Ice formation in upper tropospheric clouds plays a significant role in Earth’s radiative balance.  However, the Intergovernmental Panel on Climate Change (IPCC) states that ‘our understanding of heterogeneous ice nucleation is still in its infancy’.  Heterogeneous ice nucleation, where ice formation is catalysed by a solid surface, undoubtedly influences cloud properties but measurements of the efficiency with which key atmospheric aerosols nucleate ice are lacking.

A new instrument has been designed and developed to measure the efficiency with which heterogeneous ice nucleation occurs in liquid droplets via the immersion mode.