[ncl-talk] Calendar attribute for time_to_newtime !!! Developer Attention !!!

[Mary Haley]

Hi Alan,

When you say "this function" are you still referring to the
"time_to_newtime" function?

I took a look at this code, and it is indeed copying the "calendar"
attribute. But, it *does* make use of this attribute via the previous calls
to cd_calendar and cd_inv_calendar, which do recognize this attribute.  I
believe the "time_to_newtime" code is just making sure that the calendar
attribute is reattached to the return variable, if it existed on the input
variable.

--Mary


On Mon, Oct 6, 2014 at 12:07 PM, Alan Brammer <abrammer at albany.edu> wrote:

> What version of ncl are you using? I just tested a similar few lines of
> code in 6.1.1 and 6.2.0 and they both copied the calendar attribute as
> expected. Also have you tried cd_convert() seems to do the same thing?
>
> However in these tests and looking around I have a strong suspicion there
> is a significant bug in this function.  In that the code copies the
> calendar attribute but does not actually make use of it and thus returns
> the wrong answer disguised as the correct one.
>
>
> Attached is my edited code.  load this below a load "....contibuted.ncl"
> line if you have one and this version of the code will replace the stock
> version.  A developer will hopefully weigh in with more insight in this.
>
>
> Good luck,
>
> Alan
>
>
>
>
>
> On Fri, Oct 3, 2014 at 10:08 PM, Lam Hoang <lamhpvn at gmail.com> wrote:
>
>> Dear NCL supporting team,
>> I want to convert the time units from a CMIP5 model to make them unique.
>> I try to use time_to_newtime function but unfortunately after convert the
>> time units, the calendar attribute changes to "gregorian" as well.
>> What should I do if I want to keep the calendar attribute as the original
>> time variable?
>>
>> Regards,
>> Lam
>>
>>
>> f =
>> addfile("./oldtime_psl_day_NorESM1-M_historicalExt_r3i1p1_20060101-20121231.nc","r")
>> temp = f->psl
>> t = f->time
>>
>> printVarSummary(t)
>>
>> *** Variable: t
>>
>> *** Type: double
>>
>> *** Total Size: 20440 bytes
>>
>> ***             2555 values
>>
>> *** Number of Dimensions: 1
>>
>> *** Dimensions and sizes: [time | 2555]
>>
>> *** Coordinates:
>>
>> ***             time: [ 0.5..2554.5]
>>
>> *** Number Of Attributes: 6
>>
>> ***   bounds : time_bnds
>>
>> ***   units : days since 2006-01-01 00:00:00
>>
>> ***   calendar : noleap
>>
>> ***   axis : T
>>
>> ***   long_name : time
>>
>> ***   standard_name : time
>>
>> t = time_to_newtime(t, "days since 1850-01-01 00:00:00")
>>
>> printVarSummary(t)
>>
>> *** Variable: t
>>
>> *** Type: double
>>
>> *** Total Size: 20440 bytes
>>
>> ***             2555 values
>>
>> *** Number of Dimensions: 1
>>
>> *** Dimensions and sizes: [time | 2555]
>>
>> *** Coordinates:
>>
>> ***             time: [56978.5..59534.5]
>>
>> *** Number Of Attributes: 6
>>
>> ***   calendar : gregorian
>>
>> ***   units : days since 1850-01-01 00:00:00
>>
>> ***   bounds : time_bnds
>>
>> ***   axis : T
>>
>> ***   long_name : time
>>
>> ***   standard_name : time
>>
>>
>> --
>> Hoang Phuc Lam
>> Viet Nam National Center of Hydro-Meteorology Forecasting
>> National Hydro-Meteorological Services of Vietnam
>> Mob: +84 12 1616 5258
>> Tel:   +844 38247002
>> Fax:  +844 38254278
>>
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>>
>
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