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07-07-2018, 13:15   #106
gozunda
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Originally Posted by Oneiric 3 View Post
I think it is becoming increasingly apparent that airport data, while extremely useful for the airports themselves, may not be all that representative of the greater region climatologically speaking. With Shannon Airport, for example, I guess the clue is in the name. The data is taken at this, or any other airport, which is always going to be influenced by large areas of concrete/tarmac etc, is just that, airport data.
Spot data is always problematic although my own weather station was reporting similar figures to Shannon despite being approx 60 km further inland and east of the met station there.

The recent claim that Scotland's hottest ever day at 32.8c on June 28th was debunked after it was found that a stationary vehicle with its engine running had been parked too close to the thermometer.

Last edited by gozunda; 07-07-2018 at 20:50.
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07-07-2018, 14:08   #107
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Wouldn't normally post in this forum but this thread has irritated me a little

(Next paragraph is the impression I'm getting from this thread so please take it as a little ).

Ah, people in the east trying to justify why the west is warmer than the east. It can't be that the weather is better during the warm spell - nope - it has to be that there's something wrong with the weather station.

Anyhow, despite that fact that a number of people told ye that other nearby locations were showing similar temperatures to Shannon airport ye plowed on until you made the theory fit the narrative.

I've checked my car sensor against a temperature sensor that's accurate to +/-0.02C and I know it read's ~+1C over actual air temperature. Take it that a car sensor is not a great solution and give it another +/-1C.

Last Tuesday evening, I arrived into Shannon and left the building at 9:00PM. Was reporting 25C at Shannon - car was reporting 26C fairly consistently most of the drive home once the sensor temperature had stabilised. Far from scientific but would lead me to believe strongly that if the Shannon station is overreading it's not doing it by much. Certainly not to the degree (pun intended) that at least some people here are trying to intimate.

If you doubt the temperature - maybe look at the Tii road stations nearby? From my memory of occasionally comparing, they usually broadly agree with Shannon sensor.

Maybe look up Observational Bias
Your paragraph that you referred to is completely wrong. Nothing at all to do with East v West. That's a very narrow-minded and ill-informed opinion.

Your following paragraphs are also nonsensical. You cannot claim that a car thermometer - with has a resolution of at best 0.5 degrees, located just in front of a radiator, a lot lower than the standard 1.25 m, over a hot road - can be used as a calibration tool for an actual weather station located kms away. At 9 pm on Tuesday it was 25.6 at Shannon, as the wind was east southeasterly (from off the carpark). By 10 pm it had fallen 4 degrees to 21.6 as the wind swung around to almost southerly (i.e. more in off the estuary). That's a 4-degree change in just 1 hour at the same location. You're saying that your moving car several kms away can be used as a comparison?

Last edited by Gaoth Laidir; 07-07-2018 at 16:18.
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07-07-2018, 16:01   #108
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Just took a snapshot of the current road weather data around the country. Look at the difference between the road surface and air temperatures. Up to >20-degree differences in some parts. The air temperature sensors on these stations are generally around 2 metres above road level, so for the 1.25-metre height of Shannon's Stevenson screen you can imagine the effect of a nearby hot surface would be greater, depending on windspeed. This is why you don't trust car sensors...or weather stations just 12 metres from large carparks.

Attached Images
File Type: png road temps.PNG (37.6 KB, 185 views)

Last edited by Gaoth Laidir; 07-07-2018 at 16:06.
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07-07-2018, 16:41   #109
 
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07-07-2018, 23:50   #111
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This is Met Éireann's temperature graph for Shannon on the 28th, the day it hit 32.0 °C. We can see a short sudden spike of around half of a degree to exactly 32.0 at around 16:15Z (17:15 local time), just around the time the wind direction veered subtly by 30 degrees, bringing it over more of the carpark. Before that it was around 31.5 (32 rounded).



METAR EINN 281700Z 04010KT 010V080 CAVOK 31/10 Q1024 NOSIG=
METAR EINN 281630Z 06010KT 030V100 CAVOK 31/10 Q1024 NOSIG=
METAR EINN 281600Z 08010KT 030V120 CAVOK 32/09 Q1024 NOSIG=
METAR EINN 281530Z 07007KT 020V120 CAVOK 32/09 Q1024 NOSIG=
METAR EINN 281500Z 05006KT 010V110 CAVOK 32/09 Q1024 NOSIG=
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File Type: jpg Shannon TUCSON Temp 32.jpg (101.2 KB, 482 views)
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08-07-2018, 00:14   #112
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Wasn't that Shannon 32C a revised temp? My question being is that a raw output graph from a sensor, or quality checked/human edited data ie. after the revision?
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08-07-2018, 00:20   #113
 
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Wasn't that Shannon 32C a revised temp? My question being is that a raw output graph from a sensor, or quality checked/human edited data ie. after the revision?
How is it revised? I remember the confusion. It's either 32 or not fairly straightforward? Amazing alright that it jumped from 31.5 to exactly 32 then back down to 31.5 within an hour I think?
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08-07-2018, 00:33   #114
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How is it revised? I remember the confusion. It's either 32 or not fairly straightforward? Amazing alright that it jumped from 31.5 to exactly 32 then back down to 31.5 within an hour I think?

