The Ice in Clouds Experiment-Layer (ICE-L) field study will be performed in fall 2007 on the NSF C-130 aircraft, to test whether ice nucleation measurements and other aerosol properties can be used to predict ice particle nucleation in clouds. An aerosol time-of-flight mass spectrometer (A-ATOFMS) will be used to characterize the size-resolved mixing state of aerosols during the campaign, in order to determine whether there is a causal relationship between aerosol mixing state, ice nuclei, and ice crystal number concentrations. The A-ATOFMS provides information on the aerodynamic size and chemical composition of individual particles with sizes between 80-2000 nm. It will directly sample ambient aerosols, as well as residual nuclei from a counterflow virtual impactor (CVI) on the aircraft, to compare the chemistry of out-of-cloud and interstitial aerosols with cloud and ice nuclei. Both refractory and non-refractory elements including dust, metals, soot, sea salt, organic carbon, and secondary species can be measured. The findings will guide lab studies that focus on the variability of ice nucleation activity for a range of heterogeneously reacted dust particles. In turn, the findings from the lab studies will be used in model parameterizations to be compared with ICE-L data to determine whether more accurate predictions of ice crystal concentrations can be achieved from measured microphysical and chemical properties of clouds and aerosols. Graduate and undergraduate students will be trained in chemistry, physics, atmospheric science, and instrument development. A web page highlighting these studies will be developed as well as a public exhibit at the Birch Aquarium focusing on ice clouds and how they form in the atmosphere and impact climate. A portion of the exhibit will be mobile and taken to local schools. The project will be to help educate the public on how anthropogenic emissions and the nature of aerosols can impact climate both regionally and globally.
