gfld%expanded would
!           would be set to 0 (false), regardless of the value of input
!           argument expand.
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$


!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! SUBPROGRAM:    gf_free 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2000-05-26
!
! ABSTRACT: This subroutine frees up memory that was used to store
!   array values in derived type gribfield.
!
! PROGRAM HISTORY LOG:
! 2000-05-26  Gilbert
!
! USAGE:    CALL gf_free(gfld)
!   INPUT ARGUMENT LIST:
!     gfld - derived type gribfield ( defined in module grib_mod )
!
!   OUTPUT ARGUMENT LIST:      
!     gfld - derived type gribfield ( defined in module grib_mod )
!        gfld%version = GRIB edition number
!        gfld%discipline = Message Discipline ( see Code Table 0.0 )
!        gfld%idsect() = Contains the entries in the Identification
!                        Section ( Section 1 )
!                        This element is actually a pointer to an array
!                        that holds the data.
!            gfld%idsect(1)  = Identification of originating Centre
!                                    ( see Common Code Table C-1 )
!            gfld%idsect(2)  = Identification of originating Sub-centre
!            gfld%idsect(3)  = GRIB Master Tables Version Number
!                                    ( see Code Table 1.0 )
!            gfld%idsect(4)  = GRIB Local Tables Version Number
!                                    ( see Code Table 1.1 )
!            gfld%idsect(5)  = Significance of Reference Time (Code Table 1.2)
!            gfld%idsect(6)  = Year ( 4 digits )
!            gfld%idsect(7)  = Month
!            gfld%idsect(8)  = Day
!            gfld%idsect(9)  = Hour
!            gfld%idsect(10)  = Minute
!            gfld%idsect(11)  = Second
!            gfld%idsect(12)  = Production status of processed data
!                                    ( see Code Table 1.3 )
!            gfld%idsect(13)  = Type of processed data ( see Code Table 1.4 )
!        gfld%idsectlen = Number of elements in gfld%idsect().
!        gfld%ifldnum = field number within GRIB message
!        gfld%griddef = Source of grid definition (see Code Table 3.0)
!        gfld%ngrdpts = Number of grid points in the defined grid.
!        gfld%numoct_opt = Number of octets needed for each 
!                          additional grid points definition.  
!                          Used to define number of
!                          points in each row ( or column ) for
!                          non-regular grids.  
!                          = 0, if using regular grid.
!        gfld%interp_opt = Interpretation of list for optional points 
!                          definition.  (Code Table 3.11)
!        gfld%igdtnum = Grid Definition Template Number (Code Table 3.1)
!        gfld%igdtmpl() = Contains the data values for the specified Grid 
!                         Definition Template ( NN=gfld%igdtnum ).  Each 
!                         element of this integer array contains an entry (in 
!                         the order specified) of Grid Defintion Template 3.NN
!                         This element is actually a pointer to an array
!                         that holds the data.
!        gfld%igdtlen = Number of elements in gfld%igdtmpl().  i.e. number of
!                       entries in Grid Defintion Template 3.NN  
!                       ( NN=gfld%igdtnum ).
!        gfld%list_opt() = (Used if gfld%numoct_opt .ne. 0)  This array 
!                          contains the number of grid points contained in 
!                          each row ( or column ).  (part of Section 3)
!                          This element is actually a pointer to an array
!                          that holds the data.  This pointer is nullified
!                          if gfld%numoct_opt=0.
!        gfld%num_opt = (Used if gfld%numoct_opt .ne. 0)  The number of entries
!                       in array ideflist.  i.e. number of rows ( or columns )
!                       for which optional grid points are defined.  This value
!                       is set to zero, if gfld%numoct_opt=0.
!        gfdl%ipdtnum = Product Definition Template Number (see Code Table 4.0)
!        gfld%ipdtmpl() = Contains the data values for the specified Product 
!                         Definition Template ( N=gfdl%ipdtnum ).  Each element
!                         of this integer array contains an entry (in the 
!                         order specified) of Product Defintion Template 4.N.
!                         This element is actually a pointer to an array
!                         that holds the data.
!        gfld%ipdtlen = Number of elements in gfld%ipdtmpl().  i.e. number of
!                       entries in Product Defintion Template 4.N  
!                       ( N=gfdl%ipdtnum ).
!        gfld%coord_list() = Real array containing floating point values 
!                            intended to document the vertical discretisation
!                            associated to model data on hybrid coordinate
!                            vertical levels.  (part of Section 4)
!                            This element is actually a pointer to an array
!                            that holds the data.
!        gfld%num_coord = number of values in array gfld%coord_list().
!        gfld%ndpts = Number of data points unpacked and returned.
