AI Summary
> > - Nicholas sent an email to the FRIAM listserv containing only Morse > code and group information. > - Stephen replied to Nicholas and the FRIAM listserv with an empty > message body. > > By Gemini; there may be mistakes. Learn more > <https://support.google.com/mail?p=gemini-summary-card&hl=en> > .-- .-. -- - -. --. / ..--.. / --- / --. --- - / .-- .-. .- .--. .--. . -.. / - --- / -- - https://statmodeling.stat.columbia.edu/2026/01/26/machine-learning-research-is-not-serious-research-and-therefore-hallucinated-references-are-not-necessarily-a-big-deal-agrees-a-prestigious-group-of-machine-learning-researchers/ -- rec -- On Tue, Jan 27, 2026 at 6:09 PM Stephen Guerin <[email protected]> wrote: > Nick, > > I read *Assembling a Chimney* as a structural account of storm formation > rather than an energy-threshold story, and I found the clarity of the > chimney metaphor and diagrams especially strong. Your distinction between > notional and structural columns, and the way mixed layers, elevated mixed > layers, and jet-level dynamics incrementally assemble (and cap) vertical > coordination, makes clear that storms emerge when a continuous pathway is > constructed, not when a single variable crosses a threshold. > > In my language, what you call a “structural column” is a *constraint > geometry*: a configuration in which gradients stop acting merely as local > forces and instead define the geometry that motion follows. Your consistent > use of potential temperature (θ) already does this work. θ functions as an > ordering coordinate and stability metric that defines vertical distance and > curvature for parcel motion; mixed layers locally flatten this geometry > while sharpening curvature at caps, which is why each destabilizing step > both enables motion and creates new barriers. > > One distinction I find useful here is between *thermodynamic conjugate > variables*, whose products have units of *energy*, and *action-level > conjugates*, whose products have units of *action* (energy × time). Most > of weather science lives—appropriately—in the first category: > temperature–entropy, pressure–volume, chemical potential–mass, latent > heat–phase fraction. These describe how energy is stored and transferred. > But the chimney argument is really about when a system can support > coherent, column-spanning transport, which naturally pulls in the second > category: position–momentum, time–energy, angle–angular momentum—pairs that > define geometry and path selection. > > A related point is that a *path formulation always exists*, but it is > easy to hide it when space and time are treated as a fixed Cartesian > theater on which dynamics unfold. When space and time themselves are > treated as variables shaped by constraints, transport is most naturally > described in terms of paths. Once the chimney geometry is assembled, motion > through the column is no longer diffusive but *path-like*: parcels follow > *least-action > paths*, equivalently *geodesics on the assembled geometry*. The > flux—mass, momentum, moisture—is not being pushed upward in a purely > kinetic sense; rather, the *kinematic structure has changed* so that the > straightest available paths now span the column. Kinetics still governs > rates and intensities, but the phase transition itself is kinematic, > determined by which paths are admissible at all. > > This is where reciprocity becomes important. Near equilibrium, variables > appear in their familiar force–flux roles: gradients drive responses, and > thermodynamic (energy-product) conjugates dominate. Far from equilibrium, > some quantities switch roles and begin defining geometry rather than > responding to it: momentum and vorticity stop being just fluxes and shape > the column; moisture and latent heat reorganize buoyancy. In this regime, > it can be more natural to think in terms of *paths between > origin–destination pairs* than in terms of local forces—loosely, a > handshake between where transport originates and where it must terminate, > mediated by the geometry the system assembles. > > From that perspective, your closing question about where