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

!     cgrib    - Character array that contains the GRIB2 message
!     lcgrib   - Length (in bytes) of GRIB message in array cgrib.
!
!   OUTPUT ARGUMENT LIST:      
!     listsec0 - Contains information decoded from GRIB Indicator Section 0.
!                Must be dimensioned >= 2.
!                listsec0(1)=Discipline-GRIB Master Table Number
!                            (see Code Table 0.0)
!                listsec0(2)=GRIB Edition Number (currently 2)
!                listsec0(3)=Length of GRIB message
!     listsec1 - Contains information read from GRIB Identification Section 1.
!                Must be dimensioned >= 13.
!                listsec1(1)=Id of orginating centre (Common Code Table C-1)
!                listsec1(2)=Id of orginating sub-centre (local table)
!                listsec1(3)=GRIB Master Tables Version Number (Code Table 1.0)
!                listsec1(4)=GRIB Local Tables Version Number 
!                listsec1(5)=Significance of Reference Time (Code Table 1.1)
!                listsec1(6)=Reference Time - Year (4 digits)
!                listsec1(7)=Reference Time - Month
!                listsec1(8)=Reference Time - Day
!                listsec1(9)=Reference Time - Hour
!                listsec1(10)=Reference Time - Minute
!                listsec1(11)=Reference Time - Second
!                listsec1(12)=Production status of data (Code Table 1.2)
!                listsec1(13)=Type of processed data (Code Table 1.3)
!     numfields- The number of gridded fields found in the GRIB message.
!     numlocal - The number of Local Use Sections ( Section 2 ) found in 
!                the GRIB message.
!     maxlocal-  The size of the largest Local Use Section ( Section 2 ).
!                Can be used to ensure that the return array passed
!                to subroutine getlocal is dimensioned large enough.
!     ierr     - Error return code.
!                0 = no error
!                1 = Beginning characters "GRIB" not found.
!                2 = GRIB message is not Edition 2.
!                3 = Could not find Section 1, where expected.
!                4 = End string "7777" found, but not where expected.
!                5 = End string "7777" not found at end of message.
!                6 = Invalid section number found.
!
! REMARKS: None
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$

!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! SUBPROGRAM:    getlocal 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2000-05-25
!
! ABSTRACT: This subroutine returns the contents of Section 2 ( Local 
!   Use Section ) from a GRIB2 message.  Since there can be multiple
!   occurrences of Section 2 within a GRIB message, the calling routine
!   indicates which occurrence is being requested with the localnum argument.
!
! PROGRAM HISTORY LOG:
! 2000-05-25  Gilbert
!
! USAGE:    CALL getlocal(cgrib,lcgrib,localnum,csec2,lcsec2,ierr)
!   INPUT ARGUMENT LIST:
!     cgrib    - Character array that contains the GRIB2 message
!     lcgrib   - Length (in bytes) of GRIB message in array cgrib.
!     localnum - The nth occurrence of Section 2 requested.
!
!   OUTPUT ARGUMENT LIST:      
!     csec2    - Character array containing information read from 
!                Section 2.
!                The dimension of this array can be obtained in advance
!                from argument maxlocal, which is returned from subroutine 
!                gb_info.
!     lcsec2   - Number of bytes of character array csec2 read from
!                Section 2.
!     ierr     - Error return code.
!                0 = no error
!                1 = Beginning characters "GRIB" not found.
!                2 = GRIB message is not Edition 2.
!                3 = The section 2 request number was not positive.
!                4 = End string "7777" found, but not where expected.
!                5 = End string "7777" not found at end of message.
!                6 = GRIB message did not contain the requested number of
!                    Local Use Sections.
!
! REMARKS: Note that subroutine gribinfo can be used to first determine
!          how many Local Use sections exist in a given GRIB message.
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$


!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! SUBPROGRAM:    gf_getfld 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2000-05-26
!
! ABSTRACT: This subroutine returns the Grid Definition, Product Definition,
!   Bit-map ( if applicable ), and the unpacked data for a given data
!   field.  All of the information returned is stored in a derived
!   type variable, gfld.  Gfld is of type gribfield, which is defined
!   in module grib_mod, so users of this routine will need to include
!   the line "USE GRIB_MOD" in their calling routine.  Each component of the 
!   gribfield type is described in the OUTPUT ARGUMENT LIST section below.
!
!   Since there can be multiple data fields packed into a GRIB2
!   message, the calling routine indicates which field is being requested
!   with the ifldnum argument.
!
! PROGRAM HISTORY LOG:
! 2000-05-26  Gilbert
! 2002-01-24  Gilbert  - Changed to pass back derived type gribfield
!                        variable through argument list, instead of
!                        having many different arguments.
!
! USAGE:    CALL gf_getfld(cgrib,lcgrib,ifldnum,unpack,expand,gfld,ierr)
!   INPUT ARGUMENT LIST:
!     cgrib    - Character array that contains the GRIB2 message
!     lcgrib   - Length (in bytes) of GRIB message array cgrib.
!     ifldnum  - Specifies which field in the GRIB2 message to return.
!     unpack   - Logical value indicating whether to unpack bitmap/data
!                .true. = unpack bitmap and data values
!                .false. = do not unpack bitmap and data values
!     expand   - Boolean value indicating whether the data points should be
!                expanded to the correspond grid, if a bit-map is present.
!                1 = if possible, expand data field to grid, inserting zero
!                    values at gridpoints that are bitmapped out.
!                    (SEE REMARKS2)
!                0 = do not expand data field, leaving it an array of
!                    consecutive data points for each "1" in the bitmap.
!                This argument is ignored if unpack == 0 OR if the
!                returned field does not contain a bit-map.
!
!   OUTPUT ARGUMENT LIST:      
!     gfld - derived type gribfield ( defined in module grib_mod )
!            ( NOTE: See Remarks Section )
!        gfld%version = GRIB edition number ( currently 2 )
!        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 )
!                             7 - US National Weather Service
!            gfld%idsect(2)  = Identification of originating Sub-centre
!            gfld%idsect(3)  = GRIB Master Tables Version Number
!                                    ( see Code Table 1.0 )
!                             0 - Experimental
!                             1 - Initial operational version number
!            gfld%idsect(4)  = GRIB Local Tables Version Number
!                                    ( see Code Table 1.1 )
!                             0     - Local tables not used
!                             1-254 - Number of local tables version used
!            gfld%idsect(5)  = Significance of Reference Time (Code Table 1.2)
!                             0 - Analysis
!                             1 - Start of forecast
!                             2 - Verifying time of forecast
!                             3 - Observation time
!            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 )
!                              0 - Operational products
!                              1 - Operational test products
!                              2 - Research products
!                              3 - Re-analysis products
!            gfld%idsect(13)  = Type of processed data ( see Code Table 1.4 )
!                              0  - Analysis products
!                              1  - Forecast products
!                              2  - Analysis and forecast products
!                              3  - Control forecast products
!                              4  - Perturbed forecast products
!                              5  - Control and perturbed forecast products
!                              6  - Processed satellite observations
!                              7  - Processed radar observations
!        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)
!                      0 - Specified in Code table 3.1
!                      1 - Predetermined grid Defined by originating centre
!        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