Changed wind conditions - A question to pilots in Sydney

[old man emu]

If you fly gliders out of Camden, or use the airspace southwest between Bankstown and Camden, I wonder if you can give me some information?

 

Have you noticed any changes in the strength or direction in the winds, or in the behaviour of thermals over the past five years or so?

 

The background for my question is that, over the past five years, there has been an explosive increase in the area which has changed from pasture land to residential use. The majority of houses which have been built have dark coloured roofs.

 

What I am wondering is, "Has the heat stored in these dark coloured roofs due to their low albedo resulted in increased heating of the air moving over the residential areas, thereby increasing the size and strength of thermals, and increasing the strength of the afternoon nor'easterlies.

 

Albedo is the measure of diffusive reflection of solar radiation out of the total solar radiation received by a body. A high albedo means it reflects a lot of solar energy and a low albedo means it absorbs a lot of solar energy

 

Here are some sample albedo values. The range of possible values is from zero (totally unreflective) to one (fully reflective).

 

New asphalt, 0.04 - 0.05

 

Aged asphalt, 0.1 - 0.12

 

Bare soil, 0.17

 

Deciduous trees, 0.15 - 0.18

 

Green grass, 0.25

 

Aged concrete, 0.2 - 0.3

 

New concrete (traditional), 0.4 - 0.55

 

New concrete with white portland cement, 0.7 - 0.8

 

Water, 0.03 - 1.0

 

Soil (Dark/Wet) 0.05

 

Soil (Light/Grey) 0.4

 

Sand 0.15 - 0.45

 

galvanized steel - 0.24

 

terra cota tile - 0.28

 

tar & gravel - 0.33

 

Notice that the good old terracotta tile has an higher albedo than trees, so the old areas of Sydney might be cooler than the the bush they replaced.

 

And I'll castrate the first bloke who introduces libido to the discussion.

 

 

[SDQDI]

Well technically OME you introduced said subject into the conversation first and assuming you are a 'bloke' I think you will be performing said castration upon yourself.

 

But otherwise am watching this thread in interest as the whole stronger thermal thingy interests me.

 

 

[Old Koreelah]

... the area which has changed from pasture land to residential use. The majority of houses which have been built have dark coloured roofs...

Interesting point, OME. I bet the dark roofs cause more thermals. I despair for my country when I see so many dark-coloured houses- totally dependent on air conditioners to cope with Australia's not climate. No wonder our power network overloads on hot days.

 

No verandahs. Bugger all eaves, near-black walls and roof. After two centuries in this place we've learned nothing.

 

Dumb.

 

 

[old man emu]

The fault lies with the people who do the appearance design of these buildings. After all, they are calling for dark grey roof tiles, which are made by adding colouring compound to the brick pre-mix. They could just as easily call for terracota colours and the manufacturers would simply change the colouring compound. Same for the bricks.

 

Why are the buildings on the Greek Islands, such as Santorini, white? Why do men in the Middle East go about in white clothing? It's all about taking advantage of albedo rates.

 

We did develop a building style suited to a hot, dry climate,

 

 

but you can't have houses like this when developers want to cram as many house lots as they can per acre as they have done in Gregory Hills, near Camden

 

 

 

[Old Koreelah]

...you can't have houses like this when developers want to cram as many house lots as they can per acre as they have done in Gregory Hills, near Camden.

I disagree, OME. Of course we can design hot-climate housing for small blocks. It just requires a little imagination. Australia produces world-class architects, but too many of them are working overseas where their talents are appreciated. Back home, most people have to take what they can get- and too much of it is crud. Near-identical, poorly-designed houses with uniform high metal fences and no room for kids to play. Slums of the (near) future.

 

Australia's love affair with the individual houses is no longer appropriate when suburban blocks have become so small. Many of our social problems stem from expecting nuclear or single-parent families to live in urban feedlots for humans, far from services and family support. The escalating cost of Childcare for busy young parents is being matched by the escalating cost of housing our idle elderly. Can't anyone in power see the obvious solution?

 

We'd be far better off learning from people overseas, and living in small unit blocks with shared facilities and outdoor space. Several generations in the one building; neighbours of all ages to help each other and enrich lives. Many of our immigrants already do this. Why can't we learn from them?

 

 

[BirdDog]

It beggars belief as to why you would put black tiles on a house in Australia. I purchased a fully enclosed trailer a while ago and it was a dark green colour. After about a week I realised it was getting VERY hot inside, and considering I was transporting some PA and instruments in it, I went about fixing the problem. Easy fix - I painted it white. Now, the temp inside is amazingly cooler than it was when it was green.

 

I don't understand the whole black roof thing!

 

 

[Old Koreelah]

Given the widespread availability of science-based information, there is an amazing shortage of common sense in people, and especially in our decision-makers.

 

I'd like a dollar for each time someone has told me that "black attracts the heat...".

 

 

[facthunter]

Black absorbs all colours of the spectrum and infra red as well. A black object like a car gets very hot in the sun, while a white or polished aluminium one will not absorb anything like as much heat.. The same applies to radiated heat from bushfires . Dark houses are not good for that situation.. Nev

 

 

[old man emu]

An interesting paper on the subject, written in 1992.

 

High-albedo materials for reducing building cooling energy use (Technical Report) | SciTech Connect

 

 

[facthunter]

ISIS using black . Not a sign of appropriate application of science. Dumb? Nev

 

 

[Yenn]

If Australia produces world class architects I wonder what happens to them.

 

I have worked with architects and found them to be pretty useless. They have little idea of how to make a house liveable.

 

About all they can do is cause the costs to blow out for the house they design.

