From NASA Science News: I’ve always wondered what cumulative effect increased global shipping might have on low level clouds over the ocean. These NASA images suggest ship cloud tracks are much like contrails following jets, though with differing mechanisms.
Clouds form when water vapor condenses or freezes onto tiny solid or liquid particles, such as dust, soot, or crystals of sea salt. Over the remote ocean, the air is usually cleaner than it is over land, so there are fewer particles to act as seeds for cloud droplets. The scarcity of particles means that the droplets that do form grow relatively large.
This pair of images demonstrates how air pollution can change the size of droplets in marine clouds. The top image is a photo-like view of the North Pacific Ocean (south of the Aleutian Islands) on September 29, 2009. A blanket of clouds—a little thin in places—spans the scene. The lower image shows the size of cloud droplets within the area outlined in white in the top image. Bigger droplets are darker colors (blue, purple); smaller droplets are brighter (pink, yellow).
The bright yellow arcs that streak the marine cloud layer are ship tracks—clouds that form when water vapor condenses onto the myriad tiny pollution particles in ship exhaust. There are more seed particles in ship exhaust than are found in clean marine air, and the available water vapor gets spread out more thinly among them. Because the available water is spread among more particles, the cloud droplets that form in the ships’ wakes are smaller than typical marine layer cloud droplets.
By increasing the number and decreasing the size of cloud droplets, pollution often makes clouds brighter (more reflective to incoming sunlight), in the same way that a crushed ice cube is more reflective than a solid one. In this image, however, the ship tracks don’t appear significantly brighter than the surrounding cloud layer, perhaps because the cloud layer was already fairly bright. (A March 2009 image from this area demonstrates the cloud-brightening effect more dramatically).
In marine layer clouds, an abundance of small particles may also delay the onset of precipitation, which depends on cloud droplets colliding and coalescing into larger, heavier drops. Said another way, pollution can increase the lifetime of clouds.
Human pollution has likely been modifying clouds on a global scale throughout the modern (industrial) era. In fact, climate scientists suspect that these modifications—increasing cloud brightness and lifetime—have probably helped offset some of the warming influence of rising greenhouse gas concentrations.
NASA Earth Observatory image created by Jesse Allen, using data obtained from the Goddard Level 1 and Atmospheric Archive and Distribution System (LAADS). Caption by Rebecca Lindsey.
- Instrument:
- Terra – MODIS
Why do ships move in such daft curves? Or is this a north-westerly wind showing up?
How will the changing quantities/types of particles released by industry over the last 200 years affect clouds, and will the reduced amount as a result of the clean air acts have improved things?
I’m surprised I didn’t see any obvious reference above to Prof. Nir J Shaviv’s interesting discussion of ship tracks which he posted quite some times ago:
http://www.sciencebits.com/ship_tracks
That’s really neat, though it’s gotta be a hugely smaller effect than contrails. Contrails add albedo when there may be clouds below, but often when there’s clear sky below. These add albedo to an already high albedo environment.
Methinks muons have a bigger effect, though from that other image it appears ship exhaust can make clouds where their are none.
Does that mean increased shipping provides a negative feedback that partially offsets the increase CO2 emissions during economic growth?
Tom says:
July 22, 2010 at 4:19 am
> Why do ships move in such daft curves? Or is this a north-westerly wind showing up?
My guess is it’s showing horizontal wind shear – the ship may be leaving an area of high winds and moving to an area of low winds. It could also be a temporal thing – if wind speed is declining over a large area that would produce the same effect.
“Ship Tracks – what do they do to albedo?”
What, the whole Earth’s albedo?
Naff all. A cloud droplet in the ocean.
In fact, climate scientists suspect that these modifications—increasing cloud brightness and lifetime—have probably helped offset some of the warming influence of rising greenhouse gas concentrations.
Global dimming reinvented?
Offtopic news –
[snip]
Reply: Take it to tips and notes please. Thanks RT-mod
Back in February, I think, there was a post here about a geo-engineering solution using special ships to throw tons of salt water high into the sky to form clouds like these. Seems to me that instead of building new ships they could retrofit existing ships with a small version of that and come out ahead in the long run. Less water per ship, but many more ships, and they’re already spanning the seas.
So that’s why they switched from global warming to climate change.
When the climate starts cooling, the emissions of industrial civilization can be blamed for bringing on the cooling as a result of increased cloud formation.
They getcha coming and going.
According to Woods Hole Oceanographic Institution, the oceans sality has changed on the surface of the oceans. This would mean any disruption(such as ships) would bring up the normal salty ocean water and also the evaporation water trail.
One thing I found that NASA REALLY stinks at is cross referencing!
A quote “Human pollution has likely been modifying clouds on a global scale throughout the modern (industrial) era. ”
Where to start…hmmm.
Dams? Oil industry? Water trapping, consumption and waste facilities? Aquifers? Water trapping and transportation for products and industrial use? Housing and industrial land/farm land?
