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It's on a small island but it isn't surrounded by deep waters. It's similar to Venice.
And the density is nothing special, around 5.000 inhabitants for square km is a normal urban density and similar to my city and many other medium cities. Portsmouth municipality is tiny and doesn't include countryside areas, so density is high.
Genoa (as well as Nice, Cannes) is much more south, sheltered by mountains, it lies along a very deep and much warmer sea, it's a large city and has an extremely high density. And it has a very mild climate, maritime, breezy and cloudy. It's basically frost free. It's the mildest and warmest city in the world for its latitude, at 44°N.
Portsmouth is "sheltered" only by gentle downs, surrounded by shallow waters, it's smaller, and much less densely populated, at a latitude 50°N.
I have some real doubt it has the same average low temperature in January.
Well the density is something special as it is the most densely populated place in the UK, fact. And being 12th most densely populated place in the whole of Europe is also fairly noteworthy. Genoa is a bigger city, but Portsmouth is more densely populated, it is that high concentration of buildings which makes Portsmouth an urban heat island similar to central London...
Obviously Genoa is further south, but what does that have to do with anything? It is a larger city but it is less densely populated than Portsmouth. The population density for Genoa is 2483/sq km compared to Portsmouth which is 5145/sq km as we are comparing like for like (within the administrative city limits)...
And it doesn't have the same average low in January, Portsmouth's is 5.1C compared to Genoa's 5.5C, so Genoa is slightly milder. Record temperatures for both cities are similar though Genoa has a record high of 35.4C, Portsmouth's is 35.0C & Genoa's record low is -6.8C, when Portsmouth's is -8.0C...
I really don't understand why people doubt these figures for Portsmouth...
Most plants, palms included, don't grow much at all below 50F. The base temp for corn and tomatoes is 50F, for cotton it is 60F, peanuts=56F, potatoes and sunflowers=45F and the lowest wheat, barley, rye, oats, asparagus, lettuce=40F. CIDP grow very slowly as it is, which is why I think they will grow so much more slowly in the UK with the minimal amount of GDD they get with a base of 50F.
Phoenix canariensis in Portsmouth actually grow quite fast, on many palms/exotic plant forums people from the USA, Australia, New Zealand have all commented on how fast they grow here. A tiny one I planted in my backyard 10 years ago now spans the entire length & more than the width & reaches as high as the guttering on the house...
The CIDP's planted on the seafront at Southsea have also grown very fast, some have commented that it may be due to our warmer summer nights, milder winters or higher annual mean than many parts of the UK, no one knows for sure, but they don't grow slowly here for sure...
Well the density is something special as it is the most densely populated place in the UK, fact. And being 12th most densely populated place in the whole of Europe is also fairly noteworthy. Genoa is a bigger city, but Portsmouth is more densely populated, it is that high concentration of buildings which makes Portsmouth an urban heat island similar to central London...
Obviously Genoa is further south, but what does that have to do with anything? It is a larger city but it is less densely populated than Portsmouth. The population density for Genoa is 2483/sq km compared to Portsmouth which is 5145/sq km as we are comparing like for like (within the administrative city limits)...
Portsmouth's data are not "impossible" since we all know it has a mild climate, but they're dubious.
Maybe they were recorded in a inner courtyard, a walled garden, a point sheltered by buildings or trees, or something similar. A place where nocturnal radiation is minimal all year round and where low temperatures stay high.
In each medium/large city may occurr a similar effect at night: airport 0°C - city 2°C - sheltered point 3°C.
But these data are totally not comparable with an airport. In a fictional Portsmouth airport in the nearby countryside, january low would probably be around 2°C.
However, Genoa is not less densely populated at all. The urban area is 64 sq km wide, the remaining 180 sq km of the municipality are mountains and valleys. Density is around 9.000/sq km. The city centre has a density of 16.000/sq km.
This is what I call a high density:
Portsmouth's data are not "impossible" since we all know it has a mild climate, but they're dubious.
Maybe they were recorded in a inner courtyard, a walled garden, a point sheltered by buildings or trees, or something similar. A place where nocturnal radiation is minimal all year round and where low temperatures stay high.
In each medium/large city may occurr a similar effect at night: airport 0°C - city 2°C - sheltered point 3°C.
