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Total rainfall over Natal, South Africa is the composite of rainfall from a number of synoptic rainfall-producing systems. This paper identifies eight synoptic types and employs discriminant analysis in order to determine whether the defined synoptic types are statistically distinct. Eighty-one per cent of the total rainfall is shown to be associated with four of the eight synoptic types. The dynamic characteristics of each synoptic type are examined and the seasonal and spatial rainfall patterns of the principal rainfall-producing systems are described.

Surfers at Durban, South Africa, reveal a tendency to cluster in a number of different spaces off the bathing beaches. While this activity appears to function in a social environment that is at the same time companionable, competitive or exclusive, the manner in which the usually robust interaction with the material environment contributes to the construction of surfing space is not visibly evident to the outsider. A survey reveals that surfers construct surfing space out of images of a normative wave environment and practices and processes that are both sensory and social. Images of the perfect wave that describe the normative wave environment sought by surfers are acquired from surfing magazines and other media sources. Knowledge of wave shapes, winds and currents is provided by sensory-derived experience gained in the waves. Individual and group attitudes and behaviour in surfing spaces are socially constructed around issues of identity and exclusion. The path of surfing space construction is shown to ...

Few writers have commented on how seaside leisure spaces are socially constructed, who competes for their use, and how they may change. This paper discusses how these spaces have been identified and partitioned at Durban, South Africa, as new tourist populations discover them. Given the history of ethnic separation and contemporary social and political change in this country, attention is focussed on the extent to which groups retain and express a sense of identity in the construction of leisure spaces. Selected spaces are discussed to illustrate how they may be constructed around notions of cultural identity, the possession of particular skills, or access to scarce spatial and material resources.

As part of the cultural life of the city, restaurants provide sacred spaces in which the pleasures of eating and communicating can be experienced and valued. They also chronicle trends and shifts in cultural tastes, social behaviour and community fears as urban residents respond to the influence of globalization, the experience of cultural interaction, and perceptions of threats to personal safety. The purpose of this paper is to examine these trends in the ‘colonial’ core region of Durban, South Africa. Restaurants were shown to cluster in four districts: the central business district, the beachfront, and two districts in a suburban environment where the residents are predominantly white South Africans. Once the domain of white privilege, the central business district and beachfront are shown to have undergone a transformation towards multiculturalism in recent years. Impelled by images of urban disorder and increasing crime levels associated with this trend, white consumers increasingly have sh...

Low-level jets (LLJ) over various regions of southern Africa are shown to occur mostly as a result of a thermal gradient established over gently sloping terrain and have been observed to overlie the nocturnal temperature inversions. Strong low-level winds associated with plain-mountain and mountain-plain circulations have also been observed over the central Namib desert and Natal interior. With the exception of the Namib and Natal, where no temperature profiles accompanied wind profile observations, the LLJ is seen to increase in strength as the nocturnal surface temperature inversion intensifies through the night. The height of the LLJ above the surface also increases as the inversion deepens. Wind speeds in all regions exceed 10 m s−1 in the jet core, which typically is located between 200 and 300 m above ground level (agl). Over the central Namib, the summertime plain-mountain wind reaches similar wind speeds in a jetlike core located about 200 to 600 m agl. The Natal mountain-plain winds may exceed 10 m s−1 in a layer of up to 1000 m deep. It is suggested that all these regional-scale wind systems transport pyrogenic products in excess of 400 km during a single night. Subsequent daytime convective lifting of these ozone precursors, coupled with synoptic-scale anticyclonic circulation, provides a transport mechanism for pyrogenic products over southern Africa toward the Atlantic and Indian Oceans.

Political and economic struggles over the environment usually emanate from competition for scarce resources. In the Lake St. Lucia area in South Africa, the conflict is over biodiversity, minerals and land. The competitive interaction between relatively affluent supporters of conservation measures, the residents of tribal lands who eke out a subsistence living in comparative poverty and a multinational mining group that seeks to dredge‐mine the titanium‐rich dunes that line the eastern shores of the lake serves to preserve nonsustainable development polarities and welfare inequities. Given that development implies change, proposals are advanced for sustainable development initiatives that would benefit the entire community. The line of reasoning is developed in three parts. First, the case of each interest group is presented. Secondly, the role of government in making choices between development options is assessed and the problem of rent‐seeking between special interest groups is identified. Thirdly, it ...

The objective of interest-groups is to influence policy. Conflict is inevitable when two or more interest-groups are in competition for scarce resources. It then becomes the responsibility of the state to accommodate or resolve the conflict. However, an additional complexity occurs if the state agencies are themselves undergoing transformation, as has recently occurred in South Africa.These issues are explored, using as a case-study the conflict that occurred between environmental interestgroups and a mining company over an application to dredge-mine the sand dunes that line the eastern shores of Lake St Lucia in Natal. The nature and objectives of these groups is discussed, and the role of the press in the controversy is analysed. The interests of black settlers who wish to return to their ancestral lands following the collapse of apartheid are shown to complicate further the dilemma that confronts state policymakers. The changing nature of the ‘decision environment’ in South Africa is addressed, and group theory is used to explain the relationship between state agencies and the mining, environmental, and black settler group, interests. Stages in the policy environment to match the modes of change over the period of political transformation in South Africa are identified by levels of conflict and ambiguity in a contingency model.

