Top PDF An assessment of temperature variability over South Africa

An assessment of temperature variability over South Africa

An assessment of temperature variability over South Africa

25 Various homogenization algorithms to eliminate inhomogeneities are continuously being developed and improved with time, some of which are outlined below. The Rhtest V4 software, based on the Penalized Maximal t (PMT) test utilises a reference series (Wang et al., 2007) and assumes a zero trend and Gaussian errors in the base series. The software detects change points that could be significant at the nominal level (i.e., p=0.95), even without metadata support (i.e. Type 1 change points) (Wang and Feng, 2013). Careful consideration must be taken to determine which detected change points would be adjusted. The Quantile Matching (QM) adjustment adjusts the empirical distribution of all segments of the base series to match each other (Wang et al., 2010). The advantage of using QM is that the adjustments differ according to where the monthly temperature value is situated in the probability distribution (Vincent et al., 2012). The Rhtest also contains the Penalized Maximal F (PMF) test, which detects undocumented mean shifts without a reference series and allows the base series to have a linear trend (Wang, 2008). Wang and Feng (2013) emphasized the need for caution when using the Rhtest V4 without a reference series. In addition, one of the outcomes of the COST (European Cooperation in Science and Technology) Action ES0601 project: advances in homogenization methods of climate series: an integrated approach (HOME), is that these absolute homogenizations typically decrease the homogeneity of the data for monthly and annual means (Venema et al., 2012). In addition, absolute homogenization was found to make the station data more inhomogeneous in a study using a benchmark dataset, with known change points (Venema et al., 2012). The Rhtest V3 software (an earlier version), however, has been used by recent studies, such as by Aschcroft et al. (2012), where both PMF and PMT are used to detect change points in temperature data over southeastern Australia for the period 1860-2011. The absolute homogenization technique is used in the aforementioned study due to a lack of reliable neighbouring stations for use as reference series.
Show more

217 Read more

oa Water SA - Environmental life cycle assessment for potable water production – a case study of seawater desalination and mine-water reclamation in South Africa

oa Water SA - Environmental life cycle assessment for potable water production – a case study of seawater desalination and mine-water reclamation in South Africa

Water is regarded as one of the most precious and critical resources worldwide. In South Africa, the scarcity of water presents various challenges, mainly relating to efficient development, management and utilisation (Knüppe, 2011). To overcome these obstacles and ensure that South Africa has sufficient water supply, various water treatment techniques have been explored. As is the case with all industrial processes, there are substantial environmental impacts that occur from the construction of the infrastructure, through to commissioning, operation and decommissioning. In order to effectively evaluate the environmental burden of each water treatment system as well as its associated processes, a life cycle assessment (LCA) can be utilised. The use of such a sustainability tool provides a true reflection of the product’s life cycle from ‘cradle to grave’ by systematically quantifying the amount of energy used, the consumption of raw materials, emissions to the atmosphere as well as the amount of waste generated (ISO, 2006).
Show more

10 Read more

Ethical challenges in assessment centres in South Africa

Ethical challenges in assessment centres in South Africa

A further concern dealt with the question of whether an AC (in future) should ever be classified as a psychometric test. In this respect, the Guidelines for Best Practice Use of the Assessment Centre Method in South Africa (5th edition) (Assessment Centre Study Group Taskforce on Assessment Centres in South Africa, 2015) state that ACs are not single tests, but rather a sequence of stimuli eliciting participant behaviour that can be linked to competencies, skills and work-related constructs. Such ACs are not psychological tests. When an AC is used as part of a selection process, it has to comply with the EEA’s requirements of validity, reliability, fairness and lack of bias. It furthermore should measure aspects inherently required for job performance based on information obtained from a thorough job analysis. To add to the scientific rigour of the process, an AC design model is recommended by Schlebusch and Roodt (2008) that incorporates four distinct design phases: analysis, design, implementation and evaluation, and validation. By paying adequate attention to each phase, the psychometric properties and overall fairness of the process may be enhanced. If a psychological construct is measured during an AC by means of an appropriate psychological test, the measurement should adhere to any legal requirements that may pertain to psychological tests in that context. A final concern related to contemporary notions of the construct validity in the context of assessment. While contemporary scientific evidence implies a continuum of evidentiary support to confirm validity (as a multidimensional construct), the EEA – in both its original and amended versions – places upon practitioners an unrealistic demand with which they have to comply, namely that of absolute validity: a dichotomy of a test or measure being either valid or invalid. Research participants highlighted their vulnerability in this respect: Would it actually be possible to provide what is legally required of them? Participants agreed
Show more

