Publication Details

AFRICAN RESEARCH NEXUS

SHINING A SPOTLIGHT ON AFRICAN RESEARCH

earth and planetary sciences

Contrasting the impact of aerosols at northern and southern midlatitudes on heterogeneous ice formation

Geophysical Research Letters, Volume 38, No. 17, Article L17802, Year 2011

Three cloud data sets, each covering four months of observations, were recently recorded with a lidar at Punta Arenas (°53S), Chile, at Stellenbosch (34S, near Cape Town), South Africa, and aboard the research vessel Polarstern during three north-south cruises. By comparing these observations with an 11-year cloud data set measured with a lidar at Leipzig (°51N), Germany, the occurrence of heterogeneous ice formation (as a function of cloud top temperature) for very different aerosol conditions in the northern and southern hemisphere is investigated. Large differences in the heterogeneous freezing behavior in the mostly layered clouds are found. For example, <20%, 30%-40% and around 70% of the cloud layers with cloud top temperatures from-15°C to-20°C, showed ice formation over Punta Arenas, Stellenbosch, and Leipzig, respectively. The observed strong contrast reflects the differences in the free tropospheric aerosol conditions at northern midlatitudes, that are controlled by anthropogenic pollution, mineral dust, forest fire smoke, terrestrial biological material and high southern midlatitudes with clean marine conditions. Copyright 2011 by the American Geophysical Union.
Statistics
Citations: 148
Authors: 7
Affiliations: 3
Identifiers
Research Areas
Environmental
Study Locations
South Africa