But what do you mean hottest?Is it in terms of maximums?Bsc ok in terms of maximums what is the use anyway?
Wouldnt it be more scientifically appropriate to find the area in Portugal that has the highest summer mean temperature?....By the looks of it the minimums in Guidiana are distasterous....Maybe if we go more to the south towards Faro BUT in an area that is much less affected by the sea breeze?Is it possible we will find there the actual hottest part of Portugal in summer long means?
I wonder if science knows something like "better" questions as science knows no better, worse etc when it comes to questions to be answered. These are value judgments never to be proven in itself.
If you want to know which place is the warmest on average based on its maxima, it is as valid as any other question you might want an answer to.
The seabreeze is a major factor, but if it is about average high temperatures I am not so sure. I saw that Pinhão in the Douro valley although it gets to 33,5 C as daytime max (1961-1990) it has an average of 25,8 C. So in this case, it could be any valley if you ask me more inland and in fact I'd say in this case the Douro valley further inland is a good point.
In the Guadiana I saw Moura from 1941-1962 at 26,2 C or so...If so, translated to the warmer 1971-2000 period you may add a bit. I'd say above 27,0 will be very hard. To me, Athens is warmer from that perspective. I have little doubt. With or wihtou heatisles.
And on Athens...my point is that it has always been populated and that the Urban heat isles rises very rapidly once buildings and trees (but buildings more) and asphalt roads enter the scene. Some figures: with 1000 people per square kilometer the rise is 1,4 C compared to rural and when it is 7000 it is only 0,6 C more.
Athens has always been a city of some size of course, but much smaller as you have shown in the past. I think it is at least likely that the National Observatory station has had a clear influence and so the study, this one, did not detect more.
What is seriously hampering this study in my view is this:
- They show a trend and have zero comparisons with other stations that were rural all the time. You need that to distinguish between climatic trends and human induced heatisle and comparible trends. I didn't see anything of it.
We cannot know what has caused this trend if we do not know everything about these things.
I also see no explanation as to why the heat isle hasn't kicked in. They look at the trend, compare with other station in the valley and then conclude something.
Another point is that the site specifications are not according to WMO standards aswell. The park is full with trees, there is in no way an open space with a at least 200 m radius where there are no trees (and this might as well be 400 metres, look it up).
In short: this area has human influence written all over it. If you look at WMO guidelines this area is off limits. Really. And just to use a study with no explanation but a lot of assumptions, with no station maintenance records in it (not mentioned) etc you cannot compare this with stations in the country.
Besides: Athens Airport is a good comparison to get some facts. THis is more rural. It is notin the basin, but the mountains clearly indicate it is sheltered, cut of an on its own. Now I amy be wrong, but why is the minimum tempeture year round 1,6 C higher than that of the airport. They are at the same altitude, yet the airport is cooler all year long and all the time 1,6 C or so.
I see no explanation that makes any sense this less sheltered airport would be cooler at night, especially in winter. Apart from a city of that size surrounding a small place just 50 m above it, this is another indication that the station is clearly influenced by city.
If not, what is wrong with MArtinez data? In the stations that are weird, they are so because they show exactly this signature.
Anyway: I find the study seriously lacking, it is not peerreviewed it does not provide clear answers.
To me personally I attach no value for Athens when it comes to an intercomparison with rural stations.
Sevilla airport has this signature also with its exceptional warm nights. 24,0 C is the average to this point in august. Looking at agrometeostation data situated at La Rinconada (7 m height) and Tomejil (also about this height) at 5 and 10 km NNE of the city, we see this. Also added Lora del Rio, same river basin, 47 km ENE from the station, 40m high.
Average min till 11 august 2010:
La Rinconada 20,2
Tomejil 20,9
Lora del Rio: 21,4
Sevilla Tablada: 24,0 C
Average max till 11 august 2010:
La Rinconada: 37,9
Tomejil: 38,1
Sevilla Tablada: 38,5
Lora del Rio: 39,0
SW of the city (Aznalcazar, Lebrija) all note minima of 20,0 C or lower and maxima at about 36,0 C.
Agrometeo station data is not ideal and there are some that measure in yards. Although int the field, yards with trees around it have a similar effect on temperatures especially during daytime.
But the trend is very clear: Sevilla airport is warmer than expected. Also the daytime maxima which are still a bit higher than cities 15-20 km more inland. But the nights, as expected from theory even more.
So how come Guadiana river valley is so cool? Don't know, but things become much smaller if we take Sevilla out of the equation. And we can do so for obvious reasons. For Athens, the same applies. Although I cannot so to what extend.