20 Read more

An Assessment of the Effectiveness of Monetary Policy in South Africa

An Assessment of the Effectiveness of Monetary Policy in South Africa

The current monetary policy system in South Africa came into existence from 1979 onwards, when the De Kock Commission prompted the adoption of market-oriented mechanisms over the previously favoured direct controls (Akinboande et al., 2004, p. 7). This system attempts to control monetary aggregates or money circulation within the economy by influencing demand for money and credit through interest rates. These mechanisms all form part of the monetary policy, which is controlled by the SARB and entails the regulation of money supply and interest rates in South Africa. In doing so, the SARB aims to achieve a stable pricing system, full employment and as a result, economic growth (SARB, 2017a). There are multiple instruments used to implement monetary policy that contradict the direct measures which were historically used (Taylor, 2015, p. 3). Modern instruments seek to inspire financial institutions to conduct themselves in such a way as to promote the goals of monetary policy (SARB, 2017a). However, the South African economy may need a different approach to assist in regulating price level fluctuations, increasing employment (to reduce the high level of unemployment) and to finally enable the economy to grow at acceptable levels. Current measures have not been totally effective in reaching the desired outcomes (Mellet, 2012, p. 2).
Show more

15 Read more

Assessment of Vietnam’s capacity and commitment to ratify and implement the International Convention on Oil Pollution Preparedness, Response and Co-Operation (OPRC), 1990

Assessment of Vietnam’s capacity and commitment to ratify and implement the International Convention on Oil Pollution Preparedness, Response and Co-Operation (OPRC), 1990

Attaining quality in maritime education and training is very crucial for effective maritime development. Quality MET has therefore become an imperative for countries wishing to effectively develop their maritime sectors. This dissertation sought to assess the quality of maritime education and training from the perspectives of seafarers in Africa, with specific reference to South Africa and Ghana. Participants for the study included maritime administrators, MET lecturers, and seafarers, in both Ghana and South Africa, who were selected using the purposive sampling method. The qualitative research method was employed to investigate the objectives of the study. The findings of the study revealed that deficient maritime instruction methods are employed in the MET institutions of the two countries and that seafarers are not able to effectively apply knowledge acquired from their education and training in their lines of work. The findings of the study also revealed that a number of challenges impede the attainment of quality MET in Africa. These findings therefore have implications for the development of the maritime potentials of Africa as a whole. One major recommendation by the study is that there should be institutional collaborations across Africa in MET as stressed by the African Maritime Transport Charter.
Show more

86 Read more

Bridging minds and markets:  The South African experience

Bridging minds and markets: The South African experience

• Current attempts by environmental organizations in South Africa to set in place measures for the certification of professionals. In the context of growing market demand and attempts by the tertiary education system both to meet the requirements of the market and to establish and maintain standards commensurate with responsibility to clients, this article reports on a pilot study undertaken in the Western Cape to determine in what aspects of their work environmental assessment practitioners initially considered themselves to be inadequate and vulnerable. The Western Cape was selected as nearly one quarter of all professionals in the environmental sector are currently employed in this region (Wesgro 2000). Deriving from this, areas of core competence in the discipline were identified. It is argued that facility in these would ensure that environmental management in South Africa maintains international standards and is recognised by international accreditation bodies.
Show more

14 Read more

Some international perspectives on legislation for the management of human-induced safety risks

Some international perspectives on legislation for the management of human-induced safety risks

