Monday, November 06, 2006

The Weather: 56; Human Race: 0

kw: book reviews, nonfiction, weather, climatology, history, world events

A kiloton of TNT, the basic unit of nuclear explosion energy, is just over a million kilowatt-hours (1.16x106 KWH). The Megaton, about the energy of the smallest thermonuclear bomb, is a thousand kilotons, or about a billion KWH. These factors allow us to compare large amounts of solar and wind energy with the largest energies we are capable of directly wielding.

The atmosphere weighs about 11.6 quintillion pounds, or 5¼ quintillion kg. This mass is kept in motion by a small amount of the solar energy that strikes Earth, at a speed that averages a few meters per second. The earth intercepts 172 trillion KW of solar energy, mostly in the tropics and subtropics. Some fraction of this drives the atmosphere, and a (very roughly) similar fraction evaporates water from the oceans into the air. Condensation of water back out of the air drives those focused thermal energy systems we call storms, from summer showers to tornadoes and hurricanes.

Water vapor condensing to rainfall in a category 1 hurricane releases heat energy of about 14 trillion KWH per day. Divide that by the billion or so KWH in a kiloton bomb, and we see the energy equivalent of thousands of H-bombs, daily, in an "ordinary" hurricane. It took all the members of the Nuclear Club about sixty years to stockpile enough bombs to equal about two days' energy release by a "small" hurricane.

So where am I going with this? I just read Blame it on the Rain: How the Weather Has Changed History by Laura Lee. The book consists of 56 stories, in essay form, of the weather having a strong impact on human events. (Before I go further, I should mention that the stories we hear of a "nuclear winter" being caused by a nuclear war are overdone. We don't get a "hurricane winter" each time one of these storms roars through a tropical sea or pummells a coastline. Nor when a similarly-sized winter supercell (rarer, but just as energetic) covers the middle third of a continent and drops something like four feet of snow over a half million square miles. Such a supercell, a thousand miles wide, shut down all the airports from Oklahoma City to Chicago about thirty years ago...Winter ended on schedule anyway. And by the way, none of the numbers above are in the book. It's just my musings to get this essay rolling...)

One point of Ms Lee's book is that all human plans and powers need to take the powers of nature into account, or we are the losers. Among the essays are the four-part saga of various belligerent nations trying to defeat Russia, which is always well defended by "General January". Less well known is the spring mud that follows, the "rasputitsa". This "coroner" buries the dead the General kills...and most of the survivors as well.

Other stories include fog hiding armies, rain delaying battles until crucial reinforcements arrive, and winds helping or hindering, seemingly at random, our various schemes. One ill-timed wind gust ensured that the Wright brothers' first flight was not scooped by Langley. An extra-strong El NiƱo did away with Robert Scott in Antarctica, while aiding Amundsen's team to the first South Pole visit.

Mark Twain (or a co-author) wrote, "Everybody talks about the weather, but nobody does anything about it." We're a long way from doing so. So-called "weather modification" is typically "weather irritation", and the storm in questions tends to act like a flea-bit dog and scratch back. In 1972, west of Rapid City, SD, a small airplane flew up the front of a gathering storm and "seeded" it with silver iodide. This storm stopped in its tracks, blasted through to the stratosphere, and dumped a foot of rain into Rapid Valley, just below a flood-control dam. A quarter of Rapid City was washed downstream. This isn't in the book, either; most of the stories are about political and military events.

So don't go around singing "Don't rain on my parade." The weather just might take you up on it.

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