Boundary layer winds over the Etosha Pan at Okaukuejo reveal a diurnal oscillation. Wind direction is characteristically northeast by day and south by night. Daytime winds appear to be synoptically forced, being part of the easterly airflow around the continental high, while the nocturnal airflow appears to be the result of thermo-topographical forcing between the higher standing plateau to the south and west of Okaukuejo and the Etosha Pan. The diurnal wind variation is suppressed by synoptic forcing when the high over the sub-continent strengthens or when a mid-latitude trough moves westward across the sub-continent.

Policies that arise out of conflict or collaboration between specific interest groups and government agencies are often explained by theoretical constructs that fall under the umbrella of group theory. Triangulation theory is one of these constructs and serves to explain the mutuality of interests that exist between government agencies and interest groups expressed as points linking geometric forms. Conflict tends to occur when competing interest groups are excluded from the linkage, in this case between the opponents and proponents of hormone herbicides in the Tala area in Natal, South Africa. In opposition to the use of hormone herbicides were vegetable farmers and their supporters: in linked support were agricultural interest groups who used hormone herbicides, the manufacturers of the herbicides, and the government agency responsible for agriculture. Because of the influence exerted through mutual support by the proponents of hormone herbicides, the formulation of policy decisions directed towards the resolution of the conflict was delayed. When the minister of agriculture finally intervened, the policy decisions were designed to secure the support of those opposing the use of hormone herbicides by introducing issues that cut across those maintaining the discord.

Climatological records of hourly rainfall at recording stations in Natal describe the diurnal va riation of rai nfall t!vents lkrived from a number of different rainfall-producing systems. This paper seeks first to identify these rainfall-producing systems and then to examine the nature of the diurnal rainfall event curve for each system. A subjective classification of rainfall-producing system, is developed and discriminant analysis is employed to test the validity of the classification sc heme. Eighty-onc per cent of the: integrated annual rainfall over Natal is shown to be associated with four of the eight defined rainfall-producing synoptic types. The diurnal rainfall event eurve at three stations along a transect normal to the Natal coast at Durban is then discussed for each of these four synoptic types.

The implementation of the Clean Air Act Amendments of 1970 by the Environmental Protection Agency and State Administrations has led to a remarkable decline in the levels of most “criteria” pollutants in the United States. The nature of the regulatory control imposed by this legislation, together with subsequent amendments, is described. Over the past decade, however, the need to maintain economic growth in the face of the Arab oil embargo, and the economic impact of a national recession in the mid-1970's, led to the grafting of various economic incentive schemes onto the direct control-by-regulation system. The nature of these incentives, together with the political and economic environment in which they were introduced, is examined. With air pollution in South Africa differing from that in the United States in degree rather than in kind, a comparative perspective is offered which may be of use in the consideration of future amendments to the South African Atmospheric Pollution Prevention Act 45 ...

Radiosonde data for the years 1969–1972 have been processed to determine non-surface inversion conditions over Southern Africa. Results are presented to show, first, the spatial and point characteristics of mean non-surface inversions by season and by month, and secondly, the nature of inversion occurrence within six layers of the lower atmosphere.

Radiosonde data for the years 1969-1972 have been processed to determine surface inversion conditions over Southern Africa. Results are presented to show the actual and probable frequency of occurrence, depth and strength of surface inversions at midnight, early morning and midday for the year as a whole and for summer, autumn, winter and spring.

An array of 24 climatic variables for each of 73 stations in South Africa is submitted to Q-mode factor analysis and four complex indices, Winter Rainfall, Thermality, Summer Rainfall and Continentality are derived. The spatial variation of factor scores is described and an equation defining each of the factors is specified. By grouping factor scores using a distance statistic, South Africa is separately divided into 8 and 19 climatic regions. The results are compared with Jackson’s (1951) classification of the climates of South Africa.

Attention is directed towards the growing divergence between geography as it is taught at South African schools and universities, the widening rift between environmental and locational components of geography and the effect of increasing specialisation within the discipline. The lack of a unifying paradigm is seen as a fundamental cause of these problems. It is recommended therefore that environmentalism be adopted as a core paradigm to unite the discipline followed by syllabus restructuring at both school and university levels. It is suggested that this action will provide a more focussed geographical training and will also demonstrate the utility of geography to a wider public.

The interaction between public, press and local government is examined in relation to a controversial decision to pump sewage out to sea. Information flows and the structural characteristics of the political culture are specified. Within this structure the conflict is shown to be initiated by both dissatisfaction with the elected authorities and the emergence of an environmental issue which permitted community mobilization, aggravated by official secrecy and finally resolved by community acceptance of institutional authority following a public meeting. Although ostensibly an environmental issue, press support of the commercial and recreational interests of the dominant group and criticism of official handling of the issue, rather than concern for the marine ecology, was a major factor in the emergence and maintenance of the controversy.

