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Shannon Airport synoptic weather station siting

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    #62
    Ultimate Seduction
    Closed Accounts Posts: 4,464 ✭✭✭Ultimate Seduction


    Someone posted the guidelines for the position of a weather station off the Met website recently, can it be posted here again?


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    #63
    Rougies
    Registered Users Posts: 2,674 ✭✭✭Rougies


    Here's some guidelines from the WMO, see chapter 1.3.3 (siting and exposure).
    https://www.weather.gov/media/epz/mesonet/CWOP-WMO8.pdf

    Here's an interesting chapter:
    Meteorological observing stations are designed so
    that representative measurements (or observations)
    can be taken according to the type of
    station involved. Thus, a station in the synoptic
    network should make observations to meet
    synoptic-scale requirements, whereas an aviation
    meteorological observing station should make
    observations that describe the conditions specific
    to the local (aerodrome) site. Where stations are
    used for several purposes, for example, aviation,
    synoptic and climatological purposes, the most
    stringent requirement will dictate the precise
    location of an observing site and its associated
    sensors.     A detailed study on siting and exposure
    is published in WMO (1993a).
    So basically the Shannon site should be sited as a synoptic station. There are a few things about the shannon site that could be called into question using these guidelines.
    The site should be well away from trees,
    buildings, walls or other obstructions.

    How far is well away? Does a carpark full of cars count as another obstruction? I would say yes.
    (g)
    If in the instrument enclosure surroundings,
    maybe at some distance, objects like trees or
    buildings obstruct the horizon significantly,
    alternative viewpoints should be selected for
    observations of sunshine or radiation;

    (h)
    The position used for observing cloud and
    visibility should be as open as possible and
    command the widest possible view of the
    sky and the surrounding country;


    These are also questionable.


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    #64
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Thank for the new photos, Sully. On closer inspection I hold my hand up about my comment on the non-standard Stevenson Screen on a concrete slab (foreground, right). This is not, in fact, a Stevenson Screen at all, but looks more like some sort of an electronics housing. The Stevenson Screen is the far side in the photo, is a standard design and is over grass. It is, however, only 12 metres from the nearest part of the carpark (to its northeast) and 18 metres from the southeast part).

    Also visible are the two rain gauges (but above ground level).

    The overall site is still not suitable and is prone to reporting high.

    20180705_170701.jpg


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    #65
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Regarding the position of the anemometer, there are allegedly two on the site (page 7), one south of the Tower (I can't find it) and another adjacent to Taxiway C, near the north central part of the airfield (marked in red below). You can just make it out in the distance in this Streetmap view and this Bing aerial shot.

    Airport Diagram

    455052.PNG


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    #66
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Using Bing, I measured the total area of the station enclosure to be 1020 m².
    The total area of the whole carpark extending from the north right around to the south of this enclosure has an area of over 22,000 m².
    This area is just 12-18 metres from the Stevenson screen.
    The longest fetch of tarmac is 220 metres from a southeasterly direction. So in a southeasterly breeze we could expect to get some of the worst anomalies, but even northeast will do (and has done) it too.

    455054.PNG


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    #67
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,819 Mod ✭✭✭✭Meteorite58


    Just wondering is that an ultrasonic anemometer ? Something like this https://shop.profec-ventus.com/product_info.php?language=de&info=p14_ultrasonic-anemometer-thies---1d.html

    DMtQnKo.jpg


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    #68
    Rougies
    Registered Users Posts: 2,674 ✭✭✭Rougies


    Meteorite58 wrote: »
    Just wondering is that an ultrasonic anemometer ? Something like this https://shop.profec-ventus.com/product_info.php?language=de&info=p14_ultrasonic-anemometer-thies---1d.html


    That was my first thought as well, but initially I dismissed it because I'd never seen an ultrasonic anemometer with only two "sensor arms" before, they usually have 3 or 4. But seems like two armed ones do exist after all.


    I also thought that pole only looks about 5m high, and it needs to be 10m. The fence right beside it looks to be about 2m high max, maybe Sully can confirm?