Legislation that governs the health and safety of communities near major-hazard installations in South Africa is largely based on existing legislation that had been developed in the United Kingdom and other European Union countries. The latter was developed as a consequence of several major human-induced technological disasters in Europe. The history of the evolution of health-and-safety legislation for the protection of vulnerable communities in European Union (EU) countries, France, Malaysia and the USA is explored through a literature survey. A concise comparison is drawn between EU countries, the USA and South Africa to obtain an exploratory view of whether current South-African legislation represents an optimum model for the protection of the health-and-safety of workers and communities near major-hazard installations. The authors come to the conclusion that South-African legislation needs revision as was done in the UK in 2011. Specific areas in the legislation that need revision are an overlap between occupational health and safety and environmental legislation, appropriate land-use planning for the protection of communities near major-hazard installations, the inclusion of vulnerability studies and the refinement of appropriate decision-making instruments such as risk assessment. This article is the first in a series that forms part of a broader study aimed at the development of an optimised model for the regulatory management of human-induced health and safety risks associated with hazardous installations in South Africa.
Show more

8 Read more

Future Extremes Temperature: Trends and Changes Assessment over the Mono River  Basin, Togo (West Africa)

Future Extremes Temperature: Trends and Changes Assessment over the Mono River Basin, Togo (West Africa)

A global view of climate change impacts is important to quantify the aggregated effects in a given region since large scale processes can influence driving forces at subregional or mesoscale. Indeed, the detection of the planetary warming trend, attributed to anthropogenic activities, has been presented with greater certainty in the 4th report of the IPCC (2013) [1]. According to this report, the average global temperature will increase and can reach 4.5˚C by 2100, the precipitation will change and the extreme events will be increasingly recurring. Furthermore, Lewis and King (2018) [2] in the study on evolution of mean, variance and ex- tremes in the 21st century temperatures have showed that warming of the cli- mate system can result in very large corresponding changes in the occurrence of climate extremes. Temperature extremes may occur due to a shift in the whole distribution, where there is an increase in the entire temperature probability dis- tribution, or to changes in the shape of the distribution, such as an increase in variability causing a widening of the distribution. Several studies [3] [4] [5] show that impacts of climate extremes are mostly depending on the spatial scale con- sidered and vary from a region to another, from country to country and even from one local area to another within the same country. For Africa, many pre- vious studies have investigated extreme events and have showed that changes in extreme temperature and precipitation are contrasting [6] [7] [8].
Show more

17 Read more

Holocene climate variability in the winter rainfall zone of South Africa

Holocene climate variability in the winter rainfall zone of South Africa

and Indian Ocean sectors (Beal et al., 2011). Instrumental and modeling studies demonstrate that southward displace- ment of the austral westerlies and attendant southward shift of the subtropical front enable an increased leakage of warm and saline Agulhas water into the South Atlantic (Beal et al., 2011; Biastoch et al., 2008, 2009; Shannon et al., 1990). Modern observations also show that the incursion of Agulhas water into the southern BUS warms the surface water and weakens the coastal upwelling due to changes in the den- sity structure of surface water (Hardman-Mountford et al., 2003; Biastoch et al., 2009; Lutjeharms et al., 2001). Rain- fall observations in the WRZ between 1950 and 1999 show that with exception of the central area winter rainfall de- clined significantly in the south, in the north, and inland of the WRZ of Namaqualand (MacKellar et al., 2007). Overall, instrumental observations of the last 4–5 decades of the last century show that there is a clear temporal coincidence and most likely causal links between southward displacement of austral westerlies and subtropical front, enhanced Agulhas leakage, increase in nss Ca 2+ accumulation over Antarctica, a weakening of the southern BUS, and decline of winter rainfall in large parts of Namaqualand. Therefore based on the links deduced from modern observations we suggest that the middle Holocene dry conditions in Namaqualand and the weakening of the southern BUS most likely were linked to a poleward shift of the austral westerlies and an enhanced amount of Agulhas water leakage, as indicated by geochem- ical analysis in Antarctic ice cores (Roethlisberger et al., 2002) and the shift in planktonic foraminiferal composition off South Africa (Peeters et al., 2004), respectively (Fig. 6a and b). Furthermore, we suggest that increased leakage of Agulhas water into the southern BUS and resultant warming of the coastal water during the middle Holocene may have reduced coastal fog formation. At present, coastal fog forma- tion over the cold upwelled coastal water presents an impor- tant moisture source for the flora of Namaqualand (Cowling et al., 1999; MacKellar et al., 2007). Warming of the coastal water reduces the thermal gradient between air and surface water temperature and fog formation.
Show more

18 Read more

How To Understand The History Of The Empire

How To Understand The History Of The Empire

The Japanese attack in the Far East (against American and British colonies) finally brought America into the war, but almost stretched the British to breaking point. Within a year the Japanese over-ran a huge area of south- eastern Asia. They were only held back at the Indian border, in New Guinea, the Coral Sea and at Midway Island. In late 1942 the Allies began limited moves to push back the Japanese. By 1944 the offensive was gaining momentum, and by the summer of 1945 the Allies were poised to invade mainland Japan.

