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Title: What physical mechanism drives the Madden-Julian oscillation?
Plain: The Madden-Julian oscillation is a giant cluster of storms that moves slowly eastward around the tropics every 30 to 90 days, affecting weather worldwide. There is still no agreed theory of why it exists and moves at its speed.
Precise: Explain the planetary-scale (zonal wavenumber 1 to 3), intraseasonal (30 to 90 day), eastward-propagating (about 500 cm/s) convective envelope over the Indo-Pacific warm pool, distinguishing moisture-mode theories, skeleton and gravity-wave theories, and radiative-convective feedback mechanisms. An answer is a theory predicting the scale selection, propagation speed and growth rate, verified against observations and convection-permitting simulations.
Settled by: A theory whose predicted dispersion relation and growth rate match observations and whose critical feedbacks, when removed in convection-permitting models, eliminate the oscillation.
Kind: phenomenon
Answer type: mechanism
References: (empty)
Literature status: contested
Status note: (empty)
Posed since: 1971