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Purpose: While much has been debated about venture formation and demise, the behavioral dynamics of why entrepreneurs intend to continue and persevere post-startup have received scant attention and scrutiny. Building upon the rich tapestry of entrepreneurial cognition, the purpose of this paper is to forward entrepreneurial continuance logic as a theoretical framework to empirically investigate the antecedents, contingencies and mediators of entrepreneurial continuance. Design/methodology/approach: Using observations from surveying 156 practicing entrepreneurs across the USA, UK, South Africa and India, this research offers interesting findings. Findings: Results surface attitudinal tensions between the transactional attitudes of entrepreneurial climate, entrepreneurial responsiveness and calculative commitment and the relational attitudes of affective and normative continuance. Specifically, the authors find that affect is the strongest direct predictor of continuance intentions but only in the absence of entrepreneurial responsiveness behavior. Research limitations/implications: Entrepreneurial responsiveness, rather than commitment, is found to be a core continuance constituent, traceable as a positive influence on continuance as a direct antecedent, a moderator and a mediator. Practical implications: The research reveals that entrepreneurs willing to seize and adapt to a changing entrepreneurial landscape are more like to continue with their ventures, but not just driven by strict underpinnings of affect and norms but by a strong sense of economic rationality. Social implications: Entrepreneurial continuance is an important behavioral phenomenon with substantial socio-economic consequences. Given the scant attention paid to entrepreneurial continuance – symptomatic of broader downstream effects of entrepreneurial survival and positive socio-economic spillovers, the authors embark on a systematic investigation of continuance intention as post-startup behavior. Originality/value: The paper explains post-startup entrepreneurial behavior in several ways. First, while affective commitment, a relational attitude, still drives continuance intentions, calculative commitment, a transactional attitude, is a significant contender. Interestingly, the nature of contemporary entrepreneurship disregards continuance behavior based on norms. Second, entrepreneurial responsiveness needs to be cautiously examined in relationship to commitment and continuance. Entrepreneurial responsiveness, a transactional attitude, positively influences continuance; however, in the presence of a relational attitude such as affective commitment, the interplay reduces continuance intentions. Third, perceptions of entrepreneurial climate are found to trigger more opportunity-seeking behavior among entrepreneurs, which in turn increases an entrepreneur's intention to continue. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide useful information about climate conditions of transcontinental shipments from Hungary and compare them to the climate profiles of conditioning standards. The climatic environments inside ISO intermodal containers carrying automotive products to three different destinations in India, China and South Africa were measured. All three recorded surveys contain temperature and relative humidity data while the containers were stored outdoors and indoors and travelled on truck, rail and ship. The measured data was analyzed and mean statistical values of daily temperature and RH shifts were determined for each route. The recorded data shows that 50 % of maximum temperature and RH shifts occurred in the EU continent. Temperature and relative humidity distribution as a function of cumulative percentages [%] of the duration of total shipping was also determined and compared to the climate profiles of conditioning standards. It shows that peak temperature and RH ranges occur mostly in the defined duration of conditioning testing time. [ABSTRACT FROM AUTHOR]

Climate change adds an additional layer of complexity to existing sustainable development and biodiversity conservation challenges. The impacts of global climate change are felt locally, and thus local governance structures will increasingly be responsible for preparedness and local responses. Ecosystem-based adaptation (EbA) options are gaining prominence as relevant climate change solutions. Local government officials seldom have an appropriate understanding of the role of ecosystem functioning in sustainable development goals, or access to relevant climate information. Thus the use of ecosystems in helping people adapt to climate change is limited partially by the lack of information on where ecosystems have the highest potential to do so. To begin overcoming this barrier, Conservation South Africa in partnership with local government developed a socio-ecological approach for identifying spatial EbA priorities at the sub-national level. Using GIS-based multi-criteria analysis and vegetation distribution models, the authors have spatially integrated relevant ecological and social information at a scale appropriate to inform local level political, administrative, and operational decision makers. This is the first systematic approach of which we are aware that highlights spatial priority areas for EbA implementation. Nodes of socio-ecological vulnerability are identified, and the inclusion of areas that provide ecosystem services and ecological resilience to future climate change is innovative. The purpose of this paper is to present and demonstrate a methodology for combining complex information into user-friendly spatial products for local level decision making on EbA. The authors focus on illustrating the kinds of products that can be generated from combining information in the suggested ways, and do not discuss the nuance of climate models nor present specific technical details of the model outputs here. Two representative case studies from rural South Africa demonstrate the replicability of this approach in rural and peri-urban areas of other developing and least developed countries around the world. [ABSTRACT FROM AUTHOR]

