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.

A Cloud is a Cloud is a Cloud...

    Because my recent foray into meteorology has revealed a black hole of understanding of chemistry—the structure of a water molecule (the building blocks of clouds), for instance—I have borrowed my son’s college text book on Conceptual Chemistry, a book he acquired from a textbook rental company called Chegg until August 1. It is June 22. I must hurry.

     I put the book on the small table next to the chair where I write in morning. I love the cover: a cloudless blue sky in the background, a snowy Yosemite National Park in the middle ground, and a sky-blue, computer-enhanced river in the foreground. In the water are the reflections of the snowy landscape and submerged models of water molecules—two small white balls attached to one red ball. I get it. Water as a solid, water as a liquid and…uh oh…where is the gaseous phase?

    I turn the book over and see that the entire back cover is dedicated to explaining the front-cover photograph. The gaseous phase is not shown, because, water vapor is invisible. (Remember, visible steam is not water vapor—it is liquid water, condensed water vapor). The back cover explains that when skies are clear, as in the Yosemite scene, the amount of water vapor in the atmosphere is relatively low. “This, in turn, makes it easier for the water molecules of snow to scatter directly into the gaseous phase. This process, called sublimation, explains why much of the fresh snow seen on dry sunny mountain peaks soon disappears without ever melting.”

     And then the best part of this book, the part that makes me know this book and I are going to be friends:  “These molecular perspectives enhance our ability to see beauty, rhyme, and reason in the world around is. This is the premise upon which this book you are now holding was written.”

     I love the fact that I am holding a book, an actual paper book of considerable weight (I am sorry about the trees, but am cutting back on paper consumption elsewhere in order to avoid e-books.) I love the fact that by holding this book—and also reading it—more beauty, rhyme, and reason will come into my life.

      I love the fact that a few years back, I was in Yosemite National Park in January to give a talk on marbled murrelets. My husband and I arrived at the park on a rare warm and sunny day. There was plenty of snow on the ground--just like in the photo above. It was stunning and perfect. The afternoon before my talk, we took a hike. I hadn’t walked on snow in a long time. It felt good. My head was down, watching my step, looking for the trail. It occurred to me that I was walking on former clouds. These were clouds in their packed down, solid, crunchy form. The waterfall across the valley was a former cloud, too. So was the river that has cut its way through the granite. As we hiked up the trail, my warm breath condensed with each exhalation. The visible vapor was a kind of cloud and I, therefore, was a cloud maker. As we followed the switchback up the mountain, I warmed up and started to sweat. My skin was moist. I had the potential to vaporize. All the liquid inside my body, my organs, my blood cells could vaporize. Then I remembered my skin had pores. I hoped they hadn't forgotten how to close. I really didn't want to be part of the water cycle--literally.

    This morning, I opened Conceptual Chemistry. Naturally, I do not start with Chapter 1, but Chapter 4, which is the chapter my son told me would be most helpful. It is about subatomic particles—electrons, protons, and neutrons—and how we understand these parts of the atom through conceptual, not physical, models. The two small white balls attached to the sides of one larger red ball is a conceptual model of a water molecule, the white balls representing hydrogen, and the red representing oxygen. We cannot create a physical model—a large-enough-to-be-visible replica of a water molecule—because we cannot actually see individual water molecules. Nor can we see the atoms of hydrogen or oxygen. Nor can we see the atoms’ electrons orbiting around a center of protons and neutrons the way planets orbit the sun.

   This planetary approach--the pretty darn good conceptual model I grew up with, has, according to the author of Conceptual Chemistry, become outdated. In new and more accurate conceptual models of the atom, electrons appear as…you guessed it…a cloud.