Impact of LW scattering on MJO
MJO development is sensitive to radiation. Current studies all employed radiation schemes without consideration of longwave scattering. We use combined active and passive satellite cloud property retrievals to quantify the one‐layer cloud OLR and heating rate (HR) biases introduced by neglecting cloud longwave scattering in the Indian Ocean and Maritime Continent in the context of MJO, with a focus on its phases 3, 5, and 6.
If longwave scattering is neglected, the composite mean OLR overestimation over the one‐layer ice cloud area from 5 days before to 4 days after the MJO passage is approximately 3.5 to 5.0 W m−2. Neglecting longwave scattering also leads to a heating-rate underestimation at cloud base and an overestimation at cloud top, making the base‐to‐top heating gradient less sharp at the cloud‐resolving scale.
In order to fully capture the complicated interactions between dynamics, radiation, and cloud microphysics for the MJO life cycles, the long cloud scattering should be included for its non-negligible role in the in-cloud radiative heating and cooling, especially for the ice cloud.