Atene, che forno!

dedalus27 · 23/07/2010, 13:56

[QUOTE=mesogeiakos;1058333492]Dedalustutiempo contro autorita ufficiale di Grecia

Ecco la Grecia in primo posto per ieri 38.5 Leonidio

QUOTE]

Leonidio (Grecia), Andujar (Spagna), Catenanuova (Sicilia) sono stazioni secondarie, non hanno aeroporto, per questo motivo non incluso nella lista dei woitalia / Ogimet, ecc.

Ma se tu lo vuoi, da oggi e devo includere Leonidio, Andujar

Qualcuno sa come ottenere Catenanuova dati?

**Borat** · 23/07/2010, 13:59

Originariamente Scritto da mesogeiakos

However the 2-3 temperature increase is clearly in terms of minimums.

Right. Figures I mentioned refer to mean monthly (in table 3) and yealry (in regression) tmin. The impact on the (tmin+tmax) / 2 statistics is of course 1/2 of that.

Originariamente Scritto da mesogeiakos

There is no room for misimpretation my dear borat.The means close near norm averages and I cherry picked the obvious conclusions for Thiseio.

This means nothig without obseerving the same pattern in rural data. You are arguing that urban data did not change in time and then uhi did not impact them. You should be able to show, instead, that the difference between urban and rural data did not change. In fact, if the natural environment mean changes in the opposite direction of the changes in the urban heat island, the two effects can compensate each other and balance to zero. And that's likely to be occoured, as the regression suggests. The regression says that mean (tmin) raises stright with population.

One weak side of that regression itself is that it does not use rural data, so the effects of uhi and natural environment (measurable in rural area) can mix and produce strange and unclear effects.

Originariamente Scritto da mesogeiakos

Now the question is how we find the UHI of Tablada airport since it is obvious this station is surrounded by urban settlements regardless of the administrative borders of the city of Seville

I partially agree with this. Tablada seems suburban, not urban. It is a large field. Perhaps wind may lead there some heat from the city but it is not clear how much.

I'd like to mention that if Sevilla is really the warmest Spanish city, it would deserve a better monitoring. Some amateur stations around it (but outside uhi) would be gold. They would help in estimating a true mean (and not a single measurement point mean) for it. When you have several point, you can handle variability in space and estimate a mean of different points.

**Borat** · 23/07/2010, 14:02

Originariamente Scritto da dedalus27

L'effetto isola di calore in una città di medie dimensioni: Palma de Mallorca (400.000 abitanti).

AEMET (Servizio Meteorologico della Spagna) ha due stazioni ufficiali a Palma di Maiorca, uno presso l'aeroporto, una vicino al centro della città (cerchio verde), in il porto.

Allegato 169194

La temperatura media in agosto 2003 (Ufficiale):
Valores extremos - Agencia Estatal de Meteorología - AEMET. Gobierno de España

Palma de Mallorca-aeroporto (altitudine 3 metri) 27,7ºC
Palma de Mallorca-cittá (altitudine 4 metri) 29,4ºC

Allegato 169196
Quasi due gradi piu in centro città di Palma de Mallorca. Nelle grandi città come Barcelona, Roma..., l'effetto isola di calore urbana è più intenso (circa 3ºC o 4ºC piu). Atene più.

Temperature medie :

Barcelona-aeroporto 27,8ºC ------> Barcelona downtown circa 30,8ºC-31ºC
Valores extremos - Agencia Estatal de Meteorología - AEMET. Gobierno de España

Siviglia-aeroporto 30ºC ---->Siviglia downtown circa 32ºC – 33ºC
Valores extremos - Agencia Estatal de Meteorología - AEMET. Gobierno de España

The case of Palma del Mallorca is a very good example.

dedalus27 · 23/07/2010, 14:06

Originariamente Scritto da mesogeiakos

Ecco Atene ieri

Allegato 169133

Ecco Siviglia e Cordoba ieri

El Tiempo. Últimos datos: Andalucía - Resumen de ayer - Mapa - Agencia Estatal de Meteorología - AEMET. Gobierno de España

Come sempre Atene come la citta piu calda in Europa in estate ha fatto la piu alta Tmed con 31.5C

Ci sono ancora persone che non credono che Atene è veramente imbattibile in estate?

Yes, 31,5ºC in Stazione urbana, nell aeroporto di Atene 28,4ºC , nell aeroporto di Siviglia 28,05 (con avezzione freda nella peninsula iberica)

dedalus27 · 23/07/2010, 14:15

Data Thisio.jpg

Questi dati di temperatura sono assurde:
1. Atene-Thisio è sempre stata il centro geografico di Atene
2. Il strumentale nel XIX secolo era scadente. In Spagna nel XIX secolo ci furono una temperatura di 50 º C 51 º C a Siviglia e Cordoba.

