Cities Influence Their Own Weather

CalamityJones writes "In the 'Well, DUH!' department, this story from the AP shrieks 'Cities May Make Their Own Weather.' As if anyone with half a brain could possibly have missed this point." Not having a weather supercomputer to crunch the numbers, it wasn't quite that obvious to me, but then what do I know. Living in Michigan I'm used to the lake effect - if I lived east of some major asphalt, I guess I'd get the L.A. effect.

An explanation ...

[Jim Tyre (100017)]

The story sez:

But in Atlanta, the new research showed storms popping up around the city on otherwise clear days.

There is an explanation for this.

It is called the John Rocker effect.

(Sue me, I'm a baseball fan.)

Urban Greenspace

[Whyte Wolf (149388)]

A major contributing factor is that developers recklessly chop down trees to make room for suburbs, the scientists said. Trees provide shade from the heat and absorb many of the sun's harmful rays. Without them, the effect is a sort of urban desert.

I come from a very rural part of Canada--the smallest province in fact, and on Prince Edward Island we have lots of trees, and not much in the way of urban sprawl.

My first experience in the big city came quite a few years back when I moved to Calgary, Alberta, and in retrospect I feel very lucky. Calgary has an imense amount of greenspace within it's limits--heck we still see deer and get the occasional bear in the 'berbs.

However, coming from the countryside as I do, I have to say I do miss the trees. If I lived in a larger or more urban city, I'd likley have worse bouts of homesickness :)

People who grow up in cities often don't see nature the same way I do. Parks are very organized in comparison to raw Canadian wilderness. That said, I'd love to see more green in the urban landscape--and there does seem to be a larger move towards this kind of 'greening of the urban jungle.'

I remember a report several years back about a high-tech company in Toronto adding an atrium to their front lobby--one that was essentially a giant watershed (read swamp). A fascinating concept--no less than the idea of planting trees and creating parks on the roof's of office buildings.

I guess what I'm saying is that it's nice to see everyone--urban pesant and country hick living in the big city, see the benefits of greening our cities.

Maybe one more would be weather moderation. With the thunderstorm raging outside my window right now, that would be a welcome change :)

obvious?

[nomadic (141991)]

The problem with doing this sort of research is the tremendous amount of variables (it's why we can't forecast the weather more than a few days in advance); how exactly it changes seem to differ from region to region. Some industrial cities in Britain show cool islands, presumably from the water released by industrial processes. Cities in western desert areas often have lower temperatures due to increased vegetation and surface water (though the increased humidity often makes it more uncomfortable). If you have access to a good library, Robert Balling [aapg.org] is probably the best known researcher working on it today; for fundamentals on urban climate, anything by Helmut Landsberg on the subject would probably be informative.

The problem is really, what are we going to do about this? A few storms are one thing, but a lot of cities are probably going to be running out of water in a few decades due to the fact that nobody wants to tell people things they don't want to hear; things like maybe the environmental health of a region is more important than having a really nice lawn or golf course, or that just because you've had a constant supply of water for the past 100 years, that it's going to continue. There's a very good reason that only recently have desert areas started attracting real estate development; through most of history they haven't been sustainable. And just because we have better plumbing and air conditioning that didn't exist a hundred years ago doesn't mean the environment has gotten better for us on an environmental level.

I guess I'm seriously off-topic, but I sometimes obsess with this subject the way some people obsess with the GPL license or open source...

10,000 years of sheep

[Perdo (151843)]

Cities are a minor effect on the weather when it comes to man made alterations. The weather is "critically dependent on initial conditions" (chaos theory) So, to find the things that man has done you need to look far into the past and find the event with the greatest impact in its time. I believe it is sheep grazing. In Kuwait the US Army has a firing range where no Bedouin shepherds are allowed. The Impact area is verdant and lush. It looks a lot like the great plains (USA) do. Outside of the impact area sheep over graze, ripping vegetation out by the roots, leaving baked dust and sand. This has gone on for thousands of years. Kuwait is very near the Tigris and Euphrates rives, the cradle of civilization. The entire middle east is man (domestic sheep) made desert. About the time god cast man out of Eden he also decided that being a shepherd was better than being a farmer(Cain and Able). I speculate that early man even in Africa domesticated animals and possible even created the Sahara. The loss of Eden was not from god, but man destroying Eden. Cities are recent have a small effect compared to the thousands of years man made deserts have had to work their magic on the environment.

Re:I heard there was a way to minimze tornados...

[thogard (43403)]

There seems to be lots of evidence in Oklahoma that manmade stuff effects the weather. For example tornados will follow highways. A picture taken on the founding day of Ponca City shows no trees at all. The land was thick grass at the time (the bufflo had not been clearing it for years) but that was cleared to farm. The result was the dustbowl. The solution to that problem was lots of trees. In Kansas now you can see lines of trees along the edge of the farms on the section line roads. Its amazing how well a few trees stop the wind from building up. The large number of man made lakes in Oklahoma have also increased the rainfall in the area.

