Computer forecast models are pointing to a change in the jet stream pattern over the coming week that could provide some drought relief to the southern half of the U.S., including eastern Texas, Oklahoma, and Arkansas. The jet stream so far in January has been blowing in a somewhat "zonal" fashion--straight across the U.S., from about Oregon to New England. The jet has had only modest dips to the south (troughs), associated with rain storms that have tracked rapidly across the northern tier of states. Beginning Saturday, however, the jet stream is expected to take on a more bowed pattern, bringing a sharp trough of low pressure all the way down to Mexico. This trough will bring cold air and moisture with it, giving southern California needed rains, and the first snows of winter to Flagstaff, AZ. Amazingly, Flagstaff had over 83 inches of snow fall by this time last year, but so far this winter has had none!
By Monday, as the trough moves across the country, the drought-ravaged areas of eastern Texas, Oklahoma, and Arkansas have a chance of up to .5 inches of rain. This would be the first significant rains in nearly 100 days in some areas. Another major trough is expected to follow about a week later, and indications are that this trough will also swing far enough south to bring rain and snow to portions of the southern U.S. in need of moisture. However, since there is no cold Arctic air in Canada for these troughs to tap into, only short periods of winter-like conditions are expected in the U.S. over the next ten days. The country remains on track to record our warmest-ever January.
Figure 1. Number of days since the last .25 inch rain for each county in Oklahoma.
Jeff Masters
This cloud of smoke is from a wildfire in Irion county, as seen from Tom Green county, near San Angelo.
notice how far this marker is away from the water's current level
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Did you see the chart on the right in regards to global warming? Did you see that its a natural process of the planet.
If you upwell and cool the Gulf Stream by 20 degrees, you are going to change the climate of the east coast and the UK.. etc.
It would probably take TRILLIONs of dollars to even move the water you want. Its just unrealistic, and thats why you are having a hard time getting people to support it.
And lets say it is feasible, and it is done. Not only will we control the hurricanes that hit our shores, but it would affect the entire earth, and we would have some control of the weather for the entire world.
Its just not natural, and it has huge repercussions on the environment and the ecosystems.
Its just not a good idea. I agree with HurricaneChaser that the earth natural warming is just that almost entirely natural. I don't think messing with mother nature is a good way to do much of anything. Hurricanes form for a reason, and release latent heat energy for a reason.
but on the other hand, if we ever get in a war with Europe, it might be fun to try, to send drought and blizzards their way. If we did it in a time of peace we might end up at war with Europe anyway. which would not be a good thing.
Nonetheless, we can do our best modelling and we can make empirical observations - and currently both point to the fact that global warming has been occurring since at least the early 1800s. The big question is whether human activity has contributed to that warming. The majority of climatologists think it has, but a vocal minority suggest it hasn't.
Either way, there are sensible measures we can hopefully agree are worth undertaking for their own sake, which would help address any human-induced contributions to the current warming:
- develop more fuel efficient cars and machines;
- develop alternative energy sources (eg. solar, wind, etc);
- insulate our homes better;
- reduce our air emissions of CO2 and methane and other greenhouse gases wherever possible;
- plant lots of trees;
- there's lots more but you get the drift.
Just got caught up on your earlier lengthy posts. You're kind of stuck on this issue aren't you, and on somehow proving you're view is correct. I respect your solid experience in the field of meteorology (esp. with respect to hurricanes), but on this issue (climatology and global warming) I just have to disagree with your position.
As for my position, I'm not saying human activity is causing the currently observed global warming but that it's my view that human activity is contributing to it. I have no problem with others having other views. Time will tell on this issue, and with each passing year the effects are becoming harder to ignore.
I was taking climatology courses in the late 1970s, and they pointed to the strong possibility of human activity causing global warming. The argument then was "but there's no sign of global warming occurring". Now that the signs are unmistakeable (just think about the "winter" we're having), the argument is "well, you can't prove human activity is contributing to the observed warming". The problem with this (your) argument is that by the time it can be proven that human activity is contributing to the observed warming (if it is occurring) it will be too late.
So in the meantime (while we're all debating the issue), why wouldn't we at least do what we reasonably can to reduce emissions, improve fuel efficiency, insulate homes better, etc. In the rest of the civilized world these measures are being pursued because they're good things to do anyways, and because if humans are contributing to global warming then these measures will help.
For some bizarre ideological reason, the US administration is however insisting on Americans' rights to drive gas-guzzling cars, live in shoddily built and poorly insulated houses, allow their factories to pollute like crazy (eg. up here in Canada your emissions have killed all aquatic life in thousands of our lakes through acid rain... ), and generally trash the US environment.
The rest of the civilized world is sincerely hoping that Americans will someday wake up to the mess you're making (and which we're also making, though to a lesser extent) and try to join us in reversing the damage... if for no other reason than to give our children a better future and a more liveable planet.