I have no idea. I presume the initial reading was from a digital thermometer fed directly into their network. What quality control checks they have in place I have no idea, I presume at least two thermometers are in the stevenson's screen, but are they both digital? Are there two digital and one mercury for human reading?
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08-07-2018, 00:45   #115
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This is why you don't trust car sensors
Now Gaoth Laidir, there are several several several reasons why we don't trust car sensors, and to be honest the most prominent ones don't include being in a car park.

Also, in regards to your last post which have the metars, I don't see that 30 degrees wind shift that you are referencing? Am I terrible at maths or missing something?

I'm not disputing that Shannon's weather station, if in that location, is poorly located, however I am dusputing some of your points and would be very interested to know what effect the car park actually has on temperature readings. We all know the heat capacity of black tarmacadum is lower than that of a green field, however I've not once seen even rough figures on what effect, in figures, it has.
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08-07-2018, 01:48   #116
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Originally Posted by Rougies View Post
I have no idea. I presume the initial reading was from a digital thermometer fed directly into their network. What quality control checks they have in place I have no idea, I presume at least two thermometers are in the stevenson's screen, but are they both digital? Are there two digital and one mercury for human reading?
I remember at the time Gerry said on the TV (SixOne or the 18:55 bulletin) that the high was likely to be 31.something, but it needed to be confirmed. By 18Z they had it at 32.0, as that was the stated 12-hr max in that hour's synop report. Then they tweeted the chart confirming the 32.0. Not sure why Gerry was saying lower a little earlier. 32.0 occured around 16:15Z, so well before he went on air. It's as if that spike hadn't been there then but was there after.

There are two PT100 electronic sensors, one as backup. The 32.0 must be legit, however strange it looks.
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08-07-2018, 01:51   #117
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Originally Posted by JCX BXC View Post
Now Gaoth Laidir, there are several several several reasons why we don't trust car sensors, and to be honest the most prominent ones don't include being in a car park.

Also, in regards to your last post which have the metars, I don't see that 30 degrees wind shift that you are referencing? Am I terrible at maths or missing something?

I'm not disputing that Shannon's weather station, if in that location, is poorly located, however I am dusputing some of your points and would be very interested to know what effect the car park actually has on temperature readings. We all know the heat capacity of black tarmacadum is lower than that of a green field, however I've not once seen even rough figures on what effect, in figures, it has.
The 30 degrees is from 050 to 080 degrees. The spike occured around the 080 time.

Look at the snapshot of road temperatures I posted a few posts back. The road surface temperature was up to 20 degrees hotter than the air at 2 metres, so I don't see why you don't get how a carpark could have a similar surface temperature. You could walk on the grass in your bare feet but sure would feel the heat walking on a road at that temperature.
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08-07-2018, 08:48   #118
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I was at Ringmoylan pier in the Pallaskenry area of Co. Limerick directly across the estuary from Shannon at 3.30 pm. My car was reading 24to 25c. Shannon Airport reported 23c at 1500 and 24 at 1600.
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08-07-2018, 09:22   #119
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Some temp data from the Met Eireann archive for Adare Manor, the nearest climatological station to Shannon that I can find (N. Limerick) for a couple of the warmer days in the last decade.

Max at Shannon/Adare Manor

2009

June 1: 25.6 / 26.1
June 2: 26.9 / 27.1
June 3: 24.9 / 26.9


2013

July 18: 26.9 / 27.2
July 19: 29.5 / 29.9
July 20: 29.3 / 28.0

Surprisingly, Adare Manor, by and large, tended to record higher maxes overall during these peak hot days.


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09-07-2018, 09:44   #120
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The last few of my posts to this thread was comparing my temperature figure on the car in driving mode not when it was stationary for a while with a hot engine affecting the thermometer. Yesterday evening I was passing near Shannon shortly after 7 pm. It was 22c on the car. The Airport station reported 21c at 1900 and 2000. Therefore I am not buying in that the weather station more or less surrounded by car parks has a major effect on how it records the temperature at any given time.
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