    There's another one at the opposite side of the site visible in the very first pic Sully posted yesterday. Maybe they are for wireless comms.


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    #69
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,819 Mod ✭✭✭✭Meteorite58


    Yeah the pole looks a bit short all right.


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    #70
    Oneiric 3
    Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Rougies wrote: »


    I also thought that pole only looks about 5m high, and it needs to be 10m. The fence right beside it looks to be about 2m high max.

    Perhaps it is 'ultrasonicing' some sort of receptive beam up another 5m?

    Going by those great pics posted by Sully, the car park seems to be higher than the weather station area. Since heat rises, maybe this helps to offset any major heating effect it otherwise would have?

    New Moon



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    #71
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Oneiric 3 wrote: »
    Perhaps it is 'ultrasonicing' some sort of receptive beam up another 5m?

    Going by those great pics posted by Sully, the car park seems to be higher than the weather station area. Since heat rises, maybe this helps to offset any major heating effect it otherwise would have?

    It's only a few cms higher at best, not enough to make any difference.


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    #72
    Oneiric 3
    Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    The logic does not follow that a professional met service would take readings from a station located in an area that does not fall within the 'guidelines'. Perhaps the thermometer is calibrated in such a way as to offset any potential extra heating that the nearby environment would have in that particular spot? But then, this in itself would have an effect on readings on more sunless days and also the time of day and night.

    New Moon



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    #73
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Oneiric 3 wrote: »
    The logic does not follow that a professional met service would take readings from a station located in an area that does not fall within the 'guidelines'. Perhaps the thermometer is calibrated in such a way as to offset any potential extra heating that the nearby environment would have in that particular spot? But then, this in itself would have an effect on readings on more sunless days and also the time of day and night.

    It would be both crazy and impossible to try to offset any warm bias with any accuracy. As you say, the biggest effect is on sunny days, so what happens on the cloudy ones? This is the very reason there are guidelines in the first place. The longterm Shannon climatic temperature trend is now contaminated and hence unreliable due to the relocation to such an unsuitable location. Half a degree here or there makes a huge difference, as as been argued ad nauseum in the other thread.


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    #74
    Oneiric 3
    Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Curious how Met Eireann did not respond to Arkrasia's query either.

    Just looking at those aerial shots of Oak Park's station. That seems to be a huge amount of dried out, cut grass in the nearby field. Since green grass itself is 'cooled' somewhat in sunny weather by constant evaporation, the drier looking grass in that field, which is of a considerable size, must have some bearing on the readings at the station also, especially if the wind direction is coming from there.

    New Moon



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    #75
    Rougies
    Registered Users Posts: 2,674 ✭✭✭Rougies


    Oneiric 3 wrote: »
    Curious how Met Eireann did not respond to Arkrasia's query either.

    Just looking at those aerial shots of Oak Park's station. That seems to be a huge amount of dried out, cut grass in the nearby field. Since green grass itself is 'cooled' somewhat in sunny weather by constant evaporation, the drier looking grass in that field, which is of a considerable size, must have some bearing on the readings at the station also, especially if the wind direction is coming from there.


    Probably, but at least that's representative of the larger area in general as there would be many similar fields around the Carlow station taking up a considerable percentage of the land area. That's not the case with tarmac carparks in Shannon.


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    #76
    Oneiric 3
    Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Rougies wrote: »
    Probably, but at least that's representative of the larger area in general as there would be many similar fields around the Carlow station taking up a considerable percentage of the land area. That's not the case with tarmac carparks in Shannon.


    Even out the countryside, temps can vary over very short distances though. Carlow is quite hilly I believe? (not sure, as I never graced the county with my presence) but if so, then Oak Park's reading my not be all that representative of the county as a whole.

    New Moon



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    #77
    Akrasia
    Registered Users Posts: 22,235 ✭✭✭✭Akrasia


    No reply to the first email so I have just popped off another mail to met.eireann@met.ie
    Dear Sir/Madam

    Over the course of the past number of weeks, some of the highest temperatures in Ireland appear to have been recorded at Shannon Airport. Questions were raised about the suitability of the site for the synoptic weather station at Shannon Airport.

