by Steve Goddard
The Atlantic Hurricane Basin remains dead quiet, and is now falling below the 1944-2005 average.
http://www.weatherstreet.com/hurricane/2010/Hurricane-Atlantic-2010.htm
I have not spent a lot of time studying hurricanes, but I have read that the “purpose” of hurricanes is to move heat quickly from the tropics to higher latitudes. Heat flow is always driven by differences in temperature. If two places were at the same temperature, there would be no heat flow.
Suppose that temperatures at higher latitudes (60N) were very warm – as they have been. What motivation would there be for hurricanes to form? The video and stil below shows UNISYS SST anomalies, with all anomalies between -1.0°C and +1.0°C removed.
Note that the Atlantic hurricane basin has very few places which are warmer than 1.0°C above normal. This agrees with Bob Tisdale’s graph.
By contrast, SST anomalies in the North Atlantic are far above normal. The difference in temperature between the tropical and north Atlantic is far below normal. Supposedly, it is that difference which gives hurricanes their raison d’être .
Things can change quickly. 1950 was the second most active hurricane season on record, and the first hurricane didn’t form until August 12.
Does it make sense that the heat engine which drives hurricane formation is basically shut down? What do you think?
It would be relatively straight-forward to create one. Besides the “dry bulb” temperature, all you need is some measure of humidity, such as wet bulb, dew point, or relative humidity. Find the two on a psychrometric chart, and you have the enthalpy.
http://en.wikipedia.org/wiki/Psychrometrics
stevengoddard says:
August 16, 2010 at 8:58 am
Have you ever looked at SSTs before/after a hurricane moves through?
Temperatures drop several degrees, because of energy transferred from the water to the atmosphere. Higher latitudes are colder than the tropics, so the heat necessarily moves towards the higher latitudes (basic thermodynamics.)
Actually the heat transfer may be even larger because of the water vapor transmitted, which releases huge amounts of heat when it condenses into rain.
However, some (or all) of the SST reduction after a hurricane passes through may come from the turbulence mixing the surface water with the colder deeper water. Any tropical weather pattern will take heat with it.
“”” Frederick Michael says:
August 16, 2010 at 3:10 pm
stevengoddard says:
August 16, 2010 at 8:58 am
Have you ever looked at SSTs before/after a hurricane moves through?
Temperatures drop several degrees, because of energy transferred from the water to the atmosphere. Higher latitudes are colder than the tropics, so the heat necessarily moves towards the higher latitudes (basic thermodynamics.) ”
Actually the heat transfer may be even larger because of the water vapor transmitted, which releases huge amounts of heat when it condenses into rain. However, some (or all) of the SST reduction after a hurricane passes through may come from the turbulence mixing the surface water with the colder deeper water. “””
“”” some (or all) “””
Are you sure that you proof read your post ?
Why do you suppose that the SSTs “drop several degrees” as Steve stated; if it isn’t in giving up the latent heat of evaporation required to transport that huge amount of water into the vapor phase ?
And just how would you plan to vaporize that much surface water if (all) of the SST reduction comes from mixing.
Roy Spencer once quoted the rate of energy transport to the atmosphere in something like a Cat-3 Hurricane; and the number makes Total Global Thermo-Nuclear War sound very attractive, in comparison.
Who says that there is tubulent mixing of surface waters with deep ocean waters during a hurricane; if that was occurring the destruction of shallower water life would be amazing. and it would take one hell of a ruckus to get all that cold water to the surface in almost nothing flat.
All those oil rigs ride out Hurricanes that pass through there, so I doubt that there is much mixing of waters for more than a few tens of metres; much of which is not too different from the surface temperature.
Suppositions and opinions with out real data reference, is why I quit reading Scientific American, and other rags, and went to the research library to read research papers back in the 80’s.
Have any of you been out at sea in a small boat in a gale?
As the wind rises the whitecaps grow larger, along with the waves, until the top of every wave is breaking and cascading forward (down wind) into the trough ahead. This constant churning of the water creates a foam which blows in the wind like suds. As the wind rises the entire surface of the sea is either churning whitecaps or cascading breakers or suds. (I think the suds are called “spindrift.”) The sea is less and less blue or green, and more and more white. There is also salt spray all over the place, snatched from the tops of waves and whistled down wind.
I experienced this when I was an idiotic teenager. (I’d decided only wimps stuck to the intercoastal waterway, and sailed from Newport straight to Cape May, in October.) At the height of the storm I was a bit less than scientific and objective, and a bit more prone to blubbering and pleading than I’ll ever publicly admit, yet the peak gusts were never up to hurricane force. I can’t even imagine what the sea surface must be like inside a force five hurricane.
