Our research focus can be divided into the following topics: (1) to investigate detailed microstructure of atmospheric ice crystals and (2) the link to ice crystal optical properties and (3) to understand the role of ice clouds in our climate system.


Fritz Waitz
Ice crystals imaged by the PHIPS probe in US east cost during the IMPACTS campaign

Almost all ice crystals are complex...


Emma Järvinen
Angular scattering functions of plate-like crystals (b) and columnar crystals (c). Similar angular scattering behaviour is measured for both cases although the underlying habit is different.

3. Radiative Properties of Ice Clouds

Emma Järvinen
Change in the top-of-the-atmosphere short-wave cloud radiative effect due to crystal complexity. From Järvinen et al., 2018, ACP.

There exists still a large uncertainty related to the radiative effect of cirrus clouds. Climate and weather forcast models usually assume simplified ice crystals shapes, whose optical properties do not necessary match those of natural cirrus ice crystals. This can cause significant bias in the model. Our studies have shown that cirrus clouds are actually more reflecting than previously though. This can be explained by the increased side- and backscattering from complex crystals compared to their pristine counterparts. We want to improve the short-wave optical parameterisation of cirrus clouds by introducing new optical ice crystal model that is validated using in-situ measurements. 


Read more here:

Järvinen, E., Jourdan, O., Neubauer, D., Yao, B., Liu, C., "Additional global climate cooling by clouds due to ice crystal complexity.", Atmos. Chem. Phys., 18, 15767-15781, 2018,