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Tópico em 'Instrumentos Meteorológicos' iniciado por Amending 23 Mai 2011 às 16:51.
Observatório Nacional de Atenas (National Observatory of Athens)
In the last years we have read a lot in Eurpean weather forums about the National Observatory of Athens weather station.
I have decided to collect some informations about it, by asking the National Observatory of Athens.
Sorry for writing in English, but google translate performs too much poorly to use it in this context.
Oggetto: NOA Thiseio weather station
Hello, I got your email address from http://www.eurometeo.gr/contact.htm
I am an Italian weather enthusiast. I read every day the weather data from Athens, especially those from Thissio. Despite of several searches, I have not
been able to retrieve many informations about the NOA weather station from the internet. All what I know is here: http://www.meteo.noa.gr/ENG/iersd_station-images.htm, a webpage that does not show the details I am interested to know. I would like to know how the NOA temperature station in Thissio is installed;
for instance if it is on a terrace or roof or at the ground instead, how far from buildings, with which kind of shelter (passive vs fan aspirated), and if
any picture of the instruments for the measurement of temperature exist and may be supplied.
Oggetto: Re: [Fwd: NOA Thiseio weather station]
Dear Mr. ********
The National Observatory of Athens has three stations measuring temperature in the area of Thissio. One is a class A manned meteo station, the other two are automated meteo stations.
Two of the stations are very closely located and serve different purposes.
The manned station (operating since 1858) is located on top of the Nymphs hill (107m) close to the historical building of NOA. It consists of a 1m3 Stevenson screen equipped with both classic liquid-in-glass thermometers and bimetalic thermograph as well as Pt100 sensors for continuous logging. Manual observations are performed at 6:00, 12:00 and 18:00 UTC. The data collected are reported on a monthly basis to the WMO (through HNMS) and published in the form of Monthly Climatological Buletins every year. If one asks for temperature data from NOA, this is what he/she'll get.
One of the automated stations is located on top of the Pnyx hill (107m again) surrounded by trees (with heights slightly lower than the station) (coordinates in GoogleEarth 37.9720009N 23.718624E). It operates since the late 80s and was originally mentioned to provide local meteorological information relevant to the operation of the actinometric instruments. The data collected by this station are those presented in our web page.
It has a Qualimetrics fan aspirated radiation shield (this looks like two metallic pipes - probably some aluminum alloy- one inside the other and the thermohygrometer lies in the middle of the inner pipe (I can send you a photo in a few days if you wish) and the thermohygrometer is a Rotronic MP101A-W4W (since 2009, a Qualimetrics 5129-C sensor before that). Both instruments have capacitance hygrometers and resistance thermometers (Pt100 for the Rotronic and a combination of three thermistors -if i am not mistaken- for the Qualimetrics). The thermohygrometer is routinely calibarated every two years (at least for the past ten years or so).
The system is located about 3.5m high, protruding about 0.5m from a meshed metallic structure surrounding the mast and supporting the raingauges. You can see a view from below at (http://www.meteo.noa.gr/ENG/iersd_station-images.htm). The shield is the white L-shaped pipe hanging to the right of the raingauge (and the mast)
The second automated station is a Davis (24h aspirated) located in the former gas factory known as Gazi (maybe 750m to the northwest and lower elevation than Thissio). This station is installed on a 2m mast at the edge of a balcony (totaly about 8m above ground) facing Peiraios str. (a 4 lanes street) the ancient cemetary of Kerameikos and the Ermou pedestrian street (GoogleEarth coordinates 37.978384N 23.715263E). You can see the data at (http://penteli.meteo.gr/stations/athens/) and the station also has a web camera.
Please let me know if you need any further information.
Se here we learn that there are 3 weather stations in the very centre of Athens managed by NOA
1) the "historical" NOA station in front of the NOA building, that is the 16714 WMO-labeled one.
2) the instruments (good instruments in my opinion) at the actinometric site
3) the totally urban Davis at the Gazi site.
What we find in monthly bulletins is the data coming from station 1
What we see in real time pages comes from station 2
I mean, this page
It is not very clear if the informations reported here http://www.meteo.noa.gr/ENG/iersd_climatological.htm refer to one of those stations or they are a mixture of them or they add up all them. Perhaps there are described instruments and features of both stations.
Next I reply Mr. Lykoudis and ask him another couple of details.
Oggetto: R: Re: [Fwd: NOA Thiseio weather station]
Thankyou for your detailed and quick reply, you provided me with most of the informations I was interested in.
