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04-02-2019, 14:10   #2986
Oneiric 3
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It is generally seen as good practice not to locate an official station in a 'frost hollow'.

Try as I might, I just can't take min data from D.A seriously, and most certainly not from a climatological perspective. If anything, minima there often deviates more from very nearby station data, and God knows there is plenty in the region, than Shannon's maxima does during hot weather from other stations in the greater region (Athenry, Gurteen, Moorpark etc) And as I showed last Summer, max temps during very hot weather often came in higher in nearby Adare Manor (SW of Shannon), than Shannon itself, and which would be in more open location than the airport.

It would seem that while Shannon's data is always up for debate, Dublin Aps is seen as sacrosanct. I don't subscribe to such selectivity. Having said that, D.A's mins are very probably 'correct' for that one particular spot, but I question its anomalous min figures as being 'representative' for the greater region, especially when other nearby data shows this not to be the case.


Edit: Wind direction at the time Dublin Apt was reporting a -5.0c figure:




While light, it was still straight in off the sea (of which it is only a hop, skip and jump away), while at the same time, Casement Aerodrome, which I believe would be more sheltered from the moderating effects of such a wind direction, was reporting just -1.1c at the time and Johnstown Castle, which would be located in a roughly similar distance from the sea (open to correction) than D.A, was reporting just 0.6c. Stations well inland at the time in the north Midlands and the North, were reporting temps of between -1.0c and -4.0c at the time, which would make more sense.

Last edited by Oneiric 3; 04-02-2019 at 14:47.
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04-02-2019, 14:12   #2987
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In Sligo we got one snow day and one snowy Saturday morning.

Snowy Saturday mornings are great. Cant remember the last one but because its a stress free day I was able to have great fun with the kids that will remain long in the memory.

We were all snow angels and snow was drier than Wednesdays so we werent soaked. Then we were lifting big blocks of ice and trying to file them on top of each other but my hands got too numb in the end...i should invest in gloves.

A faint hope of another episode next weekend but wont believe until Kermit sets up a thread. Every time he has we have got snow. (maybe set one up weekly!!)

P.S. My neighbours think im an awful child coz I get so excited at snow.



Last year my neighbours apparently made a snowman... they are all aged over 60!
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04-02-2019, 14:14   #2988
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Lovely sunny day and been outside gazing at the last few confetti sprinklings of snow atop the mountains... Fare thee well, snowfest! Do come back!
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04-02-2019, 23:37   #2989
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Originally Posted by Oneiric 3 View Post
It is generally seen as good practice not to locate an official station in a 'frost hollow'.

Try as I might, I just can't take min data from D.A seriously, and most certainly not from a climatological perspective. If anything, minima there often deviates more from very nearby station data, and God knows there is plenty in the region, than Shannon's maxima does during hot weather from other stations in the greater region (Athenry, Gurteen, Moorpark etc) And as I showed last Summer, max temps during very hot weather often came in higher in nearby Adare Manor (SW of Shannon), than Shannon itself, and which would be in more open location than the airport.

It would seem that while Shannon's data is always up for debate, Dublin Aps is seen as sacrosanct. I don't subscribe to such selectivity. Having said that, D.A's mins are very probably 'correct' for that one particular spot, but I question its anomalous min figures as being 'representative' for the greater region, especially when other nearby data shows this not to be the case.


Edit: Wind direction at the time Dublin Apt was reporting a -5.0c figure:




While light, it was still straight in off the sea (of which it is only a hop, skip and jump away), while at the same time, Casement Aerodrome, which I believe would be more sheltered from the moderating effects of such a wind direction, was reporting just -1.1c at the time and Johnstown Castle, which would be located in a roughly similar distance from the sea (open to correction) than D.A, was reporting just 0.6c. Stations well inland at the time in the north Midlands and the North, were reporting temps of between -1.0c and -4.0c at the time, which would make more sense.
Sorry, not this Dublin v The Rest of the Country shíte again.

There is nothing wrong with DUB's readings. As I've said before, it's probably the best sited station in the country. It's the only truly rural enclosure, on flat open ground, without trees, with the nearest building being half a kilometre away. Being from the general area and knowing it intimately, to me it has always at least seemed colder as I was growing up. I note car temperature dropping a few degrees as I head up the Ashbourne road off the M50. It all relatively flat, rural landscape with little in the way of large trees, forested areas, etc.).

Dublin Airport's enclosure is 11-12 km from the nearest sea. Johnstown Castle's is actually just 4 km (to its NE, 11 km to its south). Wind there was NE that night.

Casement's enclosure is 16 km and a whole city from the sea and just 25 metres from a building to its west, 60 metres from the apron and hangars to its north and east. The wind at Casement was stronger and coming from the northeast (from the city) at the time of the coldest temperatures there (a couple of hours later than you showed).

Phoenix Park.. well, let's not even talk about that. It's just 15 metres from a large building to its southeast and 30 metres from a whole heap of others to its northeast. That while being totally enclosed by mature trees 50 metres to the west. It's so poorly located they didn't bother putting in an anemometer (by their own admission).

Dunsany's enclosure is 26 km from Dublin Airport's, so not in the same area. While is it relatively open too it does have a large cluster of buildings 150 metres to its northeast.

At the time you showed, Oak Park was at -3.7 °C, only just over a degree warmer than Dublin Airport. Mullingar had already gotten down to -4.8 °C at 9 pm before the cloud piled in. How do you explain that, given its more built-up location? At 9 pm Dublin Airport was only -0.8 °C.