Across South Africa, a wide range of activities is influenced by differences in seasonality. In a South African context, there is little consensus on the timing of seasonal boundaries. Inconsistency exists through the use of ad-hoc approaches to define seasonal boundaries across South Africa. In this paper, we present one of the very first uniform statistical classifications of South African seasonal divisions on the basis of daily temperature data. Daily maximum and minimum temperature data were obtained from 35 selected South African Weather Service meteorological stations that had sufficiently complete data sets and homogeneous time series, spanning the period 1980--2015. An Euclidean cluster analysis was performed using Ward's D method. We found that the majority of the stations can be classified into four distinct seasons, with the remaining 12 stations' data best classified into three seasons, using Tavg as the classifier. The statistically classified seasonal brackets include summer (October/November/December/ January/February/March), early autumn (April) and late autumn (May), winter (June/July/August), and spring (September). Exploring the boundaries of seasons, the start of summer and end of winter months follow a southwest to northeastwards spatial pattern across the country. Summers start later and winters end later in the southwestern parts of the country, whereas in the northeast, summers start earlier and winters end earlier. Significance: * The findings contribute to the common knowledge of seasonality in South Africa. * New seasonal divisions in South Africa are proposed. [ABSTRACT FROM AUTHOR]

Flux towers provide essential terrestrial climate, water, and radiation budget information needed for environmental monitoring and evaluation of climate change impacts on ecosystems and society in general. They are also intended for calibration and validation of satellite-based Earth observation and monitoring efforts, such as assessment of evapotranspiration from land and vegetation surfaces using surface energy balance approaches. In this paper, 15 years of Skukuza eddy covariance data, i.e. from 2000 to 2014, were analysed for surface energy balance closure (EBC) and partitioning. The surface energy balance closure was evaluated using the ordinary least squares regression (OLS) of turbulent energy fluxes (sensible (H) and latent heat (LE)) against available energy (net radiation (Rn) less soil heat (G)), and the energy balance ratio (EBR). Partitioning of the surface energy during the wet and dry seasons was also investigated, as well as how it is affected by atmospheric vapour pressure deficit (VPD), and net radiation. After filtering years with low-quality data (2004-2008), our results show an overall mean EBR of 0.93. Seasonal variations of EBR also showed the wet season with 1.17 and spring (1.02) being closest to unity, with the dry season (0.70) having the highest imbalance. Nocturnal surface energy closure was very low at 0.26, and this was linked to low friction velocity during night-time, with results showing an increase in closure with increase in friction velocity. The energy partition analysis showed that sensible heat flux is the dominant portion of net radiation, especially between March and October, followed by latent heat flux, and lastly the soil heat flux, and during the wet season where latent heat flux dominated sensible heat flux. An increase in net radiation was characterized by an increase in both LE and H, with LE showing a higher rate of increase than H in the wet season, and the reverse happening during the dry season. An increase in VPD is correlated with a decrease in LE and increase in H during the wet season, and an increase in both fluxes during the dry season. [ABSTRACT FROM AUTHOR]

Reporting to the public on climate change impacts, adaptation, and mitigation requires journalists to be equipped to engage with a wide range of technical content in order to communicate it in an accessible and engaging way. Recognizing the need for journalists from a wide range of backgrounds, including those from community newspapers and radio stations in South Africa, to be able to undertake this task, the South African Department of Environment Affairs in partnership with GIZ commissioned the authors to develop and deliver a four-day climate change reporting training programme. This paper presents an overview of the structure and content of the course, and details the reflections after undertaking such an endeavor. Based on the lessons learned, and an awareness that this kind of training may take place in the context where working community-level journalists may have a low knowledge base (of both the journalistic craft, as well as the content of climate science) the following recommendations emerge: scientific training may need to be combined with basic journalistic training (depending on the participants); learning-by-doing is central to journalists building their capacity in climate reporting training; and mother-tongue delivery of material is critical to the success of such technical training courses. [ABSTRACT FROM AUTHOR]

