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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