I know the coaxial tubes dual fan-aspirated shield architecture, it performs very very well and has very cheap maintenance. [... snapshot, omitting irrelevant details ...]
It would be interesting to know which average and peack difference you observe in tmax between the Stevenson shelter at the NOA building and the dual tubes Qualimetrics fan aspirated one at Pnyx hill. I suppose theat because of the sunny summer climate of Athens, the fan aspirated shield will have about 0,6/0,8°C less in yearly tmax average, with peacks above 1,6/2,0°C less in summertime slow wind conditions.
My last questions are
1) if the Stevenson shelter at NOA building is passive or fan-aspirated;
2) if it is possible to see the coordinates of the Stevenson shelter at the NOA building;
3) and eventually if it possible to see a picture of it with its distance from buildings, obstacles etcetera.
Thankyou very much again, also for replying to me so soon in a holiday.
Oggetto: NOA Thiseio weather station]
Attachments: Klovos2006.rar (5.9 MB);
Dear Mr. ********,
Our Stevenson screen is a passive one and it's located at 37.973412°N 23.718071°E.
The screen is rather close to NOA historical building to the east (less than 15m) as well as to some high pine trees to the south (about 12m) that grew on the hill over the years.
The screen is shaded both by the building and by those trees, eventhough at different seasons and hours. I''m sending older pictures (4 years old) since for the past two years we are in the process of replacing the screen by a new one (same type and size) so there are two screens located almost side by side.
Regarding the temperature differences between the actinometric station and the Stevenson screen I am not aware of anyone having done this comparison, but it woukld be a good to do this as well when we compare the data from the two Stevenson screens.
So we earn some other informations. The WMO NOA station has passive Stevenson shelter and it is located less than 15 meters from the NOA building (google-maps measure tool suggests 9,6 meters). We can read elsewhere that the shelter is located 150 cm from the ground (here http://www.meteo.noa.gr/ENG/iersd_climatological.htm).
The exact location is this: http://maps.google.com/maps?f=q&sou...73367,23.718125&spn=0.001013,0.00239&t=h&z=19 (the green arrow) and because of threes there is some shadow that is not due to orography.
I have here the pictures of it they sent me, but I didn't ask permission to redistribute them, so I prefer not to do it.
Here is a picture where we see well the anemometer
and in this view we see where it is (with a red circle around the shelter and a yellow line for the anemometer)
and in this other one we see east as the station "sees" it
Here how the site is today:
and here how it used to be
while here we see well the courtyard where the Stevenson shelter is located
Now let's watch a larger perspective:
So, I decide to reply again and to report Mr Lykoudis with the information I currently have about the differences between the two stations.
Oggetto: R: NOA Thiseio weather station]
Thanks a lot once again,
perhaps that vegetation growing next to the station partially accounts for the limited impact the urban heat island has on the Thissio station in yearly averages. Perhaps cutting it would cause an increase of tmax and a decrease of tmin I guess.
It would be interesting also to install a Davis VP2 24h fan aspirated over a tripod next to the stevenson screen for the forthcoming summer. The Gazi station is interesting and close but it is fully urban. A VP2 next to the stevenson shelter would show quickly which is the difference between stevenson shelter and fan aspirated shelter with a low-cost instrumentation.
By the way, about comparing the actinometric fan-aspirated station and the stevenson shelter at the NOA building, it seems that some boys in the British weather forum UKWeatherworld did it last year. They derived daily minimum and maximums from the graphs you publish from the Qualimetrics shielded station, and at the end of the summer when the montly bulletin was published with the Stevenson shelter results, they compared the averages.
But is seems they do not know that the data come from two different stations, they seem to treat them as a unique station.
If you have patience to browse it, at last final results are reported.
Their final results (The Qualimetrics has lower maximums and higher minimums) is very compatible with the difference between Stevenson shelter and a good fan-aspirated shelter we often find in the literature. By the way, I can't understand which rationality these people show in comparing UHI-affected stations like Elefsina with all the thermal pollution of its industries and Thiseio to airport stations like Sevilla S.Pablo, Tablada, Moron de la Frontera etcetera (and fan aspirated stations: the Spanish AEMET uses fan aspirated stevenson screens) and then to derive climatological genealizations from these single-year comparisons with stations in different urban vs non-urban environments, but they do...
Best regards again.
Notice one detail. In the pictures of AEMET stations with zoom enough that I have seen, a tube inside the Stevenson shelter is clearly visible. That tube is typically used in fan aspirated shelters. I am not too sure that all AEMET shelters are fan aspirated, but some of them are. By the way, here we have Mr Lykoudis response.