55 Read more

Drivers of spatial and temporal variability of streamflow in the Incomati River basin

Drivers of spatial and temporal variability of streamflow in the Incomati River basin

Climate change intensifies the global hydrological cycle, leading to more frequent and variable extremes. For southern Africa, recent studies forecast an increase in the occurrence of drought due to decreased rainfall events (Shongwe et al., 2009; Rouault et al., 2010; Lennard et al., 2013). Further- more, it is expected that temperatures will rise, and thus the hydrological processes driven by them will intensify (Kruger and Shongwe, 2004; Schulze, 2011). Compounding the ef- fect of climate change are the increased pressures on land and water use, owing to increased population and the conse- quent requirements for food, fuel and fibre (Rockström et al., 2009; Warburton et al., 2010, 2012). Areas of irrigated agri- culture and forestry have been expanding steadily over the past decades. Urbanisation also brings with it an increase in impervious areas and the increased abstraction of water for domestic, municipal and industrial purposes (Schulze, 2011). In southern Africa, these pressures have led to changes in natural streamflow patterns. However, not many studies are available concerning the magnitude of such changes and what the main drivers are (Hughes et al., 2014). Projec- tions on the impact of climate change on the water resources of South Africa were investigated by Schulze (2012) and streamflow trends of some southern Africa rivers have been analysed (Fanta et al., 2001; Love et al., 2010), but no such studies are available for the Incomati basin.
Show more

17 Read more

Variability of Future Rainfall over the Mono River Basin of West Africa

Variability of Future Rainfall over the Mono River Basin of West Africa

For the specific case of Togo, according to the report of Togo Republic [9], floods, droughts, late rains, high temperatures and high winds, are the major risks in the country. The drought covers the entire territory except for the coast- al zone which is however facing sea level rise risk. It should be noted that among the latest climatic events, flooding takes precedence over other risks with its share of material damage and loss of life. It is becoming more and more dan- gerous across the whole country. Activities which are most exposed to these risks are farming, livestock farming, marketing of agricultural products and market gardening. Mono river basin that is our study area has not been spared by these events [10] [11].
Show more

19 Read more

Impacts of literacy rate and human development indices on agricultural production in South Africa

Impacts of literacy rate and human development indices on agricultural production in South Africa

Abstract: Agriculture is an important sector in South Africa, and the impact that education and human development would have made in this sector via non-white small scale farming was limited through biased policies of the apartheid era. Due to apartheid laws, South Africa found itself with high levels of unskilled labour force. Th is study seeks to fi nd the impacts of literacy rate and human development indices on agricultural production using Auto Regressive Distributed Lag (ARDL) Bounds Test approach to co-integration. A long run relationship among the variables, agricultural production (ag- riculture GDP), literacy rate and human development indices were found. Literacy rate has a positively signifi cant eff ect on agricultural production in the long run while Human Development Index has a positive and signifi cant impact in the short run. Th is indicates that the apartheid regime fell short in recognizing the positive eff ect of education in the agricultural sec- tor by denying a descent education to the majority of non-whites which were farm labourers or small scale farmers. Th is study provides some policy recommendations.
Show more

6 Read more

Variability of Wintertime Surface Air Temperature over the Kingdom of Saudi Arabia

Variability of Wintertime Surface Air Temperature over the Kingdom of Saudi Arabia

