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: [email protected]
Phone: 303-497-3604
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