Now, with twenty-twenty hindsight, I can be scientific and objective, and I think few people have any idea of the mixing that occurs at the sea’s surface, when winds rise above thirty knots. In a force five hurricane the spindrift suds must get sucked right up to the top of the troposphere. All sorts of organic oceanic matter winds up mixing with ozone in the lower stratosphere. All the organic stuff that ends with “ine,” such as bromine and chlorine and fluorine and iodine, reacts with ozone and, among other things, utterly screws up climate models.
Not only is heat whipped off the sea’s surface and hurtled upwards, but huge amounts of latent heat is released as the water vapor turns to liquid water, and again as that liquid water turns to ice crystals at the very top of a hurricane.
Then where are we, with all that heat? We are nearly three times as high as Mount Everest, at an altitude where there is next to no air between the heat and outer space. Because there is little CO2 left above, there is no way any “greenhouse effect” can keep a huge amount of heat from radiating out into the icy depths of inky space.
It would be neat to focus a satellite on the top of a hurricane, and measure the amount of heat the top releases. I imagine the amount would be staggering. And this is even before the hurricane acts as a “heat transport,” moving tropical heat towards the poles.
All this discussion about how hurricanes form and why they go where they do is interesting and thought provoking. However, growing up in South Florida, taught me that the time to discuss the number of hurricanes in the current season is Oct. 15, not Aug.15. Let’s do it again in a couple months. After all that’s when we’ll have the data.
This hurricane season seems to be turning into an object lesson in science by press release. How else to explain the way the TV weather forecasters seem to be reading from the same script as they report, in breathless excitement, on how the remnants of tropical depression five seem to be on the brink of reforming into a tropical depression before making landfall?
We’ve gone from major hurricanes to minor hurricanes to tropical storms to now we’re to get excited about the state of tropical depressions (or their remnants)? Let’s see how the next six weeks unfold before getting all excited about possible tropical depressions or prematurely naming them before they turn into tropical storms.
A circulation dome south of the equator in the mid South Atlantic is now in place – might not last but it is there now. The dome in the North Atlantic is ill defined. A “spinner” came off the east coast of Africa in the last 24-hours around Cape Verde’s latitude, which quickly started to dissipate because of the dry air north and east of it.
Another interesting thing to note is that for the first time this season, Indian Ocean moisture has now reached the west coast of Africa.
You can see all of this here:
http://www.nrlmry.navy.mil/sat-bin/display10.cgi?SIZE=full&PHOT=yes&AREA=global/stitched&PROD=vapor&TYPE=ssmi&NAV=global&DISPLAY=Latest&ARCHIVE=Latest&CGI=global.cgi&CURRENT=20100817.0900.multisat.wv.stitched.Global.x.jpg&MOSAIC_SCALE=15
Animate using the last 10 or so images available.
Feet2theFire says:
August 16, 2010 at 8:09 am
………………………………………..
Dust in the air is indicative of very dry air, which violates one of the parameters for hurricane development given in your Wiki article, “High humidity is needed, especially in the lower-to-mid troposphere; when there is a great deal of moisture in the atmosphere, conditions are more favorable for disturbances to develop.”
There is nothing for the dust to nucleate.
………………….
tree hugging sister says:
August 16, 2010 at 11:43 am
As an addendum to this “strange” season, TD5 is backing off the continent and heading back over the GoM….
If it continues southward for the next day, it may well become the tropical storm (or even weak hurricane) that was originally expected.
We have been quacking like ducks for 3 days straight now, here in P-cola, and am not looking forward to more of the same. Ivan came back at us eventually, too…I guess we’re well nigh irresistible
……………………………………
Well, it did go south over the Gulf, was given a 60% chance of becoming at least a TS, and has now fizzled out. Another miss. The next eight weeks will tell the tale.
That is my point exactly.
Steve Goddard says
Heat convects UPWARD, not because heat in an atmospher goes from hot to cold, but because it is less dense and rises.
Heat does not travel horizontally along the surface because of heat or cold. I travels because of PRESSURE differential and air currents. The heat goes with the air masses. But so does cold. Actually it is COLD air masses that move toward WARM air, which is less dense.
In both horizontal and vertical movements, it is PRESSURE that drives the air and the heat/cold gets carried with it.
I agree with Tom that it has “[n]othing to do with going from colder to warmer or warmer to colder.” I believe I was trying to say that. I must have stated it incorrectly. Steve Goddard is the one who is claiming it has something to do with moving heat. I think that Steve’s statements quoted in this comment are wrong.
“In both horizontal and vertical movements, it is PRESSURE that drives the air and the heat/cold gets carried with it.”