Oggetto: Re: NOA Thiseio weather station]
Thanks for the info about the document from the UKWeatherworld. I'll check it out.
Regarding the impact of the vegetation in contrast to the UHI you're probably right, especially if you consider that the vegetation more or less grew in tandem with the city around the station. In the early 20th century the hill was practicaly barren and the city (or the state) repeatedly planted pine and other trees till the 50s. Unfortunately, any attempt of - or even discussion about - clearing the area around the station is out of the question.
Several people have asked us about the relative performance of various shield designs. We could certainly do the test, but getting the permit for the extra installation might be an issue....
You may want to have a look at our automated weather stations network around Greece (all of them Davis VP2 and almost all of them 24h fan aspirated)
select the tab Observations-NOA to the left.
Here is where the Gazi station is located (green arrow)
and here we find the weather station with the data online in realtime (here http://www.meteo.noa.gr/WeatherOnLine/s_Thiseio/meteo_tableEN.html) (green arrow)
Now let's do a quick comparison between the WMO NOA station in front of the NOA building and the NOA Davis at the Gazi site.
We know well that in climatology single year comparisons have small interest, but in this case the distance between the stations under comparison is less than 1 km and it is difficult to conceive contrasting anomalies, different synoptic conditions etcetera. The differences we are seeing depend mainly on instruments, sites and installation standards.
Here we see monthly and yearly means of min, max and mean temperatures.
(sources are http://penteli.meteo.gr/stations/athens/NOAAPRYR.TXT and http://www.ukweatherworld.co.uk/forum/forums/thread-view.asp?tid=40958&DisplayType=flat&setcookie=1)
Trained eyes can see lots of interesting and unexpected details in these comparisons.
- the yearly averages of simple means are equal for the station in the park and the fully urban one.
- the yearly averages of integration means and simple means are almost equal for the Gazi station
- the fan aspirated shield (an perhaps the greater heigth from the ground) of the Gazi station keeps its tmaxs lower than those measured at the NOA building with the Stevenson shielded instruments.
Well, leaving aside the ''salad'' comparisons and constant tabulations that Borat/Amending etc loves to do in order to manipulate data with honestly one of the weirdest ,NON systemic,non scientific and amateurish ways in various,Italian,Spanish,Portuguese etc forums which by the way make sense only inside his mind I think and most of which are coming as responses to my observations on Thiseio.
Here what we have in more detail from the NOA site itself on Thiseio station which are actually classed as laboratories according to NOA itself.
The above laboratories are equipped with:
Two complete first class meteorological stations (Thissio & Penteli sites)
Two complete actinometric stations (Thissio & Penteli sites)
A research class daylight station
An atmospheric electricity station
An atmospheric chemistry laboratory
A mobile atmospheric pollution measurement station (SO2, NOx, O3, CO, HC, PM10)
Dashibi Ozone meter
A DOAS (Differential Optical Absorption System) pollution monitoring station
Radiosonde and tethered balloon atmospheric profiling system
Portable instrumentation (infrared camera, portable temperature and relative humidity sensors and data loggers)
A mobile X-band dual polarisation Doppler weather radar
A state-of-the-art video disdrometer
A portable raingauge network
A network of five automatic raingauges, deployed currently over Crete
A network of six lightning detectors (ZEUS network: Denmark, UK, Portugal, Romania, Cyprus and Senegal) with a server for data collection and archiving at IERSD
A computing center with infrastructure for operational weather forecasting (a 14-CPU cluster of Linux-PC (Athlon 1800), an 11 Dual-CPU cluster of Linux-PC (Opteron 250) and a 4-CPU HP UNIX system for archiving of satellite data)
A multi-analyser of temperature and lighting
A combustion gas analyser
An experimental outdoor photovoltaic bench coupled with underground air-to-ground heat exchangers
A library with scientific journals and books
The Climatological Bulletin is published annually and contains summaries of meteorological observations gathered at the Institute of Environmental Research and Sustainable Development of the National Observatory of Athens (NOA) on the Hill of Nymphs at Thissio (latitude 37° 58' N, longitude 23° 43' E, height of 107 m above MSL) near the center of Athens. Continuous observations of standard meteorological parameters have been carried out at this location, the close surroundings of which remain unaltered, since 1858.
The Bulletin includes tables with values of the following meteorological parameters:
Air temperature (°C) (hourly, daily and monthly means, maximum and minimum values).
Soil temperature at a depth of 0.15 m (°C) (hourly, daily and monthly mean values).
Relative humidity (%) (hourly, daily and monthly mean values).