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In 2005, the South African Weather Service installed a state-of-the-art cloud-to-ground lightning detection network across the country. The data recorded by this network in 2006 was utilised in the development of an initial lightning climatology of South Africa. Until 2010, this climatology was based on data from a single year. This paper updates this climatology with the lightning data for the 2006-2010 period, which is the first actual lightning climatology by the South African Weather Service based on data covering 5 years. A number of different maps were created from these lightning data. These were lightning ground flash density, median peak kiloampere, percentage positive and average flash multiplicity maps. These four maps were in turn used to develop lightning intensity risk, positive lightning risk and total lightning risk maps. Analysis of the maps showed that the highest concentrations of lightning are found over the central to northern interior of the country, with areas along the northern parts of the eastern escarpment experiencing the highest flash densities and falling within the extreme risk category. Both the positive and total lightning risks are severe for almost the entire country. Only towards the west of the country does the lightning risk decrease. This lightning climatology can now be used throughout South Africa for various disciplines. It will be especially useful for setting lightning safety standards and identifying priority areas for installing lightning conductors and conducting public awareness campaigns. [ABSTRACT FROM AUTHOR]

The purpose of this article is to review progress in the fields of atmospheric science and physical oceanography made by workers based at South African institutions over approximately the last 5 years. Research published by South African scientists working abroad is not included. Most published research in these fields falls within the broad areas of climate variability, climate change, aerosols and atmospheric pollution, seasonal forecasting, numerical modelling (both atmospheric and oceanic), and the physical oceanography of the Agulhas and Benguela current systems. Most but not all of the atmospheric science papers relate to South Africa or southern Africa; however, some work pertaining to the southern hemisphere as a whole or to other regions has been done. We note that funding and institutional support for atmospheric science and physical oceanography research in South Africa remains poor and this situation significantly hampers local efforts. [ABSTRACT FROM AUTHOR]

Aim Rainfall reliability has been neglected as a determinant of plant trait convergence and divergence in mediterranean-climate ecosystems. This paper reports on patterns of rainfall reliability — quantified as interannual variation in monthly and seasonal rainfall, and as the frequency of individual events in terms of their size, duration and intensity — for four fire-prone mediterranean-climate ecosystems. Location The four mediterranean-climate regions of the world with fire-prone ecosystems, namely SW Cape (South Africa), SW Australia, California and the Mediterranean Basin (Andalusia, Spain). Methods Using long-term monthly rainfall data from stations dispersed across the four regions, we computed monthly means and interannual variation for each month of the year — the latter quantified as the coefficient of variation (CV) — and divided these into winter and summer seasons. We also computed the mean number of rainfall events, the mean frequency in various categories of event duration (days), the amount of rainfall per event (mm) and the rainfall intensity per event (mm/day) per year for winter and summer seasons for a subset of the rainfall stations. Results The fraction of rain falling in summer was lowest in California (5%) and similarly low ( c. 25%) in the other three regions. The hierarchy of values of coefficient of variation (CV) of monthly rainfall during the winter period was as follows: California > Andalusia >> SW Cape > SW Australia; results for summer were: California > > Andalusia >> SW Australia ∼ SW Cape. SW Australian sites experienced the greatest frequency of short, small and low-intensity rainfall events in both seasons; patterns in the SW Cape were intermediate between Australia and the two northern hemisphere sites which both received fewer, larger and more intense events. Overall, the two southern hemisphere regions (SW Australia and the SW Cape) had significantly more reliable regimes than the two northern hemisphere ones (Mediterranean Basin and California). Main conclusions These differences in rainfall reliability regimes may provide a novel perspective on the distribution of certain plant life-history traits in mediterranean-climate ecosystems. Less reliable regimes would select for germination and seedling survival traits that enable persistence of genets in the face of uncertain moisture conditions during the winter and spring establishment phase. Study systems that accommodate for phylogenetic constraints, namely invasive species derived from mediterranean-climate ecosystems, as well as shared lineages, provide good opportunities to develop and test hypotheses on the implication of different rainfall reliability regimes. One of the novel implications of this study is that the distinctive trait of assemblages in the southern hemisphere regions may be a consequence not so much of their shared nutrient-poor soils as of their similarly reliable rainfall regimes. [ABSTRACT FROM AUTHOR]

Aerosol–cloud interactions (ACI) play an essential role in understanding precipitation occurrence and climate change but remains poorly understood. Conducting a climatology study on a regional or global scale constitutes a prospect better to understand ACI and their influence on precipitation and climate. This study analysed the characteristics of ACI over South Africa based on two instruments: the moderate resolution imaging spectroradiometer (MODIS) and the multiangle imaging spectroradiometer (MISR) onboard the Terra satellite, and ground-based meteorology data from South Africa Weather Service (SAWS) between 2007–2016. The region mainly splits into the upper, central, and lower sub-regions based on the aerosol loading characteristics. Findings from the study show that depending on the atmospheric conditions, aerosol exhibits dual features of increasing and decreasing the potential formation of precipitating clouds. However, more often, fine-mode predominated aerosols suppress rain-bearing clouds. Furthermore, the cloud top height (CTH) demonstrates an upward increment from the lower to the upper part of the region, and the cloud fraction (CF) is in the downward direction. Both the CF and CTH display the characteristic enhancers of the precipitation intensity, mainly when the initial conditions necessary for rain bearing occurs. Besides, the cloud optical depth (COD) depends significantly on the liquid water path (LWP) and is suggestively associated with the aerosol–vapour ratio ingested into the cloud. Also notably, the temperature over the entire region has generally increased steadily and continuously from 2013. [ABSTRACT FROM AUTHOR]

