Atmospheric Instability and Its Associated Oscillations in the Tropics

The interaction between tropical clouds and radiation is studied in the context of weak temperature gradient approximation, using very low order systems (e.g., a two-column two-layer model) as zeroth-order approximation. Its criteria for instability are derived systems. Owing to connection (unstable fixed point) oscillation (limit cycle) physics (phase) space, suggest that leads atmospheric oscillations with distinct timescales observed. That is, boundary layer quasi-equilibrium quasi-two-day oscillation, radiative convective equilibrium Madden–Julian (MJO), flux El Niño–southern oscillation. In addition, linear model first-order approximation introduced reveal zonal asymmetry response standing convective/radiative heating asymmetric resonance conditions explain why ~45-day brings about planetary-scale eastward travelling vertical circulation like MJO. systems, despite their simplicity, replicate observed, providing novel cloud parameterization weather climate models. Their further suggests models can successfully predict if they properly represent cirrus downdrafts tropics.