Inyo,
How can warming it slow it down and retuning back to normal slow it down, also? That doesn't make sense.
-sea temperature warming isnt what may be weakening the gulf stream. what may be weakening the gulf stream is changes in salinity caused by melting glaciers and ice fields in northern Canada and especially Greenland.
-it isnt heat itself but heat gradients (it is colder in the north Atlantic than in the Gulf and Caribbean, as you know) which drive the gulf stream. Cold water is heavy, so it sinks in northern latitudes and warm water flows north to take its place... it is very similar to how convection in the atmosphere works, only it is much more stable. (think of the Gulf Stream as a jet stream that doesnt migrate as much due to land masses constricting its flow.) Now, if the southern portion cools while the northern portion stays the same or warms, the temperature difference may weaken the 'convection', and this combined with the changing salinity could cause the jet stream to weaken significantly.
i'm not saying that using those tunnels WOULD do this, i'm saying it MIGHT. Using ocean temperature gradients to generate electricity might be a good idea at some point, but using them to try to tamper with hurricanes or other storms is a reicpe for disaster.
with fresh water may be, but sea water????
And what about other nations affected by hurricanes in the carribean?
What about the effect this would have on western europe? Even France would go to war if it effected their farmers.
You then suggested pumping the water to the surface.
Generally pumping water uses electricity not creates it.
You would be adding to Global warming as you put it, by needing further power to pump the water.
as you put it
the bottom line is these Tunnels don't work!
Can we stop flogging a dead cat please.
Sorry for the long post, but this is hilarious. While looking for information I found another message board where cyclonebuster has been and he found even more resistance there then he did here. Also a person named interloper seems to know much about the principles that cyclonebuster proposes plus more. He claims to be a mechanical engineer very well versed in the area of fluid mechanics. I'd like everyone to read his post about all the flaws in the basic principles of this design. Also, with all these questions about modeling the design, this guy did, and apparently it wasn’t to cyclonebuster's approval since he hasn’t mentioned it once here. Once again, sorry for the long post. I just felt that this information is incredibly important and really gives us a true engineering view on the plausibility of this idea.
After reading your post again, there's a few things I wanted to clear up.
In reply to:
Understand that pascal's principle applies at the base of the tunnel and Bernoulli's principle applies at the top of the tunnels.
Both principles, if they do indeed apply, will apply everywhere inside and outside the tunnel.
In reply to:
This is what creates the pressure differential within the tunnels.
As long as there is a pressure differential flow occurs.
Flow occurs in the presence of a pressure differential if the driving pressure is enough to overcome the inertia of the fluid, viscous friction effects, and other losses in the tube. Adding heavier cold water to the tunnel will bring the pressure differential back to zero.
In reply to:
It is the current that changes these pressures at both ends and therefore you have flow. Remember what pascal tell us.
Pascal's principle states that the pressure exerted on a fluid is distributed equally throughout the fluid.
...remember that Pascal's principle isn't an absolute law. It's only an observation that can be made in fluids at quasi-equilibrium...
In reply to:
This is what happens at the base of the tunnel. That force (KINETIC ENERGY) is transferred through the whole leangth of the tunnel it does not care about density.
Kinetic energy and force are two very, very different things. Force, as you said, IS transfered through the whole length of the tunnel. Force does not depend on density.
Kinetic energy, however, depends on density very much. Kinetic energy is esseintally the energy stored in an object because of motion. The equation for kinetic energy is 1/2 * mass * velocity * velocity, or, simply, 0.5*m*v^2
The mass of a fluid is it's density multiplied by its volume. The equation for the kinetic energy of a fluid is 1/2*density*volume* velocity^2. Like I said, kinetic energy is very dependant on density.
In reply to:
Kinetic energy is transferred instantly to the top.
Absolutely not. You have no guarentee that any kinetic energy will be transfered to the top. If you mean "force" instead of kinetic energy, then this is almost true, except that the process is nowhere near instant. Force is transfered to the top of the tunnel at the speed of sound, which is a far cry from instantaneous.
In reply to:
Once Bernoulli's principle is applied at the top it removes what pascal's principle forced up there and the cycle is on going untill you stop the current.
If you manage to get a pressure differential under the most ideal of circumstances, there will indeed be flow... in this case. The question is, how long will this pressure differential last until the excess weight of the cold water in the tube cancels out the small pressure difference from the current and the entire tube stagnates?
Its an intruiging problem, but a difficult one. I have some computational fluid dynamics software at my disposal, which might yield some insight as to how much pressure the current could generate, if you're really interested in pursuing this problem further. I don't suspect it will be very much.
cyclone,
I modeled a 50 foot (15 meter) duct inserted into a 2m/s uniform flow field, using the density of seawater as 1025 kg/m3. Given that you're talking about a rectangular tunnel with a wide aspect ratio, I modeled in in two dimensions using the narrow dimension as the cross section, figuring that most of the water that goes around the tunnel's mouth would do so by going over or under it.
