High clouds in the atmosphere interact with solar radiation, but also with thermal radiation coming from Earth’s surface. Through these radiative interactions, high clouds play a key role in Earth’s climate, by changing the temperature in the atmosphere, affecting winds and precipitation. Furthermore, high clouds in the atmosphere are composed mainly by ice crystals, with a variety of morphologies. Understanding which ice crystal geometries are present in ice clouds can also help to better predict weather and climate.

There are many ways to measure ice clouds properties and ice crystals, satellite instrumentation being one of the most common. Satellites can measure the polarization state of the radiation coming from clouds, that is, how the vibration of the electromagnetic waves align in certain directions. Although there are some satellite instruments measuring the polarization of shortwave radiation, there are also some developments of new instruments to measure the polarization of longwave (LW) radiation, which hasn’t been explored much yet.

In this study, we simulate the polarized LW signal coming from ice clouds, considering a variety of cloud thickness and heights. We look to understand how different ice cloud properties influence LW polarization, and to evaluate new polarimeter instrumentation.