[MITgcm-support] Particle tracking with MITgcm (flt package)

[Andrea Cimatoribus]

Do I understand right that exch2 is derived from curvilinear, so that if 
flt works with exch2 it works also with more simple curvilinear? My 
domain is in fact rather small (~100km), but its shape is more naturally 
represented in a curvilinear grid.
Thanks,
Andrea


Andrea Cimatoribus
postdoctoral researcher
EPFL ENAC IIE ECOL
https://people.epfl.ch/andrea.cimatoribus

On 14/10/16 16:47, Jean-Michel Campin wrote:
> Hi Andrea,
>
> Just one clarification:
>> I have used it with cartesian and sphericalpolar grids. I to NOT know if
>> it works correctly with llc / exch2 / etc. Maybe Jean Michel can
>> enlighten us.
>
> I believe pkg/flt is working correctly with pkg/exch2. There are indeed some
> pkg/exch2 routines (within pkg/flt) to deal with this configuration:
>  flt_exch2.F , exch2_recv_get_vec.F , exch2_send_put_vec.F
>
> Cheers,
> Jean-Michel
>
> On Fri, Oct 14, 2016 at 03:54:31PM +0200, Andrea Cimatoribus wrote:
>> Thanks a lot for the reply! I will also certainly start looking at
>> the python repo as soon as I start getting my hands dirty with the
>> flt package.
>> Cheers,
>> Andrea
>>
>> Andrea Cimatoribus
>> postdoctoral researcher
>> EPFL ENAC IIE ECOL
>> https://people.epfl.ch/andrea.cimatoribus
>>
>> On 14/10/16 15:44, Ryan Abernathey wrote:
>>> Andrea, you are right that the MITgcm flt package is not well
>>> documented. However, it IS very capable and is almost certainly more
>>> efficient / scalable than offline codes, since it parallelizes along
>>> with the rest of MITgcm.
>>>
>>>
>>>    THE QUESTIONS to the MITgcm masters:
>>>    - does anyone know if flt can actually deal with curvilinear grids
>>>    and 3D advection (if I understand right, the answer to the latter is
>>>    yes)?
>>>
>>>
>>> I have used it with cartesian and sphericalpolar grids. I to NOT know if
>>> it works correctly with llc / exch2 / etc. Maybe Jean Michel can
>>> enlighten us.
>>>
>>> It has options for the floats to be truly 3D, isobaric, or profiling. So
>>> yes, 3D advection works.
>>>
>>>
>>>    - Is there any other verification available? I cannot find any
>>>    data.flt other than the one under flt_example.
>>>
>>>
>>> Not that I know of. Here is another example:
>>>
>>> &FLT_NML
>>> # 1 day
>>> flt_int_traj = 86400.,
>>> flt_int_prof =  0.0,
>>> flt_noise    = 0.0,
>>> flt_selectTrajOutp = 3,
>>> flt_file     = 'flt_ini_pos_hex.epac.32deg.bin',
>>> &
>>>
>>> It is pretty simple. A lot of the float behavior is determined in the
>>> input file, rather than data.flt.
>>>
>>>
>>>    - What about advection schemes? README.flt states that second-order
>>>    Runge-Kutta is the only option, but I was wandering if that is still
>>>    the case and whether that is important (I am only starting to
>>>    scratch the surface of Lagrangian methods).
>>>
>>>
>>> Runge-Kutta 4th order was implemented by Andreas Klocker, and this is
>>> the default. I believe this is considered state of the art.
>>>
>>>
>>>    - Can flt actually interface to the diagnostic and mnc packages? A
>>>    grep in its directory returns nothing, but my understanding of the
>>>    workings of the code is certainly limited at best.
>>>
>>>
>>> No. The float output is quite primitive and is on a tile-by-tile basis.
>>> This makes it hard to parse and aggregate the float data. To deal with
>>> this, we have created a python package called floater which parses and
>>> translates the float data into other more convenient storage formats:
>>> https://github.com/rabernat/floater
>>> There is also some basic capability for writing the float input files.
>>> There is still lots of room for improvement here, but it should be
>>> easier than starting from scratch. I welcome issue reports and pull
>>> requests on this repository.
>>>
>>>
>>>    Thank you very much,
>>>    Andrea
>>>
>>>    --
>>>    Andrea Cimatoribus
>>>    postdoctoral researcher
>>>    EPFL ENAC IIE ECOL
>>>    https://people.epfl.ch/andrea.cimatoribus
>>>    <https://people.epfl.ch/andrea.cimatoribus>
>>>
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>>>
>>>
>>>
>>>
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>>
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