National Weather Service Training Center

Answers to Review Questions

Quality Control Concepts

Question 1

The goals of a WFO quality control program should:

A. Ensure quality in what goes out to the user.
B. Ignore workload considerations.
C. Provide little feedback on quality to the local staff and management.
D. All of the above.

Workload is something that cannot be ignored when developing a quality control program. Typically the workload is high in comparison to the apparent tangible benefit. Similarly, if quality is to be improved, there needs to be good feedback to the data providers. Option A is a given and the correct answer.

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Question 2

Bad data rarely impact numerical models run by the National Center for Environmental Prediction.

A. True
B. False

The answer to this question depends upon how you define the word "rarely". The use of bad data in NCEP models is probably higher than realized. It only becomes apparent when a "bull's eye" or other strange pattern appears on model output.

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Question 3

Random errors are distributed more or less symmetrically about zero and do not depend upon the measured value.

A. True
B. False

This statement is true. On the other hand, systematic errors are distributed asymetrically about zero and tend to bias values in one director or another.

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Question 4

Examples of meteorological errors include:

A. Small-scale perturbations affecting an weather observation
B. Temperatures taken over asphalt
C. Misreading a thermometer
D. All of the above.

These examples and many more can be cited as typical meteorological errors. Can you think of any additions to this list?

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Question 5

Match the specific quality control method listed below to a typical situation where it might be used.

A. Meteograph of observational values: Temporal Consistency Check

B. Comparison of a WSR-88D rainfall estimate to cooperative observations: Cross-Check/Redundancy Check

C. 120oF temperatures in Lansing, Michigan: General Plausibility Check

D. Review of the temperature and dew point profile using the AWIPS skew-t: Vertical Consistency Check

E. 20BKN OVC65: Coding Error

F. Comparing winds at LaGuardia Airport, JFK International Airport, and Newark (NJ) Airport: Horizontal Spacial Consistency Check

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Question 6

Error logs allow you to:

A. Pass error information from shift to shift.
B. Easily spot inconsistencies in data.
C. Correct errors with minimal effort.
D. Show higher management you have an on-going QC program.

Passing information from shift to shift is very important. This is the correct answer. Spotting errors is never an easy task, but error logs can often make things easier to see. Similarly, correcting an error can sometimes be as easy as sending a corrected message, and sometimes near impossible to accomplish. Hopefully your quality control program consists of more than a nominal error log.

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Question 7

How can you adapt these general quality control concepts to your local operations?