 

 

[old man emu]

My wife has said, "You can tell this kitchen was designed by a man", of every house my wife and I have lived in.

 

Our current house has the hot water service 10 or more metres from the area closest to the kitchen, laundry and en suite. There is a perfect alcove outside each of these rooms where a water heater could be placed.The only bathroom close to it is the family bathroom which, being Darby and Joan, we don't use. We waste heaps of water waiting for hot water to reach the kitchen sink or en suite shower. (Wash in cold water).

 

 

[facthunter]

They do often lack a practical understanding of how a structure is "detailed". Their course isn't a building course. Nev

 

 

[facthunter]

It pays to concentrate the plumbing in one area, Cost and efficiency, especially the hot water bit.. Smaller section pipe helps but cuts flow rate.. Nev

 

 

[derekliston]

Interesting discussion. We used to live to the East of Amberley airbase in Qld. We used to watch storms approaching from the West and then they would split and go North and South around us. It was suggested that this was caused by the thermal activity due to the vast expanses of concrete and also the steel hangars, hence the rising air currents split the storm in half. I am absolutely no weather expert but it sounds feasible to me.

 

 

[facthunter]

I'm not convinced of that reason although the concrete may still be a factor. If you want to limit a cumulus cloud development reduce the moisture in it. That's where it gets it's energy from. Nev

 

 

[nomadpete]

Regarding the original question, my pondering brings me to question the influence of heat reflection (from roofs), on atmospheric thermal activity.

 

I note that asphalt absorbs heat very well. There is a lot of asphalt in new estates. Absorbed heat = higher re-radiated heat later in the day. Gliders often (in treed bush) find the last thermal of the day comeing from the release of heat stored in foliage. I'd suspect that the matrix of roads would create a layer of warm air just right to set off a thermal. I've sometimes found good air (rising air) by following a highway.

 

 

[ClintonB]

I have found the trend of black and silver caravans to be quite pointless (except for a new look) I have measured the wall temps at 30 degrees hotter externally than the white ones in same amount of sunlight. With 19 to 25 mm wall thickness an aircon struggles to cool the inside. Colours make a huge difference in heat absorption. Even black decals make the fibreglass sandwich panels gas up and bubble the surface.

 

 

[spacesailor]

And now:

 

Has anyone tried putting "microspheres in the paint?. I used it on a cruising yacht with good results (flush decked).

 

so will it work on a very hot galvanized roof, collects extra heat very quickly. 40 D c outside & 51 inside (ouch too hot to work in there).

 

spacesailor

 

 

[coljones]

I disagree, OME. Of course we can design hot-climate housing for small blocks. It just requires a little imagination. Australia produces world-class architects, but too many of them are working overseas where their talents are appreciated. Back home, most people have to take what they can get- and too much of it is crud. Near-identical, poorly-designed houses with uniform high metal fences and no room for kids to play. Slums of the (near) future.Australia's love affair with the individual houses is no longer appropriate when suburban blocks have become so small. Many of our social problems stem from expecting nuclear or single-parent families to live in urban feedlots for humans, far from services and family support. The escalating cost of Childcare for busy young parents is being matched by the escalating cost of housing our idle elderly. Can't anyone in power see the obvious solution?

 

We'd be far better off learning from people overseas, and living in small unit blocks with shared facilities and outdoor space. Several generations in the one building; neighbours of all ages to help each other and enrich lives. Many of our immigrants already do this. Why can't we learn from them?

It used to be a 15 Square (about 10m**2) on a quarter acre block. The norm now appears to be 25m**2 on a 1/8 acre block, filling it to the boundaries with no green space, no eaves, much A/C and electric clothes drying (McMansions) - the new age slums are with us now.

 

 

[Jerry_Atrick]

certainly looked that way from the aerial photograph, above

 

 

[Litespeed]

As a aside from dumb colours and cooling costs

 

I was in the previous century, a chimney sweep in the blue mountains and all the post war houses had the fireplace/slow combustion on the perimeter wall. Absolutely stupid, a massive heat loss, lots more wood used and the bedrooms would be cold. Also a huge fire risk if not properly cleaned, which given a tall chimney or pipe at the edge of the building rather than on the ridge, meant most were never properly cleaned.

 

And it was bloody dangerous for me the sweep.

 

Brainless bloody builders and developers.

 

 

[Ayecapt]

I have often thought that the Sydney basin generates its own weather effects. I cant prove it , but they seem to get many more severe events ( hail strong thunder storms ) than we do here in the Hunter region.

 

Energy cannot be destroyed . So each car , electric train , airconditioner or person simply converts or moves energy from other forms back into heat. Looking at cars alone every bit of energy in the fuel air mixture ends up as heat. Waste heat from engines, rolling resistance and brakes etc . So all this stored energy from fuels ( electricity, oil, gas and food). All enters the atmosphere. It must have an effect on local weather ?

 

 

[Ayecapt]

It used to be a 15 Square (about 10m**2) on a quarter acre block. The norm now appears to be 25m**2 on a 1/8 acre block, filling it to the boundaries with no green space, no eaves, much A/C and electric clothes drying (McMansions) - the new age slums are with us now.

Money rules the world and us cattle provide the means of obtaining it.

 

We fly cattle class and we live cattle class !

 

 

[Old Koreelah]

If Australia produces world class architects I wonder what happens to them.I have worked with architects and found them to be pretty useless. They have little idea of how to make a house liveable.

About all they can do is cause the costs to blow out for the house they design.

Some of our best Aussie architects have spent the past decade or so employed in building booms overseas- The Gulf, China, SEAsia...

Perhaps there's not too much talent amoung the ones left behind...