Re: netCDF time representation

• To: netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: Re: netCDF time representation
• From: knight@xxxxxxxxxx (Fred Knight)
• Date: Wed, 12 Feb 1992 10:43:55 -0500

Here are a few examples of data requiring more than 32 bits of precision and
the measurement time to reach the IEEE 64-bit double precision:

   Research Field               Required Precision              Time for 54bits
   --------------               ------------------              ---------------
1. Radio pulsar timing          0.1 microseconds over years     50 years  
2. Astronomical X-ray data      0.01 microseconds over years    5 years*
3. Planet Ephemerides           1 microseconds over decades     500 years
4. Laser/Atomic Spectroscopy    0.1 femtoseconds over msec      1 second*
5. Fusion                       1 nanoseconds over seconds      1 month
6. Neutrino detection           1 millisecond over decades      500,000 years#

* Already exceeded
# Unlikely to exceed (my opinion)

The point is that there needs to a hierarchy of time levels exceeding 2, as
as pack@xxxxxxxxxxxx as proposed.

I doubt I will respond to the next question (Does anybody know of any
datasets requiring ...?).

I am a new user of netCDF.  I was attracted to it because it had no inherent
properties dedicated to a particular discipline, like FITS, for example.
I hope the developers keep this discipline-free attribute ranked high as they
decide how to improve a useful system.

=Fred Knight   (INTERNET:knight@xxxxxxxxxx)