Dirty Air, No Rain, or Floods?
Clouds gather, a storm looks imminent ... you grab your umbrella and head for the door, but by the time you reach your destination, those same black clouds have dispersed without a single drop of rain falling, and you realise you should have grabbed your hat instead.
A common scenario these days. No use debating whether we are responsible for both floods and no rainfall at all any more, or indeed whether our manmade pollution affects the atmosphere and global warming. We all know the answer to these questions, no big surprise .. we release huge amounts of pollution particles into the air that are so tiny, they float and have begun to affect our weather. Needless to say that before we began this madness, air above land contained up to twice as many of these so called aerosol particles as air above oceans. Nowadays, this ratio has increased to as much as a hundredfold.
The big question now is how to fix the problem (if we can), or at least maintain it until all the oil runs out?
To find out more about this mystery, an international team of scientists, headed by Prof. Daniel Rosenfeld of the Institute of Earth Sciences at the Hebrew University of Jerusalem, got together to study exactly how dirty air affects rainfall, depending on the local environment. Their findings on the issue of whether air pollution increases or decreases rainfall has been surprising and highly significant for over developed areas like Israel, which suffers from excessive land clearing, man made pollution, and growing water shortages.
Natural and manmade aerosols influence our climate : that much is agreed. But much controversy has remained over which way these particles push the equation? Some believing they produce more clouds and more rain, others claiming that they produce fewer clouds and less rain.
This disputed role of aerosols has been the greatest source of uncertainties in our understanding of the climate system, and the question of global warming and erratic weather patterns, for decades.
Cloud seeding is not new, but its costly as aeroplanes spill salt particles into the lower atmosphere to help nature bind the molecules to the carbon particles that form the rain droplet. But there are no guarantees and worse, eventually it doesn/t work because pollution particles not only increase rainfall, but they can decrease it too!
The question remained .. how?
Publishing their findings in Journal of Science (5th September), the team began with what we did know; clouds, (and precipitation), come about when moist, warm air rises from ground level and water condenses, or freezes onto the aerosol particles, floating in the atmosphere. The energy responsible for evaporating the water from the earth's surface and lifting the air, is of course, provided by the sun.
These little aerosol particles hold all the answers. It seems they play a double role in polluted atmosphere, by giving nature options to producing rain at all. On the one hand, they make like a sunscreen, reducing the amount of sun energy reaching the ground - less water evaporates and the air at ground level stays cooler and drier, with less of a tendency to rise and form clouds. On the other hand, there can be no cloud droplets without aerosols.
Some of the paticles act as the gathering points for air humidity, so called condensation nuclei. On these tiny particles with diameters of less than a thousandth of a millimetre the water condenses (similar to dew on cold ground), releasing energy in the process. This is the same energy that was earlier used to evaporate the water from the earth's surface. In these cases, the released heat warms the air parcel, so that it can rise further, taking the cloud droplets with it ~ to about 40,000 feet ~ where they gather to critical mass, eventually falling back to earth as rain.
This latest finding has revelaed that if there is a surplus of these gathering points, the droplets never reach the critical mass needed to fall to earth as rain : there just is not enough water to share between all the aerosol particles, there are just too many to bond with. Also, with a rising number of droplets their overall surface increases, which increases the amount of sunlight reflected back to space, cooling and drying the earth even more.
IN A NUTSHELL THEN: With rising pollution, the amount of precipitation at first rises, then maxes out and finally falls off sharply at very high aerosol concentrations. The practical result is that in relatively clean air, adding aerosols up to the amount that releases the maximum of available energy increases precipitation. Beyond that point, increasing the aerosol load even further, lessens precipitation. Therefore, in areas with high atmospheric aerosol content, due to natural or manmade conditions, the continuation or even aggravation of those conditions can lead to lower than normal rainfall, and even man~induced drought.
Stale mate?
Maybe not . The lead author, Prof. Rosenfeld thinks not, feeling that the study results should act as a red light to all of those responsible for controlling the amounts of pollution we release into the atmosphere."
I hope he is right, and someone is paying attention?
