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Hot week - guess the temperature competition

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12 minutes ago, Nick L said:

I'm sorry, but any site used in official readings should already be deemed fit for official use. It should not require extra checks just because it might have a record resting on it, standards and checks should already be stringent enough. If they're having to check THEIR OWN SITE to see if it's fit to be giving data, just because there's a record at stake, then frankly that's poor form for a globally renowned institution.

But, each and every time a new record is set, climate change deniers mount a series of spurious 'objections'. Whether the 'defect' is supposed to be caused by a/c units, jet engines, alien artefacts, or the wrong species of tree, the raison d'etre is the same...to obfuscate the findings of climate scientists...? 

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Posted (edited)
2 minutes ago, Ed Stone said:

But, each and every time a new record is set, climate change deniers mount a series of spurious 'objections'. Whether the 'defect' is supposed to be caused by a/c units, jet engines, alien artefacts, or the wrong species of tree, the raison d'etre is the same...to obfuscate the findings of climate scientists...? 

You never see cold records questioned funnily enough. 🙃

Edited by cheese

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2 minutes ago, johnholmes said:

Indeed they are, best you look at the Met web site that lists all their stations, full, part time etc.

I didn't know they had this many, why are people worrying about not having stations in certain areas, look at this - seems we have enough of them - how accurate though?

https://wow.metoffice.gov.uk/

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2 minutes ago, Ed Stone said:

But, each and every time a new record is set, climate change deniers mount a series of spurious 'objections'. Whether the 'defect' is supposed to be caused by a/c units, jet engines, alien artefacts, or the wrong species of tree, the raison d'etre is the same...to obfuscate the findings of climate scientists...? 

Climate change deniers also conveniently ignore global mean temperatures and instead focus on local cold anomalies (such as the recent "cool" spell across much of the US) despite the overall global anomaly being above average.

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Just now, feb1991blizzard said:

I didn't know they had this many, why are people worrying about not having stations in certain areas, look at this - seems we have enough of them - how accurate though?

https://wow.metoffice.gov.uk/

Why ask me, e mail Met and ask politely what the differences between sites, they will probably also give you details of siting limitations.

There are at least 2 or 3 folk on Net Wx who send their observations to UK Met as official stations. Perhaps try them.

I really do despair of how questioning some of you are but never actually ask the folk who are able to tell you. UK Met is the official custodian of weather data, whatever some posts in here seem to suggest.

I'll go so please no more questions to me please.

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Are they checking out the site or just the temperature sensor? Has that been mentioned at all?  If it's a manually read site, then verifying if its working accurately by taking comparative readings with another sensor makes some sense to me. It is a potential national record after all so its best to make sure everything is up to scratch. Automatic weather stations are flagged as suspect straight away if the data coming in shows unusual rises or decline.

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If one defines accurate as lowest possible temperature reading in a given area, then that site looks a bit less than ideal, but nobody could say it wasn't fairly representative of where millions of people live, the average back garden in southeast England must be smaller and more enclosed than that. I've seen a variety of "climate stations" that get data into publication after some time passes for collection and quality control and they are broadly similar to this one. They all tend to run a bit warmer than your "perfectly sited" location might run, and I know the range quite well from doing an extensive research project on it, without exposing instruments to badly flawed locations with nearby heat reflectors, you can still get a 2 to 3 C range in daytime temperatures and even larger on a clear night over snow cover. I have a hunch that they will let this reading pass. As to all-time records, was there not a reading back in 1868 that was over 100 F that nobody ever seems to mention any longer, but I recall reading about it in Lamb's work so it must have had some official sanction half a century ago. 

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9 minutes ago, feb1991blizzard said:

I didn't know they had this many, why are people worrying about not having stations in certain areas, look at this - seems we have enough of them - how accurate though?

https://wow.metoffice.gov.uk/

i had a look one station at histon recorded 41.4c yesterday?

Met Office WOW -.pdf

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This really is the last from me, all available on BBC news site

Image copyright Getty Images

Thursday was the UK's hottest July day on record, with temperatures reaching 38.1C (100.6F) in Cambridge.

