CF "The Hurricane-Climate Connection" <ftp://texmex.mit.edu/pub/emanuel/PAPERS/Haurwitz_2008.pdf> (PDF). *Bulletin of the American Meteorological Society <https://en.wikipedia.org/wiki/Bulletin_of_the_American_Meteorological_Society>* . *89* (5): ES10–ES20
On Saturday, September 15, 2018 at 7:35:38 PM UTC-4, Russell Seitz wrote: > > Stephen, I'd direct your editors to Kerry Emmanuel's seminal paper on > hurricane track cooling, as the published basis for considering both > hurricane track cloud nucleation and sea surface albedo modulation to > moderate strorms > > On Saturday, September 15, 2018 at 4:19:10 AM UTC-4, Stephen Salter wrote: >> >> Hi All >> >> I was asked to write something about hurricanes for a well known popular >> news outlet but they thought that it was too technical. However it might >> still be useful. I hope that the ETC group can comment. >> >> The formation of a hurricane depends on many factors including >> atmospheric water vapour, distance from the equator and the recent history >> of wind patterns. But an essential requirement is a high sea surface >> temperature. To get from a tropical storm to the lowest category of >> hurricane requires a temperature of 26.5 C. We can moderate hurricanes, >> or even prevent them, by reducing water temperature. >> >> A useful start to any engineering project is the estimation of all the >> energy flows. One cubic metre of air at a temperature of 30 C can hold >> about 30 grams of water vapour. The energy to evaporate this is about the >> same as in 13 grams of TNT, enough for a nasty anti-personnel mine. A >> cubic kilometre of such air contains the same energy as the Hiroshima bomb. >> Hurricanes can be hundreds of kilometres in diameter and so contain tens >> of thousands of Hiroshimas. If you have read this far you will know >> about the billions of lost dollars and thousands of deaths from this amount >> of energy. >> >> Most of the hurricanes that reach America (with the exception of Harvey), >> start on the African side of the Atlantic near Cape Verde and grow as they >> move west. We can use Google Earth to measure the hurricane breeding area. >> The US National Weather Service gives a warm water depth of 45 metres. >> To cool this volume by 2 C in 200 days needs more than 600 times the mean >> US electricity power generation. If you want to moderate a hurricane >> tomorrow, today is much too late. You should have started last >> November. >> >> All this heat has come from the sun. Some could be reflected back out >> to space by clouds. The reflectivity of clouds was studied by Sean Twomey. >> He flew over many clouds, scooped samples and measured the solar energy >> reflected from their tops. He showed that reflectivity depends on the >> size distribution of drops. Lots of small drops reflect more than the >> same amount of liquid water in fewer, larger ones. In typical >> conditions, doubling the cloud drop number increases reflectivity by a bit >> over 0.05. >> >> Making cloud drops needs a high humidity but also some kind of ‘seed’ >> called a condensation nucleus on which to start growth. There are >> thousands of condensation nuclei per cubic centimetre of air over land but >> fewer in air over mid ocean, often less than 50. John Latham suggested that >> the salt residues left from the evaporation of a spray of sub-micron drops >> of sea water would be excellent condensation nuclei. They would be moved >> from the sea surface by turbulence to produce a fairly even distribution >> upwards through the marine boundary layer to where clouds form. >> >> The condensation nuclei could be produced by wind-driven sailing vessels >> cruising along the hurricane breeding areas getting energy from their >> motion through the water. We can make spray by pumping water through very >> small nozzles etched in the silicon wafers used for making microchips. The >> main technical problem is that sea water is full of plankton much larger >> than nozzles. This can be filtered using ultra-filtration technology >> with back-flushing, originally developed for removing polio viruses from >> drinking water. Each vessel would produce 0.8 micron diameter drops at 10 >> 17 a second. >> >> Spray operations would depend on the pattern of sea surface temperatures >> as measured by satellites. We want the trajectory of temperature rises >> through the year from November to the following July to be those that an >> international panel of meteorologists think will give a desirable rainfall >> pattern from ‘gentle’ tropical storms. >> >> Most ships are made in quite small numbers. An exception was the Flower >> class corvettes built for the Royal Navy during World War II. If we >> index-link the 1940 cost to today we can predict that in mass production >> each spray vessel would cost $4 million. With assumptions which have not >> yet been rejected by hurricane experts, we think that controlling the >> Atlantic hurricane breeding paths would need about 100 vessels. With >> typical ship lifetime the annual ownership and maintenance cost would be >> about $40 million. If these figures and recent estimates of the cost of >> hurricane damage are correct the benefit-to-cost ratio is quite attractive. >> >> >> >> Because of official UK Government policy updated in May 2018 the project >> is privately funded. >> >> I will send anyone who asks an update on recent hardware development, >> still privately funded. >> >> Stephen >> >> >> -- >> Emeritus Professor of Engineering Design, School of Engineering, Mayfield >> Road, University of Edinburgh EH9 3DW, Scotland >> > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