A common scenario these days. No use debating whether we are responsible for both floods and no rainfall at all any more, or indeed whether our manmade pollution affects the atmosphere and global warming. We all know the answer to these questions, no big surprise .. we release huge amounts of pollution particles into the air that are so tiny, they float and have begun to affect our weather. Needless to say that before we began this madness, air above land contained up to twice as many of these so called aerosol particles as air above oceans. Nowadays, this ratio has increased to as much as a hundredfold.
The big question now is how to fix the problem (if we can), or at least maintain it until all the oil runs out?
To find out more about this mystery, an international team of scientists, headed by Prof. Daniel Rosenfeld of the Institute of Earth Sciences at the Hebrew University of Jerusalem, got together to study exactly how dirty air affects rainfall, depending on the local environment. Their findings on the issue of whether air pollution increases or decreases rainfall has been surprising and highly significant for over developed areas like Israel, which suffers from excessive land clearing, man made pollution, and growing water shortages.
Natural and manmade aerosols influence our climate : that much is agreed. But much controversy has remained over which way these particles push the equation? Some believing they produce more clouds and more rain, others claiming that they produce fewer clouds and less rain.
This disputed role of aerosols has been the greatest source of uncertainties in our understanding of the climate system, and the question of global warming and erratic weather patterns, for decades.
Cloud seeding is not new, but its costly as aeroplanes spill salt particles into the lower atmosphere to help nature bind the molecules to the carbon particles that form the rain droplet. But there are no guarantees and worse, eventually it doesn/t work because pollution particles not only increase rainfall, but they can decrease it too!
The question remained .. how?
Publishing their findings in Journal of Science (5th September), the team began with what we did know; clouds, (and precipitation), come about when moist, warm air rises from ground level and water condenses, or freezes onto the aerosol particles, floating in the atmosphere. The energy responsible for evaporating the water from the earth's surface and lifting the air, is of course, provided by the sun.
These little aerosol particles hold all the answers. It seems they play a double role in polluted atmosphere, by giving nature options to producing rain at all. On the one hand, they make like a sunscreen, reducing the amount of sun energy reaching the ground - less water evaporates and the air at ground level stays cooler and drier, with less of a tendency to rise and form clouds. On the other hand, there can be no cloud droplets without aerosols.
Some of the paticles act as the gathering points for air humidity, so called condensation nuclei. On these tiny particles with diameters of less than a thousandth of a millimetre the water condenses (similar to dew on cold ground), releasing energy in the process. This is the same energy that was earlier used to evaporate the water from the earth's surface. In these cases, the released heat warms the air parcel, so that it can rise further, taking the cloud droplets with it ~ to about 40,000 feet ~ where they gather to critical mass, eventually falling back to earth as rain.
This latest finding has revelaed that if there is a surplus of these gathering points, the droplets never reach the critical mass needed to fall to earth as rain : there just is not enough water to share between all the aerosol particles, there are just too many to bond with. Also, with a rising number of droplets their overall surface increases, which increases the amount of sunlight reflected back to space, cooling and drying the earth even more.
IN A NUTSHELL THEN: With rising pollution, the amount of precipitation at first rises, then maxes out and finally falls off sharply at very high aerosol concentrations. The practical result is that in relatively clean air, adding aerosols up to the amount that releases the maximum of available energy increases precipitation. Beyond that point, increasing the aerosol load even further, lessens precipitation. Therefore, in areas with high atmospheric aerosol content, due to natural or manmade conditions, the continuation or even aggravation of those conditions can lead to lower than normal rainfall, and even man~induced drought.
Stale mate?
Maybe not . The lead author, Prof. Rosenfeld thinks not, feeling that the study results should act as a red light to all of those responsible for controlling the amounts of pollution we release into the atmosphere."
I hope he is right, and someone is paying attention?





















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ive read alot on how CFCs break down ozone and change how the sunlight penetrates the atmosphere but i think this is the first thing ive read on how pollution affects precipitation!
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Interesting that you lived in China..
Wow, when was that ... surprised that they used rockets for cloud seeding..
Thats upper atmosphere stuff. They must have been experimenting because although I know they tried the upper atmosphere in Europe, it was the lower atmosphere science that seemed to work best. There is so much cutting edge science coming out of both Russia and China that is so overlooked by the western world. Especially Russia (both amaze me in their breakthroughs towards truth and not deception too) ... not surprising really, who can hear them above the roar / screech of the Mighty Eagle... so much so that sometimes i wish they'd shut up. Reason?
