The Water Cycle

Winner for most artistic and mist-like arrows. (Source: National Geographic Society, Exploring Your World)

   Certainly everyone remembers their very first Water Cycle poster from elementary school. Typically, the poster featured a body of water, a land mass, and some clouds with three wide curving arrows showing how water moves (evaporates) from the ocean or lake, becomes (condenses into) clouds, which then rain or snow (precipitate) onto the land and then flow underground and/or back into the ocean or lake. Three arrow--ocean, cloud, land--right?--kind of like the plastics recycling logo.
   I am sure many of you are nodding your heads, happy to have remembered this much. And, I am sure many of you are shaking your heads and saying, "Ah, if it were only that simple!"
   Yesterday, I went in search of the water cycle illustration. I pulled several books from my book shelf, flipped to the index looking for "water cycle" or "hydrologic cycle." The first one I found (above) is the work of Robert Hynes and comes from my go-to geography books published by the National Geographic Society in 1989. The illustration is beautiful, misty, round, and feels fluid like a water cycle. However, it includes not three arrows but five. Or maybe two. Some of them are double headers. Naturally, because this is a product of the NGS, all you need to know is packed into a text block/caption adjacent to the illustration.
   Before reading that text, I went to my next favorite book and found another lovely misty scene (below) and was surprised to see that there were seven arrows and they did not move in the continuous cycle imprinted in my mind from grade school. Huh! I grabbed another book.

Pretty darn artistic, but the labels kind of ruin the mood. (Source: Ahrens, Meteorology Today)

   That book was a college biology text book for a community-college class I signed up for fifteen years ago and then remembered I had two pre-schoolers at home and would have much homework, a lab, and an hour commute to the campus. I withdrew and kept the book--despite the fact that its water cycle looks more like a design for a water elevator (below). Rectilinearity aside, this illustration includes some enormous numbers--such as 425,000 cubic kilometers for the amount of water evaporated from the world oceans every year. Looking at water cycle maps without such numbers makes it easy to be lured into the notion that a big fat arrow is going to dump 425,000 cubic kilometers of water back on the earth. Do not be so lured. An estimated 385,000 cubic km of that evaporated ocean water falls as precipitation back into the ocean; and 111,000 cubic km falls onto land. That makes 496,000--not 425,000. The "extra" 71,000 cubic km of precipitation comes from evaporation from land plants (evapotranspiration).

(Source: Starr/Taggart, Biology: The Unity and Diversity of Life)

  I reached for my least popular cloud book, Cloud Physics: A Popular Introduction to Applied Meteorology, which included an illustration I mistook for a water cycle diagram (below). It is not, but you can see my confusion.

A cascade impactor may move water, but it does not seem capable of producing clouds.  (Source: Battan: Cloud Physics)

   I almost missed this diagram (below) in my best-present-ever-from-my-husband-that-wasn't-butterfly-larvae book. The coastal landscape was unscenic, the clouds were not lovely, it was black-and-white, and the the cycle just didn't flow the way I wanted it to. This diagram resembles a cascade impactor (above).

(Source: Allaby, Encylopedia of Weather and Climate)

  A few books on my shelf are too smart for me. There were no color pictures in it. Nor were there any diagrams that represented the water cycle. I did wonder if this equation (below) might be the water cycle in code, but decided to turn the page.

Huh? (Source: McIntosh/Thom, Essentials of Meterology) And I saw this:  I really like this, but it is a diagram of the exchange of air in the troposphere. (Source:  ibid) And then this:  These caught my eye, but represent convergence, divergence, and vertical motion of something called "flow" I think that's air. (Source: ibid)

And then, from yet another book, this:

A little something from the HR Department? (Source: Barry/Chorley: Atmosphere, Weather & Climate)

  Lastly, in a most wonderful book, I found a water cycle lacking in artistry, color, and clouds (!) but one that depicts with elegant simplicity my local, Puget Sound water cycle (below). In fact, the vantage point of the reader, the Olympic Mountains are on left, Cascades on the right, and where I live, right in the center. And it has a dizzying array of arrows--about two dozen of them. This water cycle gets under my skin. In a good way.

