This is a comment on proposal 1 by Beate Geyer and Ronny Petrik on 20 August for a new standard name surface_normalized_direct_downwelling_shortwave_flux_in_air. My response was delayed by trouble posting due to my changed email address.
In the solar energy community, this quantity, as described by Beate and Ronny, is almost universally referred to as "direct normal irradiance". Here "normal" means measured on a plane perpendicular (that is, normal) to the incoming solar beam. I note that the World Meteorological Organisation follows a different convention, naming the quantity measured on a normal plane "direct irradiance" and that measured on a horizontal plane "direct horizontal irradiance", but that convention is not followed in the renewable energy sector. Thus I suggest that the proposed name should be changed to surface_direct_normal_downwelling_shortwave_flux_in_air to better align with solar energy practice. However, there might be CF rules/conventions/precedents I am unaware of that make the normalized_direct form preferable.
Regards,
Ian Grant
Ian Grant | Research Scientist
Science To Services Program | Satellite Applications Team
Bureau of Meteorology
GPO Box 1289, Melbourne VIC 3001, AUSTRALIA
Level 9, 700 Collins Street, Docklands VIC 3008, AUSTRALIA
Tel: +61 3 9669 4080 | ian.grant at bom.gov.au
www.bom.gov.au
-----Original Message-----
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> On Behalf Of cf-metadata-request at cgd.ucar.edu
Sent: Saturday, 31 August 2019 3:10 AM
To: cf-metadata at cgd.ucar.edu
Subject: CF-metadata Digest, Vol 196, Issue 2
Send CF-metadata mailing list submissions to
cf-metadata at cgd.ucar.edu
To subscribe or unsubscribe via the World Wide Web, visit
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
or, via email, send a message with subject or body 'help' to
cf-metadata-request at cgd.ucar.edu
You can reach the person managing the list at
cf-metadata-owner at cgd.ucar.edu
When replying, please edit your Subject line so it is more specific than "Re: Contents of CF-metadata digest..."
Today's Topics:
1. New standard names for norm. direct radiation and atm. mass
content of rain and snow + comments on existing descriptions
(beate.geyer at hzg.de)
2. Re: New standard_name of quality_flag for corresponding
quality control variables (Kehoe, Kenneth E.)
----------------------------------------------------------------------
Message: 1
Date: Tue, 20 Aug 2019 09:08:59 +0200
From: beate.geyer at hzg.de
To: cf-metadata at cgd.ucar.edu
Subject: [CF-metadata] New standard names for norm. direct radiation
and atm. mass content of rain and snow + comments on existing
descriptions
Message-ID:
<OF5D396235.9078C54C-ONC125845C.002501BE-C125845C.00274681 at LocalDomain>
Content-Type: text/plain; charset="utf-8"
Dear CF-metadata group,
we have several proposals, which we send as a numbered list. Thanks for your help beforehands!!
1.
Basing on surface_direct_downwelling_shortwave_flux_in_air we want to apply for the new standard name surface_normalized_direct_downwelling_shortwave_flux_in_air for use in renewable energy tasks.
It is the surface_direct_downwelling_shortwave_flux_in_air on a plane, oriented perpendicular to the incoming beam.
New name: surface_normalized_direct_downwelling_shortwave_flux_in_air
Description: The surface called "surface" means the lower boundary of the atmosphere. ?Normalized_direct" radiation is radiation that has followed a direct path from the sun to a plane perpendicular to the direction of the sun (in contrast to the ?direct? radiation, which falls on a plane horizontal at the earth surface). Downwelling radiation is radiation from above. It does not mean "net downward". The sign convention is that "upwelling" is positive upwards and "downwelling" is positive downwards.
The term "shortwave" means shortwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics.
Unit: W m-2
<snip>
Best regards,
Beate Geyer and Ronny Petrik
Helmholtz-Zentrum Geesthacht
Zentrum f?r Material- und K?stenforschung GmbH Max-Planck-Stra?e 1 I 21502 Geesthacht I Deutschland/Germany
Gesch?ftsf?hrung/Board of Management: Prof. Dr. Wolfgang Kaysser, Silke Simon Vorsitzender des Aufsichtsrates/Chairman of the Supervisory Board: Ministerialdirigent Dr. Herbert Zeisel Amtsgericht L?beck HRB 285 GE (Register Court)
Internet:
http://www.hzg.de
<snip>
Received on Mon Sep 16 2019 - 21:57:39 BST