The east coast of South Africa has been the subject of numerous coastal developments over recent years. The design of such developments requires a thorough analysis of the local wave climate. Richards Bay and Durban's Waverider data are two relatively long east coast data sets (18 years). These data sets have not been formally reviewed since Rossouw (1984) analysed existing wave data for South African and Namibian coastal waters. This paper aims to provide a formal analysis of the KwaZulu-Natal wave data. Seasonal exceedance probability plots, wave roses and typical wave parameter statistics are presented. Return periods for extreme waves are estimated from the generalised extreme value distribution, and the associated limitations are discussed. The average peak period on the east coast of South Africa is 10.0 seconds, the average significant wave height is 1.65 m and the average wave direction is 130 degrees. Autumn has the most frequent and the largest wave events while summer is the only season unlikely to produce either large or frequent events. The recurrence interval of the largest recorded significant wave height (8.5 m) was estimated to be between 32 and 61 year. [ABSTRACT FROM AUTHOR]

To optimise the functioning of the grapevine in a specific environment and to improve grape and wine quality, suitability of climatic parameters for key grapevine physiological processes needs to be assessed at fine scales. This paper presents methodology using hourly weather data in three wine producing regions of South Africa (Coastal Region -- Stellenbosch district; Breede River Valley -- Robertson district; Central Orange River Region -- Upington district) during the pre- (November to December) and post-véraison (January to February) periods. Durations inside and outside an optimum climatic range and of extreme climatic conditions were calculated over a 5-year period (1999/2000 to 2003/2004) to quantify a climatic profile related to grapevine physiological requirements. Climatic requirements for optimum photosynthetic activity were defined as follows: temperature 25°C to 30°C, windspeed <4 m/s, relative humidity 60% to 70%. Unsuitable climatic periods for vine performance were calculated as <20°C and >35°C, >4m/s, <50% and >80%. A coefficient was assigned to each climatic parameter according to an assumed importance level for physiological processes. Optimum temperature requirements for other physiological parameters were also investigated. A diurnal minimum/maximum temperature range of 25°C to 30°C was used for sugar content and organic acid levels and a maximum night/day temperature range of 15°C/25°C for colour and lavour. Light intensity was accepted as being sufficient. Stations were classified according to their potential for meeting the climatic requirements of each physiological parameter. Marked variation in climatic profiles and available time for optimal physiological functioning occurred between regions. All factors considered, the climatic profile of the Coastal Region (Stellenbosch district) seemed to best satisfy the climatic requirements of the physiological parameters studied. [ABSTRACT FROM AUTHOR]

Understanding different adaptive capacities is a prerequisite for targeting interventions to reduce the adverse impacts of climate change. Indicators and indices are common tools in this process, but their construction embodies many uncertainties, not least of which is their scale specificity. This paper describes the development of two empirical adaptive capacity indices for use at different scales of analysis: a national index for cross-country comparison in Africa and a household index for cross-household comparison in a village in Limpopo province, South Africa. Explaining the decisions made at each stage of construction illuminates the degree of uncertainty involved when assessing adaptive capacity, and how this uncertainty is compounded when looking across different scales of analysis. It concludes that the central elements of adaptive capacity, based on institutional collective response and the availability of and access to resources, are common at different scales, although the structure of each index is scale-specific. Hence the findings of these apparently irreconcilable scales of analysis converge to demonstrate points of leverage for policy intervention to raise resilience and the capacity to adapt to the risks posed by climate change. [Copyright &y& Elsevier]

