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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