[wxqc] Comparing stations

Ted Lum gladstonefamily45.net at tedlum.com
Sat Oct 29 23:26:34 CDT 2011

Not flawed in that sense. It checks for stuck sensors. It checks for 
bounds; temperature must be between -60 and +130 for example. It checks 
for Temporal Consistency; temperature can't vary by more than 35 F/hour 
for example. It does an Internal Consistency check; Dew Point 
Temperature can't exceed Air Temperature for example. And it does the 
Spatial Consistency check but we don't know what station(s) it uses when.

Most of all MADIS does NOT throw out any data at all. Worst it ever does 
is flag it with the checks it failed.

On 10/29/2011 10:25 PM, Paul Grace wrote:
> Right.  I think it's not very good at determining what is "flawed" 
> when looking at data that has no close neighbors.  It exhibits a 
> tendency to throw out the very data that it most needs to fill in its 
> holes.
> *From:*wxqc-bounces at lists.gladstonefamily.net 
> [mailto:wxqc-bounces at lists.gladstonefamily.net] *On Behalf Of *Ted Lum
> *Sent:* Saturday, October 29, 2011 19:13
> *To:* Discussion of weather data quality issues
> *Subject:* Re: [wxqc] Comparing stations
> Well, we don't really know what MADIS includes so we can't say if it 
> does that or not, but it does take out flawed readings. Someone at 
> NOAA ESRL/GSD might be able to say how the algorithm works; I've never 
> seen it as anything but a black box.
> On 10/29/2011 7:34 PM, Paul Grace wrote:
> I would guess that data should be accepted into the model, **unless** 
> it has a nearby data (hundreds of feet, not hundreds of miles) with 
> which it does not agree, or exhibits flaws such as stuck, zero, over 
> limit, sensors, etc.
> *From:*wxqc-bounces at lists.gladstonefamily.net 
> <mailto:wxqc-bounces at lists.gladstonefamily.net> 
> [mailto:wxqc-bounces at lists.gladstonefamily.net] *On Behalf Of *Ted Lum
> *Sent:* Saturday, October 29, 2011 15:32
> *To:* Discussion of weather data quality issues
> *Subject:* Re: [wxqc] Comparing stations
> AFAIK Philip takes the nearest 10 or so. MADIS has its own way of 
> doing things. I'd put it back on you and ask what would you like it to 
> do? Nothing can really invent stations and data where there isn't any, 
> nor can it manufacture a particular type of data. So there is no other 
> data near you, and no other data that has the same profile as you. 
> What exactly is it that you want?
> On 10/29/2011 4:33 PM, John M. Markle wrote:
>   Not sure what going on here and as always when I ask something on 
> wxforums I get ingored so I really  don't expect an answer here either.
>  Why are station that are 150 miles to 500 miles from me listed on my 
> summa ry page for comparsion. This is totally useless to me and I ame 
> sure it is also would be useless to anyone else also. Another thing I 
> notice some of these
> stations are under Continetal influces where I am under maritime 
> influences. Seem to be one would want to be compared to station in one 
> own enviroment. On this list the first station  listed is 150 miles 
> from me and the last one is 504 miles. Just 140 miles shy of Seattle, 
> Washington.  Other thing I notice is that they are all PWS stations. 
> Too me this is the poorest choice to use for comparison as most PWS 
> owner  just throw their station up and walk away. As long as it seems 
> to be close it is good enough for them.
>  Here is the link. http://weather.gladstonefamily.net/site/D1453
>  Like I said I don't expect an answer but thought I try any ways.
> John

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