!        gfld%idrtnum = Data Representation Template Number 
!                       ( see Code Table 5.0)
!        gfld%idrtmpl() = Contains the data values for the specified Data 
!                         Representation Template ( N=gfld%idrtnum ).  Each 
!                         element of this integer array contains an entry 
!                         (in the order specified) of Product Defintion 
!                         Template 5.N.
!                         This element is actually a pointer to an array
!                         that holds the data.
!        gfld%idrtlen = Number of elements in gfld%idrtmpl().  i.e. number 
!                       of entries in Data Representation Template 5.N 
!                       ( N=gfld%idrtnum ).
!        gfld%unpacked = logical value indicating whether the bitmap and
!                        data values were unpacked.  If false, gfld%ndpts
!                        is set to zero, and gfld%bmap and gfld%fld 
!                        pointers are nullified.
!        gfld%expanded = Logical value indicating whether the data field
!                         was expanded to the grid in the case where a
!                         bit-map is present.  If true, the data points in
!                         gfld%fld match the grid points and zeros were
!                         inserted at grid points where data was bit-mapped
!                         out.  If false, the data values in gfld%fld were
!                         not expanded to the grid and are just a consecutive
!                         array of data points corresponding to each value of
!                         "1" in gfld%bmap.
!        gfld%ibmap = Bitmap indicator ( see Code Table 6.0 )
!                     0 = bitmap applies and is included in Section 6.
!                     1-253 = Predefined bitmap applies
!                     254 = Previously defined bitmap applies to this field
!                     255 = Bit map does not apply to this product.
!        gfld%bmap() - Logical*1 array containing decoded bitmap, 
!                      if ibmap=0 or ibap=254.  Otherwise nullified.
!                      This element is actually a pointer to an array
!                      that holds the data.
!        gfld%fld() = Array of gfld%ndpts unpacked data points.
!                     This element is actually a pointer to an array
!                     that holds the data.
!
! REMARKS: 
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$



C$$$  SUBPROGRAM DOCUMENTATION BLOCK
C
C SUBPROGRAM: GETGB2         FINDS AND UNPACKS A GRIB MESSAGE
C   PRGMMR: IREDELL          ORG: W/NMC23     DATE: 94-04-01
C
C ABSTRACT: FIND AND UNPACK A GRIB MESSAGE.
C   READ A GRIB INDEX FILE (OR OPTIONALLY THE GRIB FILE ITSELF)
C   TO GET THE INDEX BUFFER (I.E. TABLE OF CONTENTS) FOR THE GRIB FILE.
C   FIND IN THE INDEX BUFFER A REFERENCE TO THE GRIB FIELD REQUESTED.
C   THE GRIB FIELD REQUEST SPECIFIES THE NUMBER OF FIELDS TO SKIP
C   AND THE UNPACKED IDENTIFICATION SECTION, GRID DEFINITION TEMPLATE AND
C   PRODUCT DEFINTION SECTION PARAMETERS.  (A REQUESTED PARAMETER
C   OF -9999 MEANS TO ALLOW ANY VALUE OF THIS PARAMETER TO BE FOUND.)
C   IF THE REQUESTED GRIB FIELD IS FOUND, THEN IT IS READ FROM THE
C   GRIB FILE AND UNPACKED.  ITS NUMBER IS RETURNED ALONG WITH
C   THE ASSOCIATED UNPACKED PARAMETERS.  THE BITMAP (IF ANY),
C   AND THE DATA VALUES ARE UNPACKED ONLY IF ARGUMENT "UNPACK" IS SET TO
C   TRUE.  IF THE GRIB FIELD IS NOT FOUND, THEN THE
C   RETURN CODE WILL BE NONZERO.
C
C   The decoded information for the selected GRIB field
C   is returned in a derived type variable, gfld.
C   Gfld is of type gribfield, which is defined
C   in module grib_mod, so users of this routine will need to include
C   the line "USE GRIB_MOD" in their calling routine.  Each component of the
C   gribfield type is described in the OUTPUT ARGUMENT LIST section below.
C
C PROGRAM HISTORY LOG:
C   94-04-01  IREDELL
C   95-10-31  IREDELL     MODULARIZED PORTIONS OF CODE INTO SUBPROGRAMS
C                         AND ALLOWED FOR UNSPECIFIED INDEX FILE
C 2002-01-11  GILBERT     MODIFIED FROM GETGB AND GETGBM TO WORK WITH GRIB2
C
C USAGE:    CALL GETGB2(LUGB,LUGI,J,JDISC,JIDS,JPDTN,JPDT,JGDTN,JGDT,
C    &                  UNPACK,K,GFLD,IRET)
C   INPUT ARGUMENTS:
C     LUGB         INTEGER UNIT OF THE UNBLOCKED GRIB DATA FILE.
C                  FILE MUST BE OPENED WITH BAOPEN OR BAOPENR BEFORE CALLING