Atmospheric pressure (hPa) (hourly, daily and monthly mean values).
Wind speed m/s) (hourly, daily and monthly mean values).
Wind direction (deg) (hourly values, wind rose).
Rainfall amount and duration (mm, hrs).
Saturation deficit (mm Hg).
Vapour pressure (mm Hg).
Sunshine duration (hrs).
Cloudiness and cloud type (octals).
Degree days (°C).
Total solar radiation on horizontal surface (W/m2) (hourly, daily and monthly values with Eppley pyranometer).
Diffuse solar radiation on horizontal surface (W/m2) (hourly, daily and monthly values with Eppley pyranometer and shadow ring,
not corrected for shadow-ring effect).
Total illuminance on horizontal surface (kLux) (hourly, daily and monthly values)
Diffuse illuminance on horizontal surface (kLux) (hourly, daily and monthly values, corrected for shadow-ring effect).
Climatological Means (normal values).
Measurements of additional parameters on a routine basis but not published in the Climatological Bulletin include ground surface temperatures and temperatures at depths: 0.02m, 0.05m, 0.10m, 0.15m, 0.20m, 0.30m, 0.40m, and 0.50m and in cups at depths: 0.30m, 0.60m, 0.90m and 1.20m.
PS.Please visit the Aosta valley topic ,which is a continuous. tiring tabulation,graph bs from Amending in the Italian forum.A constant fixation and worthless repetition and/or analysis of Amending's ways to do research. Honestly one of the weirdest topics ever in a meteorological forum (which I might say Amending seems to be the only one to understand what he is on about). I havent found a single forum user to actually understand he constant flights of thought ,leaving aside the constant nonsense tabulations that ''proove'' something.I take it from a sociological aspect...hehe
You have to give Dr. Lykoudis some credit for this response though!
In this publication of the email we see an effort from our Italian friend to drag Dr. Lykoudis to an antagonistic logic as always .If we assume that all the above emails are of genuine nature (something which can be confirmed by Dr. Lykoudis since I take it Amending has his approval to post his emails).
Notice how subtly Dr. Lykoudis reacts when Amending brings up ''the boys from the UK'' forum.He politely ignores Amending's anxious effort to blackmail a response against the ''UK boys''. I am sorry I just had to bring it up!
Now, for the life of me I can not understand what does this rambling/ tantrum-like writing does in a serious email
Provided that this email is genuine again notice how Dr. Lykoudis a) does not get what Amending is on about and b) how subtly he ignores this antagonistic effort.
My understanding is that Dr. Lykoudis, who by the way is a Dr. of Atmospheric Physics whose profile u can see here http://gr.linkedin.com/in/spyroslykoudis,
has either understood that he is dealing with someone who has a ''pressing'' issue (i might go to the extreme of saying a ''personal one'' towards Mesogeiakos) and b) did not go at all in the ''essence'' of the malignant effort coming from Amending to drag Dr. Lykoudis into a blackmailed response for the ''UK boys''
What seems far more interesting is that Dr. Lykoudis did not give a single comment on the antagonistic language used by Amending.
Look for example this here:
Apart from a rather cheap comment from Amending's side , anyone would understand that there is more to it just by reading comments such as this. I take it Dr.Lykoudis has answered Amending the right way
PS. All of the above with the reservation that off course the emails are genuine and that Dr.Lykoudis consent for them to appear on a Portuguese Meteorological Forum was secured.
And here on the replacement of the other one
Now this answer covers me.He mentions pretty much all the elements that consist a proper WMO station!So is Amending saying that the Thiseio WMO station is not complaint to the WMO standards and if not which are the exact standards that this station does not comply to?
Btw assuming that this is indeed the one not reporting on the main site,the ''UK boys'' have found minimal differences between the automated one and the WMO one .You do remember that right?
Finally,apart from that, we have seen that the ''UK boys'' are careful enough as to always give out the WMO monthly bulletin from Thiseio so the ''rationality'' is that at the end of the day we have comparisons between WMO stations in Europe.
Take it easy. Please cool it. Nobody is threatening Thiseio station. Why do you perceive a couple of maps and pictures and some more detailed informations than those previously known as a threat?
Cool it, take it easy. There are not terrible monsters around, no ghosts, no bad tables full of slanders of the devil and treacherous pitfalls orchestrated by the demons of hell, orcs or stuff like that. It is just basic station metadata. Where it is and how it is, location, shielding etcetera.