Badajoz: 31ºC Luglio 1866:
Valores extremos - Agencia Estatal de Meteorología - AEMET. Gobierno de España

dedalus27 · 23/07/2010, 14:20

Originariamente Scritto da Borat

The case of Palma del Mallorca is a very good example.

Yes, very good: same month (August 2003), same height (3 metri / 4 metri). Palma de Mallorca' airport is on semiurban area, Palma de Mallorca's Port is near downtown, but not exactly (on exact downtown temperatures could had been even hotter).

**mesogeiakos** · 23/07/2010, 14:20

Originariamente Scritto da Borat

Right. Figures I mentioned refer to mean monthly (in table 3) and yealry (in regression) tmin. The impact on the (tmin+tmax) / 2 statistics is of course 1/2 of that.

This means nothig without obseerving the same pattern in rural data. You are arguing that urban data did not change in time and then uhi did not impact them. You should be able to show, instead, that the difference between urban and rural data did not change. In fact, if the natural environment mean changes in the opposite direction of the changes in the urban heat island, the two effects can compensate each other and balance to zero. And that's likely to be occoured, as the regression suggests. The regression says that mean (tmin) raises stright with population.

One weak side of that regression itself is that it does not use rural data, so the effects of uhi and natural environment (measurable in rural area) can mix and produce strange and unclear effects.

I partially agree with this. Tablada seems suburban, not urban. It is a large field. Perhaps wind may lead there some heat from the city but it is not clear how much.

I'd like to mention that if Sevilla is really the warmest Spanish city, it would deserve a better monitoring. Some amateur stations around it (but outside uhi) would be gold. They would help in estimating a true mean (and not a single measurement point mean) for it. When you have several point, you can handle variability in space and estimate a mean of different points.

And this would be extremely problematic to do...

If we want to see how Thiseio is affected compared let's say to a completely rural area outside Athens then we would need to compare it directly with the whole dataset of Thiseio.Unfortunatelly this is not possible

1.Given that Thiseio is the oldest meteorological station of Greece with a database dating back to 1830's

2.Given that there was no other proffesional meteorological station directly outside Athens for that period...In fact I have seen newspaper articles of 1850-60 that show that the everyday normal residence of Athens of that time was learning what was the temperature only for Thiseio as representative of Athens

**Borat** · 23/07/2010, 14:28

The strongest evidences in that paper are table 3 and the regression.

I have criticized the regression because it does not use the available rural data.

Computing

(tmin_u - tmin_r) = a + b*pop^(1/4)

would be easy and would purify the results from variations in free atmosphere and environment temperature.

Perhaps they had not as many year of rural data as a good regression requires (in political science analyses of 23 cases are often published also in top journals, but this is much sub-optimal: one should not rely on asymptotic properties of OLS estimators below 50 observations and personally I avoid falling below 2-300 observations).

Table 3 is this

What is questionable in this table is that the stations are at different altitudes, with differences up to 100-130 meters that can account for about 1°C if we assume the typical vertical temperature gradient of 0.65°C/100 m.

This evening if I haven't anything better to do I'll compute a rescaled version of that table, where the effects of differential altitudes are purified (in practice, I add -0.65°C for every 100 meters difference altitude to all entries). The uhi depicted by the table will be less drastic.

With me as a referee, that article wouldn't get published. Problems in regression, no supply of information with reasonable correction for altitude etc etc.

**mesogeiakos** · 23/07/2010, 14:38

Originariamente Scritto da Borat

The strongest evidences in that paper are table 3 and the regression.

I have criticized the regression because it does not use the available rural data.

Computing

(tmin_u - tmin_r) = a + b*pop^(1/4)

would be easy and would purify the results from variations in free atmosphere and environment temperature.

Perhaps they had not as many year of rural data as a good regression requires (in political science analyses of 23 cases are often published also in top journals, but this is much sub-optimal: one should not rely on asymptotic properties of OLS estimators below 50 observations and personally I avoid falling below 2-300 observations).

Table 3 is this
Immagine

What is questionable in this table is that the stations are at different altitudes, with differences up to 100-130 meters that can account for about 1°C if we assume the typical vertical temperature gradient of 0.65°C/100 m.

This evening if I haven't anything better to do I'll compute a rescaled version of that table, where the effects of differential altitudes are purified (in practice, I add -0.65°C for every 100 meters difference altitude to all entries). The uhi depicted by the table will be less drastic.

With me as a referee, that article wouldn't get published. Problems in regression, no supply of information with reasonable correction for altitude etc etc.

Agreed because the altitude is a substantial issue. But how do we sovle the case of direct comparility of the whole Thiseio dataset with a rural area?

Note than in 1860 Athens was not more than 50.000(?) residents I think....