The Sensitivity of the INP Number from Different Mineral Species to Fundamental Dust Properties in a Global Model

The effect of aerosol particles on ice nucleation and, in turn, the formation of ice and mixed phase clouds is recognized as one of the largest sources of uncertainty in climate prediction. An improved sectional dust module in NASA GISS Earth System ModelE, which distinguishes eight different mineral species and accretions between iron oxides and the other minerals is utilized to calculate the ice nucleating particle (INP) concentration from different mineral species. In recent work, applying an active site parameterization for immersion freezing, we have found that the INP number from K-feldspar is sensitive to the geographic source distribution of dust as well as a changed emitted mineral size distribution that results from the consideration of soil aggregation, brittle fragmentation theory, and large particle emission of dust minerals. The bias varies geographically with the mineral composition of the sources. This work is being extended here to test the sensitivity to fundamental dust properties of the INP number calculated from other active mineral species for the same type of active site parameterization. We also examine whether the results can be generalized to other parameterizations like a time-dependent water activity based immersion freezing model. The calculations are done for the ranges of temperatures and, where applicable, for the ranges of relative humidities for which the parameterizations are valid.