Two different perspectives on heatwaves within the Lagrangian framework

Abstract

Although heatwaves are one of the most dangerous types of weather-related hazards, their underlying mechanisms are not yet sufficiently understood. In particular, there is still no scientific consensus about the relative importance of the three key processes: horizontal temperature transport, subsidence accompanied by adiabatic heating, and diabatic heating. The current study quantifies these processes using an Eulerian method based on tracer advection, which allows one to extract Lagrangian information. For each grid point at any time, the method yields a decomposition of temperature anomalies into the aforementioned processes, complemented by the contribution of a pre-existing anomaly. Two different approaches for this decomposition are employed. The first approach is based on the full fields of the respective terms and has been established in prior research. In contrast, the second approach is based on the anomaly fields of the respective terms, i.e. deviations from their corresponding climatologies, and i