mirror of https://github.com/ecmwf/eccodes.git
99 lines
3.4 KiB
Fortran
99 lines
3.4 KiB
Fortran
! (C) Copyright 2005- ECMWF.
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!
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! This software is licensed under the terms of the Apache Licence Version 2.0
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! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
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!
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! In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
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! virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
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!
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!
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!
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! Description: How to read data for a given beam from scatterometer BUFR messages.
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!
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! Please note that scatterometer data can be encoded in various ways in BUFR. Therefore the code
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! below might not work directly for other types of messages than the one used in the
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! example. It is advised to use bufr_dump first to understand the structure of these messages.
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program bufr_read_scatterometer
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use eccodes
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implicit none
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integer :: ifile
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integer :: iret
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integer :: ibufr
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integer :: i, count = 0
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integer(kind=4) :: numObs, ii
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real(kind=8), dimension(:), allocatable :: latVal, lonVal, bscatterVal
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real(kind=8), dimension(:), allocatable :: year
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call codes_open_file(ifile, '../../data/bufr/asca_139.bufr', 'r')
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! The first BUFR message is loaded from file,
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! ibufr is the bufr id to be used in subsequent calls
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call codes_bufr_new_from_file(ifile, ibufr, iret)
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do while (iret /= CODES_END_OF_FILE)
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write (*, '(A,I3)') 'message: ', count
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! We need to instruct ecCodes to expand all the descriptors
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! i.e. unpack the data values
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call codes_set(ibufr, "unpack", 1);
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! The BUFR file contains a single message with 2016 subsets in a compressed form.
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! It means each subset has exactly the same structure: they store one location with
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! several beams and one backscatter value in each beam.
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!
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! To print the backScatter values for beamIdentifier=2 from all the subsets
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! we will simply access the key by condition (see below).
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! Read the total number of subsets.
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call codes_get(ibufr, 'numberOfSubsets', numObs)
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write (*, '(A,I5)') "Number of values:", numObs
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! Get latitude (for all the subsets)
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call codes_get(ibufr, 'latitude', latVal);
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! Get longitude (for all the subsets)
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call codes_get(ibufr, 'longitude', lonVal);
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allocate (year(numObs))
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call codes_get(ibufr, 'year', year);
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do ii = 1, size(year)
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write (*, '(A,I4,A,F8.1)') 'year(', ii, ')=', year(ii)
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end do
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! Get backScatter for beam two. We use an access by condition for this key.
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! (for all the subsets)
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call codes_get(ibufr, '/beamIdentifier=2/backscatter', bscatterVal);
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! Check that all arrays are same size
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if (size(latVal) /= numObs .or. size(lonVal) /= numObs .or. size(bscatterVal) /= numObs) then
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print *, 'inconsistent array dimension'
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exit
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end if
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! Print the values
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write (*, *) 'pixel lat lon backscatter'
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write (*, *) "--------------------------------------"
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do i = 1, numObs
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write (*, '(I4,3F10.5)') i, latVal(i), lonVal(i), bscatterVal(i)
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end do
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! Free arrays
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deallocate (latVal)
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deallocate (lonVal)
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deallocate (bscatterVal)
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! Release the bufr message
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call codes_release(ibufr)
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! Load the next bufr message
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call codes_bufr_new_from_file(ifile, ibufr, iret)
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count = count + 1
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end do
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! Close file
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call codes_close_file(ifile)
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end program bufr_read_scatterometer
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