scholarly journals Optical properties of atmospheric aerosol over Cape Town, Western Cape of South Africa: Role of biomass burning

2020 ◽  
Author(s):  
Abdulaziz Tunde Yakubu ◽  
Naven Chetty
Keyword(s):  
South Africa ◽  
Optical Properties ◽  
Biomass Burning ◽  
Atmospheric Aerosol ◽  
Cape Town ◽  
Western Cape

scholarly journals Optical properties of atmospheric aerosol over Cape Town, Western Cape of South Africa: Role of biomass burning

Atmósfera ◽  
2020 ◽  
Author(s):  
Abdulaziz Tunde Yakubu ◽  
Naven Chetty
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Atmospheric Aerosol ◽  
Cape Town ◽  
Optical Characteristics ◽  
Western Cape ◽  
Climate Trend ◽  
General Terms ◽  
Coarse Mode ◽  
The Impact

The optical characteristics of atmospheric aerosol are vital in the determination of the regional climate trend. Biomass burning is typically known to influence aerosol optical characteristics. Following the incessant biomass burning and the recent drop in precipitation over Western Cape, the aerosol optical properties with a focus on the impact of biomass burning are studied over Cape Town using data from AERONET (Aerosol Robotic Network) and MODIS (Moderate Resolution Imaging Spectroradiometer). In general terms, measurements from both platforms significantly agree on the estimates of aerosol optical depth (AOD) and water vapor content (WVC). The mean AOD 0.075 (± 0.022) and Ångström exponent (AE) 0.63 (± 0.19) derived from AERONET demonstrate the dominance of coarse mode aerosol typical of maritime aerosol. Similarly, aerosol particle size distributions display the predominance of coarse mode particles. However, the derived refractive index is more representative of urban-industrial aerosol. Also, estimated back-trajectories show that more than 70% of the aerosol particles over the region originate over the ocean. Atmospheric vapor increases from winter to summer and mainly influenced by air temperature, supersaturation level, and absorbing aerosol. Furthermore, two significant sources accounted for biomass burning related to high AOD values: local biomass burning and regionally transported aged smoke majorly from elsewhere in Sothern Africa.

scholarly journals One year of Raman lidar observations of free-tropospheric aerosol layers over South Africa

2015 ◽  
Vol 15 (10) ◽  
pp. 5429-5442 ◽  
Author(s):  
E. Giannakaki ◽  
A. Pfüller ◽  
K. Korhonen ◽  
T. Mielonen ◽  
L. Laakso ◽  
...  
Keyword(s):  
South Africa ◽  
Optical Properties ◽  
Biomass Burning ◽  
Mean Value ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Tropospheric Aerosol ◽  
Wide Range ◽  
Significant Difference ◽  
532 Nm

Abstract. Raman lidar data obtained over a 1 year period has been analysed in relation to aerosol layers in the free troposphere over the Highveld in South Africa. In total, 375 layers were observed above the boundary layer during the period 30 January 2010 to 31 January 2011. The seasonal behaviour of aerosol layer geometrical characteristics, as well as intensive and extensive optical properties were studied. The highest centre heights of free-tropospheric layers were observed during the South African spring (2520 ± 970 m a.g.l., also elsewhere). The geometrical layer depth was found to be maximum during spring, while it did not show any significant difference for the rest of the seasons. The variability of the analysed intensive and extensive optical properties was high during all seasons. Layers were observed at a mean centre height of 2100 ± 1000 m with an average lidar ratio of 67 ± 25 sr (mean value with 1 standard deviation) at 355 nm and a mean extinction-related Ångström exponent of 1.9 ± 0.8 between 355 and 532 nm during the period under study. Except for the intensive biomass burning period from August to October, the lidar ratios and Ångström exponents are within the range of previous observations for urban/industrial aerosols. During Southern Hemispheric spring, the biomass burning activity is clearly reflected in the optical properties of the observed free-tropospheric layers. Specifically, lidar ratios at 355 nm were 89 ± 21, 57 ± 20, 59 ± 22 and 65 ± 23 sr during spring (September–November), summer (December–February), autumn (March–May) and winter (June–August), respectively. The extinction-related Ångström exponents between 355 and 532 nm measured during spring, summer, autumn and winter were 1.8 ± 0.6, 2.4 ± 0.9, 1.8 ± 0.9 and 1.8 ± 0.6, respectively. The mean columnar aerosol optical depth (AOD) obtained from lidar measurements was found to be 0.46 ± 0.35 at 355 nm and 0.25 ± 0.2 at 532 nm. The contribution of free-tropospheric aerosols on the AOD had a wide range of values with a mean contribution of 46%.