Some truths perhaps in Dan Browns, Deception Point perhaps?
Certainly there is in China building a space platform for the highest bidder, which if you read the book outlines clearly why NASA has tried to maintain control of space : the absolute peril another unregulated space platform will place us all in on terra firma is mind boggling. Not surprisingly from rich American cowboys who want to drag in meteorites for mining without a single thought towards the earths polarities and gravity fields. Luckily NASA has held the monopoly (manuafacturing continuing reason for its presence perhaps yet costing some $11 million a year). Too bad when China opens up to the highest bidder?
But I digress : Outside of Israel, (and perhaps Germany), I think China is leading the world in cloud seeding technologies, so much so that I was really amazed to see them using cannons from the ground to seed before the olympics?
I didn't think it could work that low... so they must know more than me?! *chuckle* .. which is what triggered of this research of mine to find out..
... fascinating stuff ..
Thanks for commenting.
Lilla ...
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As far as I am aware (and I am not a qualified scientist), but we are only talking about the carbon particles as they form the centre of the condensation nuclei and the droplets attach to them directly. When there are too many ther is confusion and not enough water to go around, so my understanding is that mother anture just simply goes, forget it then!
Hydrogen particles form a different cycle I think.
I'll PM you if I find out anything to the contrary (or perhaps youll let me know here, if I have got it wrong?)
The way I understand it from one scientist, is that Cloud seeding removes mother natures ability to choose, by the interfence of a kind of salt, causing whatever water is available to attach and produce whatever rain, regardless. I am still not sure how they get it to rise to critical mass though ... although logic would dictate that a water droplet is a water droplet is a water droplet and that it will gather height and weight to the point of critical mass anyway?
But then when is mother nature logical?
Lilla ...
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Thanks for your comment, glad you found it interesting.
I am fascinated by the ideas that scientists come up with to fix the problem their predecessors created and the ones we perpetuate daily as rabid consumers.
The irony of it all cracks me up sometimes ...
I am reminded of spiders who eat their limbs when they run out of food, to the point of their own eventual death. Still I guess you gotta keep trying and (like the Kangaroo) it is mankinds nature to move forward and not consider a pause, or retraction?
Having said all that, I am pretty sure they will succeed in sorting out a way to keep the rain falling despite the amount of pollution particles in the air, my concern is in the filtering of it (and the air itself) as it reaches a saturation point of toxicity?
Lilla ...
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too funny, i guess they think somehow the limbs will grow back...
and Lilla I am o scientist either, much as I try my eyes glaze over,
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No none at all! We'll all adapt and become lizard~like with those eyelids that dont close but blink in funny ways...
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Oh I think we will (since we created the mess) ... or dye trying?
Too bad for us, as I said on one of louies post, those with their fares already paid for MIA will be okay, so I guess it'll all start again ... So much like Wall.E.
Glad you enjoyed the read.
Lilla ...
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I am curious as to why you felt the differentiation in particle types, was important to this post?
Lilla ...
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Oh nothing erks me more, truly .. as if the poor blighters are guaranteed to have the opportunity to do that after their grandparents have taken three times their share.
We just keep on expecting the planet to cope, dont we, world without end stuff alright ... but from a pragmatists point of view, I think you are spot on.
The rality falls so short of the ideal.
It is wonderful to see you about on orble again .. take it easy hopping about wont you?
*smile*
Lilla ...
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Thanks for the lovely compliment.
Wow. Now if only we could get he governments of the western world to acknowledge the incredible need for new infrastructure methods to support sustainable resources... water tanks for each house perhaps, and solar panels, etc.. you know the stuff that they just dont seem to be able to *move on*
Further dissapointment too as I heard on the radio this morning that our govt. is pulling back on the solar subsidy grants as they had too many calls!!!
I too am incredalous?
Lovely to see you, hope alls well with you all.
Lilla ...
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I want to thank you so much for presenting this information in such an informative manner. I appreciate all that you do to give Orblers food for thought!
Mis
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Thank you. It is nice to see those words written.
I am sure many benefit from me writing them too, I figure someone has to try and make it simple enough to understand, even if it is rocket science.. *wink*
always a pleasure to see you out and about, look forward to having a drink one day.
Lilla ...