Variability of wintertime surface air temperature (SAT) in the Kingdom of Saudi Arabia (KSA) is studied. The study is based on time series over thirty one years in length (1978-2008). For the analysis, we use the coefficient of variability (COV) Mann-Kendal statistical test, running mean and cumulative annual mean (CAM). The coefficient of variability (COV) for wintertime SAT decreases gradually from the north to the south of KSA. The higher values for COV occur in northern and northeastern KSA; there are due to the effect of the traveling Mediterranean depressions and their inter- action with the inverted-V shape trough of the Sudan low. The relationship between COV and latitude is highly signifi- cant, while with longitude it is not significant. The Mann-Kendal statistical test illustrates that positive trends (warming) in wintertime SAT series occurs over the all stations, and that the trends are significant at middle and southern regions of KSA. Recent warming has only occurred during the last two decades at most stations. While cooling in the winter- time SAT appears for the short period of about 5 years, 1978-1983 and 1988-1992. These trends are consistence with trends in the global mean SAT. The results obtained from CAW lead to the conclusion that the thermic regime is modi- fying in the KSA. This dramatic enhancement, occurred at the beginning of the year 1993, is reflected in net modifica- tion in the SAT time series. The analysis of the SAT also shows a significant warming trend after the year 1997 with a rate of 0.03˚C/year.
Show more

15 Read more

Dependence analysis in BRICS stock markets : a vine copula approach

Dependence analysis in BRICS stock markets : a vine copula approach

The log-likelihood value of the selection is 307.74 with the following criteria: AIC: -585.48; BIC: -508.4. Table 4.22 reports the estimated c-vine copula parameters for the four trees. It can be seen that the Student’s t copula dominates tree 1. The estimated dependence structures are shown in the column labelled tau. The estimated standard errors are shown in the parentheses. The first parameter for the Student’s t copula is statistically significant everywhere. This parameter represents the correlation for the Student’s t copula. The second parameter represents the degree of freedom for the Student’s t copula. Table 4.22 shows that the strongest dependence was between Russia and South Africa (edge: 5,2), with 0.22. The rest of the pairs exhibited weak dependence structure. The estimated C-vine copula during the pre-crisis period can be represented graphically as shown in Appendix A. Table 4.23: C-vine estimation: Crisis period
Show more

85 Read more

Observed surface ozone trend in the year 2012 over Nairobi, Kenya

Observed surface ozone trend in the year 2012 over Nairobi, Kenya

The predominant wind flow over Nairobi was sup- ported by backward trajectories over this city during July 2012 and 2013. The trajectories were generated using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT_4) complete system, in order to compute simple air parcel trajectories to com- plex dispersion and deposition simulations using either puff or particle approaches. The model uses previously gridded meteorological data on one of three conformal map projections (Draxler and Hess, 2010). Data are analyzed by the Global Data Assimilation System (GDAS) and are available every 12 hours. They are archived on a 2.5 × 2.5º latitude/longitude grid.
Show more

8 Read more

Causes of Greenland temperature variability over the past 4000 yr: implications for northern hemispheric temperature changes

Causes of Greenland temperature variability over the past 4000 yr: implications for northern hemispheric temperature changes

Greenland is located in the northern North Atlantic, where climatic variation is considerably affected by the North Atlantic Oscillation/Arctic Oscillation (NAO/AO). Atmo- spheric dipoles of high and low pressure at the surface are located near the Azores and Iceland, respectively, and fluc- tuation in pressure differences between the two centres of action induces variations in westerlies in the North Atlantic and northerly winds in Greenland (Hurrell, 1995; Wanner et al., 2001; Hurrell et al., 2003). Therefore, Greenland un- dergoes cooling when northern Europe experiences warm- ing (positive NAO), and vice versa (Hurrell, 1995). Climate modelling and observations suggest that solar variability in- duces changes in atmospheric circulation similar to NAO/AO through ozone feedback in the stratosphere (Shindell et al., 2001; Kodera and Kuroda, 2002; Gray et al., 2010; Scaife et al., 2013). When solar activity is stronger (weaker), changes in the positive (negative) NAO/AO-like atmospheric circu- lation are induced (Shindell et al., 2001; Lean and Rind, 2008). Therefore, it can be expected that stronger (weaker) solar activity induces warming (cooling) in NH temperature, and relative cooling (warming) in Greenland through positive (negative) NAO. Consistent with this theory, Greenland tem- peratures have deviated negatively (positively) from the NH temperature trend when solar activity was stronger (weaker) over the past 800 yr (Kobashi et al., 2013). Climate modelling also indicates that the Atlantic meridional overturning circu- lation (AMOC) reduces (increases) during weaker (stronger) solar activity (Cubasch et al., 1997; Waple et al., 2002), contributing to negative Greenland temperature responses to solar variability (Kobashi et al., 2013). Currently, the past variations of NAO and/or AMOC (e.g. the Medieval Cli- mate Anomaly to Little Ice Age) are highly debated (Mann et al., 2009; Trouet et al., 2009, 2012; Olsen et al., 2012). Therefore, proper understanding of Greenland temperature variability over the past 4000 yr will provide important con- straints for these debates as well as future NAO and AMOC behaviour in a warmer climate.
Show more

