Throughout the spring and fall semesters 2007, in senior level courses in climate dynamics, meso-and storm-scale meteorology, synoptic meteorology, and junior-level courses in atmospheric dynamics and thermodynamics, 2-D non-rotating and 3-D rotating tanks were incorporated into laboratory exercises as supplements to the theoretical treatment of fronts, Ekman layers, the Hadley circulation, baroclinic instabilities, western boundary currents, free convection, and thermohaline circulations. Students were expected to compare the fluid simulations with synoptic and climatological data available via the MIT “Weather in a Tank” web-site and the in-house data acquired via Unidata's Internet Data Distribution (IDD) system and rendered by their Integrated Data Viewer (IDV), 3-D visualization software that is uniquely suited to comparing 3-D tank simulations with real data and numerical model output. Students were responsible for setting up the experiment in accordance with laboratory procedures provided by the MIT group and establishing and quantifying experimental parameters such as rotation rate and thermal/salinity gradients. But they but were also encouraged to deviate from specified procedures and create modifications to the experiments or new experiments to which they could apply theoretical analysis. The 3-D rotating tank was used to simulate large-scale atmospheric circulation patterns that arose from density gradients influenced by rotation, as well as that evolution of patterns as rotation rate varied. The slope of a front was quantitatively determined by measuring the difference in density introduced by a salinity gradient and compared to the frontal slope calculated using Margules formula with surprisingly good agreement.
Through the use of experiments, students gained a much deeper appreciation of the nature of rotating fluids and the role of rotation in shaping large-scale circulation patterns and their transition to modes of instability. The 2-D non-rotating tank proved especially useful for creating simulations of free convection and the development of over-shooting tops of thunderstorms and the subsequent generation of gravity waves and the anvil. It was also useful in demonstrating ocean upwelling and the return circulation that results from persistent wind forcing across a water surface (e.g. trade winds), an experimental idea that originated with the UMass-Dartmouth group.
In addition to employing the portable tanks in courses for meteorology and ocean sciences majors, both tanks are being used for demonstrating characteristics of atmosphere and ocean circulations for large enrollment, general education geosciences survey courses taken by non-science majors. These courses, which typically have enrollments of 100-150, can benefit significantly from demonstrations that provide visual learners a better grasp of complex topics such as fronts, Rossby waves, Ekman layers, and thermohaline circulations, to name a few.
All partner institutions benefit from the project's collaborative agenda, which includes sharing of ideas and experimental procedures to the development of new experiments along with their conceptual and/or theoretical underpinnings. Face-to-face meetings of project partners and select students provides further opportunity for the group to glean more from shared initiatives than would be realized by going it alone. Moreover, the intended outcomes that teaching with tanks has on student learning are subjected to a formal evaluation and assessment component that includes pre- and post-tests, instructor input, and feedback to the instructor for improvement.
This paper will report on the value of teaching with tanks for the participating universities and their students, and will provide examples of experiments that can be accessed online by the community.
Supplementary URL: