Large-scale self-organization in dry turbulent atmospheres

Area of Science:

• Fluid dynamics
• Planetary science
• Atmospheric physics

Background:

• Turbulent convective fluctuations in planetary atmospheres lack quantitative understanding regarding large-scale structure formation.
• The inverse cascade theory, proposed for 2D fluids, is debated for its applicability to atmospheric and oceanic flows, impacting energy balance insights.

Purpose of the Study:

• To investigate the organization of turbulent convective fluctuations in planetary atmospheres.
• To determine if an inverse cascade mechanism is responsible for forming larger-scale structures in 3D atmospheric flows.
• To provide quantitative answers regarding energy balance in planetary systems.

Main Methods:

• Direct numerical simulations were employed to model rotating and stratified fluid flows.
• High spatial resolutions (12288^2 × 384 points) were utilized to capture relevant flow dynamics.
• The study analyzed flows with Rossby and Froude number ratios similar to Earth's atmosphere.

Main Results:

• Demonstrated that rotating and stratified flows support a bidirectional energy cascade in three dimensions.
• Confirmed the existence of an inverse cascade mechanism in dry atmospheres.
• Showed that turbulent fluctuations organize into larger-scale structures via this inverse cascade.

Conclusions:

• Spontaneous order arises in dry planetary atmospheres through an inverse cascade to the largest scales.
• The findings support the applicability of inverse cascade theory to 3D atmospheric and oceanic flows.
• This research advances the understanding of energy balance in planetary systems.