Because this is a 2D approximation of a 3D problem, there is one major limitation. The solution assumes that the duct is infintely wide, and thus no water is escaping by going around the sides, only over or under. Because you've got an aspect ratio of 1/4, this is a fairly reasonable approximation. In reality, the pressure boost would be a little bit less.
To solve the problem, I used Fluent 6, which is an industry-standard CFD program. Assuming invicid flow (seems reasonable given our Reynolds numbers are on the order of 10^7), the software solves the governing equations in an iterative process. I ran the solution for about 1000 iterations, adapting the mesh twice to smooth out some of the rough spots. Other than that, it converged pretty nicely.
I modeled the duct as if it were sealed, which represents your tunnel just as you point the mouth into the current and none of the seawater has started moving. The pressures during startup will be the highest the tunnel sees, because (to explain it simply) once the water starts moving the current stops running into it so hard.
So the picture below shows the pressure contours around the tunnel mouth at startup. Each colored line is a line of equal pressure, and you can see the strength of the pressure on the colored scale on the left. As you can see, the highest pressure is inside the tunnel, starting right at the mouth, and it's about 2.09x10^3 N/m2.
That's 2090 Pascals, or about 0.3 psi, which isn't much. It would certainly be enough to start a really slow flow, but the temperature effect comes into play pretty quickly.
Just looking at some basic seawater density figures, a cubic meter of seawater at 60°F weighs about 5.0kg (11 lbs) more than a cubic meter of seawater at 90°F (I think 90°F is a little unrealistic for the water's surface temperature, that's like a hot tub).
How far the 0.3psi will push the water column will depend on the actual temperatures, and the temperature gradient of the ocean between the surface and the depth you want the tunnel's mouth at.
If you could dig up some of that information... even something as basic as temperature measurements every 100ft of depth in the geographic area you want to put the tunnel, we could figure out exactly how much pressure you need to drive the flow.
If you're comparing an empty tube to one that's already filled with water, you're compairing apples to oranges.
But I will say this: if you stick an empty tube down through 500 feet warm water at 25C so that the tube's end is just inside a layer of cold water, the warm water above will be producing a gauge pressure of 1518 kPa at the bottom of the tube.
When you open that valve, the cold water rushes in. Let's say the cold water is at 5C. The difference in density is 4.2kg/m3. Because the cold water is heavier, the same amount of pressure will raise it a smaller distance. Based on some quick calculations, the cold water will rise just under 497 feet, which means that looking at the top of the tube sticking out of the water you will notice a three foot difference in water height.
Now, we're not talking about an empty tube. We're talking about one that's full of warm water, and instead of a 1518 kPa pressure difference, we're talking about a 5kPa pressure difference.
5kPa is not a lot of pressure. Atmospheric pressure, for example, is 101kPa. I figured out earlier that at the temperatures you gave me, the cold water weighs 50 Newtons more per cubic meter than warm water. 5kPa will hold up 5000 Newtons per square meter, which means you get 100 meters of additional cold water weight before everything stops.
You either need more pressure or a smaller temperature difference before you can show that this idea has a chance of being technically feasible... which is what a company will want to see before they spend money proving that it can be done.
If you don't believe me, find another mechanical engineer competent in this area of fluid mechanics. I'll even send you the spreadsheet I did my calculations on.
The tunnels are Busters idea to reduce the SST’s around the Gulf and Eastern Seaboard by using tunnels to bring cold water up from the sea bed to mix with the Gulf stream to cool it down. This in turn stop major hurricanes hit the US, while the upwelling tin the tunnels will create ‘clean’ electricity.
The bones of contention are:
1) Would the tunnels even work.
2) The effect on the gulf stream and Western Europe’s climate.
3) If your preventing hurricanes and heat being removed thro the gulf stream isn’t the Caribbean just going to get warmer and warmer. Where is the ocean heat going to go?
STOP DISCUSSING THIS! ARGH! Can we get back to *real* weather?!?!
The new ENSO report is out, and it's official - La Nina is coming.
O_O 2006 is going to be *insane*
whats up! ForecasterColby 2006 is going to be *insane* what do you mean?this is going to be a bad hurricane year this year and more storm then we had last year
Idiotic question? Perhaps. To the point? Yes... Why? because while it seems there are some global temperature anamolies in progress as we speak, it seems like there are way too many people on "the earth is doomed" bandwagon. Should we be responsible with the environment? Of course... that's not my point. Should this issue, like any other, be approached with common sense? Of course. From some sides of this debate, common sense is lacking.
LINK.
Link
it's also the reason the area often goes 5 or 6 months out of the year with no rain (in the summer). It seems that even destructive hurricanes are a small price to pay in exchange for the summer rains that sustain 4/5ths of our country (even the Southwest Monsoon has been linked to Atlantic hurricanes)
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