Re: odd ut_calendar behavior

Rich,

Okay, this confirms what you expected in the first place, the output
from print(ut_calendar(inptr->time, -3)) should be 2006010100. The
final "24" (hours) should never be seen. The function should always
carry up to the next day, so that hours is always 00 to 23.

This looks like a roundoff problem in the ut_calendar function or
calendar support routines. There was a previous bug report on a
problem like this in the UDUNITS support library, but I think that
was fixed years ago. Are you using a very old version of NCL?
Beyond that, I should say no more and let NCL support staff take a
closer look.

--Dave

On 12/13/2010 2:35 PM, Rich Neale wrote:
> Here it is Dave, thanks!
>
> Variable: time
> Type: double
> Total Size: 8 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [time | 1]
> Coordinates:
> time: [364.5..364.5]
> Number Of Attributes: 4
> long_name : time
> units : days since 2005-01-01 12:00:00
> calendar : noleap
> bounds : time_bnds
> (0) 364.5
>
>
> On 12/13/2010 02:33 PM, Dave Allured wrote:
>> Rich,
>>
>> To simplify diagnosis, please show the full output from this command:
>>
>> print(inptr->time)
>>
>> --Dave
>>
>> On 12/13/2010 2:06 PM, Rich Neale wrote:
>>> Hi, I am getting strange behavior from ut_calendar when I run the
>>> following on cgd systems for those interested). I am trying to
>>> test that
>>> the date of a CAM file is January 2006.
>>>
>>> inptr =
>>> addfile("/project/convection/juliob/CAMruns/twdLL05/twdLL05.cam2.h1.2006-01-01-00000.nc","r")
>>>
>>> print(ut_calendar(inptr->time, -3))
>>>
>>> *Result
>>>
>>> Variable: unnamed (return)
>>> Type: integer
>>> Total Size: 4 bytes
>>> 1 values
>>> Number of Dimensions: 1
>>> Dimensions and sizes: [1]
>>> Coordinates:
>>> Number Of Attributes: 1
>>> calendar : noleap
>>> (0) 2005123124
>>>
>>>
>>>
>>> I would expect this to be 2006010100
>>> Any idea why this is 24 at the end and not 00?
>>> Below is an ncdump -h on the file.
>>> The time units are a little odd
>>> time:units = "days since 2005-01-01 12:00:00" ;
>>>
>>> And I am wondering if ut_calendar is having difficulty with the '12'
>>>
>>> Thanks!!
>>> Rich
>>>
>>> *********************************************
>>>
>>> netcdf twdLL05.cam2.h1.2006-01-01-00000 {
>>> dimensions:
>>> lat = 96 ;
>>> lon = 144 ;
>>> slat = 95 ;
>>> slon = 144 ;
>>> lev = 30 ;
>>> ilev = 31 ;
>>> isccp_prs = 7 ;
>>> isccp_tau = 7 ;
>>> isccp_prstau = 49 ;
>>> time = UNLIMITED ; // (1 currently)
>>> tbnd = 2 ;
>>> chars = 8 ;
>>> variables:
>>> double P0 ;
>>> P0:long_name = "reference pressure" ;
>>> P0:units = "Pa" ;
>>> double lat(lat) ;
>>> lat:long_name = "latitude" ;
>>> lat:units = "degrees_north" ;
>>> double lon(lon) ;
>>> lon:long_name = "longitude" ;
>>> lon:units = "degrees_east" ;
>>> double slat(slat) ;
>>> slat:long_name = "staggered latitude" ;
>>> slat:units = "degrees_north" ;
>>> double slon(slon) ;
>>> slon:long_name = "staggered longitude" ;
>>> slon:units = "degrees_east" ;
>>> double w_stag(slat) ;
>>> w_stag:long_name = "staggered latitude weights" ;
>>> double lev(lev) ;
>>> lev:long_name = "hybrid level at midpoints (1000*(A+B))" ;
>>> lev:units = "level" ;
>>> lev:positive = "down" ;
>>> lev:standard_name =
>>> "atmosphere_hybrid_sigma_pressure_coordinate" ;
>>> lev:formula_terms = "a: hyam b: hybm p0: P0 ps: PS" ;
>>> double ilev(ilev) ;
>>> ilev:long_name = "hybrid level at interfaces
>>> (1000*(A+B))" ;
>>> ilev:units = "level" ;
>>> ilev:positive = "down" ;
>>> ilev:standard_name =
>>> "atmosphere_hybrid_sigma_pressure_coordinate" ;
>>> ilev:formula_terms = "a: hyai b: hybi p0: P0 ps: PS" ;
>>> double isccp_prs(isccp_prs) ;
>>> isccp_prs:long_name = "Mean ISCCP pressure" ;
>>> isccp_prs:units = "mb" ;
>>> isccp_prs:isccp_prs_bnds = 0., 180., 310., 440., 560.,
>>> 680., 800., 1000. ;
>>> double isccp_tau(isccp_tau) ;
>>> isccp_tau:long_name = "Mean ISCCP optical depth" ;
>>> isccp_tau:units = "unitless" ;
>>> isccp_tau:isccp_tau_bnds = 0., 0.3, 1.3, 3.6, 9.4, 23.,
>>> 60., 379. ;
>>> double isccp_prstau(isccp_prstau) ;