Ok,so Amending you are telling us here that you have not opened this topic to discredit the WMO status of the National Observatory of Athens ( following the history of what seems spiteful personal issues between us) by trying to blackmail a response against the ''UK boys'' from poor Dr. Lykoudis who is probably unaware of your particular fixation with Thiseio station and who probably is unaware that his responses are published in a forum?
I say you cool it down Italiano one thing is to have issues with the comments of a forum user and another to try and drag or blackmail a side taking response from an official of a Greek institution with an antagonistic logic. At least Dr. Lykoudis has managed to see through this one and ignored your references and tantrums on Elefsina,Hellenikon,Mars,Moon and what not
Precisely. I say exactly that the stuff you are saying is not the aim of the topic. The object of the topic is describing the station by reporting known but sparse informations and information reported by personnel handling the station. This allows us to move one step forward with respect to information that is already available. For instance, did you know that there were two temperature stations? And that the actinometric station is fan aspirated? I did not know that, as I did not know where the Stevenson shield is located exactly. I have searched for it a lot of time but I found it in Bing-maps only after I was given its exact location.
By the way, readers will form their own opinion - if they are interested in the topic. It is quite unclear why you struggle against showing basic station metadata. For now the new information adds very little to what was already known based upon public information like the station generic coordinates. If the public perception of the station gets damaged or improved, it is not a problem of mine.
I told Lyoukoudis my opinion about comparing UHI and non-UHI stations without taking into account UHI magnitude mainly in order to excuse myself in front of him for indicating to a professional like him such a kind of extravagant comparisons as I ignored that doing so is heretic. See it like taking the distance from something that is disapproved, a way to save the face And 1) I do not have to give account to you or anyone else of this; 2) I did not expect anything further from him (notice that I have not asked him or solicited an opinion about).
Actually quite the contrary.This is why I am moving away from your cunning attempt to discredit the station since I also believe there is nothing of essence that compromises the station.
For this reason I am focusing on your attempt to drag Dr.Lykoudis into a side-taking response. It is quite obvious in the ''untrained'' eye the attempt to blackmail an answer from him by quoting irrelevant issues regarding Elefsina,Seville etc.I think that is why Dr.Lykoudis ignored you
What Dr.Lykoudis is unaware of is your fixation on discrediting the Thiseio WMO status in various forums.
For example even in an earlier post here you have shown your true colors by once again negating WMO stations through irony,a comment which you quickly edited (I take it in fear that this thread will reach Dr.Lykoudis and the NOA administration)
I think the main focus of this thread should be to initiate a round of talk of what your motives are so as the National Observatory of Athens and other authorities would be in a position to assess your false pretense.
For starters,I say we inform Dr.Lykoudis and the NOA of your antagonistic comments of NOA station and its WMO status
Below is the Italian forum link, in which you appear under the nickname Borat.Anyone who can follow the thread until the end can see your ''love'' for NOA's WMO status,your irony and off course the history behind that forced you to even try and blackmail a response against the ''UK boys'' from Dr.Lykoudis.
OK, thankyou for visiting the topic.
As you email Dr. Lykoudis please forward to him my best regards and ask him the permission to reproduce here the pictures of the temperature station in the courtyard of the main NOA building. Thanks in advance
Here is the 1961-1990 climatic table for the National Observatory of Athens - Thissio site (source: http://www.meteo.noa.gr/ENG/iersd_climat-table.htm)
In the previous table, the means that are computed by NOA are reported.
However in several climatological applications, simple means are used. These are defined as
mean = (tmax + tmin) / 2
and some climate monitoring institutions compute means this way. Let's recalculate the means of the NOA station using that simple formula.
It seems that the means reported by NOA are computed using a different formula than the simple (tmin+tmax)/2. In fact, when studying old climatological materials and articles, I have found several different formulas used in different parts of Europe, for instance
mean = (tmax+tmin + t8 + t14 +t18)/5
mean = (t7 + t14 +t21*2) / 4
and other fomulas. I actually do not know how the values reported by NOA are computed. In a old article about Athens urban heat island effect the following formula was used to compute daily means (http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450(1985)024<1296:IOTUHI>2.0.CO;2):
mean = (t8 + t14 +t20 + tmin + tmax)/5
Maybe the climatic table in http://www.meteo.noa.gr/ENG/iersd_climat-table.htm are computed using this formula. A first interesting detail is that the simple mean is 0,6°C higher than the mean reported in the original climatic table. This does not always happen when analyzing Greek meteorological data. In Italy it is quite common to find a +0,6°C difference between simple mean and integration method mean reported by automated stations (where integration mean is typically 0,6°C cooler).