19 Read more

The South American monsoon variability over the last millennium in climate models

The South American monsoon variability over the last millennium in climate models

the Medieval Climate Anomaly (MCA, ca. 950–1250 CE) and the Little Ice Age (LIA, ca. 1450–1850 CE; e.g. Masson- Delmotte et al., 2013a). Recent high-resolution records from the area of the South American monsoon system (SAMS) domain have been used to reconstruct precipitation over this region. Records include speleothems (Novello et al., 2012, 2016; Kanner et al., 2013; Apaestegui et al., 2014), pollen (Ledru et al., 2013), lake sediments (Bird et al., 2011), and tree-ring reconstructions (Morales et al., 2012). Vuille et al. (2012) reviewed currently available proxy records for the SAMS region. Most reconstructions show good corre- lations with NH temperature and Intertropical Convergence Zone (ITCZ) reconstructions. According to these palaeocli- mate studies, the LIA was characterized by a cool north equa- torial Atlantic and a warm south equatorial Atlantic (Haug et al., 2001; Polissar et al., 2006), whereas an opposite pat- tern was present during the MCA. This meridional temper- ature gradient led to a southward (northward) migration of the Atlantic ITCZ during the LIA (MCA; Haug et al., 2001). Indeed, SAMS reconstructions during the last millennium show a weaker monsoon during the MCA period and a rela- tively stronger monsoon during the LIA period (e.g. Bird et al., 2011; Vuille et al., 2012; Ledru et al., 2013; Apaestegui et al., 2014), indicating an anti-correlation with reconstruc- tions of the Southeast Asian monsoon (Zhang et al., 2008; Shi et al., 2014; Polanski et al., 2014), as well as with the North African and North American monsoons (Asmerom et al., 2013), for those periods.
Show more

11 Read more

The financial effect of cross listing on Sub-Saharan African exchanges for Johannesburg Stock Exchange, (JSE), listed companies

The financial effect of cross listing on Sub-Saharan African exchanges for Johannesburg Stock Exchange, (JSE), listed companies

The Nairobi Securities Exchange, (NrSE), formed in 1954, is one of the active capital markets in Africa. The NrSE is sub-Saharan Africa's fourth-largest bourse with 61 listed companies as well as market capitalization, which has grown from $453 million in 1990 to $14.8 billion in 2012. It successfully installed an automated trading system (ATS) in November 2007 and central securities depositories (CSD) in November 2004. The NrSE may be classified as both emerging market and frontier market due to its growing liquidity and higher turnover and market capitalisation compared to other exchanges in sub-Sharan African. It is therefore a model market in view of its high returns, vibrancy and well developed market structure. It therefore, raises interest and sets a precedent for comparison with other emerging markets in Eastern Africa and the world at large (Onyuma, 2012). The NrSE also remains an active member of the East African Securities Exchange Association (EASEA), whose aim is to standardize regulations and operations within the region to make cross border investing easier for citizens of the East African Community. In addition to this, the NrSE which is currently an Associate member of the WFE, has formally written to the WFE to confirm its intention to pursue full membership (ASEA Yearbook, 2014). The NrSE has general rules that companies looking to cross-list would need to comply with and some of the key requirments are shown in footnote below 6 .
Show more

54 Read more

Marlene E. Haffner, MD, MPH CEO, Haffner Associates, LLC Center for Drug Research and Development U of British Columbia Vancouver, Canada Tuesday,

Marlene E. Haffner, MD, MPH CEO, Haffner Associates, LLC Center for Drug Research and Development U of British Columbia Vancouver, Canada Tuesday,

South Africa South African Foundation for Rare Disorders No strength compliance funding South Africa South African Foundation for Rare Disorders No strength, compliance, funding. Austral[r]

34 Read more

Show all 10000 documents...