>>> isccp_prstau:long_name = "Mean pressure (mb).mean
>>> optical depth (unitless)/1000" ;
>>> isccp_prstau:units = "mixed" ;
>>> double time(time) ;
>>> time:long_name = "time" ;
>>> time:units = "days since 2005-01-01 12:00:00" ;
>>> time:calendar = "noleap" ;
>>> time:bounds = "time_bnds" ;
>>> double time_bnds(time, tbnd) ;
>>> time_bnds:long_name = "time interval endpoints" ;
>>> char date_written(time, chars) ;
>>> char time_written(time, chars) ;
>>> int ntrm ;
>>> ntrm:long_name = "spectral truncation parameter M" ;
>>> int ntrn ;
>>> ntrn:long_name = "spectral truncation parameter N" ;
>>> int ntrk ;
>>> ntrk:long_name = "spectral truncation parameter K" ;
>>> int ndbase ;
>>> ndbase:long_name = "base day" ;
>>> int nsbase ;
>>> nsbase:long_name = "seconds of base day" ;
>>> int nbdate ;
>>> nbdate:long_name = "base date (YYYYMMDD)" ;
>>> int nbsec ;
>>> nbsec:long_name = "seconds of base date" ;
>>> int mdt ;
>>> mdt:long_name = "timestep" ;
>>> mdt:units = "s" ;
>>> int nlon(lat) ;
>>> nlon:long_name = "number of longitudes" ;
>>> int wnummax(lat) ;
>>> wnummax:long_name = "cutoff Fourier wavenumber" ;
>>> double hyai(ilev) ;
>>> hyai:long_name = "hybrid A coefficient at layer
>>> interfaces" ;
>>> double hybi(ilev) ;
>>> hybi:long_name = "hybrid B coefficient at layer
>>> interfaces" ;
>>> double hyam(lev) ;
>>> hyam:long_name = "hybrid A coefficient at layer
>>> midpoints" ;
>>> double hybm(lev) ;
>>> hybm:long_name = "hybrid B coefficient at layer
>>> midpoints" ;
>>> double gw(lat) ;
>>> gw:long_name = "gauss weights" ;
>>> int ndcur(time) ;
>>> ndcur:long_name = "current day (from base day)" ;
>>> int nscur(time) ;
>>> nscur:long_name = "current seconds of current day" ;
>>> int date(time) ;
>>> date:long_name = "current date (YYYYMMDD)" ;
>>> double co2vmr(time) ;
>>> co2vmr:long_name = "co2 volume mixing ratio" ;
>>> double ch4vmr(time) ;
>>> ch4vmr:long_name = "ch4 volume mixing ratio" ;
>>> double n2ovmr(time) ;
>>> n2ovmr:long_name = "n2o volume mixing ratio" ;
>>> double f11vmr(time) ;
>>> f11vmr:long_name = "f11 volume mixing ratio" ;
>>> double f12vmr(time) ;
>>> f12vmr:long_name = "f12 volume mixing ratio" ;
>>> double sol_tsi(time) ;
>>> sol_tsi:long_name = "total solar irradiance" ;
>>> sol_tsi:units = "W/m2" ;
>>> int datesec(time) ;
>>> datesec:long_name = "current seconds of current date" ;
>>> int nsteph(time) ;
>>> nsteph:long_name = "current timestep" ;
>>> float OMEGA(time, lev, lat, lon) ;
>>> OMEGA:units = "Pa/s" ;
>>> OMEGA:long_name = "Vertical velocity (pressure)" ;
>>> float PBLH(time, lat, lon) ;
>>> PBLH:units = "m" ;
>>> PBLH:long_name = "PBL height" ;
>>> float PRECC(time, lat, lon) ;
>>> PRECC:units = "m/s" ;
>>> PRECC:long_name = "Convective precipitation rate (liq +
>>> ice)" ;
>>> float PRECL(time, lat, lon) ;
>>> PRECL:units = "m/s" ;
>>> PRECL:long_name = "Large-scale (stable) precipitation
>>> rate (liq + ice)" ;
>>> float PRECSH(time, lat, lon) ;
>>> PRECSH:units = "m/s" ;
>>> PRECSH:long_name = "Shallow Convection precipitation
>>> rate" ;
>>> float PS(time, lat, lon) ;
>>> PS:units = "Pa" ;
>>> PS:long_name = "Surface pressure" ;
>>> float Q(time, lev, lat, lon) ;
>>> Q:units = "kg/kg" ;
>>> Q:long_name = "Specific humidity" ;
>>> float T(time, lev, lat, lon) ;
>>> T:units = "K" ;
>>> T:long_name = "Temperature" ;
>>> float U(time, lev, lat, lon) ;
>>> U:units = "m/s" ;
>>> U:long_name = "Zonal wind" ;
>>> float V(time, lev, lat, lon) ;
>>> V:units = "m/s" ;
>>> V:long_name = "Meridional wind" ;
>>>
>>> // global attributes:
>>> :Conventions = "CF-1.0" ;
>>> :source = "CAM" ;
>>> :case = "twdLL05" ;
>>> :title = "atm case twdLL" ;
>>> :logname = "juliob" ;
>>> :host = "be1005en.ucar.ed" ;
>>> :Version = "$Name$" ;
>>> :revision_Id = "$Id$" ;
>>> :initial_file =
>>> "/fs/cgd/csm/inputdata/atm/cam/inic/fv/cami-mam3_0000-01-01_1.9x2.5_L30_c090306.nc"
>>>
>>> ;
>>> :topography_file =
>>> "/fs/cgd/csm/inputdata/atm/cam/topo/USGS-gtopo30_1.9x2.5_remap_c050602.nc"
>>> ;
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Received on Mon Dec 13 15:45:48 2010