    The very active weather community at Boards.ie, who I’m sure you’re aware of, it has tens of thousands of daily views during weather events, tried to track down the siting details of the weather station but we noticed that the coordinate details on both Met Eireann’s own site, and location details on the GHCN and other official climate monitoring services were also inaccurate.

    Eventually we got someone to take photographs of the site we had suspected to be the location for the weather station and we were dismayed at the apparently poor standard of site that we saw

    The details of this are documented on this thread at https://www.boards.ie/vbulletin/showthread.php?t=2057887821

    It would be great if someone from your organisation could come reply to this email to explain when the station was moved from it’s original location, and how it meets the siting guidelines from the WMO and other climatological services, and if the record high temperatures recorded in the past number of days are reliable given the change in location and the proximity of these sensors to a large and busy car park.

    Even better, if someone could pop onto the thread itself and talk directly to us we would greatly appreciate it.

    Best regards...

    If anyone with a big weather related following on twitter could send them a question, they might be more likely to respond.


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    #78
    Rougies
    Registered Users Posts: 2,674 ✭✭✭Rougies


    Oneiric 3 wrote: »
    Even out the countryside, temps can vary over very short distances though. Carlow is quite hilly I believe? (not sure, as I never graced the county with my presence) but if so, then Oak Park's reading my not be all that representative of the county as a whole.


    Not sure about Carlow being hilly, it looks like mostly flat farmland on satellite



    https://www.google.ie/maps/place/Carlow,+Co.+Carlow/@52.7101408,-7.06815,84757m/data=!3m1!1e3!4m5!3m4!1s0x485d5a126b7eb365:0x400c7a72e2a7660!8m2!3d52.7232217!4d-6.8108295


    But what I meant was that at least the Carlow station is more representative of the general area as in a few square kilometers around it, I didn't mean the whole county. I don't think any of us here are qualified meteorologists or climatologists but we can all agree that the Shannon station could be moved a few hundred meters to a location that would be more representative of the few square kilometers around the airport. It could come back to the previous debate over what is actually representative, the local micro climate that people feel vs. stringent weather station criteria that are unrepresentative of that, but I don't think that's relevant here because the Shannon site location is an anomaly compared to the rest of the Met Eireann sites.


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    #79
    Oneiric 3
    Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Rougies wrote: »
    Not sure about Carlow being hilly, it looks like mostly flat farmland on satellite



    https://www.google.ie/maps/place/Carlow,+Co.+Carlow/@52.7101408,-7.06815,84757m/data=!3m1!1e3!4m5!3m4!1s0x485d5a126b7eb365:0x400c7a72e2a7660!8m2!3d52.7232217!4d-6.8108295


    But what I meant was that at least the Carlow station is more representative of the general area as in a few square kilometers around it, I didn't mean the whole county. I don't think any of us here are qualified meteorologists or climatologists but we can all agree that the Shannon station could be moved a few hundred meters to a location that would be more representative of the few square kilometers around the airport. It could come back to the previous debate over what is actually representative, the local micro climate that people feel vs. stringent weather station criteria that are unrepresentative of that, but I don't think that's relevant here because the Shannon site location is an anomaly compared to the rest of the Met Eireann sites.

    My general point is that with so much modification to grasslands around there, that will more likely have an effect of some sort on 'natural' temp readings at the station, as it is a 'man made' influence. Come to think of it, isn't the required 'short grass' that is recommended a weather station to be set up on a manmade influence in itself? Grass is not short by nature.

    Yes, I am a pedantic fecker. :p

    New Moon



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    #80
    Rougies
    Registered Users Posts: 2,674 ✭✭✭Rougies


    Oneiric 3 wrote: »
    My general point is that with so much modification to grasslands around there, that will more likely have an effect of some sort on 'natural' temp readings at the station, as it is a 'man made' influence. Come to think of it, isn't the required 'short grass' that is recommended a weather station to be set up on a manmade influence in itself? Grass is not short by nature.

