Stevenson Screen vs Davis fan aspirated head on comparison
May 6, 2024 20:04:17 GMT -5
Cheeseman likes this
Post by southathens on May 6, 2024 20:04:17 GMT -5
Ok here is the long awaited comparison between the 2 Downtown Athens WMO stations.
The first one is the historic Stevenson Screen atop the hill of Thiseio at 107 m asl . More info here:
cdweather.boards.net/post/270726/thread
The second one is the nearest WMO station to the Stevenson Screen, basically right next to it (around 600 meters distance) at 50 m asl. Its a rooftop Davis fan aspirated station smack bang below the hill of Thiseio in urban Athens.
oscar.wmo.int/surface/#/search/station/stationReportDetails/0-300-1-athens
Here is the actual station placement
Here is the rough distance between both stations
Feel free to cross check me using the link below for the data of both stations
www.meteo.gr/Monthly_Bulletins.cfm
The NOA climate bulletins are in Greek however its pretty straight forward. Once you go to a climate bulletin for a specific month the first page is the tables of the Stevenson Screen station. Then as you scroll down with the list of the 500+ Davis fan aspirated stations you should check for the station named ''Αθήνα-Κέντρο''.
So the POR of parallel operation is 17 years
Here's how they are looking
Immediately two major takeaways:
1) Trust the fucking minimum Ts of rooftop Davis fan aspirated stations. They are actually lower year round by about 0.2C despite it being a rooftop station. So what happened to the dogma of '' yeah a rooftop Davis fan aspirated station would overestimate minimums by 5C''
lol
2) Look at how the Davis fan aspirated station significantly underestimates max Ts. Especially during the two hottest months we see a -1.1C T difference when compared to the Stevenson Screen data. That's obviously due to the mechanical aspiration. So basically when you look at my Rate this climate threads make sure to add at least 1C for July and August to get the right Stevenson Screen value.
Mind you that this is what we see in almost EVERY other location we have run the past 19 years comparisons between our Davis fan aspirated stations and the nearby Stevenson Screen stations.
Here's a similar comparison I run for Rhodes:
cdweather.boards.net/thread/4013/absolute-champion-european-lindos-greece?page=6&scrollTo=236291
The first one is the historic Stevenson Screen atop the hill of Thiseio at 107 m asl . More info here:
The Thiseio Downtown Athens station that you see in wikipedia is an A class Stevenson Screen station atop the hill of Nymphs. It has been operational since 1842 and has been at the same position from 1890. It is a fully manned station 24/7 (4 NOA staff in rotation oversee it daily) and it is not allowed to change location as per Greek law in fact. The Thiseio station is a sacred totem for Greece's climatology and it is one of the oldest continuously working stations in the same location in Europe. The only centennial station in Greece. Btw I had visited the station on an educational school trip when I was in high school. It is like an outdoors laboratory...Extremely taken care of. We were not allowed to come near it.
cdweather.boards.net/post/270726/thread
The second one is the nearest WMO station to the Stevenson Screen, basically right next to it (around 600 meters distance) at 50 m asl. Its a rooftop Davis fan aspirated station smack bang below the hill of Thiseio in urban Athens.
oscar.wmo.int/surface/#/search/station/stationReportDetails/0-300-1-athens
Here is the actual station placement
Here is the rough distance between both stations
Feel free to cross check me using the link below for the data of both stations
www.meteo.gr/Monthly_Bulletins.cfm
The NOA climate bulletins are in Greek however its pretty straight forward. Once you go to a climate bulletin for a specific month the first page is the tables of the Stevenson Screen station. Then as you scroll down with the list of the 500+ Davis fan aspirated stations you should check for the station named ''Αθήνα-Κέντρο''.
So the POR of parallel operation is 17 years
Here's how they are looking
Immediately two major takeaways:
1) Trust the fucking minimum Ts of rooftop Davis fan aspirated stations. They are actually lower year round by about 0.2C despite it being a rooftop station. So what happened to the dogma of '' yeah a rooftop Davis fan aspirated station would overestimate minimums by 5C''
lol2) Look at how the Davis fan aspirated station significantly underestimates max Ts. Especially during the two hottest months we see a -1.1C T difference when compared to the Stevenson Screen data. That's obviously due to the mechanical aspiration. So basically when you look at my Rate this climate threads make sure to add at least 1C for July and August to get the right Stevenson Screen value.
Mind you that this is what we see in almost EVERY other location we have run the past 19 years comparisons between our Davis fan aspirated stations and the nearby Stevenson Screen stations.
Here's a similar comparison I run for Rhodes:
cdweather.boards.net/thread/4013/absolute-champion-european-lindos-greece?page=6&scrollTo=236291