During strong El Niño events, below-average rainfall is expected in large parts of southern Africa. The 1992 El Niño season was associated with one of the worst drought episodes in large parts of South Africa. Using reanalysis data set from NCEP-NCAR, this study examined circulation types (CTs) in Africa south of the equator that are statistically related to the El Niño signal in the southwest Indian Ocean and the implication of this relationship during the 1992 drought episode in South Africa. A statistically significant correlation was found between the above-average Nino 3.4 index and a CT that features widespread cyclonic activity in the tropical southwest Indian Ocean, coupled with a weaker state of the south Indian Ocean high-pressure. During the analysis period, it was found that the El Niño signal enhanced the amplitude of the aforementioned CT. The impacts of the El Niño signal on CTs in southern Africa, which could have contributed to the 1992 severe drought episode in South Africa, were reflected in (i) robust decrease in the frequency of occurrence of the austral summer climatology pattern of atmospheric circulation that favors southeasterly moisture fluxes, advected by the South Indian Ocean high-pressure; (ii) modulation of easterly moisture fluxes, advected by the South Atlantic Ocean high-pressure, ridging south of South Africa; (iii) and enhancement of the amplitude of CTs that both enhances subsidence over South Africa, and associated with the dominance of westerlies across the Agulhas current. Under the ssp585 scenario, the analyzed climate models suggested that the impact of radiative heating on the CT significantly related to El Niño might result in an anomalous increase in surface pressure at the eastern parts of South Africa. [ABSTRACT FROM AUTHOR]

Fourier and spectral analysis of rainfall records at 163 South African stations over the period 1910-1969, and at thirty-nine stations from 1880–1969, shows that cyclical fluctuations with periods of about 18–20, 13–15, 10, 4.5, 3.5, 2.8, and 2.3 years account for much of the observed rainfall variance over the country. These fluctuations exhibit distinctive regional distributions that appear to have changed little over the last century. [ABSTRACT FROM AUTHOR]

Identifying and quantifying drought in retrospective is a necessity for better understanding drought conditions and the propagation of drought through the hydrological cycle and eventually for developing forecast systems. Hydrological droughts refer to water deficits in surface and subsurface storage, and since these are difficult to monitor at larger scales, several studies have suggested exploiting total water storage data from the GRACE (Gravity Recovery and Climate Experiment) satellite gravity mission to analyze them. This has led to the development of GRACE-based drought indicators. However, it is unclear how the ubiquitous presence of climate-related or anthropogenic water storage trends found within GRACE analyses masks drought signals. Thus, this study aims to better understand how drought signals propagate through GRACE drought indicators in the presence of linear trends, constant accelerations, and GRACE-specific spatial noise. Synthetic data are constructed and existing indicators are modified to possibly improve drought detection. Our results indicate that while the choice of the indicator should be application-dependent, large differences in robustness can be observed. We found a modified, temporally accumulated version of the indicator particularly robust under realistic simulations. We show that linear trends and constant accelerations seen in GRACE data tend to mask drought signals in indicators and that different spatial averaging methods required to suppress the spatially correlated GRACE noise affect the outcome. Finally, we identify and analyze two droughts in South Africa using real GRACE data and the modified indicators. [ABSTRACT FROM AUTHOR]

The atmospheric boundary layer (BL) is the atmospheric layer coupled to the Earth's surface at relatively short timescales. A key quantity is the BL depth, which is important in many applied areas of weather and climate such as air-quality forecasting. Studying BLs in climates and biomes across the globe is important, particularly in the under-sampled southern hemisphere. The present study is based on a grazed grassland-savannah area in northwestern South Africa during October 2012–August 2014. Ceilometers are probably the cheapest method for measuring continuous aerosol profiles up to several kilometers above ground and are thus an ideal tool for long-term studies of BLs. A ceilometer-estimated BL depth is based on profiles of attenuated backscattering coefficients from atmospheric aerosols; the sharpest drop often occurs at BL top. Based on this, we developed a new method for layer detection that we call the signal-limited layer method. The new algorithm was applied to ceilometer profiles which thus classified BL into classic regime types: daytime convective mixing, and a double layer at night of surface-based stable with a residual layer above it. We employed wavelet fitting to increase successful BL estimation for noisy profiles. The layer-detection algorithm was supported by an eddy-flux station, rain gauges, and manual inspection. Diurnal cycles were often clear, with BL depth detected for 50% of the daytime typically being 1–3 km, and for 80% of the night-time typically being a few hundred meters. Variability was also analyzed with respect to seasons and years. Finally, BL depths were compared with ERA-Interim estimates of BL depth to show reassuring agreement. [ABSTRACT FROM AUTHOR]