    Yes, I am a pedantic fecker. :p

    You'll love this then, Development of Siting Criteria and Metadata Standards - WMO :D

    https://www.google.ie/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwj-pOrWjoncAhXSY8AKHTplDNoQFgg0MAE&url=https%3A%2F%2Fwww.wmo.int%2Fpages%2Fprog%2Fwww%2FOSY%2FMeetings%2FET-AWS4-2006%2FDoc%25204.3(2).doc&usg=AOvVaw3iV5solbBwCYkblyceX8w4

    It's mostly talking about providing additional information along with readings.

    One key part to read is "ANNEX 1.D STATION EXPOSURE DESCRIPTION".

    It contains the line "In practice, an ideal site with perfect exposure is seldom available", which is fair enough in the case of most stations, but Shannon is more like "In practice, it's grand"


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    #81
    Oneiric 3
    Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    I just find some of the critiria oddly contradictory.

    For example

    "The surface of the observing area must be left in its natural state (grass should be kept down to 20 cm).

    "It should be sodded, but wherever the normal climate and soil do not -permit a sod cover to be maintained, the ground cover should have, as far as possible, natural cover common to the area. Weeds should be removed and grass in and around the enclosure should be frequently mown to keep it uniformly short"

    Also, when observers take temp readings, isn't a certain level of enhanced exposure on the thermometer occuring while the readings are taking place? What if the observer touches the thermo, or breathes on it? Or what about the glass (or whatever material they use) used on the thermo itself, does this retain or lose heat more rapidly than the surrounding ambient air, thus having an influence on the actual measurement?

    New Moon



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    #82
    Rougies
    Registered Users Posts: 2,674 ✭✭✭Rougies


    Oneiric 3 wrote: »
    I just find some of the critiria oddly contradictory.

    For example

    "The surface of the observing area must be left in its natural state (grass should be kept down to 20 cm).

    "It should be sodded, but wherever the normal climate and soil do not -permit a sod cover to be maintained, the ground cover should have, as far as possible, natural cover common to the area. Weeds should be removed and grass in and around the enclosure should be frequently mown to keep it uniformly short"

    Also, when observers take temp readings, isn't a certain level of enhanced exposure on the thermometer occuring while the readings are taking place? What if the observer touches the thermo, or breathes on it? Or what about the glass (or whatever material they use) used on the thermo itself, does this retain or lose heat more rapidly than the surrounding ambient air, thus having an influence on the actual measurement?


    Of the most interesting things about meteorology for me is that other than the measurement instruments themselves it's quite an inexact science. We should genetically engineer mosquitoes to fly in a perfectly uniform global grid pattern with nano weather stations implanted in their asses.


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    #83
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Oneiric 3 wrote: »
    I just find some of the critiria oddly contradictory.

    For example

    "The surface of the observing area must be left in its natural state (grass should be kept down to 20 cm).

    "It should be sodded, but wherever the normal climate and soil do not -permit a sod cover to be maintained, the ground cover should have, as far as possible, natural cover common to the area. Weeds should be removed and grass in and around the enclosure should be frequently mown to keep it uniformly short"

    Also, when observers take temp readings, isn't a certain level of enhanced exposure on the thermometer occuring while the readings are taking place? What if the observer touches the thermo, or breathes on it? Or what about the glass (or whatever material they use) used on the thermo itself, does this retain or lose heat more rapidly than the surrounding ambient air, thus having an influence on the actual measurement?

    The opening in a Stevenson screen is to the north to prevent solar radiation entering when opened. Observers are trained to not touch the sensor parts, and the glass used is standard glass that responds naturally. In any case, I believe Met Éireann's probes are PT100 thermocouples that don't need to be read manually. I think the whole process is automatic.

    Regarding ground cover, places like Dubai will have no grass, which is fine, as bare ground is the natural state. In the Oak Park case, it is largely surrounded by natural vegetation which won't heat up like an asphalted carpark with metal vehicles to reflect and possible focus solar radiation onto the site. In and around the site is mown grass, not the barley crop.


