The energy in a nuclear bomb is quite small, but very concentrated, compared to that of a hurricane. The eye, as I understand, is primarily convective, so it's probably the wrong place. Dropping a nuclear bomb in advance of the hurricane, beyond the outer wall, would perhaps have more chance of disrupting its progress. The ability of a nuclear weapon to instantly create huge clouds of seawater mist and steam would probably have significant effects by changing albedo - probably more than that of the energy input from the weapon itself. However, the effect on marine life from the shockwave would be likely to be pretty devastating.
2009/6/8 Eugene I. Gordon <[email protected]> > > Has anyone considered droppong a miniature atomic bomb; such as used in > artillery shells, down the middle of a hurricane before it makes landfall? > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Alvia Gaskill > Sent: Saturday, June 06, 2009 8:38 PM > To: [email protected]; dsw_s; Geoengineering > Subject: [geo] Re: Just in Time for Hurricane Season > > Some more info about the effect of hurricanes or more generally, tropical > cyclones on SST (sea surface temperature) from NOAA and the Wikipedia. > Most > of the temperature decrease is due to the mixing of water in the upper > layer > of the ocean by winds and most of the decrease occurs after the storm has > passed. Limited data show that the decrease from evaporation of water is > much less. NOAA also throws some cold water on artificial dissipation > strategies including the one that got this discussion started, ocean pipes. > They didn't address indirect approaches like the cloud ships and the desert > cover. > > http://www.aoml.noaa.gov/hrd/tcfaq/H7.html > > > Subject: H7) How does the ocean respond to a hurricane and how does > this feedback to the storm itself? > Contributed by Joe Cione > > > The ocean's primary direct response to a hurricane is cooling of the > sea surface temperature (SST). How does this occur? When the strong winds > of > > a hurricane move over the ocean they churn-up much cooler water from below. > The net result is that the SST of the ocean after storm passage can be > lowered by several degrees Celsius (up to 10° Fahrenheit). > > Figure 1 shows SSTs ranging between 25-27°C (77-81°F) several days > after the passage of Hurricane Georges in 1998. As Figure 1 illustrates, > Georges' post storm 'cold wake' along and to the right of the superimposed > track is 3-5°C (6-9°F) cooler than the undisturbed SST to the west and > south > > (i.e. red/orange regions are ~30°'C [86°'F]). The magnitude and > distribution > > of the cooling pattern shown in this illustration is fairly typical for a > post-storm SST analysis. > > One important caveat to realize however is that most of the 3-5°C > (6-9°F) ocean cooling shown in Figure 1 occurs well after the storm has > moved away from the region (in this case several days after Georges made > landfall). The amount of ocean cooling that occurs directly beneath the > hurricane within the high wind region of the storm is a much more important > question scientists would like to have answered. Why? Hurricanes get their > energy from the warm ocean water beneath them. However, in order to get a > more accurate estimate of just how much energy is being transferred from > the > > sea to the storm, scientists need to know ocean temperature conditions > directly beneath the hurricane. Unfortunately, with 150kph+ (100mph+) > winds, > > 20m+ (60ft+) seas and heavy cloud cover being the norm in this region of > the > > storm, direct (or even indirect) measurement of SST conditions within the > storm's "inner core" environment are very rare. > Thankfully in this case "very rare" does not mean "once in a > lifetime". Recently, scientists at the Hurricane Research Division were > able > > to get a better idea of how much SST cooling occurs directly under a > hurricane by looking at many storms over a 28 year period. By combining > these rare events, HRD scientists put together a "composite average" of > ocean cooling directly under the storm. > > Figure 2 illustrates that, on average, cooling patterns are a lot > less than the post storm 3-5°C (6-9°F) cold wake estimates shown in Figure > 1. In most cases, the ocean temperature under a hurricane will range > somewhere between 0.2 and 1.2°C (0.4 and 2.2°F) cooler that the surrounding > ocean environment. Exactly how much depends on many factors including ocean > structure beneath the storm (i.e. location), storm speed, time of year and > to a lesser extent, storm intensity (Cione and Uhlhorn 2003). > While the estimates in Figure 2 represent a dramatic improvement when > it comes to more accurately representing actual SST cooling patterns > experienced under a hurricane, even small errors in inner core SST can > result in significant miscalculations when it comes to accurately assessing > how much energy is transferred from the warm ocean environment directly to > the hurricane. With all other factors being equal, being "off" by a mere > 0.5°C (1°F) can be the difference between a storm that rapidly intensifies > to one that falls apart! With that much at stake, scientists at HRD and > other government and academic institutions are working