Adopting a state-of-the-art numerical model system, we investigate how the diurnal variations in precipitation and local breeze systems are characterized by lower-boundary conditions related to the Drakensberg highland and warm SST associated with the Agulhas Current. A control simulation can simulate the hydrometeorological climates in the region realistically, but the terrestrial rainfall is overestimated. During daytime, the precipitation is confined to the Drakensberg highland, and there is an onshore local breeze, while during midnight to morning, the rainfall is confined to the Agulhas Current, and the breeze is offshore. These variations are captured by the numerical simulation, although the timing of maximum rainfall is early over the land and delayed over the ocean. The sensitivity experiment in which the Drakensberg is absent shows a drastic modification in the diurnal variations over land and ocean. The terrestrial precipitation is largely decreased around the Drakensberg and is largest along the coast during daytime. The nocturnal marine precipitation along the Agulhas Current is also reduced. Although the daily residual breeze is still pronounced even without the Drakensberg, wind speed is weakened. We attribute this to the reduction of precipitation. In another sensitivity experiment with smoothened warm SST due to the Agulhas Current, the amplitudes of diurnal variations are not modified remarkably, but the coastal rainfall is diminished to some extent due to less evaporation along the Agulhas Current. This study concludes that the Drakensberg plays a crucial role for the diurnal cycle, and the impact of the Agulhas Current is limited on the diurnal cycle of the coastal precipitation in this region. [ABSTRACT FROM AUTHOR]

The article offers information on an emergence of green bonds as an integral component of climate finance in South Africa. It mentions various platforms in a concerted effort to combat climate change as the annual Conference of the Parties (COP), a regular meeting and also mentions the most vulnerable to the impacts of climate change.

The Middle Stone Age (MSA) of southern Africa, and in particular its Still Bay and Howiesons Poort lithic traditions, represents a period of dramatic subsistence, cultural, and technological innovation by our species, Homo sapiens. Climate change has frequently been postulated as a primary driver of the appearance of these innovative behaviours, with researchers invoking either climate instability as a reason for the development of buffering mechanisms, or environmentally stable refugia as providing a stable setting for experimentation. Testing these alternative models has proved intractable, however, as existing regional palaeoclimatic and palaeoenvironmental records remain spatially, stratigraphically, and chronologically disconnected from the archaeological record. Here we report high-resolution records of environmental shifts based on stable carbon and oxygen isotopes in ostrich eggshell (OES) fragments, faunal remains, and shellfish assemblages excavated from two key MSA archaeological sequences, Blombos Cave and Klipdrift Shelter. We compare these records with archaeological material remains in the same strata. The results from both sites, spanning the periods 98–73 ka and 72–59 ka, respectively, show significant changes in vegetation, aridity, rainfall seasonality, and sea temperature in the vicinity of the sites during periods of human occupation. While these changes clearly influenced human subsistence strategies, we find that the remarkable cultural and technological innovations seen in the sites cannot be linked directly to climate shifts. Our results demonstrate the need for scale-appropriate, on-site testing of behavioural-environmental links, rather than broader, regional comparisons. [ABSTRACT FROM AUTHOR]

The mfecane is thought to be a massive upheaval and devastation of Nguni tribal chiefdoms in the second decade of the 19th century in what is now KwaZulu-Natal and the Eastern Cape of South Africa. Other historians have challenged this extreme interpretation suggesting that the use of the term mfecane be discontinued. We show that pervasive cycles of drought and cold periods in southern Africa are significantly amplified and extended by volcanic eruptions and that, in particular, the eruption of Tambora in 1815 triggered a prolonged and extreme climatic event which bears all of the characteristics ascribed to the mfecane. These findings are supported by a coupled ocean-atmosphere numerical model and by tree-ring rainfall and sea surface temperature analyses, suggesting that the term mfecane is an appropriate description of a singular climatic event. [ABSTRACT FROM AUTHOR]

The seasonal occurrence of white sharks visiting Gansbaai, South Africa was investigated from 2007 to 2011 using sightings from white shark cage diving boats. Generalized linear models were used to investigate the number of great white sharks sighted per trip in relation to sex, month, sea surface temperature and Multivariate El Niño/Southern Oscillation (ENSO) Indices (MEI). Water conditions are more variable in summer than winter due to wind-driven cold water upwelling and thermocline displacement, culminating in colder water temperatures, and shark sightings of both sexes were higher during the autumn and winter months (March–August). MEI, an index to quantify the strength of Southern Oscillation, differed in its effect on the recorded numbers of male and female white sharks, with highly significant interannual trends. This data suggests that water temperature and climatic phenomena influence the abundance of white sharks at this coastal site. In this study, more females were seen in Gansbaai overall in warmer water/positive MEI years. Conversely, the opposite trend was observed for males. In cool water years (2010 to 2011) sightings of male sharks were significantly higher than in previous years. The influence of environmental factors on the physiology of sharks in terms of their size and sex is discussed. The findings of this study could contribute to bather safety programmes because the incorporation of environmental parameters into predictive models may help identify times and localities of higher risk to bathers and help mitigate human-white shark interactions. [ABSTRACT FROM AUTHOR]

