Too Fast to Measure

I'm thrilled to report that the book that grew out of the Synthesis project, the parent project of this blog, is now out: Earth & Mind II: A Synthesis of Research on Thinking and Learning in the Geosciences, Geological Society of America Special Publication 486, edited by Cathy Manduca and myself. It's available from the Geological Society of America bookstore ( This site may be offline. )

However, having shared my thrill at holding the book in my hands, I have to admit that there are some ideas in the book that I have already outgrown during the months that the book has been in production. A distinctive feature of the book are a set of concept maps that map the intellectual territory of each of the book's major themes: spatial thinking, temporal thinking, systems thinking, and field-based teaching and learning.

Readers of Earth & Mind: The Blog had a preview of a portion of the temporal thinking concept map in post on Temporal Reasoning in Geosciences. One limb of that concept map deals with "Timing of Observations versus Process." This relative timing matters because it controls the nature of the reasoning and evidence that you can put forward to make logical connections between what you can observe and the processes that caused the observable phenomena. The published concept map sketches three possibilities:

• Observable active processes: In such a situation, the process that caused the product is active, and functions on a fast enough time scale that formation or modification of the product can be observed, for example, a tidal current (process) is causing sand ripples (product) to form and migrate.
• Active process, too slow to observe: In such a situation, the process and conditions that gave rise to the product are still in place and active, but the process is too slow to observe on the timescale of a typical research project. Soil formation or erosion of a mountain range would be examples.
• Product of prior processes: In such a situation, the process and circumstances that gave rise to the product or structure are no long present or active. For example, metamorphic rocks at the Earth's surface have been divorced from the process and circumstances that formed them.

I now realize that there is a fourth possibility:

• Changing too fast to measure synoptically, requires a model to interpolate: In such a situation, the phenomenon of interest is too spatially heterogeneous and is changing too fast to be able to measure all of it at once. It is, however, possible to measure at selected locations and build a model to interpolate between measured localities, and thus visualize the entire phenomenon.

An atmospheric scientist, Yochanan Kushnir, first got me thinking along these lines, when we were discussing the relative virtues of observational data versus model output. He helped me to see that for something as fast moving as the atmosphere, even the best observational data set is only temporarily accurate, and that a model can actually be a more truthful representation of Nature than any single observational data set. This idea took some getting used to for me, as I had spent my geo-career observing and mapping structures that sit still for their portrait.
I was reminded of this issue recently when I saw the most amazing dynamic visualization of wind patterns (more info) over the continental United States. The beautiful clipping at the right shows a small fragment of the map for May 12, 2012. You've got to go see the original, where the wind lines for today are swirling and swooshing before your very eyes. The data come from the National Digital Forecast Database, and the visualization is by Fernanda Viégas and Martin Wattenberg who collaborate under the name HINT.FM.
So I feel a need to add a new node to the Time in Geosciences concept map; here it is: