Contrasting the impact of aerosols at northern and southern midlatitudes on heterogeneous ice formation
Date
2011
Authors
Kanitz T.
Seifert P.
Ansmann A.
Engelmann R.
Althausen D.
Casiccia C.
Rohwer E.G.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
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.
Description
Keywords
Anthropogenic pollution, Cape Town, Cloud data, Cloud layers, Cloud-top temperatures, Forest fires, Germany, Heterogeneous freezing, Ice formations, Leipzig, Midlatitudes, Mineral dust, Research vessels, South Africa, Southern Hemisphere, Strong contrast, Tropospheric aerosols, Air pollution, Atmospheric aerosols, Biological materials, Deforestation, Dust, Marine pollution, Optical radar, Ships, Ice, aerosol, anthropogenic source, atmospheric pollution, data set, dust, forest fire, freezing, heterogeneity, lidar, marine environment, midlatitude environment, Northern Hemisphere, research vessel, smoke, Southern Hemisphere, troposphere, Aerosols, Air Pollution, Deforestation, Dust, Forest Fires, Germany, Radar, Ships, South Africa, Chile, Germany, Leipzig, Magallanes, Punta Arenas, Saxony, South Africa, Stellenbosch, Western Cape
Citation
Geophysical Research Letters
38
17
http://www.scopus.com/inward/record.url?eid=2-s2.0-80052486976&partnerID=40&md5=2c4fba8d5a65e582a37541037d67dd98
38
17
http://www.scopus.com/inward/record.url?eid=2-s2.0-80052486976&partnerID=40&md5=2c4fba8d5a65e582a37541037d67dd98