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    #84
    Akrasia
    Registered Users Posts: 22,235 ✭✭✭✭Akrasia


    Gaoth Laidir wrote: »
    The opening in a Stevenson screen is to the north to prevent solar radiation entering when opened. Observers are trained to not touch the sensor parts, and the glass used is standard glass that responds naturally. In any case, I believe Met Éireann's probes are PT100 thermocouples that don't need to be read manually. I think the whole process is automatic.

    Regarding ground cover, places like Dubai will have no grass, which is fine, as bare ground is the natural state. In the Oak Park case, it is largely surrounded by natural vegetation which won't heat up like an asphalted carpark with metal vehicles to reflect and possible focus solar radiation onto the site. In and around the site is mown grass, not the barley crop.

    A barley field is no more natural than a car park though. All measurements should be taken from inside native woodland or on lakes.


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    #85
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Akrasia wrote: »
    A barley field is no more natural than a car park though. All measurements should be taken from inside native woodland or on lakes.

    Even a barley field won't heat up the same way a tarmaced area will.

    Take a look at the photos of the stations on this page https://www.met.ie/climate/weather-observing-stations. Especially look at Mace Heat, Mt. Dillon and Newport. Mace Head is on rocky ground, Mt. Dillon on peaty ground, and Newport is more grassy. All natural surfaces, but slightly different. Each station, however, is a good representation of that area.

    Shannon, on the other hand, is greatly affected by one large manmade feature that is not representative of the greater area. I'm sure the current site is there so as to be as close as possible to the original site, however why wasn't the original site further inland, say between the runways?

    On another note, Casement also suffers from the proximity of the large apron and hangars to its north and northeast. I've noted large temperature variations on cold, frosty mornings, with a sharp rise when the wind swings around the the north from south or southwest. The Air Corp and Garda choppers take off nearby, as does the Casa, which departs before 8 am every morning. There is ample ground further to the south that could have been used...in hindsight.

    https://binged.it/2MTCLoa

    455089.PNG


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    #86
    Ultimate Seduction
    Closed Accounts Posts: 4,464 ✭✭✭Ultimate Seduction


    I'd love to see the station in Motherwell, how far away was the single car from the station that they had to cancel the record


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    #87
    Donegal Storm
    Registered Users Posts: 2,023 ✭✭✭Donegal Storm


    Thought I'd check out some UK stations for comparison, Heathrow broke the record for the hottest July temp in the UK a few years ago while Northolt also frequently records very high temps.

    This is Heathrows location, even worse than Shannons imo

    Screen_Shot_2018_07_06_at_09_48_55.png


    Northolt only slightly better, right beside the A40 and a huge area of tarmac about 50 metres to the north.

    Screen_Shot_2018_07_06_at_09_49_04.png


    St James Park is another that records high temps, at least its surrounded by grass but again hardly a natural environment!

    Screen_Shot_2018_07_06_at_09_56_40.png


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    #88
    lovelyhurler
    Registered Users Posts: 305 ✭✭lovelyhurler


    Interesting thread.
    I've been lurking in and out over the past few days, and just a few things that I've noticed.

    The site at Shannon was there before the car park.
    The local airport authority is the 'landlord', and can effectively do whatever it feels is necessary to improve facilities/generate revenue etc.
    This generally is at the expense of 'tennents' i.e. car rental companies; airlines; concession stands; local Met station.
    If ME need to move the station, I'm sure that there's a whole rig-ma-roll to go through and knowing how government bodies work, this probably takes an inordinate amout of time.

    I would imagine in the case of Casement, that the Dept of Defence have a huge say in when and where equipment goes.
    (I also know for a fact that the site is moving there anyway - just don't know when).

    Just my 2 cents worth. ;)


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    #89
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    This is the photo of Shannon Airport from the new met.ie site. Doesn't show the station at all, just the radar.

    Shannon-Radar-1024x768.jpg


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    #90
    Akrasia
    Registered Users Posts: 22,235 ✭✭✭✭Akrasia


    In terms of climate change monitoring, the sites themselves need not be perfect, but they need to be consistent.