I've been keeping a daily watch on Dublin's minima over the past several years and have absolutely no concerns over the data. The station is a very accurate representation of a large area of north Co. Dublin. I don't know why anything mentioning Dublin becomes almost part of some conspiracy theory by those from the west. Listen to the UKMO forecasts and you'll hear them always say "these are city temperatures; rural locations will be several degrees colder". Well, they're right.
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05-02-2019, 05:01   #2990
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Originally Posted by Gaoth Laidir View Post
Sorry, not this Dublin v The Rest of the Country shíte again
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Originally Posted by Gaoth Laidir;109337098I[B
don't know why anything mentioning Dublin becomes almost part of some conspiracy theory by those from the west[/B].
Before I address your typically well made points. I am more intrigued for now at how you framed your post in answer to mine, and how you came to these conclusions from my post? I mentioned my scepticism in D.A's anomalous min readings, which, as you know, is not the first time I have done this, and I stated my reasons why. So forgive me if I find these above comments of yours just the tiniest bit perplexing.
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05-02-2019, 07:16   #2991
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Originally Posted by Oneiric 3 View Post
Before I address your typically well made points. I am more intrigued for now at how you framed your post in answer to mine, and how you came to these conclusions from my post? I mentioned my scepticism in D.A's anomalous min readings, which, as you know, is not the first time I have done this, and I stated my reasons why. So forgive me if I find these above comments of yours just the tiniest bit perplexing.
It was this...

Quote:
It would seem that while Shannon's data is always up for debate, Dublin Aps is seen as sacrosanct. I don't subscribe to such selectivity. 
If I took you up wrong then apologies. It seemed to be along the same lines as one or two other posters, but it now seems that it's not what you meant.
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05-02-2019, 19:08   #2992
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If I took you up wrong then apologies.
Obviously a crossed wire, and you have no need to apologise to me.

I take on board all of your points, but I am still not fully convinced. Somebody mentioned 'frost hollow'. If indeed D. A is located within one, then 1. its readings would not representative of even that smaller, north Dublin area. If every other station in the midlands and north were located within known frost hollows, then it stands to reason that at the time of the map posted above, and given the general synoptic pattern at the time, that their temperatures would have read even lower than that of the Airport.

As I have said, I don't doubt the reading itself, but more its representative value. It deviates too much away from other nearby local readings, of which the closest was the -3.9c min (I think) on the same night at P Park.

For what is worth, here is the 'total column water' chart (based on 6hr forecast from 18z analysis) for around the time of the contested reading.



I use these charts (perhaps wrongly) to judge how 'wet' an airmass would be, and going from this, it looks as if the Dub region would have a lower reading compared to all other regions bar the far NE, so perhaps this might have something to do with that odd reading in the region? I honestly wouldn't have clue.
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05-02-2019, 22:20   #2993
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Originally Posted by Oneiric 3 View Post
Obviously a crossed wire, and you have no need to apologise to me.

I take on board all of your points, but I am still not fully convinced. Somebody mentioned 'frost hollow'. If indeed D. A is located within one, then 1. its readings would not representative of even that smaller, north Dublin area. If every other station in the midlands and north were located within known frost hollows, then it stands to reason that at the time of the map posted above, and given the general synoptic pattern at the time, that their temperatures would have read even lower than that of the Airport.

As I have said, I don't doubt the reading itself, but more its representative value. It deviates too much away from other nearby local readings, of which the closest was the -3.9c min (I think) on the same night at P Park.

For what is worth, here is the 'total column water' chart (based on 6hr forecast from 18z analysis) for around the time of the contested reading.



I use these charts (perhaps wrongly) to judge how 'wet' an airmass would be, and going from this, it looks as if the Dub region would have a lower reading compared to all other regions bar the far NE, so perhaps this might have something to do with that odd reading in the region? I honestly wouldn't have clue.
It's not located in a frost hollow. It's pretty flat ground all around. As I said, Mullingar had already gotten down to near -5 by just 9 pm, so it's not restricted to just the D.A. area.

On cold mornings I see a similar phenomenon as I drive from Celbridge to Casement. Driving a few kms through the very flat, open rural area from Celbridge to Hazlehatch and across to Newcastle the temperature is at its lowest and many times the frost is hardest here. Then suddenly it starts to rise at Newcastle as the elevation rises ever so slightly. By Casement the temperature will have risen by 3-4 degrees, all in the space of about 2 kms. The total rise in elevation between Celbridge and Casement is only around 30 metres. That's another reason why Casement sometimes reads higher than other areas. The ground slopes slightly away southwards from the station enclosure, which was aided by the light northeasterly the other night. Which area is correct? Both are. The colder area extends for a large area of east Kildare, across Lyons Estate to Ardclough and towards Clane. I would say if a station were located there it would read similar to D.A. Casement's area extends several km towards Tallaght and the city.

Have a look at the D.A. station on Google maps and see if you can spot any reason why it's in a bad spot. My guess is you'll agree it looks legit.

https://maps.app.goo.gl/Njeyk

By the way, the station enclosure at Johnstown Castle is the same distance from the sea as the D.A. enclosure is from the Terminal building (4 km)! The enclosure is at the very furthest (western) end of the airfield.

Last edited by Gaoth Laidir; 05-02-2019 at 22:29.
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05-02-2019, 22:31   #2994
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But if you search within the parameters of the airport using google maps. You can see that the airport fire service are following the Google car around for security.

https://www.google.com/maps/@53.4214...6!9m2!1b1!2i39
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05-02-2019, 22:52   #2995
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But if you search within the parameters of the airport using google maps. You can see that the airport fire service are following the Google car around for security.

https://www.google.com/maps/@53.4214...6!9m2!1b1!2i39
Airside, everyone is escorted by a credentialed member of staff. No exceptions unless you're a contractor that will be there for some time in which case you go through the vetting process.
Had to escort journalists around the place (as a side duty to pushing trolleys) years ago.
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