Store bending angle reflection code in a branch

[Ian Culverwell]

Estel Cardellach (IEEC) has sent the attached files together with this email:

- I send you today the core routine, ropp_fm_abel_refl.f90, together 
with a document that explains the changes w.r.t. the original one 
and why this strategy was decided.

- I'd ask Ian to attempt to run it, and see what problems he 
encounters. 

Ian will need, among the input parameters, an observation object 
that includes a vector of impact parameters with values below the 
impact at the surface level.

Once this is compiling/running well I can send another piece of code 
(the equivalent to ropp_fm_bangle_1d.f90. However, if Ian thinks it 
is not needed we could stop it here, otherwise I could continue 
building up other required routines.

The intention is to merge this with a recent release of ROPP - say ROPP10.0 - and store the result in a branch for safekeeping. There's no intention to include it in the official release yet.

[Ian Culverwell]

ropp_fm_abel_refl.f90

[Ian Culverwell]

Reflected_BendingImpact_FM.pdf

[Ian Culverwell]

Consider in ROPP-11.1.

[Ian Culverwell]

The branch https://trac.romsaf.org/ropp/browser/ropp_src/branches/dev/Share/IEEC_reflection_code has been created (at r7204) to hold this work.

[Ian Culverwell]

A slightly tidied up version of the attached ropp_fm_abel_refl.f90 has been added to the repos at r7205.

Changes to the build system needed to compile the code are included. It builds OK.

Changes needed to integrate the code into the bending angle executable have not been included. Thus, although we know the code compiles, we don't know if it runs. Someone else can try that. They can also attach example input data sets to this ticket.

For these reasons, the ticket has been shifted to ROPP-12.0.

[Ian Culverwell]

Another point (for the distant future): if people want this code incorporated ib the official release, then it must be accompanied by the corresponding tangent linear and adjoint codes (cf. ropp_fm_abel_tl.f90 and ropp_fm_abel_ad.f90).