Background: Most rural people in the Limpopo Province depend on plant resources to meet their livelihood needs. However, there is insufficient recorded information regarding their use and management. The current study therefore was carried out in selected villages of the Limpopo Province, to close this knowledge gap. Methods: Information was collected from 60 people residing in two villages, using a semi-structured questionnaire, supplemented with field observations. Results: A total of 47 wild plant species (95% indigenous and 5% exotics) from 27 families, mostly from the Fabaceae (17%), Anacardiaceae (9%), and Combretaceae (9%) were documented. These species were used primarily for firewood (40%), food (36%) and medicine (29%). Significantly used species included Sclerocarya birrea (85%), Combretum kraussii (35%) and Harpephyllum caffrum (35%). Local traditional rules and regulations including taboos, social beliefs and fines are in place to aid in the management of communal resources. However, a significant number (67%) of participants mentioned that they were not pleased with these rules and regulations. Conclusion: The current study concluded that plant resources still play an important role in the surveyed rural areas of the Limpopo Province. Furthermore, for sustainable utilization and long-term conservation of plants in these areas the government should assist communities in the management of their plant resources. [ABSTRACT FROM AUTHOR]

This study is an analysis of AGCM model results to understand the dynamics of the response of precipitation over southern Africa (SA) to anomalies in the sea surface temperature (SST) over the Pacific Ocean. The pattern of interannual precipitation anomaly over SA and its temporal variations are quite similar in both the ensemble mean of the control (where AGCM is forced with observed SSTs in all ocean basins) and experimental runs (where AGCM is forced with seasonally varying climatological SST over the Pacific Ocean). However, the amplitude of the variability is found to be relatively reduced in the experimental runs. This is shown to be a result of the modulation of the Walker circulation by the variability of Pacific Ocean SST. The regional tele-connection pattern between the dominant mode of SA precipitation variability and SST anomalies over the eastern Indian Ocean is also influenced by the variations in Pacific SST. The nature of the teleconnection between SA precipitation and eastern Indian SST is apparent only when the Pacific SST variability is excluded. This is corroborated from observations as well. [ABSTRACT FROM AUTHOR]

We have investigated the inter-annual variability of temperature in the upper troposphere and lower stratosphere over Durban for the 20-year period from 1980 to 1999. A spectral analysis of morning and afternoon temperatures at four heights (10, 12, 16 and 18 km) revealed a number of oscillations which could be associated with the annual cycle, the Quasi-biennial Oscillation (QBO) and the El Niño/Southern Oscillation (ENSO). The annual and QBO (27 months) cycles were present at 10, 16 and 18 km, with the former being dominant. Peaks at ∼2.7, 4 and 6.7 years were also detected and were linked to ENSO cycles. By contrast, these cycles were either absent or not well developed (in the case of the annual cycle) at a height of 12 km. Possible reasons for this lack of consistency were sought, with the presence of the jet stream at 12 km being a likely explanation. [ABSTRACT FROM AUTHOR]

The importance of aerosols in influencing the earth's climate is well recognized. In this study we investigated the vertical distribution of aerosols over Durban based on MDAR measurements taken on six cloud-free days between July and October 1997. The aerosol loading in the lower troposphere (<5 km) varied between 100 and 320 photon counts and was characterized by marked stratification. Peaks occurred in the intervening layers between shallow stable layers that inhibited vertical mixing. A marked discontinuity, which coincided with the presence of a persistent and ubiquitous stable layer over southern Africa, occurred at 5 km, where aerosol concentrations dropped to zero. Above 5 km, concentrations increased slightly but remained below values recorded in the lower troposphere. The discontinuity in aerosol loading at 5 km marks the top of the haze layer, which is commonly observed over South Africa, particularly in winter. The vertical distribution of aerosols changed dramatically as a function of synoptic weather patterns. Anticyclonic circulation over the subcontinent was associated with high aerosol loadings, whereas the passage of a mid-latitude westerly wave cleansed the atmosphere and was associated with photon counts below 50 throughout the troposphere. [ABSTRACT FROM AUTHOR]

Assesses the appropriateness of environmental reconstruction and climate modelling of the late Quaternary in the winter rainfall region of the Western Cape, South Africa. Accuracy of the model; Temperature and precipitation; Pollen analysis.

