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arXiv · 2610.33827

Energy cascades in atmospheric moist convection

Paweł Jędrejko·Marta Wacławczyk·Benjamin Luce·Szymon P. Malinowski·Jakub Nowak·J. Christos Vassilicos
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Abstract

We analyze scale-by-scale budgets of velocity and buoyancy second-order structure functions using Large Eddy Simulation of the BOMEX trade-wind cumulus layer. The simulation utilizes a $10\,\mathrm{m}$ grid resolution under the anelastic approximation, incorporating moist thermodynamics to capture phase changes. The analysis of derived turbulence kinetic energy (TKE) and turbulence potential energy (TPE) budgets reveals four regions of distinct turbulence dynamics. For three of these regions, approximate balances holding over wide range of length scales are identified, highlighting the importance of interspace and pressure transport. Above the lifting condensation level ($\approx 800\,\mathrm{m}$), phase changes introduce forcing across all resolved scales, leading to an inverse TPE cascade spanning all scales. The TKE, inter-scale transfer is inverse above the vertical velocity integral length scale but below the horizontal velocity scale. In the upper cloud layer ($>1400\,\mathrm{m}$), forward inter-scale transfers are recovered despite ongoing phase changes. A phenomenological interpretation of these features, referring to the different formation stages of convective updrafts, is also proposed. Finally, 1D horizontal subsamples from the simulation show good agreement with recent airborne measurements, validating the numerical framework and confirming the departure of moist convective turbulence from standard energy cascade models.

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Paweł Jędrejko, Marta Wacławczyk, Benjamin Luce, Szymon P. Malinowski, Jakub Nowak, J. Christos Vassilicos. 2026-10-24. Energy cascades in atmospheric moist convection. https://arxiv.org/abs/2610.33827

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