AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Combining Field and Laboratory Studies to Understand the Dominant Sources and Mechanisms of Cirrus Cloud Formation
DANIEL CZICZO, Sarvesh Garimella, Karl D. Froyd, Daniel Murphy, MIT
Abstract Number: 164 Working Group: Aerosols, Clouds, and Climate
Abstract The formation of clouds is dependent on the availability of aerosols to initiate the condensation of water vapor. In the case of cirrus clouds, ice nucleation can occur homogeneously at low temperature and high saturation on the vast majority of particles or heterogeneously at high temperature and low saturation on the small fraction of atmospheric aerosols that are efficient ice nuclei (IN). The critical properties that make for a good IN are slowly being established. This work focuses on those particles which have been shown to be important IN through in situ studies: mineral dust and metallic particles are the dominant source of residual particles, whereas sulfate/organic particles are underrepresented and elemental carbon and biological material are essentially absent. We have conducted ice nucleation studies using the Droplet Measurement Technologies SPectrometer for Ice Nuclei (SPIN) on mineral dust and metallic aerosol and report ice nucleation conditions. A comparison to the types that are not observed in cirrus and to the onset of homogeneous freezing is made.