Questions about the oil spill and hurricanes

By Jack Williams ©2015

If someone were still paying me to write about weather and science, here are some of the questions I’d ask about a possible Gulf of Mexico hurricane and and the huge oil spill.

A story with the answers to even one or two of my questions would help answer some questions that I’m sure many people have.

1. Could a hurricane’s winds blow any of the oil inland?  One possibility that’s been mentioned is that a hurricane’s winds would pick up drops of oil from the Gulf and blow them inland to fall as “oil rain?” Maybe.

In this image from NASA's Terra Satellite on May 17, the oil slick appears as a dull gray on the water's surface and stretches south from the Mississippi Delta with what looks like a tail.

A science writer who wants to find out whether an an oil rain is possible would have to find a scientist who can talk about the potential effects of the boundary layer that forms when a fluid, such as air, flows over any surface and also if a hurricane helps break up the oil into drops, how large and heavy would the drops be? The big question then would be whether the wind in the boundary layer in direct contact with the oil be strong enough to loft such drops? Answering these questions would probably require some heavy duty computational fluid dynamics (CFD) to see what happens to an oil slick like the one on the Gulf when high winds blow across it. This assumes those who write the necessary CFD program know enough about wind effects on oil slicks to model what happens.

What happens to the salty spray that a hurricane creates right above the water might offer some clues. I can’t recall seeing any reports of widespread damage by sea spray blown inland by a hurricane. Large amounts of salty water could kill plants. But.I have no idea whether sea spray is a good analogy for an “oil spray.”

Whether or not oil drops blowing off the water could create an oily rain, we also have to wonder about compounds in the “oil” that evaporate into the air, which leads to the next two questions.

2. Which of the many compounds in the “oil” floating on the Gulf (is? are?) volatile enough to evaporate at the temperatures now found in the top layer of the Gulf’s water and air right above it?

3. Can people near the oil smell it?  If so, this means something is evaporating into the air.  If  the oil can be smelled,  how high above the water does the smell extend? Does the height of the layer of air with the stuff in it make any difference to potential effects?

4. Is the oil affecting the amount of solar radiation the water absorbs? That it, is the oil having any effects on sea-surface temperatures? If this is the case, could it have weather effects, such as more or less rain falling on places downwind from the Gulf? (More water would evaporate from a warmer ocean, less from a cooler ocean.) If the oil is causing water temperature changes, could the resulting water density changes affect ocean currents in the Gulf?

5. One hears about pouring oil on troubled waters to calm a rough sea. I recall reading that there is at least some truth to this, but don’t recall how it works. Answering this question–both how it works and whether there is there enough oil to affect a hurricane–would be worth at least a small sidebar to a big spill story.

6. If the oil is slowing evaporation of water from the Gulf, this in theory would reduce the water vapor needed to “fuel” a hurricane by releasing latent heat if the reduction in evaporation is large enough. On the other hand, the area covered by the oil is a relatively small part part of the ocean source of humidity that the winds feed into a hurricane. Is the oil slick big enough to make a difference?

7. If  #4, #5, or # 6 are possible, are hurricane modelers plugging some figures into their models to check it out?  I’d start with NOAA’s Hurricane Research Division, NOAA’s Geophysical Fluid Dynamics Lab, or one of the several other groups that model hurricanes.

8. Could the oil have any effect on the amount of sea spray a hurricane kicks up? If so, this could be important. As I explain in text and in a two-page graphic in 0n pages 237 to 240 of my AMS Weather Book, a hurricane is not only a heat engine, but a “turbocharged” heat engine. A turbocharger on an auto or airplane engine uses some of the energy of the exhaust gasses coming from the engine to drive a turbine, which pumps more air into the engine’s air and fuel intake, which feeds back some of the engine’s energy that otherwise would have been wasted. This increases the engine’s efficiency–in the thermodynamic sense. As the AMS Weather Book graphic shows, the sea spray a hurricane’s winds kick up feeds energy back into the storm that would otherwise have been lost.

By the way, in the AMS Weather Book text I quote extensively from Divine Wind: The History and Science of Hurricanes by Kerry Emanuel, a leading hurricane researcher. I highly recommend this book for anyone who’s interested in hurricanes.   

9. A hurricane mixes water near the ocean surface with deeper water. Would such mixing push some of the oil deeper under the Gulf? If so, how far and with what potential consequences for sea life?

Someone who’s knowledgeable about the questions being asked might say they are silly because amounts of matter or energy involved are too small. But, many people who are very intelligent about other things have no clue about the order of magnitude of the forces and matter involved in natural events whether they are hurricanes, tornadoes, or volcanoes.

Think of all of the people who over the years have suggested using nuclear weapons to kill a hurricane. Some who ask this question have been far from ignorant. (If you’re wondering about the answer, see nuking hurricanes on NOAA’s Hurricane Research Division Web site.)

Good science writers often answer questions for ordinary people that some scientists think are so obvious that they aren’t worth asking.

These ideas tumbled out of my mind in less than five minutes after reading the material under the “Nathan Hegedus: Will Hurricane Season Mean “Oilmageddon” For The United States?” in a posting by Charlie Petit on the Knight Science Journalism Tracker.

Some of the questions I ask above are “answered” in the Hegedus story at the link above. But, from the little bit said there, I don’t have a huge amount of faith in the answers.

Even though I’m retired from regular science writing, I haven’t retired from thinking about questions the news prompts about science. I’m on vacation now and will probably noodle around as a sip a beer looking for answers. I’d love to hear from anyone who finds the answers and publishes them.

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