Opposition Growth in Dominant Party Systems: Coalitions in South Africa

2013 ◽  
Vol 49 (2) ◽  
pp. 290-312 ◽  
Author(s):  
Danielle Langfield
Keyword(s):  
South Africa ◽  
Party System ◽  
Cape Town ◽  
Party Systems ◽  
Western Cape ◽  
Western Cape Province ◽  
Dominant Party ◽  
Party Strategies ◽  
Party Elites ◽  
Dominant Parties

What is responsible for the decline of democratically dominant parties and the corresponding growth of competitive party systems? This article argues that, despite a ruling party's dominance, opposition forces can gain by winning important subnational offices and then creating a governance record that they can use to win new supporters. It focuses on South Africa as a paradigmatic dominant party system, tracing the increased competitiveness of elections in Cape Town and the surrounding Western Cape province between 1999 and 2010. These events show how party strategies may evolve, reflecting how party elites can learn from forming coalitions.

van Wyk Louw, Nicolaas Petrus (1906–1970)

2018 ◽  
Author(s):  
Heilna du Plooy
Keyword(s):  
South Africa ◽  
South African ◽  
Cape Town ◽  
Western Cape ◽  
The Family ◽  
South African Literature ◽  
Literature History ◽  
Faculty Of Education ◽  
University Of Cape Town ◽  
The University

N. P. Van Wyk Louw is regarded as the most prominent poet of the group known as the Dertigers, a group of writers who began publishing mainly in the 1930s. These writers had a vision of Afrikaans literature which included an awareness of the need of thematic inclusiveness, a more critical view of history and a greater sense of professionality and technical complexity in their work. Van Wyk Louw is even today considered one of the greatest poets, essayists and thinkers in the Afrikaans language. Nicolaas Petrus van Wyk Louw was born in 1906 in the small town of Sutherland in the Western Cape Province of South Africa. He grew up in an Afrikaans-speaking community but attended an English-medium school in Sutherland as well as in Cape Town, where the family lived later on. He studied at the University of Cape Town (UCT), majoring in German and Philosophy. He became a lecturer at UCT, teaching in the Faculty of Education until 1948. In 1949 he became Professor of South African Literature, History and Culture at the Gemeentelijke Universiteit van Amsterdam. In 1960 he returned to South Africa to become head of the Department of Afrikaans and Dutch at the University of the Witwatersrand in Johanneshurg. He filled this post until his death in 1970.

scholarly journals Building Bridges: Linking universities with the manufacturing industry

2009 ◽  
Vol 2 ◽  
pp. 144-159
Author(s):  
Robert Knutsen ◽  
Charlene Steyn ◽  
Martin Nicol
Keyword(s):  
South Africa ◽  
Manufacturing Industry ◽  
University Research ◽  
Manufacturing Industries ◽  
Western Cape ◽  
Research Institutions ◽  
Science And Engineering ◽  
Research Activities ◽  
Local Manufacturing

This article explores ideas for linking university research entities with small- and medium-sized manufacturing industries. In an environment such as the Western Cape, South Africa, where well established teaching and research activities in science and engineering exist at several universities and research institutions, it is astonishing to realize that the local manufacturing industry struggles to obtain assistance with research and development in order to remain competitive locally and globally. Some of the reasons for this situation are outlined and solutions are proposed. In particular, the role of a gateway organization which aims to build networks between universities, research institutions and industry is described.

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