Cecelia
I support 1) mostly for backward compatibility. I would also strongly
encourage but not demand that users change their base dates to after 1800
when it makes sense to do so.
And, I (again) want to make sure that LTMs and their time values are
addressed before any decisions are made as to negative times and using
base dates of 1-1-1 and the issue of what year to use for climatologies.
LTM dates are a problem when one needs to use a calendar based on real
dates.
Cathy
On 12/12/12 9:04 AM, Cecelia DeLuca - NOAA Affiliate wrote:
> Hi Steve, Jonathan and all,
>
> There are not that many options being discussed.
>
> With respect to the default calendar:
>
> 1 keep the Julian-Gregorian calendar as default (no change)
> 2 remove the Julian-Gregorian calendar as default, and have no default
> calendar (grid analogy)
> 3 replace the Julian-Gregorian calendar as default with the proleptic
> Gregorian calendar
> 4 replace the Julian-Gregorian calendar as default with a strict
> Gregorian calendar
>
> Maybe it makes sense for people to cite (or rank) their preference at
> this point?
>
> There were a couple other proposals, depending on which of above is
> selected:
> 5 create a strict Gregorian calendar (optional for 1, 2, 3 and needed
> for 4)
> 6 remove the Julian-Gregorian calendar (impossible for 1, optional for
> 2, 3, 4)
>
> Again, maybe worth it to see where people are after the round of
> discussion?
>
> Best,
> Cecelia
>
>
>
> On 12/10/2012 12:40 PM, Steve Hankin wrote:
>> Hi Jonathan,
>>
>> I'm not sure if my remarks below conflict with your proposed
>> resolution. But they do dispute the facts you assert, and these
>> waters are so muddy that agreeing on the facts seems an important
>> first step.
>>
>> On 12/10/2012 1:21 AM, Jonathan Gregory wrote:
>>> Dear Jon
>>>
>>>> Just to repeat a remark that Steve Hankin made whose implications have not been explored in this discussion: different countries adopted the Gregorian calendar at different times. (Greece didn't adopt it till 1923!) So what is considered a valid Gregorian date varies from country to country (and some of those countries don't even exist any more, or at least the boundaries have changed...)
>>>> 2. The non-proleptic Gregorian calendar is extremely problematic for historical observations as well as for models (astronomers use the Julian calendar consistently for this reason).
>>> Yes, that's right. Nonetheless I don't think we can abolish the real-world
>>> calendar, despite its ambiguities, because *_it's the one we really use!_*
>>
>> Are you sure this is true? Evidence seems to suggest that our
>> community has _no use for the mixed Gregorian/Julian calendar at
>> all_, except the need to resolve the backwards compatibility mess we
>> have created for ourselves.
>>
>> * In everyday life we use is the modern Gregorian calendar, and are
>> not concerned with historical calendar changes.
>> * In numerical climate modeling we use the proleptic Greogorian
>> calendar. (I'll wager you there is no serious paleo-modeling
>> done with an 11 day discontinuity in its time axis. )
>> * What do Renaissance historians use when discussing dates that are
>> rendered ambiguous by differing timings of the Julian/Gregorian
>> transition in different locations? Do any of us know? Does it
>> effect any use of CF that we are aware of?
>>
>>> As you say, we should be clearer about what the real-world calendar means, in
>>> cases where _users really want to use it._
>>
>> Who are these users? Where is the user who intersects with our
>> community and really wants to use the mixed Julian/Gregorian
>> calendar? The only potential user I can think of would be a
>> Renaissance historian looking at paleo climate model output. That
>> hypothetical person would already understand that manual calendar
>> translations were needed to make sense of precise dates at that time
>> of history (and would almost surely shrug off an 11 day timing
>> uncertainty in a paleo climate model outputs in any case).
>>
>> As Cecelia said, lets drive a stake through the heart of this madness
>> ... at least to the maximum degree we can given inescapable backwards
>> compatibility concerns.
>>
>> - Steve
>>
>>
>> _______________________________________________
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>
> --
> ===================================================================
> Cecelia DeLuca
> NESII/CIRES/NOAA Earth System Research Laboratory
> 325 Broadway, Boulder 80305-337
> Email: cecelia.deluca at noaa.gov
> Phone: 303-497-3604
>
>
> _______________________________________________
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> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
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