Quantifying the impact of dust on heterogeneous ice generation in midlevel supercooled stratiform clouds

Zhang, D., Z. Wang, A.J. HEYMSFIELD, J. Fan, D. Liu, and M. Zhao (2012), Quantifying the impact of dust on heterogeneous ice generation in midlevel supercooled stratiform clouds, Geophys. Res. Lett., 39, L18805, doi:10.1029/2012GL052831.
Abstract

Dust aerosols have been regarded as effective ice nuclei (IN), but large uncertainties regarding their efficiencies remain. Here, four years of collocated CALIPSO and CloudSat measurements are used to quantify the impact of dust on heterogeneous ice generation in midlevel supercooled stratiform clouds (MSSCs) over the ‘dust belt’. The results show that the dusty MSSCs have an up to 20% higher mixed-phase cloud occurrence, up to 8 dBZ higher mean maximum Ze (Ze_max), and up to 11.5 g/m2 higher ice water path (IWP) than similar MSSCs under background aerosol conditions. Assuming similar ice growth and fallout history in similar MSSCs, the significant differences in Ze_max between dusty and non-dusty MSSCs reflect ice particle number concentration differences. Therefore, observed Ze_max differences indicate that dust could enhance ice particle concentration in MSSCs by a factor of 2 to 6 at temperatures colder than -12 C. The enhancements are strongly dependent on the cloud top temperature, large dust particle concentration and chemical compositions. These results imply an important role of dust particles in modifying mixed-phase cloud properties globally.

PDF of Publication
Download from publisher's website
Research Program
Radiation Science Program (RSP)
Mission
CloudSat
CALIPSO

 

Disclaimer: This material is being kept online for historical purposes. Though accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers. Visit https://espo.nasa.gov for information about our current projects.