As far as dropping something from a plane into a tornado, I don't like the idea of that. The tops of the cloud cells that make tornados in Oklahoma are offten 50,000 ft and have large amounts of windsheer. Flying in a huracane is one thing but a tornado is just too intense. When the F15s get retired nasa may try to adapt one to radio control for just this theory but I think the current plans involve the plane not getting back.

Phoenix, AZ

[cr0sh (43134)]

When I came here from Cali, the first year I was here (1991, fresh outta high school), we had an awe inspiring monsoon season. That was the last good monsoon I remember (though there was one a couple of years later that literally turned the street in front of my employer's office into a river, but a I digress).

I remember extreme thunder and lightning, and super heavy rains for many days straight (not constant rain, just rain that when it came down, it came down HARD) - the kind of storm where you turn out the lights, go outside, and watch.

At the time, I was living downtown. There wasn't a whole huge amount of development around the city like there is today. This year, I moved to a house north of the city - out in the more desert area (you know, we have like - coyotes, rabbits, ground squirrels, bats, birds by the ton - and saguaros in the front yard). This season hasn't been any better. Sure, it has been cooler (we are in our monsoon season right now), but it hasn't been rainy. On the days where it seems like it would rain, the clouds appear to part, and go "around" the city.

I blame it on all of the development - the leveling of desert to put in homes (the house I am in is close to 30 years old - when it was built, the desert was all around it, and the edge of Phoenix was a good 10 miles or more away), getting rid of foliage and scrub, leaving pavement, and a kind of "designed" desert area (where all the saguaroes are "just so" - and things are arranged "just right" - and no cholla allowed, lest someone get hurt!) - none of which helps to prevent what I think of as a "heat bubble" effect - which the clouds drift around.

Only on days where the cloud buildup has happenned in the previous night do we have any chance of a good rain during the monsoon. Even then, it is only a trickle...

I want my thunder and lightning back - dammit! (hey, I got UPS's on my system - come and get me!)...

Re:I heard there was a way to minimze tornados...

[spectecjr (31235)]

On a local news (KNBC (L.A.) if I remember correctly), there was a story about how this guy found a way to minimize tornados.

If it doesn't involved building a ring of trailerparks around the city you're trying to prevent them in, I'm very doubtful that it'll work :)

Simon

Re:I heard there was a way to minimze tornados...

[The_Messenger (110966)]

F-15E's have enough power to accelerate while flying straight up, but I still wouldn't send one into a tornado. ;) Above it, maybe. How high to you have to get to escape the winds and flying cows? I don't think it would require a low orbiter...

Hmph. :\ Why should we try to control the weather? I think that's awfully arrogant. If science acheives this, we're just asking for nature to bitchslap us; think "Titanic", but with reprecussions affecting more than a few hundred rich tourists (and Leonardo Dicaprio, of course).

---------///----------

Urban heat islands, people.

[GianfrancoZola (6069)]

The built-up area of cities produces 'islands' of higher temperatures, for a number of reasons, among which are:

Manmade materials like concrete, asphalt, bricks, etc. absorb solar energy much more readily than vegetation.

Water almost completely runs off because there's so much concrete everywhere, instead of standing around and slowly evaporating. Evaporation can make a significant contribution to cooling.

Waste heat from vehicles, residences, etc. doesn't help the situation.

Urban heat islands are pretty well understood. You can get nice images of them--temperature contrasts, that is--from AVHRR (Advanced Very High Resolution Radiometer) remotely-sensed imagery.

cf. W.B. Myer, "Urban heat island and urban health: Early American perspective", Professional Geographer 43, 1991, p. 38 if yer curious for a little more.

Throw more heat up into moist summertime air and that's a good prescription for thunderstorms.

Re:weird stuff...

[Frymaster (171343)]

He might mean it's being pushed down from 'Brown Cloud' level to street level.

hmmm... ground-level o3 does tend to occupy the top-bit of inverted thermal domes... a good thing as it tends to keep it out of our lungs. In theory though, ozone should only be a problem if you have:
1. the thermal inversiona from hell
2. A much-bigger-than-normal amount being produced.. ie, 250 vand de graff generators running a street level.

I vote for number 1 since if there were 250 van de graff generators being run at street level anywhere cmdrTaco would have run it as a story... viz:

posted by cmdrTaco [example.com] on Monday July 10 @04:22AM
from the It-makes-my-hair-stand-on-end-but-in-a-good-way dept.
BozoTheClown writes "The Mayfield Daily Blatt has this story [example.com] about an high school science teacher who is trying for the Guiness record for "largest baloon stuck to wall with static electricity". He has a full size replica of the Hindenberg (no, not hydrogen filled, thank god) and, get this, 250 full-sized van de graff generators... better than rubbing the blimp on your head!" 250? Wow, that's like a Beowulf cluster of van de graff generators!!

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