But these data are totally not comparable with an airport. In a fictional Portsmouth airport in the nearby countryside, january low would probably be around 2°C.
However, Genoa is not less densely populated at all. The urban area is 64 sq km wide, the remaining 180 sq km of the municipality are mountains and valleys. Density is around 9.000/sq km. The city centre has a density of 16.000/sq km.
This is what I call a high density:
The figures are not dubious, they are from the official Met Office weather station in Southsea. Now closed, it was situated in a large open area a few hundred metres from the beach on Southsea common, so far from a sheltered inner courtyard, as a Met Office site it met all the standard regulations...
The closest Met Office station to Portsmouth is the 'Solent' weather station, this is at a small airport several miles west of Portsmouth & the January average low there is 3.4C...
Genoa has a population of 604,848 within the city boundaries in an area of 94 sq miles (243.6 sq km) giving a population density of 2483/sq km...
Portsmouth has a population of 207,100 within the city boundaries in an area of 15.54 sq miles (40.25 sq km) giving a population density of 5145/sq km...
So Portsmouth clearly has a higher population density...
You can see how built up Portsmouth is from these photos:
And if you want to see really densely populated, here is North End in Portsmouth...
Pretty much the whole of the interior of Portsea Island is like this, row upon row of terraced streets...
The figures are not dubious, they are from the official Met Office weather station in Southsea. Now closed, it was situated in a large open area a few hundred metres from the beach on Southsea common, so far from a sheltered inner courtyard, as a Met Office site it met all the standard regulations...
The closest Met Office station to Portsmouth is the 'Solent' weather station, this is at a small airport several miles west of Portsmouth & the January average low there is 3.4C...
Genoa has a population of 604,848 within the city boundaries in an area of 94 sq miles (243.6 sq km) giving a population density of 2483/sq km...
Portsmouth has a population of 207,100 within the city boundaries in an area of 15.54 sq miles (40.25 sq km) giving a population density of 5145/sq km...
So Portsmouth clearly has a higher population density...
You can see how built up Portsmouth is from these photos:
And if you want to see really densely populated, here is North End in Portsmouth...
Pretty much the whole of the interior of Portsea Island is like this, row upon row of terraced streets...
Row houses with gardens = 2 floors. Low density. Low urban heat island effect.
Tall residential buildings with no gardens = 10 floors. High density. High urban heat island effect.
City administrative boundaries are meaningless.
Genoa has a population of 604,848 within the city boundaries in an area of 94 sq miles (243.6 sq km) giving a population density of 2483/sq km...
Portsmouth has a population of 207,100 within the city boundaries in an area of 15.54 sq miles (40.25 sq km) giving a population density of 5145/sq km...
So Portsmouth clearly has a higher population density...
Do you want further information on Genoa's administrative limits?
The city stretches for more than 20 km along the sea from Voltri (West) to Nervi (East). Furthermore, as mar89 already told you, Genoa extends some distance inland on mountainous terrain.
Obviously the population density is not uniform.
The city proper, as you can see from the photos mar89 posted, is very densely populated.
Portsmouth doesn't "clearly" have a higher population density
As for CIDP's growing and thriving in Portsmouth, does it make your city a sort of subtropical paradise?
Does Portsmouth have a constantly mild and benign climate?
Pull the other one!
Row houses with gardens = 2 floors. Low density. Low urban heat island effect.
Tall residential buildings with no gardens = 10 floors. High density. High urban heat island effect.
City administrative boundaries are meaningless.
But the figures prove you wrong
It doesn't matter if Portsmouth is full of more terraced houses than 10 storey blocks, (although it does have plenty of tall apartment blocks in the southern end of Portsea Island), it DOES have a higher population density than Genoa, fact.
City administrative boundaries are not meaningless, it means you can compare like for like & city to city
Not really, it's hardly 'cherry picking' when I post the average temperatures or number of days above x temperature per year.
Cherry picking would be like doing what wavehunter did and use 1 week in December to suggest than London's winters are worse than those in Iceland, despite the averages showing that any winter month in London is sunnier, drier, warmer and calmer than November in Reykjavik.
I agree…maybe that is cherry-picking – one can’t get a true feel for what a typical month is like with just one visit in that month. However, I have been to Paris (close by) several times and I can remember two raw trips in March.