Source: Kruckerberg, The Natural History of Puget Sound Country

  At this point, dear reader, you are probably wondering where I am going with all this. Perhaps you are dreading a somewhat longish explanation (in words) of the water cycle according the Accidental Naturalist. No, this would be too much at the end of an already longish posting.
   What I want to tell you is that after my unplanned and exciting foray into The Water Cycle, my arrow counting, my analysis of straight and curving lines, I seem to have discovered the perfect way to organize my book on clouds.
    More on that in my next posting.

Note: All photographs of illustrations from books paid for or borrowed by the Accidental Naturalist.

Water by Any Other Name...

On stunning sunny days when work can been accomplished al fresco, a good old-fashioned book on paper is far superior to any Kindle or e-book you could read on your laptop. No matter how many times you press the key with the blue-sun icon on it, the laptop screen just can’t compete with Old King Sol. So I spent a few sunny days last week on my back-deck desk with Michael Allaby’s fabulous Encyclopedia of Weather and Climate (a Christmas gift from my husband) and a broad-brimmed hat to create a swath of shade across the bright-white pages. As I scanned each entry (A through O in this first volume), I felt as if I were on a treasure hunt discovering sparkling gems and nuggets of gold on each page. I marked dozens of cloud-specific entries and many others that caught my fancy.

Have you ever heard of juvenile water? This is water that forms by physical and chemical processes in the magma below the earth’s crust. Juvenile water has never been in the atmosphere or near the surface of the earth; it has not, in other words, fallen to earth as precipitation and made its way through the ground water into a magma chamber. Juvenile water is released into the atmosphere during volcanic eruptions. Less poetically but more clearly, juvenile water is also called magmatic water. Michael Allaby estimates that there are about 2 billion cubic feet of juvenile water in a 4-cubic-mile layer of magma. Huh?

I tried to visualize this volume of magma and water, but I fell short at just one cubic foot (which, unfortunately, I can’t translate for you into any household item such as a cardboard wine box, computer monitor, or stack of bibles). Thanks to my son and his calculator, we figured out that there are 147+ billion cubic feet in a cubic mile. This made numbers bigger and matters worse. A few more calculations, and we arrived at a manageable number: one third This the ratio of juvenile water to magma in Allaby’s scenario. Hmmmm….two billion sounds more impressive than one third. This is a case where the language is more fun than the numbers, especially if you think anthropomorphically. Just imagine juvenile delinquent water.

How about meteoric water? This is the scientific name for water that falls from the sky as precipitation. That would include drizzle, rain, freezing rain, hail, graupel, sleet, snow, ice pellets. Meteoric, meteorite, and meteorology are all from the same Greek root word—meteor, or high in the air. Meta=above, eorus=to lift. By the way, precipitation, Allaby writes, is derived from the Latin praecipitatio, meaning “I fall headlong.”

Doesn’t all precipitation fall from the sky, you ask? No, in fact. Dew, white dew, frost, hoar frost, rime, glaze frost, and dozens of types of fog form when warm, moist air moves over a cold surface or cold air moves over a warm surface. Moisture condenses and appears on the surface of the ground, plants, roadways, car windshields, and other objects. Precipitation that falls in wispy veils from a cloud but evaporates before it reaches the ground is called virga or fallstreaks.

Connate water? That’s the water trapped when sediments were deposited and remains trapped inside sedimentary rocks. The roots of the word connate can be traced to the Latin con=with and nasci=to be born. Outside geological and hydrological contexts, connate means to be born or originated together, to be congenitally or firmly united, akin, or congenial.

Now, think of juvenile water—young water, inexperienced in the ways of the world, making a meteoric rise to fame as part of an explosive volcanic eruption, Think of the young and restless threesomes of hydrogen and oxygen flowing out with the magma over the mountain slopes, flowing over the sedimentary rocks in the landscape, over the connate water—the ancient water trapped in pores, vesicles, and interstices created when the world was young.