[wxqc] Humidity/Dew Point

[Rich Mulvey]

James & Julie McNelly wrote:
>
> What are some things that I can do to get my humidity readings closer 
> to the analysis readings? I have put my sensor in a homemade Stevenson 
> Screen and have it located about 60” above the ground. My temperatures 
> have stabilized since adding the screen, but I cannot get the correct 
> humidity readings. I am suspecting that it may just be my equipment. I 
> have a LaCrosse ws-2308. I am going to aspirate my screen with a solar 
> fan as soon as I get it. Any ideas?
>

The goal isn't to match the analysis readings - the goal is to have 
accurate data. :-)

You may very well be in a micro-climate in which the humidity readings 
are correct. In my case, for example, I'm in a narrow stream valley, and 
my dewpoint readings are *always* flagged as bad. Nonetheless, they're 
also totally accurate, when I measure independently using a precision 
thermometer and sling psychrometer.

There seems to be a huge amount of concern on the wx list about making 
sure that stations agree with the analysis - and that's simply the wrong 
approach. The analysis is, and will always be, an approximation of 
reality that doesn't necessarily derive correct results for all 
stations. There are just too many potential variables that must be 
accomodated. The analysis is useful to spot trends and flag potential 
problems - but just because it indicates that your readings are bad 
doesn't mean that they're bad. To determine that, you need independent 
confirmation of the values you generate.

- Rich