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