We have changed the evaporation patterns of the planet on a large scale including billions of gallons per day being used and in some cases such as oil production never to be used again(pumped into wells for pressure).
Tom: “Why do ships move in such daft curves? Or is this a north-westerly wind showing up?”
It’s called “The Great Circle Route”. Going toward the poles decreases the longitudinal distance traveled. It’s actually faster that way. The same reason ballistic missiles are intended to go over the poles.
[reply: Atmospheric effects in this case I think. RT-mod]
@Tom who said: “Why do ships move in such daft curves? Or is this a north-westerly wind showing up?”
This is south of the Aleutians. Could be fishing vessels.
Cap and Trade would drive even more manufacturing overseas. Taking production from the United States that has stricter pollution laws to less developed countries. So the air, water and land will be affected by more “real” pollution if the United States is forced to produce less CO2. Then those products must be shipped to the US leading to even more pollution. But it looks like by limiting the US CO2 output it really will cool the planet. Just not by the methods the warmists think.
# TomB says: July 22, 2010 at 6:50 am It’s called “The Great Circle Route”.
If the image does not only shows the track from ships going from right to left, but also from left to right (much weaker to identify), it is not a Great Circle Course but presumably wind, which would mean in opposite direction over a short distance of height. That would be astonishing.
Well, perhaps I stand corrected. But I find it amazing that these “trails” could hold together so well for so long. Overall a fascinating article and observation.
DCC – I think you nailed it. Fishing vessels running outrigger nets would curve around schools of fish. The size of the clouds kind of makes the idea of a “Great Circle Route” a non-starter. Puffy little “sheep” clouds hanging close to the water makes this image a small part of a much larger image, at least based on my experience with the marine layer.
oxonmoron says:
July 22, 2010 at 4:35 am
“I’m surprised I didn’t see any obvious reference above to Prof. Nir J Shaviv’s interesting discussion….”
Ah, but isnt Shaviv on the Black-List?? The inquisition wouldn want a reference to an heretic, mind you!
Just follow them and you’ll find a pot full of gold!, like the rainbow…keep following these “out of the limb” tracks and you’ll end up in the realm of Oz. 🙂
What the above is trying to say is: YOU ARE GUILTY DAMNED HUMANS!, you must stop polluting the air and the seas. Either you stop polluting or commit suicide.
We’ll try to help our Gaia by promoting abortion, the day after pill, the AH1N1 vaccination and “non reproductive sexual behaviors” among other intelligent measures which can only be the product of inspiration from our most holy elite of chosen ones.
When flying with the Canadian Air Force on anti-submarine patrol over the North Atlantic we often had to find ships without using radar. It was called passive search and done because we were looking for what were called Electronic Intelligence (ELINT) Trawlers. These were fishing vessels working among the vast Soviet fishing fleet that were actually festooned with antenna and monitoring all electronic emanations. They had the ability to detect when they were being detected by radar hence the need for a passive search.
We discovered that when there was low cloud or fog, which was frequently the condition in this reputedly the foggiest regions in the world, we could track vessels by the line of clear sky they created. The important point about this is not the change in albedo, but what it says about the sensitivity between water vapour, cloud cover and temperature. The heat from the engine exhaust is sufficient to ‘burn off’ the cloud cover for a considerable distance behind the ship. It underscores the importance of water vapour as a greenhouse gas and especially its atmospheric response to temperature, unlike CO2..
wsbriggs says:
July 22, 2010 at 7:52 am
DCC – I think you nailed it. Fishing vessels running outrigger nets would curve around schools of fish. The size of the clouds kind of makes the idea of a “Great Circle Route” a non-starter. Puffy little “sheep” clouds hanging close to the water makes this image a small part of a much larger image, at least based on my experience with the marine layer.
Take a good look at the scale of the picture, these outrigger nets should be several hunderd kilometers at this scale. Industrial fishing is big, but not this big.
I first thought of the Peruvian Navy on manoeuvres, and then i noticed the scale in bottom left corner.
Myron Mesecke says:
July 22, 2010 at 6:53 am
“Cap and Trade would drive even more manufacturing overseas. Taking production from the United States that has stricter pollution laws to less developed countries.”
Even better; why not move the factory on board a ship in international waters together with the workers? This way you could evade taxes, environmental regulations and work regulations. You could move the factory close to the customers country and cut down on transportation cost. It would even be a boon for the environment as less fuel is needed (there, that was the bone for the enviros).
Joe Lalonde says: “…We have changed the evaporation patterns of the planet on a large scale including billions of gallons per day being used and in some cases such as oil production never to be used again(pumped into wells for pressure).”
The water pumped into oil wells is recovered waste water from oilfield separators, usually highly brackish and contaminated with hydrocarbons. The oilfield is just pumping it back into the ground where it came from. Formation pressure is much more easily maintained by injecting waste gases or, in tertiary recovery processes, nitrogen or CO².