Vertical Structure of Horizontal Scaling of Wind and Moisture Fields during South American Cold-Air Intrusions Considering Error Growth and Scale-Dependent Predictability

There has been a great effort on understanding the atmospheric energy spectrum in recent years. However, many studies have only considered time-averaged, vertically averaged, or idealized cases, which tend to eliminate much of the variability associated with transient effects, vertical structure, and discrete events. Here, we expand previous work examining the scaling behavior of winds and moisture during South American Cold Air Intrusions (CAIs) to examine error growth dynamics linked to model representation of subgrid scale moist processes. CAIs are prominent synoptic scale features occurring along the Andes that are tied to enhanced convective activity and extreme precipitation events in the warm season captured by ground-based as well as GPM-DPR observations. Spectral analysis of the vertical structure of horizontal wind and moisture in the mesoscales shows distinctive scaling behavior for convective (spectral slopes β~-5/3) and nonconvective (β~-11/5) atmospheric conditions during these events reflecting the temporal and spatial evolution of CAI structure. Furthermore, this scaling behavior modulates model error growth linked to moist processes as a function of horizontal scale. The scaling results conditional on atmospheric stability metrics have important implications for improving the subgrid scale representation of moist processes and understanding the scale-dependent predictability during these events.