But was it the UK's hottest day ever?

While the Met Office says we can be sure it's the second hottest, it won't be able to confirm what is apparently its highest reading until next week.

Provisional figures released on Friday revealed a peak of 38.7C at Cambridge University's Botanic Gardens. If verified, that squeaks past the UK all-time high of 38.5C, reached in 2003.

Why don't we know how hot it was?

Unlike the other weather station readings that report instantaneously, Cambridge University's Botanic Gardens only reports at the end of the day - that's why it took the Met Office until Friday to release the provisional figure.

The UK's record-breaking heat in maps

Why is Heathrow so hot?

Second hottest day on record leads to travel chaos

Alex Burkill, a meteorologist at the Met Office, explained any reading that challenges the all-time record should be carefully vetted.

He says each of the UK's weather observation stations is checked over every two years to make sure everything is still in good working order.

"Thermometers should be in shade and in ventilation," he said.

"The last time that the [Cambridge University's Botanic Gardens] site had this check was the end of 2017.

"Because of the sensitivity of this reading, because it's the highest temperature ever recorded in the UK, we want to double check."

How can they be sure?

The Met Office has already sent out an engineer to inspect the station and its equipment. "They'll go out, check that the site looks fine, and that there's nothing untoward there," he said.

Anything from an overgrown tree to a new building nearby could alter the readings.

In pictures: The UK's hottest July day on record

As well as checking the area, scientists will pore through all the readings from the day to check there wasn't a spike at the time of the hottest reading.

They would expect a gradual increase throughout the day, and any sudden change could indicate some temporary interference - like a car parked nearby.

So what are the chances?

Mr Burkill said the Met Office would be able to confirm the reading early next week but insisted he would be surprised if the reading did get discounted.

"Or another reading that hasn't come in yet might beat it," he said.

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Posted (edited)
26 minutes ago, Interitus said:

The Cambridge Botanic Gardens weather station is an official Met Office climate station which reports daily values on a monthly basis as opposed to synoptic stations reporting each day or indeed in real time. The station is valuable for climatic studies as data goes back to 1898, and also as such exact precise values are less important than the homogeneity and length of the data series.

However, from appearances the site certainly wouldn't be immune to criticism, despite the assertions that the MO know best and sly digs at 'amateurs'. If in any doubt read the article from the journal Weather by Stephen Burt and the late Philip Eden linked to earlier -

The August 2003 heatwave in the United Kingdom. Part 2 - The hottest sites https://rmets.onlinelibrary.wiley.com/doi/epdf/10.1256/wea.10.04B

Sites such as Heathrow, Northolt, Gravesend, Kew Gardens and Wisley all appear to be less than perfect at the time of their analyses. Meanwhile, the Brogdale/Faversham record was considered to be possibly an anomaly of 2 degrees,- but the site looks state of the art compared to the photos of the Cambridge one.

Good post, yes the longer stations may not have class 1 quality of observations. Old station quality can be limited by their original siting but are invaluable for long range climate studies provided they are homogenous. If it moved to a class 1 from a class 3 for example it wouldn't be homogenous (if you get what I mean).

I suppose one way to get around this would be to adjust the data for biases based on any of the highlighted WMO issues back to 1898 but I'm not sure what exactly these would be. Perhaps this is one of the ways they analyse the data? and hence need more time to confirm whether the record is valid? I think the station is fine but it would be useful if the Meto went through the station in more detail and the analysis it does though.

Edited by Quicksilver1989

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9 hours ago, Nick L said:

The Met Office really don't help themselves at times. 

Will be funny if that Cambridge 38.7c is legit. Especially as it's "impossible" for it to get that hot there...

Yeah yeah, okay. I was wrong :). I honestly thought it was impossible at the current time.

