An Analysis of ice crystal number concentration versus Aerosol Related Parameters and Supersaturation during FIRE.ACE

The purpose of this work is to analyze ice crystal number concentration (Ni) versus aerosol number concentration (Na) at various thermodynamical (e.g. supersaturation with respect to ice, Si) and dynamical (e.g. vertical air velocity, w) conditions. The observations were gathered during the First International Regional Experiment. Arctic Cloud Experiment (FIRE.ACE) that took place over the Arctic Ocean during April of 1998. Data collected during research flights over 7 days were analyzed. Ten second (~1 km) averages of Ni, Na, Si, and w were calculated from the measurements of the Particle Measuring Systems (PMS) 2-Dimensional Cloud (2DC) probe, Particle Cavity Aerosol Spectral Probe (PCASP), the LiCor infrared gas analyzer (Li-Cor 6262 CO2/H2O), and the Rosemount-858 pressure probe, respectively. The total Ni versus total Na and Na at each bin including aerosol surface area were analyzed at 5C intervals. Only glaciated conditions, specified based on Rosemount icing detector and cloud microphysical measurements, were analyzed. Ni from the Forward Spectral Scattering Probe (FSSP) was used for a qualitative analysis of a relationship between Ni and Na. The results from the analysis will be discussed to understand ice crystal nucleation processes versus Na and aerosol surface area, and their importance for the climate change and modeling studies. The results will also be compared with those from earlier studies.