Fluctuations in thermal comfort and in air pollution potential are examined in relation to the passage of coastal low pressure systems along the south and east coast of South Africa. The passage of a coastal low past Durban is shown first to raise the level of heat discomfort over the city due to pre-frontal warming and then to provide relief by postfrontal cooling. Fluctuations in the height of the subsidence inversion and in the mixing layer are also illustrated. It is shown schematically that in the period preceding a coastal low squall-front, the mixing layer contracts usually with a concomitant inorease in the level of atmospheric pollution. With the passage of the squall-front the pollutants are dispersed through the well-ventilated atmosphere.

In fine weather the nocturnal low-level offshore circulation along the Natal coast is found to be compounded of a land breeze and mountain-plain wind. Initially, the land breeze is an independent system and in the early evening the growth of the circulation is marked by the progressive inland extension of a shear line separating offshore from onshore wind components. Concomitantly, mountain winds in inland valleys deepen above ridge levels and combine into a mountain-plain wind which blows towards the coast. In the Durban area integration of the two wind systems takes place over the Hillcrest-Kloof plateau.

Observation of surface winds on the Drakensberg escarpment at Sani Pass reveals a marked diurnal variation of wind direction under clear weather conditions. By night north-westerly gradient winds commonly prevail while by day easterly winds are due to the overflow or a plainmountain circulation onto the 3000 m Lesotho massif at Sani Pass.

Observations are presented to show the occurrence of boundary layer oscillations in the form of widespread and large-scale topographically-induced mountain-plain and plain-mountain winds over the deeply dissected eastern plateau slopes of Natal. By night, extensive northwesterly advection of cool air occurs between the Drakensberg escarpment zone and the coast; by day, the flow is reversed and southeasterly inland advection is characteristic of clear, fine conditions. The distinctive temporal and spatial characteristics of regional winds correspond in a near-ideal manner to those expected in a thermodynamically direct circulation caused by the diurnal cycle of insolation.

On the Natal coast maximum onshore components in .the sea breeze circulation are shown to occur below 1,000 f.t. The sea hreeze is shown on occasions to penetrate inland along a shear line for at least 40 miles and possibly even further. Characteristics of the depth, velocity and surging within this onshore air layer are examined and the relative contribution to the wind by the sea breeze circulation and by the gradient wind is discus.sed. It is suggested that on many occasions the inland penetration of the onshore wind, possibly with modified marine air properties, takes place in response to lowered pressures in adjacent inland areas in Southern Natal and East Griqualand.

The diurnal rainfall at Durban shows highest rainfall frequencies and totals at 2100 with sharp decreases thereafter. A high proportion of this nocturnal precipitation is of low intensity producing less than 1.0 mm/hr. It is suggested that the light nocturnal showers over the coast are produced by undercutting of moist sea air by the cool land breeze. The showers cease with, the arrival of the mountain-plain wind from the interior and subsequent deepening of the cool air layer.

Atmospheric circulations responsible for instability line formation in Natal are examined and instability release mechanisms and movement characteristics of associated storms are discussed. A thunderstorm model adapted after Newton (1960) is used to explain the west-east movement of storms to the left of winds in the middle and upper troposphere. It is suggested that these storms may reach the coast if regenerated by the in-phase occurrence of a passing coastal low.

Ever since the 1992 Earth Summit at Rio de Janeiro, the concept of sustainable development has supposed to guide the future pattern of economies, societies and environmental well-being. Over the years, the notion of sustainability as a process of transition towards a more caring future for people and the planet, while enterprise flourishes, has gained topicality. This paper looks at how certain ideas, implicit in the transition to sustainability, can be converted into various economic, natural resources, social and environmental protection initiatives currently being developed in South Africa. The paper argues that many key policy measures could be converted to the sustainability paradigm with a programmed, but participatory change of original direction. However, there remains a serious lack of capacity within governance generally to meet legislative and popular expectations, particularly for South Africa's poor people. For them, sustainability is a foreign word, even though many local actions an...

Atmospheric pollution over cities accumulates under light wind or stagnation conditions and, on occasion, may be supplemented by transport from distant sources. These conditions cannot easily be predicted by use of the average weather elements. However, material which is useful to decision-makers who are concerned with air pollution problems can be obtained by presenting the data, as in the case of Durban, South Africa, first in terms of the nature and characteristics of vertical mixing in the lower atmosphere, and secondly in terms of the horizontal transport of air. In this way the nature and characteristics of surface and non-surface inversions and mixingdepths, as well as of macro- and meso-scale atmospheric circulations, can more easily be appreciated. In addition, a measure of the air pollution potential can be obtained from daily maximum mixing-depth and win-speed values.