    Most climate databases have smoothing processes and algorithms that cross check stations within a larger region and exclude stations that have anomalous highs or lows, or where there is a big unexplained deviation compared to the normal readings at that site

    If the Shannon station was originally sited on a green field location and then one winter/summer the car park was built, then there would probably have been a jump in readings for this station around the time of that change

    In terms of climatological data, the Shannon site is exposed to a heat island to the southeast, east and the northeast. But the large majority of Shannon's wind come from directions unaffected by the heat islands (about 70% https://www.windfinder.com/windstatistics/shannon) This doesn't include the times when there isn't any measurable wind

    Also, the heating effect of a car park or built up areas are only really significant on warm sunny days. When it's overcast or raining, the temperature of the carpark won't be significantly high enough to cause a measurably higher reading to a thermometer located 30 metres away inside a stevenson screen.

    I'd say that the climatological data from Shannon in general is probably fine for tracking decadal trends. It's not great for long term trends as there would have been a change when the development of the car park occurred (unless they adjust for that somehow). It's maximum/minimum record temperatures are suspect, but most of the measurements are unaffected due to wind direction, or time of the year where there wouldn't be significant changes to surface temperature over concrete/tarmac compared with grass.

    When climate anomalies are measured, it's the average figures that matter, not the extremes on the rare occasions when there is a month of sunshine on the west coast of Ireland. The most important thing is consistency, All equipment siting, and sensor and screen types have their own biases and limitations, so it's important that the equipment is maintained and monitored consistently over a long period of time. Even poor siting can yield good results if the measurements properly calibrated, are collected in a consistent way, and any changes to equipment or observation practises are accounted for.


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    #91
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Akrasia wrote: »
    In terms of climate change monitoring, the sites themselves need not be perfect, but they need to be consistent.

    Most climate databases have smoothing processes and algorithms that cross check stations within a larger region and exclude stations that have anomalous highs or lows, or where there is a big unexplained deviation compared to the normal readings at that site

    If the Shannon station was originally sited on a green field location and then one winter/summer the car park was built, then there would probably have been a jump in readings for this station around the time of that change

    In terms of climatological data, the Shannon site is exposed to a heat island to the southeast, east and the northeast. But the large majority of Shannon's wind come from directions unaffected by the heat islands (about 70% https://www.windfinder.com/windstatistics/shannon) This doesn't include the times when there isn't any measurable wind

    Also, the heating effect of a car park or built up areas are only really significant on warm sunny days. When it's overcast or raining, the temperature of the carpark won't be significantly high enough to cause a measurably higher reading to a thermometer located 30 metres away inside a stevenson screen.

    I'd say that the climatological data from Shannon in general is probably fine for tracking decadal trends. It's not great for long term trends as there would have been a change when the development of the car park occurred (unless they adjust for that somehow). It's maximum/minimum record temperatures are suspect, but most of the measurements are unaffected due to wind direction, or time of the year where there wouldn't be significant changes to surface temperature over concrete/tarmac compared with grass.

    When climate anomalies are measured, it's the average figures that matter, not the extremes on the rare occasions when there is a month of sunshine on the west coast of Ireland. The most important thing is consistency, All equipment siting, and sensor and screen types have their own biases and limitations, so it's important that the equipment is maintained and monitored consistently over a long period of time. Even poor siting can yield good results if the measurements properly calibrated, are collected in a consistent way, and any changes to equipment or observation practises are accounted for.

    Yes, the prevailing wind is SW, and for that it's fine. However, one climatic metric is number of days above 25 °C (CSU). Obviously an upward bias at some point in time will cause the longterm trend to rise too. The higher the daily max, the higher the following morning minimum could be, hence the higher the daily average.

    I would also add that it's not only on hot, easterly days that the problem is. On cold, frosty mornings we could see an effect due to the proximity of multiple vehicles. OK, it's a carpark so not all engines will be running at the same time, but it is possible that the low sun angle could reflect off these vehicles, causing frost on the grass to melt that bit quicker, rising morning temperatures, and hence daily averages, that bit more too.

    The WMO guidelines are there to prevent this particular problem, so it's strange that the decision was taken to move the station to beside a massive anomalous source of heat and radiation.


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