I guess my frustration comes from when people attempt compare one climate to another and MUCH TO MUCH is made out of how one station might be a few degrees warmer/colder than another….while MUCH TOO LITTLE is made about climate genetics.
Stations like London that are poleward of 50 north latitude have different climate genetics at work that stations like Shanghai or Norfolk, VA much of the year. This is “monumentally” true at the time of low sun (winter). The polar vortex in the cold months is much more active above 50 latitude (where London is) than down in the 30’s where stations like Shanghai or Norfolk are located. The same goes for things like the solar angle/intensity – sitting in direct sun in London or Warsaw on a winter’s day (even at the same temperature!) seems to have a different feel than sitting in direct sun at 37 latitude in Norfolk.
My point was that one must spend enough time in several widely spaced latitudes to fully and truly appreciate these differences.
Quote:
Originally Posted by deneb78
I think it's more than record low temps that dictate the growth of CIDPs but the highs as well. Downtown Vancouver hasn't recorded a temp below -10C in more than 30 years and we are in zone 9a. In theory we should be able to grow them here but the days are too cool for too long which weakens them. One extra long cold snap finishes them off here.
This might be one of the few posts from Deb78 that I agree with.
The situation is similar (to a lesser degree) in my town on the Connecticut coast;
The owner of the surf shop on the beach has a weather station and she has not recorded a low below 10 F/-12 C in 16 years, and I have not recorded a low below 13 F/-11 C) in 12 years in my protected microclimate on the south side of my house – that’s 8a/8b, about the same as Myrtle Beach, South Carolina.
For 15 years I’ve taken Sabal palms back from my parents’ house in Florida, from Georgia and SC nurseries…etc, and planted them in my protected, wind sheltered, south facing garden along the Connecticut coast. They made it through a few winters – but about 80% of them eventually died because they were always in such a weakened state. The few that have survived are right up against the south side of the building (like touching the building) in an alcove - and I still only get 3 or 4 fronds a year. My microclimate is the same 8a/b as Myrtle Beach in terms of absolute cold…. but FAR different in terms of winter heat of course. There are landscapes all over Myrtle Beach like this – and the plants they grow out in the open experience the same low temps my protected microclimates do. Why can’t I get my landscape to look the same way – because there is more to it than winter lows.
Do you want further information on Genoa's administrative limits?
The city stretches for more than 20 km along the sea from Voltri (West) to Nervi (East). Furthermore, as mar89 already told you, Genoa extends some distance inland on mountainous terrain.
Obviously the population density is not uniform.
The city proper, as you can see from the photos mar89 posted, is very densely populated.
Portsmouth doesn't "clearly" have a higher population density
As for CIDP's growing and thriving in Portsmouth, does it make your city a sort of subtropical paradise?
Does Portsmouth have a constantly mild and benign climate?
Pull the other one!
The population density I posted is based on the city boundaries of Genoa, as is the population density of Portsmouth. So yes Portsmouth DOES have a higher population density than Genoa, that is fact. Portsmouth also extends outwards into a constant conurbation along the south coast towards Southampton, northwards to Waterlooville & eastwards too, but we are talking about the CITY here, not throwing in a bunch of surrounding suburbs...
And yes CIDP's DO thrive in Portsmouth but no it isn't a sub-tropical paradise & I never claimed it was
But yes it does have a pretty mild climate, so there is no need to be so ignorant about the climate here & believe all the stereotypes about the UK
Not really, it's hardly 'cherry picking' when I post the average temperatures or number of days above x temperature per year.
Cherry picking would be like doing what wavehunter did and use 1 week in December to suggest than London's winters are worse than those in Iceland, despite the averages showing that any winter month in London is sunnier, drier, warmer and calmer than November in Reykjavik.
Most people just seem to assume I am lying because the actual data doesn't fit in with the stereotype.
Stereotype's are a mighty powerful thing! Also this site is full of people from the other side of the world telling locals that they are wrong about things on their own doorstep! Sometimes they try to back things up because they once visited for an hour or two! eg (person from say Argentina: It always rains in London - person from London: Actually London gets less annual rain than Paris, Rome or Istanbul - person from Argentina: You are wrong! I once spent a weekend there and it rained all day on the Saturday!!!!) loooool.
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