Unique Quality Control Issues Derek S. Arndt Oklahoma Climatological Survey June 25, 2002

Unique Quality Control Issues

Derek S. ArndtOklahoma Climatological

SurveyJune 25, 2002

Automated QA Flags Decision-making algorithm compiles

results of automated QA tests Final flag (“good”, “suspect”, “warning”

or “bad”) determined by logic 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 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 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 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 Extreme spatial anomalies occur

Air temperature Dew point temperature / relative

humidity Wind direction Wind speed

Associated with shallow inversion and stable surface layer

Inversion PokingNorman, OK Sounding

25 Oct 20011200 UTC

Inversion PokingOK Mesonet Sfc Plot

25 Oct 20011330 UTC

Inversion PokingNorth Central OklahomaElevation (meters)

Inversion Poking 26 Oct 19990600 UTC

Cold Air Pooling 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) Radiationally cooled air is prevented

from mixing

Cold Air Pooling 26 Oct 19990600 UTC

Cold Air Pooling East Central OklahomaElevation (meters)

Cold Air Pooling 4 Nov 19991215 UTC

Mesohighs Typically occur concurrently with

convective line or cluster May trigger spatially-oriented QA

tests May be a traveling QA

phenomenon

Mesohighs 1 Jun 19990235 UTC

Mesohighs 1 Jun 19990235 UTC

Mesohighs 1 Jun 19990236 UTC

Mesolows Typically located off the trailing

edge of convective precipitation May be a traveling QA

phenomenon

Mesolows 25 May 20000700 UTC

Mesolows 25 May 20000730 UTC

Mesolows 25 May 20000800 UTC

Mesolows 25 May 20000659 UTC

Mesolows 25 May 20000730 UTC

Mesolows 25 May 20000801 UTC

Heatbursts 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 19981049 UTC

Heatbursts 20 Sep 19981148 UTC

Heatbursts 20 Sep 19981248 UTC

HeatburstsAir Temperature

20 Sep 19981145 UTC

HeatburstsWind Gusts

20 Sep 19981145 UTC

Heatbursts Mesonet Meteogram20-21 Sep 1998

Winter Precipitation Automated QA is quite good at

detecting wind sensors that accumulate ice and barometers that become sealed from the atmosphere (P ~ T at constant V!)

Unique conditions that accompany snowfall can sometimes lead to erroneous flags

Winter Precipitation Visible Imagery7 Dec 1999

Winter PrecipitationAir Temperature

7 Dec 19991000 UTC

Land-Atmosphere-Vegetation 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 ArndtOklahoma Climatological Survey

darndt@ou.edu