But I'm happy to be wrong 🙂

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32 minutes ago, Roger J Smith said:

If one defines accurate as lowest possible temperature reading in a given area, then that site looks a bit less than ideal, but nobody could say it wasn't fairly representative of where millions of people live, the average back garden in southeast England must be smaller and more enclosed than that. I've seen a variety of "climate stations" that get data into publication after some time passes for collection and quality control and they are broadly similar to this one. They all tend to run a bit warmer than your "perfectly sited" location might run, and I know the range quite well from doing an extensive research project on it, without exposing instruments to badly flawed locations with nearby heat reflectors, you can still get a 2 to 3 C range in daytime temperatures and even larger on a clear night over snow cover. I have a hunch that they will let this reading pass. As to all-time records, was there not a reading back in 1868 that was over 100 F that nobody ever seems to mention any longer, but I recall reading about it in Lamb's work so it must have had some official sanction half a century ago. 

The problem as I see it is the Stevenson screen, which is susceptible to inflating the temperature of the air inside it in conditions of light winds at the screen and in strong sunshine. This is a well known issue with all non-aspirated screens.

It isn't a problem at the 6 m/s wind speed reported at 10m by Cambridge airport on the 25th., but at 1.5 metres in an open area more like 2.5 m/s is likely; add in the wind break effect of the trees and bushes and you could be down to 40% of that at best i.e. 1 m/s. That's well into the low wind speed area where high insolation effects on Stevenson screens can produce maybe half a degree anomaly. Certainly 0.2°C or more.

But I suspect that the Met Office will be eager to get rid of the perennial thorny problem of Brogdale, the Burt/Eden analysis is far more persuasive than the Met Office press office's feeble response that doesn't even address the main points made. However, if as I expect they do ratify this 38.7, it'll just be a case of out of the frying pan into the fire - Cambridge University Botanical Gardens will be the new Brogdale, and for essentially the same reason: a huge wind break (with some bare earth to boot).

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Posted (edited)

Ultimately @Man With Beard is correct - if you continually discount the warmest station because you think it’s slightly dodgy or inaccurate then you’ll be left with nothing eventually. Where is the line drawn and just what stations are entirely unproblematic? If we want to discount Heathrow, Kew, Gravesend, Northolt, Wisley, Brogdale and god knows where else then what stations actually count? Where is the record actually held? Seems to me like certain individuals just want to discount various known hotspots because they often deliver results they simply don’t want to see.

I see no valid reason why the Met Office would want to accept stations that are not of high quality, and equally see no valid reason why anyone would place higher stock in the ramblings of random internet users over people who are actually educated on the matter. Certain people have been moaning about this for years, the same boring nonsense came up in 2015 and has predictably made a return now - maybe it’s time to just give up and move on. The aforementioned stations aren’t going anywhere and will rightfully continue to be counted in future records.

Edited by cheese

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Posted (edited)
47 minutes ago, cheese said:

Ultimately @Man With Beard is correct - if you continually discount the warmest station because you think it’s slightly dodgy or inaccurate then you’ll be left with nothing eventually. Where is the line drawn and just what stations are entirely unproblematic? If we want to discount Heathrow, Kew, Gravesend, Northolt, Wisley, Brogdale and god knows where else then what stations actually count? Where is the record actually held?.

Kew looks fine, and Cambridge NIAB too. So 38.1, in both cases.

I know the Met Office like to keep long-record stations running, and with good reason too. But there must come a point when errors in the true representative temperature for an area due to changes in the surroundings outweigh the benefits. That's when they should seek a new site in the same general area, run the two in  parallel for a period, then make the new site the primary record and perhaps close the original one. Wind breaks of one kind or another seem to be the main problem here, though not the only one.

Easier said than done I know  but they don't seem to be even trying, hence their repeated and IMO often weak justifications of old sites with known problems.

