Getting Students to Apply the Governing Equations with Real-World Data: Estimating Heat Fluxes Using Weather Station and Drone Data

A key topic in introductory atmospheric dynamics classes is derivation of the atmospheric governing equations based on the principles of conservation of mass, momentum, and energy. But, simple derivation of these equations is not sufficient. Students must then gain a physical understanding of what these equations represent and how the equations can be used to quantify atmospheric behavior. In introductory undergraduate and graduate atmospheric dynamics classes at the University of Colorado we use real-time weather observations to estimate terms in the atmospheric governing equations and in doing so develop a deeper understanding of the processes represented in these equations.

This presentation will illustrate how students estimate turbulent heat fluxes from a time series of surface weather observations from a campus weather station using the conservation of energy equation. When solving this problem the students are encouraged to consider all of the physical processes that can alter temperature at a fixed location and how these processes are quantified in the energy equation. The students then identify which terms can be estimated from the available observations and which remaining terms can or cannot be neglected. Finally, the students then identify any assumptions required to complete the calculation. After estimating the turbulent heat flux students are then provided with additional observations, including the incoming solar radiative flux, and are asked to assess whether their estimated turbulent heat flux is reasonable.

Following this in class exercise students are then assigned a similar problem as a homework assignment. For the homework problem students are given temperature profile data collected from unmanned aircraft (drones) as part of the instructor’s Antarctic field research. The unmanned aircraft data includes multiple temperature profiles at a fixed location over time and other drone observations taken in a semi-Lagrangian framework. In class discussion after the homework assignment is completed contrasts the assumptions required when using a surface time series of meteorological observations versus those required when using the drone-acquired temperature profiles. Another discussion topic relates to Eulerian versus Lagrangian forms of the energy equation and advantages and disadvantages of each form of the equation.