[MITgcm-devel] woes with exf interpolating
Matthew Mazloff
mmazloff at ucsd.edu
Sat Apr 3 15:22:47 EDT 2010
Thanks Dimitris! I'll look for other explanations
appreciate it,
-Matt
On Apr 3, 2010, at 12:14 PM, Menemenlis, Dimitris (3248) wrote:
> Matt, exf_interp assumes periodicity in zonal direction of input
> array and provides 2 overlaps on either side, which should be
> sufficient for bicubic, so I don't understand where discontinuity
> comes from.
>
> C enlarge boundary
> do j=1,ny_in
> arrayin(0,j) = arrayin(nx_in,j)
> arrayin(-1,j) = arrayin(nx_in-1,j)
> arrayin(nx_in+1,j) = arrayin(1,j)
> arrayin(nx_in+2,j) = arrayin(2,j)
> enddo
> do i=-1,nx_in+2
> arrayin(i,0) = arrayin(i,1)
> arrayin(i,-1) = arrayin(i,1)
> arrayin(i,ny_in+1) = arrayin(i,ny_in)
> arrayin(i,ny_in+2) = arrayin(i,ny_in)
> enddo
>
> A simple test would be to add one more overlap on each side of
> arrayin, and also to the related x_in and y_in, and see if it fixes
> problem.
>
> Dimitris
>
> On Apr 3, 2010, at 10:45 AM, Matthew Mazloff wrote:
>
>> Hi JMC,
>>
>> I copied it below -- I think its pretty standard. Is there something
>> I'm missing in prescribing the forcing dimensions -- do I need to
>> manually provide an overlap, or provide overlap information?
>>
>> Thanks
>> Matt
>>
>>
>>
>> login4% more data.exf
>> # $Header: /u/gcmpack/MITgcm/verification/lab_sea/input/data.exf,v
>> 1.7
>> 2004/07/11 06:21:44 dimitri Exp
>> $
>> #
>> # *********************
>> # External Forcing Data
>> # *********************
>> &EXF_NML_01
>> #
>> useExfYearlyFields = .TRUE.,
>> useExfCheckRange = .FALSE.,
>> exf_iprec = 32,
>> exf_yftype = 'RL',
>> useRelativeWind = .TRUE.,
>> /
>> #
>> &EXF_NML_02
>> #
>> atempstartdate1 = 20050101,
>> atempstartdate2 = 00000,
>> atempperiod = 21600.0,
>> #
>> aqhstartdate1 = 20050101,
>> aqhstartdate2 = 00000,
>> aqhperiod = 21600.0,
>> #
>> precipstartdate1 = 20050101,
>> precipstartdate2 = 00000,
>> precipperiod = 21600.0,
>> #
>> uwindstartdate1 = 20050101,
>> uwindstartdate2 = 00000,
>> uwindperiod = 21600.0,
>> #
>> vwindstartdate1 = 20050101,
>> vwindstartdate2 = 00000,
>> vwindperiod = 21600.0,
>> #
>> runoffstartdate1 = 20050101,
>> runoffstartdate2 = 00000,
>> runoffperiod = 0.0,
>> #
>> swdownstartdate1 = 20050101,
>> swdownstartdate2 = 00000,
>> swdownperiod = 21600.0,
>> #
>> lwdownstartdate1 = 20050101,
>> lwdownstartdate2 = 00000,
>> lwdownperiod = 21600.0,
>> #
>> atempfile = 'SO6input/NCEP_R6_tmp2m_degC_SO',
>> aqhfile = 'SO6input/NCEP_R6_spfh2m_SO',
>> uwindfile = 'SO6input/NCEP_R6_u10m_SO',
>> vwindfile = 'SO6input/NCEP_R6_v10m_SO',
>> precipfile = 'SO6input/NCEP_R6_rain_SO_DT',
>> runoffFile = 'SO6input/run-off_SO.6',
>> lwdownfile = 'SO6input/NCEP_R6_dlw_SO',
>> swdownfile = 'SO6input/NCEP_R6_dsw_SO',
>> #
>> /
>> #
>> &EXF_NML_03
>> #
>> exf_inscal_uwind = 1.,
>> exf_inscal_vwind = 1.,
>> exf_inscal_runoff = 3.170979198E-8,
>> exf_offset_atemp = 273.15,
>> #
>> /
>> #
>> &EXF_NML_04
>> #
>> atemp_lon0 = 0.5D0,
>> atemp_lon_inc = 1.D0,
>> atemp_lat0 = -79.5D0,
>> atemp_lat_inc = 60*1.D0,
>> atemp_nlon = 360,
>> atemp_nlat = 60,
>> #
>> aqh_lon0 = 0.5D0,
>> aqh_lon_inc = 1.D0,
>> aqh_lat0 = -79.5D0,
>> aqh_lat_inc = 60*1.D0,
>> aqh_nlon = 360,
>> aqh_nlat = 60,
>> #
>> precip_lon0 = 0.5D0,
>> precip_lon_inc = 1.D0,
>> precip_lat0 = -79.5D0,
>> precip_lat_inc = 60*1.D0,
>> precip_nlon = 360,
>> precip_nlat = 60,
>> #
>> uwind_lon0 = 0.5D0,
>> uwind_lon_inc = 1.D0,
>> uwind_lat0 = -79.5D0,
>> uwind_lat_inc = 60*1.D0,
>> uwind_nlon = 360,
>> uwind_nlat = 60,
>> #
>> vwind_lon0 = 0.5D0,
>> vwind_lon_inc = 1.D0,
>> vwind_lat0 = -79.5D0,
>> vwind_lat_inc = 60*1.D0,
>> vwind_nlon = 360,
>> vwind_nlat = 60,
>> #
>> swdown_lon0 = 0.5D0,
>> swdown_lon_inc = 1.D0,
>> swdown_lat0 = -79.5D0,
>> swdown_lat_inc = 60*1.D0,
>> swdown_nlon = 360,
>> swdown_nlat = 60,
>> #
>> lwdown_lon0 = 0.5D0,
>> lwdown_lon_inc = 1.D0,
>> lwdown_lat0 = -79.5D0,
>> lwdown_lat_inc = 60*1.D0,
>> lwdown_nlon = 360,
>> lwdown_nlat = 60,
>> #
>> /
>> #
>> &EXF_NML_OBCS
>> #
>> obcsNstartdate1 = 20050101,
>> obcsNstartdate2 = 00000,
>> obcsNperiod = 2635200.0,
>> #
>> /
>>
>>
>>
>> On Apr 3, 2010, at 7:07 AM, Jean-Michel Campin wrote:
>>
>>> Hi Matt,
>>>
>>> Could you send also the "data.exf" you are using ? or could I find
>>> it
>>> somewhere ?
>>> Thanks,
>>> Jean-Michel
>>>
>>> On Fri, Apr 02, 2010 at 03:17:51PM -0700, Matthew Mazloff wrote:
>>>> Hello,
>>>>
>>>> A problem has been found (thanks Fabien!) regarding a discontinuity
>>>> in
>>>> the wind fields around longitude 0/360.
>>>>
>>>> My set-up is 1/6 of a degree and I use NCEP on a 1 degree grid and
>>>> use
>>>> exf interpolation. Within ~1 degree east and west of longitude 0
>>>> there
>>>> is a discontinuity in the wind field -- it is small but quite
>>>> significant in the x-derivative. My guess is that the
>>>> interpolation
>>>> routine is not properly accounting for periodicity -- and instead
>>>> perhaps incorporating zeros.
>>>>
>>>> Some important stuff -- I am using NCEP winds -- not stress --
>>>> and I
>>>> have switched to interp_method=2 instead of the hard-coded
>>>> interp_method=1. This is because with interp_method 1 (linear)
>>>> there
>>>> are discontinuities in the wind-stress curl everywhere. With
>>>> bicubic
>>>> interp the curl is smooth -- with this exception around longitude 0
>>>>
>>>> I was hoping someone with more expertise could shed light on this
>>>> before
>>>> I go digging in the code
>>>>
>>>> Thanks!
>>>> -Matt
>>>>
>>>>
>>>> _______________________________________________
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>>>> MITgcm-devel at mitgcm.org
>>>> http://mitgcm.org/mailman/listinfo/mitgcm-devel
>>>
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>>
>>
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