[wxqc] QC Chart Help

[Philip Gladstone]

> Steve Gunn wrote:
> 
>> I posted, but received no help so I will try again.
>> Where can I get a good explaination, in laymans terms,
>> how best to use the QC Charts?
>> I am particularily interested in the longer time
>> periods as I am new and just received my 1st chart for
>> the longer period that looks totally different from
>> the short term charts.
>> Thanks, Steve

The long term charts are designed to show the performance of the sensor 
versus the analysis over a longer period of time. This chart style kicks 
in at 13 weeks.

For the barometer chart, the little circle indicates the average error 
over the week, while the bar indicates one standard deviation. An ideal 
chart would be one in which the circles were on the zero line and the 
bars were short. In practice it doesn't work out this way!

The idea is that if you recalibrate your sensor, or resite your 
temperature sensor, or change the radiation shield, then, after a few 
weeks, you should be able to see a qualitative difference.

The temperature chart is somewhat more complex as it shows the average 
daytime error and the average nighttime error as well -- these are the 
yellow dot (think 'sun') and black dot (think 'dark'). Ideally, these 
averages should be close to each other.

In my case (C0003), they are not lined up nicely as there appears to be 
cool air settling down overnight into my area, and I am often 10 degrees 
cooler than the analysis.

Does this help?

Philip
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