Influence of Cloud–Radiative Feedbacks on Convection's Moisture Sensitivity in a 10-Layer Intermediate Global Atmospheric Model with Calibrated Climatology

We seek to estimate the sensitivity of height-resolved convective activity C(p) to water vapor profiles V(p) under with and without radiation feedback settings using an intermediate 10-layer atmospheric model with tangent linear super-parameterization of convection coupled to realistic 3-D time-mean flow (Kelly et al. 2017;K17). The model’s convective heating and moistening tendencies in each column are represented as a linear matrix operating on anomalous temperature and moisture profiles. The derived convection response function (CRF) of Kuang (2010) is from a cyclic convection-permitting model (CCPM) in equilibrium with prescribed atmospheric cooling (with column moist static energy conserved- with no radiation and surface flux feedbacks included). The cloud radiation effects are accounted into the matrix (CRF) by adding its contribution (equal to the 15 % of the net condensation heating uniformly above 900 hPa) to the convective heating tendencies.

This study scrutinizes the role of convection’s free-tropospheric moisture sensitivity in tropical waves, a refinement to K17’s work-by including the cloud-radiation feedbacks.

For no radiation case, the model’s variability ranges from weak-strong convectively coupled kelvin waves for increasing the sensitivity of moisture. Whereas, after accounting for the radiation, the model simulates westward advecting waves with similar variability for different sensitivities of free-tropospheric moisture.