Issue #297 has been updated by Jitsuko Hasegawa.
- Status changed from ET discussion to Future Edition
Attempts to validate the encoding of wave observations in BUFR have revealed that BUFR does not have adequate facilities for encoding elements which have a large range and limited relative precision. Examples of such elements include, amongst many others, water wave spectral energy densities, pressure in some vertical profiles, concentrations of some atmospheric constituents, and air density.
Dr Weiqing Qu, BoM, presented his document to seek a good solution on this issue.
Several possible solutions were presented, including
a) Use a scale and magnitude representation to allow the required precision for small values without having an excessively large data width
b) Use existing BUFR operators
c) Define a new "Delayed change of scale" operator
d) Encode the logarithm of the element's value instead of the value
e) Use a standard IEEE floating point format
f) Use a "floating point" format, with separate sign, exponent and significand sub-fields
Some comments based on experiences are expressed, which are: when the same issue was discussed, the proposed Table C operator (IEEE floating point) was not adopted, but it should be possible to create operators at least for some cases without change editions; there is in general a lack of compression algorism in BUFR; Météo-France needs some compressions in BUFR for conversion from their internal format to BUFR.
The meeting concluded this issue would be discussed when talking about BUFR edition 5.
DRC #297: Encoding elements with a large range and limited precision in BUFR
- Author: Jitsuko Hasegawa
- Status: Future Edition
- Priority: Normal
- Assignee: Jitsuko Hasegawa
- Category: BUFR/CREX common aspects
- Target version:
Document: IPET-DRMM-III Doc 3.2.5
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