to improve our > ability to accurately estimate, observe and predict "under-the-storm" upper > ocean conditions. These efforts include statistical studies, modeling > efforts and enhanced observational capabilities designed to help scientists > better assess upper ocean thermal conditions under the storm. With such > improvements, it is believed that future forecasts of tropical cyclone > intensity change will be significantly improved. > > Reference > Cione, J. J., and E. W. Uhlhorn, 2003: Sea Surface Temperature > Variability in Hurricanes: Implications with Respect to Intensity Change. > Monthly Weather Review, 131, 1783-1796. > > Last updated August 13, 2004 > > > http://en.wikipedia.org/wiki/Typhoons > > Tropical cyclones are characterized and driven by the release of large > > amounts of latent heat of condensation, which occurs when moist air is > carried upwards and its water vapour condenses. This heat is distributed > vertically around the center of the storm. Thus, at any given altitude > (except close to the surface, where water temperature dictates air > temperature) the environment inside the cyclone is warmer than its outer > surroundings.[2] > > Mechanics > > > Tropical cyclones form when the energy released by the condensation of > > moisture in rising air causes a positive feedback loop over warm ocean > waters.[14] > A tropical cyclone's primary energy source is the release of the heat > of condensation from water vapor condensing at high altitudes, with solar > heating being the initial source for evaporation. Therefore, a tropical > cyclone can be visualized as a giant vertical heat engine supported by > mechanics driven by physical forces such as the rotation and gravity of the > Earth.[15] In another way, tropical cyclones could be viewed as a special > type of mesoscale convective complex, which continues to develop over a > vast > > source of relative warmth and moisture. Condensation leads to higher wind > speeds, as a tiny fraction of the released energy is converted into > mechanical energy;[16] the faster winds and lower pressure associated with > them in turn cause increased surface evaporation and thus even more > condensation. Much of the released energy drives updrafts that increase the > height of the storm clouds, speeding up condensation.[17] This positive > feedback loop continues for as long as conditions are favorable for > tropical > > cyclone development. Factors such as a continued lack of equilibrium in air > mass distribution would also give supporting energy to the cyclone. The > rotation of the Earth causes the system to spin, an effect known as the > Coriolis effect, giving it a cyclonic characteristic and affecting the > trajectory of the storm.[18][19] > > What primarily distinguishes tropical cyclones from other > meteorological phenomena is deep convection as a driving force.[20] Because > convection is strongest in a tropical climate, it defines the initial > domain > > of the tropical cyclone. By contrast, mid-latitude cyclones draw their > energy mostly from pre-existing horizontal temperature gradients in the > atmosphere.[20] To continue to drive its heat engine, a tropical cyclone > must remain over warm water, which provides the needed atmospheric moisture > to keep the positive feedback loop running. When a tropical cyclone passes > over land, it is cut off from its heat source and its strength diminishes > rapidly.[21] > > > > Chart displaying the drop in surface temperature in the Gulf of Mexico > > as Hurricanes Katrina and Rita passed over > The passage of a tropical cyclone over the ocean can cause the upper > layers of the ocean to cool substantially, which can influence subsequent > cyclone development. Cooling is primarily caused by upwelling of cold water > from deeper in the ocean because of the wind. The cooler water causes the > storm to weaken. This is a negative feedback process that causes the storms > to weaken over sea because of their own effects. Additional cooling may > come > > in the form of cold water from falling raindrops (this is because the > atmosphere is cooler at higher altitudes). Cloud cover may also play a role > in cooling the ocean, by shielding the ocean surface from direct sunlight > before and slightly after the storm passage. All these effects can combine > to produce a dramatic drop in sea surface temperature over a large area in > just a few days.[22] > > Scientists at the US National Center for Atmospheric Research estimate > > that a tropical cyclone releases heat energy at the rate of 50 to 200 > exajoules (1018 J) per day,[17] equivalent to about 1 PW (1015 watt). This > rate of energy release is equivalent to 70 times the world energy > consumption of humans and 200 times the worldwide electrical generating > capacity, or to exploding a 10-megaton nuclear bomb every 20 > minutes.[17][23] > > While the most obvious motion of clouds is toward the center, tropical > > cyclones also develop an upper-level (high-altitude) outward flow of > clouds. > > These originate from air that has released its moisture and is expelled at > high altitude through the "chimney" of the storm engine.