Oh, and Coriolis effect.
@ur momisugly George E. Smith says August 16, 2010 at 5:02 pm:
George, you might be interested in this. About 25 years ago I saw a science article which I cannot source at all right now. I did clip it and file it, but have since lost it.
In the article it discussed how much erosion occurred on the ocean bottom (I believe it was off the east coast of Florida) during a heavy storm. The scientists involved were completely surprised at the amount of erosion, which they said amounted to many, many years of normal erosion. I do not recall the depths involved, but I had the impression it was in the shallow ocean around the Bahamas – perhaps 100 feet or more. I have the general recollection that the storm was not a hurricane.
The main thrust of the article was both the amount of erosion and the surprise of the scientists. That is why I clipped it out and kept it. And why I still remember the basic facts, even if I don’t recall the numbers or names, or when this was. Mid-to late-80s come to mind. They were definitely talking about turbulence and what it did to the ocean bottom.
While you have nothing to go on here other than my poor recollection, I hope it may indicate that the mixing DOES go down to some sizable depth. I don’t know what the range of the thermocline is in hurricane areas, but 100 feet or so sounds like it might be near the thermocline. And if the erosion/mixing goes below the thermocline, then I would think that there is some colder water brought up to the surface. Perhaps not. It seems like a more complicated condition than just simply saying, “No, there is no mixing at all,” one worth studying if understanding of hurricanes and their effects.
Well, I am not a hurricane expert, but is a hurricane not just a rather large messy heat engine? Which takes energy from the ocean and dumps it out at high altitudes, where it is radiated into space? And have we not had a couple of very quiet years? I really expect a very active, very strong hurricane this year or next, depending on the jet stream shear effect. Nothing to do with global warming, just common sense. If the air conditioner has been off a while, it has to run pretty hard to catch up once it turns back on………..
“”” Feet2theFire says:
August 17, 2010 at 11:18 am
@ur momisugly George E. Smith says August 16, 2010 at 5:02 pm:
Who says that there is tubulent mixing of surface waters with deep ocean waters during a hurricane; if that was occurring the destruction of shallower water life would be amazing. and it would take one hell of a ruckus to get all that cold water to the surface in almost nothing flat.
George, you might be interested in this. About 25 years ago I saw a science article which I cannot source at all right now. I did clip it and file it, but have since lost it. “””
Well feet-2 I appreciate you recollection; and don’t doubt the truth of what you read. But I would submit, that there is a considerable difference between bottom erosion, and water turnover. Certainly if you have a tidal water flow (over the bottom) which you certainly would in the Bahamas; and then on top of that you add a dynamic loading change by adding a storm driven wave motion on top, the cyclic pressure changes on the bottom will not be inconsequential when added to a continuous current so the scooping of bottom sands etc is going to follow a pulsing pattern which yes will totally change the bottom configuration; but never bring any of that bottom water to the surface.
You only have to go snorkelling in the surf line in shallow water, and little wave motion to see the scalloping that occurs due to wave action on the top of moving water ( the bottom is typically scoured outwards by water running out from the waves breaking on the beach (even small waves) and the surface wave action is what scallops the bottom sand into waves that you can follow out to quite large depths. I spent a good part of my youth in summer time swimming all day at beaches where I could dive down and see the sand waves on the bottom. There wasn’t any bottom water coming up to the top out there.
Make me eat my words later .
I predict the weakest Huricane season in history .
Reasoning : storms develope based on large differences of temperature .
The global warming is expending the heat area more towards the poles hence leaving behind ( at the tropics ) a calmer weather , free of the punches of cold fronts decending from the pole . Hence less intense storms , NO huricanes , ZERO !
Let’s waite and see , I have the knife and fork ready to eat this .
Please comment , thank you .
PS : take a look at the phenomenal High pressure ridge stretching from Hawai to the Great Lakes , there stationed for the last three month , a Wall stopping /deflecting any cold air dropping from the pole … To see it , dark area – low humidity – go to :
http://weather.unisys.com/satellite/sat_wv_hem_loop-12.html
( home site at : http://weather.unisys.com/satellite/sat_wv_west.html
Doru
Canada
I don’t have any confidence in anyones ability to predict severe weather. The best that can be done is to track a storm after it forms. Even this is an imprecise science usually based on on 20-30% degree of probability. You might as well read the Farmers Almunac. Keep blowing smoke everyone. I can’t wait to 2013 when the solar flares are mixed into the equation. Fun reading
Whenever they say “very active hurricane season” you can be sure to expect nothing, when they say it will be a “very weak season” batten down the hatches…just like weather casters predicting our weather with an oracle bone & a chickens foot!