Edited by DaveL

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Posted (edited)

The station at the botanic gardens hasn’t changed for years. No doubt some people will say it’s not suitable because a botanic garden is man made and un-natural or something similar, just because for one time in god knows how many it’s top of the pile. It’s fine, and I see no reason why it’ll be rejected. The way some people scrutinise on here makes it sound as if every single met office recording station in the country is faulty and erroneous

Edited by mb018538

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Posted (edited)
11 hours ago, feb1991blizzard said:

I didn't know they had this many, why are people worrying about not having stations in certain areas, look at this - seems we have enough of them - how accurate though?

https://wow.metoffice.gov.uk/

Many of these are personal stations rather than official stations (unless you change the filters). My own AWS uploads to there, it's a bit like the Met Office version of Weather Underground.


The consistency with this station over the years doesn't look great.. (linking to where I saw a post on another forum rather than just copying the image) http://www.ukweatherworld.co.uk/forum/index.php?/topic/121929-temperature-watch-thursday-25th-july-2019-uk-all-time-record-falls-cambridge-botanical-gardens-387c/page__view__findpost__p__1089124 
As they say.. doesn't look good around 2008!

But what others say is true.. if we eliminate all stations for some possible reason how many will we have left? I guess nothing but grass for say 100m around a station often isn't representative of the landscape either.. 

If Stevenson screens over-read slightly in light winds, then in actual light wind weather they will over-read anyway rather than give the true air temperature? Just shows how hard getting true air temperature readings is especially without aspiration.

I guess all we can do is have a certain standard and say that's that.

Whether or not I think Cambridge Botanic Gardens should fit that standard on Thursday with the bare soil and shelter from trees to the SE.. I'm not sure.
On Wednesday the bare soil looks like it was downwind, but with shelter the air was possibly eddying/wafting around that area sometimes passing over the bare soil and then the Stevenson screen.. but I'm not an expert in how much affect this might have.

Edited by Evening thunder

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1 minute ago, Evening thunder said:

Many of these are personal stations rather than official stations (unless you change the filters). My own AWS uploads to there, it's a bit like the Met Office version of Weather Underground.


The consistency with this station over the years doesn't look great I have to say... (linking to where I saw a post on another forum rather than just copying the image) http://www.ukweatherworld.co.uk/forum/index.php?/topic/121929-temperature-watch-thursday-25th-july-2019-uk-all-time-record-falls-cambridge-botanical-gardens-387c/page__view__findpost__p__1089124 
As they say.. doesn't look good around 2008!

But what others say is true.. if we eliminate all stations for some possible reason how many will we have left? I guess nothing but grass for say 100m around a station often isn't representative of the landscape either.

If Stevenson screens over-read slightly in light winds, then in actual light wind weather they will over-read anyway rather than give the true air temperature? Just shows how hard getting true air temperature readings is especially without aspiration.

I guess all we can do is have a certain standard and say that's that.

Whether or not I think Cambridge Botanic Gardens should fit that standard on Thursday with the bare soil and shelter from trees to the SE.. I'm not sure.
On Wednesday the bare soil looks like it was downwind, but with shelter the air was possibly eddying/wafting around that area sometimes passing over the bare soil and then the Stevenson screen.. but I'm not an expert in how much affect this might have.

Yes, its not the positioning, and nothing to do with having a cold bias as Ed Stone would have you believe (really think you need to stop this because you are not doing any good to your cause), its more to do with the fact that official stations should be validated before they are allowed to be recorded, not ratified once a record is broken, OR if you want it the other way then just have the status quo but just let the record stand without having to ratify it, else its double standards, plus on these un-maned stations, who is there to calibrate the equipment, they are more sophisticated than calculators.

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1 minute ago, feb1991blizzard said:

Yes, its not the positioning, and nothing to do with having a cold bias as Ed Stone would have you believe (really think you need to stop this because you are not doing any good to your cause), its more to do with the fact that official stations should be validated before they are allowed to be recorded, not ratified once a record is broken, OR if you want it the other way then just have the status quo but just let the record stand without having to ratify it, else its double standards, plus on these un-maned stations, who is there to calibrate the equipment, they are more sophisticated than calculators.

Then why don't you ever question whichever station records the lowest temps, then? If you persist in questioning only warm record's validity, then it's you who has a 'cause'...You could, of course, question them all, regardless of whether they are warm or cold; but, that wouldn't fit the agenda, would it?