[15] This outflow > produces high, thin cirrus clouds that spiral away from the center. The > clouds are thin enough for the sun to be visible through them. These high > cirrus clouds may be the first signs of an approaching tropical > cyclone.[24] > > http://www.aoml.noaa.gov/hrd/tcfaq/C5e.html > > Subject: C5e) Why don't we try to destroy tropical cyclones by cooling > > the surface waters with icebergs or deep ocean water ? > > Contributed by Neal Dorst > > Since hurricanes draw their energy from warm ocean water, some > proposals have been put forward to tow icebergs from the arctic zones to > the > > tropics to cool the sea surface temperatures. Others have suggested pumping > cold bottom water in pipes to the surface, or releasing bags of cold > freshwater from near the bottom to do this. > > Consider the scale of what we are talking about. The critical region > in the hurricane for energy transfer would be under or near the eyewall > region. If the eyewall was thirty miles (48 kilometer) in diameter, that > means an area of nearly 2000 square miles (4550 square kilometers). Now if > the hurricane is moving at 10 miles an hour (16 km/hr) it will sweep over > 7200 square miles (18,650 square kilometers) of ocean. That's a lot of > icebergs for just 24 hours of the cyclone's life. > > Now add in the uncertainty in the track, which is currently 100 miles > (160 km) at 24 hours and you have to increase your cool patch by 24,000 sq > mi (38,000 sq km). For the iceberg towing method you would have to increase > your lead time even more (and hence the uncertainty and area cooled) or > risk > > your fleet of tugboats getting caught by the storm. > > For the bag/pipe method you would have to preposition your system > across all possible approaches for hurricanes. Just for the US mainland > from > > Cape Hatteras to Brownsville would mean covering 528,000 sq mi (850,000 sq > km) of ocean floor with devices. > > Lastly, consider the creatures of the sea. If you suddenly cool the > surface layer of the ocean (and even turn it temporarily fresh), you would > alter the ecology of that area and probably kill most of the sea life > contained therein. A hurricane would be devastating enough on them without > our adding to the mayhem. > > Last updated August 13, 2004 > > > > > > > > ----- Original Message ----- > From: "Mike MacCracken" <[email protected]> > To: "dsw_s" <[email protected]>; "Geoengineering" > <[email protected]> > Sent: Saturday, June 06, 2009 1:41 PM > Subject: [geo] Re: Just in Time for Hurricane Season > > > > Some further comments are included (labeled "MCM"): > > > On 6/6/09 3:17 AM, "dsw_s" <[email protected]> wrote: > > > > >> The air that leaves the top of a hurricane is cold already, so it is not > >> sending much energy back into space. > > > > What about radiation from cloud tops? I would expect cloud tops to > > radiate much more readily than air at that altitude, both because of > > being a condensed phase that can emit blackbody radiation effectively > > and because of being warmer than air at that altitude normally is. > > > MCM: There is some going out from cloud tops, and indeed more than from dry > air, but it is far less than would go out in absence of the clouds reaching > that high. > > >> Most of the energy to carry the air up is used to push air elsewhere > back > >> down--as air comes down elsewhere, it is compressed and this takes > >> energy--adiabatic heating. > > > > That doesn't sound right. At adiabatic lapse rate, a convection cell > > should be energy-neutral before friction is taken into account. > > Energy needed to compress air is balanced by work done by expanding > > air, just as energy needed to lift air against gravity is balanced by > > the work done by gravity on sinking air. So energy applied to drive > > convection would all be available to be dissipated in other ways. > > > > Or are you saying that cyclones occur within a situation where the > > background lapse rate is well below adiabatic, and the energy mostly > > goes to overcome that stability? > > > MCM: Air goes up at moist adiabatic rate, but has to be forced down at the > dry adiabatic rate (e.g., over deserts). This tends to go on remotely--like > monsoons rising in one place, and dry subtropics being in another. If > getting this cycle going were easy (as you suggest--self-compensating), > we'd > be having convection all the time--and we don't. It takes moisture release > to drive the system (cold air aloft does not come cascading down--the air > up > there has to be forced down over a very broad area). > > >> One way to test the theory that the tropical cyclones increase radiation > >> of > >> IR to space would be to observe the upwelling IR in the path and area > >> surrounding these storms using satellites and compare to the IR prior to > >> the > >> arrival of the storm. > > > > If you look at the path after the hurricane has gone by, the IR > > emission from the surface will be affected by the fact that the storm > > mixed warm surface water with cooler water below. So if you want to > > include the surroundings where the air sinks, you would have to > > account for that. > > > MCM: Yes, but the oceans are also cooled a lot by all the evaporation that > took place to power the hurricanes. > > > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