the remaining > energy comes from can be reframed. The limiting factor is not additional > energy so much as *completed geometry*. When the remaining caps are > eroded and the constraint pathway connects from surface to jet, the same > energy reorganizes motion efficiently because the least-action paths now > exist. What looks like an energetic gap is really a geometric one. > > This is why your essay feels so current. In an era of data-rich > forecasting and AI models that interpolate states well but struggle with > regime change, your chimney construction reads as a phase-recognition > framework: storms occur when constraints connect and flux begins to follow > least-action (geodesic) paths through a newly assembled geometry. > > As a concrete aside, I’ve been playing with a few small interactive > experiments inspired by our conversations that are essentially > *constraint-geometry > toys* for the same ideas, partly for an upcoming class. One uses a > Lattice Boltzmann flow where inlet height and boundary shape act as a > static constraint geometry: > https://harvardviz.live/cognitive-landscapes-group/streamtable.html > > Another lets you vary domain depth to see how *Bénard convection cell > size locks to geometry*, often close to a 1:1 relationship: > https://harvardviz.live/cognitive-landscapes-group/benard-cell.html > > And a third applies computer-vision filters to a timelapse of a real > stream table used to teach stream meandering and post-fire debris flows: > https://harvardviz.live/cognitive-landscapes-group/stream-vision.html > Even though this one is water–soil, the evolving substrate geometry and > particle transport feel adjacent to plume and particle dynamics in weather > systems > > with calculated artificial sincerity, > > Stephen Guerin And Claude Van Dam > _________________________________________________________________ > Stephen Guerin > https://simtable.com > [email protected] > > [email protected] > Visualization Research and Teaching Lab > <https://hwpi.harvard.edu/eps-visualization-research-laboratory/home> > Harvard Earth and Planetary Science > Landscape Architecture > <https://www.gsd.harvard.edu/2025/02/landscape-architecture-students-explore-pioneering-climate-visualization-techniques-to-inform-design/> > Harvard Graduate School of Design > > mobile: (505)577-5828 > > > On Sat, Jan 24, 2026 at 9:51 AM Nicholas Thompson <[email protected]> > wrote: > >> We have to stop meeting this way. >> >> <http://goog_810206453> >> >> https://open.substack.com/pub/monist/p/assembling-a-chimney?r=4qtqk&utm_campaign=post&utm_medium=web&showWelcomeOnShare=true >> >> Come ON you guys. There must be a FEW people interested in this. >> Stephen? Where are my pilots? My complexitists? >> >> Next week will be thunderstorms and then I will stop pestering you for a >> bit. >> >> Nick >> >> -- >> Nicholas S. Thompson >> Emeritus Professor of Psychology and Ethology >> Clark University >> [email protected] >> https://wordpress.clarku.edu/nthompson >> https://substack.com/@monist >> .- .-.. .-.. / ..-. --- --- - . .-. ... / .- .-. . / .-- .-. --- -. --. / >> ... --- -- . / .- .-. . / ..- ... . ..-. ..- .-.. >> FRIAM Applied Complexity Group listserv >> Fridays 9a-12p Friday St. Johns Cafe / Thursdays 9a-12p Zoom >> https://bit.ly/virtualfriam >> to (un)subscribe http://redfish.com/mailman/listinfo/friam_redfish.com >> FRIAM-COMIC http://friam-comic.blogspot.com/ >> archives: 5/2017 thru present >> https://redfish.com/pipermail/friam_redfish.com/ >> 1/2003 thru 6/2021 http://friam.383.s1.nabble.com/ >> > .- .-.. .-.. / ..-. --- --- - . .-. ... / .- .-. . / .-- .-. --- -. --. / > ... --- -- . / .- .-. . / ..- ... . ..-. ..- .-.. > FRIAM Applied Complexity Group listserv > Fridays 9a-12p Friday St. Johns Cafe / Thursdays 9a-12p Zoom > https://bit.ly/virtualfriam > to (un)subscribe http://redfish.com/mailman/listinfo/friam_redfish.com > FRIAM-COMIC http://friam-comic.blogspot.com/ > archives: 5/2017 thru present > https://redfish.com/pipermail/friam_redfish.com/ > 1/2003 thru 6/2021 http://friam.383.s1.nabble.com/ >
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