[wxqc] Data questions

[Philip Gladstone]

saf wrote:

> Last Question:  Is there a chart to show the correlation from headings 
> to data in the Daily Quality Reports?  I have a good idea of what it is 
> trying to tell us but two lines of headings and two lines of data seem 
> subject to interpretation errors?
> sample:
>  
>  DATE     UTC      SITE  *   ALT    * POT TEMP *  DEW PNT *    DD    
> *    FF   
>                            *   (MB)   *  (DEG F) *  (DEG F) *   (DEG)  
> *   (KNT) 
> 04-MAY-2006 Errs    CW4759 *   0/96   *   0/96   *   2/96   *   0/96   
> *   0/96  
> 04-MAY-2006 Smry    CW4759 
> *0.24(0.81)*0.41(3.13)*-3.2(2.39)*7.96(100.)*   1(1.89)
>  
> First line..........Errs
>  
> Date - no problem, easy to understand
> UTC - Will show UTC time for errors when listed in detail, no question 
> (Yep, I've had errors show up too!)
> Site - no problem
> ALT - Altimeter shows zero errors of 96 comparisons
> POT TEMP - Temp shows zero errors of 96 comparisons (ok, I'm new, what 
> is POT Temp?)
> DEW  PNT - Dew Point show 2 errors of 96 comparisons
> DD - Wind Direction? shows zero errors of 96 comparisons
> FF - Don't know what this is...
>  
> Second line...........Smry
>  
> (MB) - Millibars? expected .24 (observed .81) assuming this is the 
> difference between what the analysis expected and what it observed? How 
> is it summarized?  Average error over 24 hours?
> (DEG F) - Temp? - expected .41 (observed 3.13) analysis expected a 
> difference of .41 but saw 3.13?
> (DEG F) - Temp? Dew Point? - -3.12/2.39 says my readings are high?
> (DEG)  - Wind Direction 7.96/100 - I have no idea what this means
> (KNT) - Wind speed in knots - 1/1.89, again, no idea

POT TEMP is potential temperature. This is a notional temperature that 
would be experienced at sea level. It makes doing the analysis easier.

FF is windspeed in knots.

The Smry line contains     mean ( std dev )   for that column. Things 
get a bit easier to read if you switch to the HTML form of the email.

Anyway, for temperature, it says, the mean error was 0.41 degrees with a 
standard deviation of 3.13 degrees.

**HOWEVER** I would take these messages with a pinch of salt, and just 
go and look at the summary page for your site. This allows you to see 
averages over longer periods of time, and also breaks the temperature 
down by day and night. For your site, this seems to show that you might 
have a solar heating problem -- you read (on average) 6 degrees warm 
during the day and 2 degrees cool during the night.

The temperatures shown on your page are *actual* temperatures -- they 
have been back converted from potential temperatures.

Hope this helps.

Philip
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