Me? I'll simply take whatever the MetO decides...:oldgood:

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2 minutes ago, Ed Stone said:

Then why don't you ever question whichever station records the lowest temps, then? If you persist in questioning only warm record's validity, then it's you who has a 'cause'...You could, of course, question them all, regardless of whether they are warm or cold; but, that wouldn't fit the agenda, would it?

Me? I'll simply take whatever the MetO decides...:oldgood:

We hardly get any record breaking cold these days so therefore temperatures don't have to get 'ratified' as they are not abnormal, i had only just come onto the forum when the cold in 09/10 hit. So you will just accept them as they stand when they are normal temps but when they are very high or very low then you agree they should have to be 'ratified' - they don't call you double standards for nothing do they.

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5 minutes ago, feb1991blizzard said:

We hardly get any record breaking cold these days so therefore temperatures don't have to get 'ratified' as they are not abnormal, i had only just come onto the forum when the cold in 09/10 hit. So you will just accept them as they stand when they are normal temps but when they are very high or very low then you agree they should have to be 'ratified' - they don't call you double standards for nothing do they.

No, you don't!:oldgrin:

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Posted (edited)

Fascinating discussion this, but I can't see there's any point having an official station unless you are going to believe what it tells you, so provided there is no evidence of a malfunction or something daft like an ice cream van parked next to it at the time, I expect the Cambridge University Botanic Gardens reading will stand and it will be the new record.

Edited by Mike Poole

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Just now, Mike Poole said:

Fascinating discussion this, but I can't see there's any point having an official station unless you are going to believe what it tells you, so provided there is no evidence of a malfunction or some thing daft like an ice cream van parked next to it at the time, I expect the Cambridge a University Botanic Garden reading will stand and it will be he new record.

Agreed, that's what i am saying although not being given the credit, it should stand if they have confidence in it, else are they going to then change / nullify the records for every other day in history that has recorded at that particular station.

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12 hours ago, cheeky_monkey said:

i had a look one station at histon recorded 41.4c yesterday?

Met Office WOW -.pdf 255.01 kB · 9 downloads

I'm sure that will be investigated too,either disregarded as being a faulty reading or considered as over the top but key in allowing the Botanical gardens reading to stand as the radius of these high readings seems to be key here.

Worth noting that a couple of model runs prior to Thursday did indeed plump for a 41c in that area.

Of note too would be the cloud distribution at 1500 on Thursday,it was not  a uniform layer of cloud,some areas in the Cambridge radius could of hung onto strong sunshine a while longer nudging that temperature up further.

Lastly on the debate as to what stations should cut mustard when temperature readings are considered,only Met office verified sites are allowed when records are considered,however painful that is for some folk to have to wait a few days in the instant social media age.

We would not have the 2003 Faversham record to beat now Had we only been reliant on 'instant' data as that is a manual site too and we were left waiting a few days before we heard of the 38.5c.

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13 hours ago, cheeky_monkey said:

i had a look one station at histon recorded 41.4c yesterday?

Met Office WOW -.pdf 255.01 kB · 14 downloads

It says in the description on the PDF you shared that the station over-reads in sunshine.

That station must just be a personal one that doesn't report to the MetO.

Personally I don't see the point in even having a station linked to a Raspberry Pi etc, let alone reporting to things like WOW/Wunderground, if it over-reads in sunshine. Each to their own I suppose.

I went to a lot of effort (not expensive but took a lot of time) to make a small, aspirated screen for my sensor to ensure it doesn't over-read. The result is my readings are generally in line with the two nearest official MetO stations - sometimes mine are slightly lower and sometimes slightly higher (rarely differing by more than 0.7C), giving me confidence it's pretty accurate.

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5 minutes ago, h2005__uk__ said:

Personally I don't see the point in even having a station linked to a Raspberry Pi etc

Why? It's fast becoming the cheapest and easiest way to get weather data online.

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