Aqua satellite Moderate Resolution Imaging Spectroradiometer (MODIS) 1-km observations are collocated with Clouds and the Earth's Radiant Energy System (CERES) fields of view taken during July 2008 afternoon satellite passes over the equatorial western Pacific Ocean. Radiation simulations are compared with collocated CERES observations to better understand the sensitivity of computed fluxes to two ice cloud broadband radiation parameterization schemes and inferred ice cloud characteristics. In particular, the radiation computational schemes and ice cloud property retrievals are based on two respective ice particle models, the MODIS Collection 6 (MC6) aggregate model and a more microphysically consistent two-habit model (THM). The simulation results show that both MC6 and THM overestimate the shortwave (SW) and longwave (LW) cloud radiative effects at the top of the atmosphere, as compared to the CERES observations; the difference between the MC6 and THM-based ice cloud retrievals is too small to compensate for the differences between the two model-based radiation schemes. Therefore, the present finding suggests that broadband radiative simulations are more sensitive to the radiation parameterization scheme than to the input cloud properties retrieved using the corresponding ice cloud particle optical property model. Plain Language Summary Clouds can reflect the shortwave (SW) radiation energy coming from the sun back to space and absorb the longwave (LW) radiation energy emitted by the Earth and hence modulate the climate of the planet by changing the vertical distribution of radiative heating/cooling in the atmosphere. Satellite observations have been used to derive global cloud properties and radiation energy at the top of the atmosphere (TOA). An ice cloud optical property model is needed both in converting satellite signals over ice cloud scenes to cloud properties and computing radiation energy vertical distributions under ice cloud conditions. This study tests two widely-used ice cloud optical property models. The results show that radiation energy budget at the TOA computations are more sensitive to the selected ice cloud optical property model in the computational scheme rather than the selected ice cloud optical property model in deriving the ice cloud properties input to the computational scheme. If the influence of horizontal radiation energy transfer is considered in the computational scheme, both the simulated outgoing solar SW and terrestrial LW radiation energies are reduced.