Transcript Unique Quality Control Issues

Unique Quality Control Issues
Derek S. Arndt
Oklahoma Climatological Survey
June 25, 2002
Automated QA Flags
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Decision-making algorithm compiles results of
automated QA tests
Final flag (“good”, “suspect”, “warning” or
“bad”) determined by logic
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The final flag is never final!
The Qualparm table represents the QA
Meteorologist’s latest and best assessment of
observational quality for the given time
Automated report arrives in the QA
Meteorologist’s inbox each morning.
Capturing Real Events With
Automated QA
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Automated QA software is invaluable as
a front-line detector
However, nothing beats the trained eye
and brain of a QA meteorologist
Sometimes, unique meteorological
events fail QA tests and good data is
suggested to be “bad”
Goodparms
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Goodparms reflect observations that are
known to be good, but have failed an
automated QA test
In the next generation of OK Mesonet
QA structure, Goodparm entries will
override automated QA tests that have
been “fooled” by Mother Nature
Noteworthy Goodparm Events
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The following examples of real
meteorological phenomena that were
initially “flagged” by automated QA
processes
Thanks to automated reporting, and a
vigilant QA Meteorologist, these “bad”
events turned out to be some of the
network’s gems!
Inversion Poking
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Extreme spatial anomalies occur
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Air temperature
Dew point temperature / relative humidity
Wind direction
Wind speed
Associated with shallow inversion and
stable surface layer
Inversion Poking
Norman, OK Sounding
25 Oct 2001
1200 UTC
Inversion Poking
OK Mesonet Sfc Plot
25 Oct 2001
1330 UTC
Inversion Poking
North Central Oklahoma
Elevation (meters)
Inversion Poking
26 Oct 1999
0600 UTC
Cold Air Pooling
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Extreme temperature anomalies
develop due to radiational cooling
Events tend to occur within a few hours
of sunset, suggesting in situ cooling
(versus cold air drainage)
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Radiationally cooled air is prevented from
mixing
Cold Air Pooling
26 Oct 1999
0600 UTC
Cold Air Pooling
East Central Oklahoma
Elevation (meters)
Cold Air Pooling
4 Nov 1999
1215 UTC
Mesohighs
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Typically occur concurrently with
convective line or cluster
May trigger spatially-oriented QA tests
May be a traveling QA phenomenon
Mesohighs
1 Jun 1999
0235 UTC
Mesohighs
1 Jun 1999
0235 UTC
Mesohighs
1 Jun 1999
0236 UTC
Mesolows
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Typically located off the trailing edge of
convective precipitation
May be a traveling QA phenomenon
Mesolows
25 May 2000
0700 UTC
Mesolows
25 May 2000
0730 UTC
Mesolows
25 May 2000
0800 UTC
Mesolows
25 May 2000
0659 UTC
Mesolows
25 May 2000
0730 UTC
Mesolows
25 May 2000
0801 UTC
Heatbursts
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Originate from air that has subsided
dry-adiabatically from mid-levels of
outwardly-innocuous thunderstorms
Downdrafts sometimes cause damaging
winds and substantial temperature rises
Heatbursts occur much more often in
Oklahoma than previously thought
Heatbursts
20 Sep 1998
1049 UTC
Heatbursts
20 Sep 1998
1148 UTC
Heatbursts
20 Sep 1998
1248 UTC
Heatbursts
Air Temperature
20 Sep 1998
1145 UTC
Heatbursts
Wind Gusts
20 Sep 1998
1145 UTC
Heatbursts
Mesonet Meteogram
20-21 Sep 1998
Winter Precipitation
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Automated QA is quite good at
detecting wind sensors that accumulate
ice and barometers that become sealed
from the atmosphere
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(P ~ T at constant V!)
Unique conditions that accompany
snowfall can sometimes lead to
erroneous flags
Winter Precipitation
Visible Imagery
7 Dec 1999
Winter Precipitation
Air Temperature
7 Dec 1999
1000 UTC
Land-Atmosphere-Vegetation
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Soil temperatures are sensitive to the
characteristics of the soil and vegetation
above them
Vegetation of surrounding land areas
can impact temperature and dew point
observations at a site
Land-Atmosphere-Vegetation
Land-Atmosphere-Vegetation
Sloshing and Wave Events
That’s It!
Here’s to “bad” data!
Best of luck to you and your network!
Derek Arndt
Oklahoma Climatological Survey
[email protected]