[nws-changes] 121102 rounding algorithm for hourly02 Fwd: ADMIN NOTICE NOUS41 KWBC

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 121102 rounding algorithm for hourly02 Fwd: ADMIN NOTICE NOUS41 KWBC
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Fri, 02 Nov 2012 14:52:08 -0600

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263
NOUS41 KWBC 021229
PNSWSH

Technical Implementation Notice 11-54
National Weather Service Headquarters Washington DC
830 AM EDT Fri Nov 2 2011

To:       Subscribers
          -Family of Services
          -NOAA Weather Wire Service
          -NOAAPORT
          -Emergency Managers Weather Information Network
          Other NWS Partners, Users and Employees

From:     Jay Lawrimore
          Chief, Climate Analysis Branch
          National Climatic Data Center

SUBJECT:  Rounding Algorithm Revision for the Hourly02 and
Daily01 Products Effective December 1, 2012

Effective Tuesday, December 1, 2012, at approximately 1500
Coordinated Universal Time (UTC), The National Climatic Data
Center will change the rounding algorithm used for the hourly02
(CRNH02) and daily01 (CRND01) products. These revisions will
affect some of the reported negative values for stations of the
U.S. Climate Reference Network (USCRN) and the U.S. Historical
Climatology Network-Modernization (USHCN-M).

Prior to September 2012, USCRN used symmetric half-up (away from
zero) rounding for processing and publishing data; however, to
align with the World Meteorological Organizations requirement to
use asymmetric half-up rounding in important meteorological
summaries and the recommendations of the National Data
Stewardship Team (NDST), USCRN has switched to using asymmetric
half-up rounding for internal data processing. To finalize the
transition to asymmetric half-up rounding, USCRNs data product
software will also switch to using the new rounding algorithm.

Users of the hourly02 or daily01 products should expect to see
some of the previously reported negative values change by 0.1 in
the positive direction (towards zero). This change of rounding
algorithm will not affect the file formats of the two products.
Prior versions of both products will remain available through the
snapshot zip files that are produced weekly.

More details on the rounding practices recommended by the
National Data Stewardship Team can be found at

http://www1.ncdc.noaa.gov/pub/data/uscrn/documentation/program/ND
ST_Rounding_Advice.pdf

If you have questions or feedback, please contact:

  Scott Embler
  National Climatic Data Center
  151 Patton Ave
  Asheville, NC  28803
  828-350-2027
  Scott.Embler@xxxxxxxx

NWS Technical Implementation Notices are online at:

  http://www.weather.gov/os/notif.htm

$$