A technique for producing regional rainfall forecasts for southern Africa is developed that statistically maps or "recalibrates" large-scale circulation features produced by the ECHAM3.6 general circulation model (GCM) to observed regional rainfall for the December-February (DJF) season. The recalibration technique, model output statistics (MOS), relates archived records of GCM fields to observed DJF rainfall through a set of canonical correlation analysis (CCA) equations. After screening several potential predictor fields, the 850-hPa geopotential height field is selected as the single predictor field in the CCA equations that is subsequently used to produce MOS-recalibrated rainfall patterns. The recalibrated forecasts outscore area-averaged GCM-simulated rainfall anomalies, as well as forecasts produced using a simple linear forecast model. The MOS recalibration is applied to two sets of GCM experiments: for the "simulation" experiment, simultaneous observed sea surface temperature (SST) serves as the lower boundary forcing; for the "hindcast" experiment, the prescribed SSTs are obtained by persisting the previous month's SST anomaly through the forecast period. Pattern analyses performed on the predictor-predictand pairs confirm a robust relationship between the GCM 850-hPa height fields and the rainfall fields. The structure and variability of the large-scale circulation is well characterized by the GCM in both simulation and hindcast mode. Measures of retroactive skill for a 9-yr independent period (1991/92-1999/2000) using the hindcast MOS are obtained for both deterministic and probabilistic forecasts, suggesting that a probabilistic representation of MOS forecasts is potentially more valuable. Finally, MOS is employed to investigate its potential to downscale the GCM large-scale circulation to more specific forecasts of land surface characteristics such as streamflow. [ABSTRACT FROM AUTHOR]

Presents information on a study that examined the stability characteristics and the temporal and spatial continuity of elevated, absolutely stable layers over southern Africa during the Southern African Regional Science Initiative in the context of prevailing synoptic conditions over the region. Methodology of the study; Results and discussion on the study; Conclusions.

A wind climatology has been derived for the lowveld region of South Africa, using averaged monthly wind roses for 16 sites, and wind velocities recorded by three automatic weather stations over a five-year period. The seasonal pattern of near-surface airflow is related to the frequency of occurrence of the major synoptic circulation types. Southeasterly flow is most prevalent over the region, particularly in summer, and is associated with easterly waves, continental anticyclones and ridging anticyclones. Flow from the northwest is linked with westerly waves and coastal lows, and is more frequent in the winter months. Short-term variations in the wind regime were investigated using a sodar sited at Skukuza in the Kruger National Park. Circulation is characterized by a distinct diurnal oscillation between westerly and easterly winds, in response to thermo-topographic forcing. The regional mountain-plain and plain-mountain winds frequently extend beyond 800 m above ground level, and may have speeds exceeding 10 m s[sup -1] The evolution of a nocturnal low-level jet, with speeds approaching 20 m s[sup -1] in the core, is documented. Winds through the depth of the mixing layer were investigated by tracking radiosonde balloon ascents. Horizontal wind velocities up to the 500 hPa level are largely determined by synoptic forcing. Above 5 kin, wind direction is constant with height and frequently is from the southwest or west, in response to the position of the subtropical anticyclone. Elevated stable layers in the atmosphere exert little control over horizontal air movements in the region. Southeasterly winds at lower levels do not facilitate the export of aerosols and trace gases off the subcontinent. Above 5 km, westerly flow allows pollution to be transported over the Indian Ocean. [ABSTRACT FROM AUTHOR]

The Little Ice Age in South Africa, from around AD 1300 to 1800, and medieval warming, from before 1000 to around 1300, are shown to be distinctive features of the regional climate of the last millennium. The proxy climate record has been constituted from oxygen and carbon isotope and colour density data obtained from a well-dated stalagmite derived from Cold Air Cave in the Makapansgat Valley. The climate of the interior of South Africa was around 1 Celcius cooler in the Little Ice Age and may have been over 3 Celcius higher than at present during the extremes of the medieval warm period. It was variable throughout the millennium, but considerably more so during the warming of the eleventh to thirteenth centuries. Extreme events in the record show distinct teleconnections with similar events in `other parts of the world, in both the northern and southern hemispheres. The lowest temperature events recorded during the Little Ice Age in South Africa are coeval with the Maunder and Sporer Minima in solar irradiance. The medieval warming is shown to have coincided with the cosmogenic [sup 10]Be and [sup 14]C isotopic maxima recorded in tree rings elsewhere in the world during the Medieval Maximum in solar radiation. [ABSTRACT FROM AUTHOR]

Investigates tropical-temperate troughs and associated cloud bands over South Africa using the Regional Atmospheric Modeling System (RAMS). Common characteristics of cloud bands or tropical temperates forming in the southern hemisphere; Mechanism of the development of RAMS model; Differences between wet and dry seasons.