Francois Engelbrecht

A new research strategy for integrating studies of paleoclimate, paleoenvironment, and paleoanthropology.

Paleoanthropologists (scientists studying human origins) universally recognize the evolutionary significance of ancient climates and environments for understanding human origins. Even those scientists working in recent phases of human evolution, when modern humans evolved, agree that hunter‐gatherer adaptations are tied to the way that climate and environment shape the food and technological resource base. The result is a long tradition of paleoanthropologists engaging with climate and environmental scientists in an effort to understand if and how hominin bio‐behavioral evolution responded to climate and environmental change. Despite this unusual consonance, the anticipated rewards of this synergy are unrealized and, in our opinion, will not reach potential until there are some fundamental changes in the way the research model is constructed. Discovering the relation between climate and environmental change to human origins must be grounded in a theoretical framework and a causal understanding of the connection between climate, environment, resource patterning, behavior, and morphology, then move beyond the strict correlative research that continues to dominate the field.

Impacts of convection schemes on simulating tropical-temperate troughs over southern Africa

This study examines southern African summer rainfall and tropical temperate troughs (TTTs) simulated with three versions of an atmospheric general circulation model differing only in the convection scheme. All three versions provide realistic simulations of key aspects of the summer (November–February) rainfall, such as the spatial distribution of total rainfall and the percentage of rainfall associated with TTTs. However, one version has a large bias in the onset of the rainy season. Results from self-organizing map (SOM) analysis on simulated daily precipitation data reveals that this is because the occurrence of TTTs is underestimated in November. This model bias is not related to westerly wind shear that provides favorable conditions for the development of TTTs. Rather, it is related to excessive upper level convergence and associated subsidence over southern Africa. Furthermore, the model versions are shown to be successful in capturing the observed drier (wetter) conditions over the southern African region during El Niño (La Niña) years. The SOM analysis reveals that nodes associated with TTTs in the southern (northern) part of the domain are observed less (more) often during El Niño years, while nodes associated with TTTs occur more frequently during La Niña years. Also, nodes associated with dry conditions over southern Africa are more (less) frequently observed during El Niño (La Niña) years. The models tend to perform better for La Niña events, because they are more successful in representing the observed frequency of different synoptic patterns.

Potential impacts of climate change on extreme precipitation over four African coastal cities

This study examines the impacts of climate change on characteristics of extreme precipitation events over four African coastal cities (Cape Town, Maputo, Lagos and Port Said) under two future climate scenarios (RCP4.5 and RCP8.5). Fourteen indices were used to characterise extreme precipitation and 16 multi-model simulation datasets from the Coordinated Regional Climate Downscaling Experiment (CORDEX) were analysed. The capability of the models to reproduce past characteristics of extreme precipitation over the cities was evaluated against four satellite datasets after quantifying the observation uncertainties over the cities. The models give realistic simulation of extreme precipitation characteristics over the cities, and in most cases, the magnitudes of the simulation biases are within the observation uncertainties. For both the RCP4.5 and RCP8.5 scenarios, the models project a decrease in wet days and an increase in dry spells over the four cities in the future. More intense daily precipitation is projected over Maputo, Lagos and Port Said. The intensity and frequency of extreme precipitation events are projected to increase over Lagos, but decrease over the other cities. A decrease in annual precipitation is projected over Cape Town, Maputo and Port Said, whilst an increase is projected over Lagos, where the water surplus from the more extreme precipitation events exceeds the deficit from the less wet days. A decrease in the number of widespread extreme events is indicated over all the cities. Wet-day percentile and all-day percentile methods signal opposite future changes in the extreme precipitation thresholds over the cities (except over Lagos). The results of this study may have application in managing the vulnerabilities of these coastal cities to extreme precipitation events under climate change.

The self-organizing map, a new approach to apprehend the Madden-Julian Oscillation influence on the intraseasonal variability of rainfall in the southern African region

Abstract The Madden–Julian Oscillation (MJO) is the major mode of intraseasonal variability (30–60xa0days) in the tropics, having large rainfall impacts globally, and possibly on southern Africa. However, the latter impact is not well understood and needs to be further explored. The life cycle of the MJO, known to be asymmetric, has been nevertheless analyzed usually through methods constrained by both linearity and orthogonality, such as empirical orthogonal function analysis. Here we explore a non-linear classification method, the self-organizing map (SOM), a type of artificial neural network used to produce a low-dimensional representation of high-dimensional datasets, to capture more accurately the life cycle of the MJO and its global impacts. The classification is applied on intraseasonal anomalies of outgoing longwave radiation within the tropical region over the 1980–2009 period. Using the SOM to describe the MJO is a new approach, complimentary to the usual real-time multivariate MJO index. It efficiently captures this propagative phenomenon and its seasonality, and is shown to provide additional temporal and spatial information on MJO activity. For each node, the subtropical convection is analyzed, with a particular focus on the southern Africa region. Results show that the convection activity over the central tropical Indian Ocean is a key factor influencing the intraseasonal convective activity over the southern African region. Enhanced (suppressed) convection over the central Indian Ocean tends to suppress (enhance) convection over the southern African region with a 10-day lag by modulating the moisture transport.

Paleoscape model of coastal South Africa during modern human origins: progress in scaling and coupling climate, vegetation, and agent-based models on XSEDE

To better understand the origins of modern humans, we are developing a paleoscape model that simulates the climatic conditions and distribution of natural resources available to humans during this critical stage of human evolution. Our geographic focus is the southern Cape region of South Africa, which was rich in natural resources for hunter-gatherer groups including edible plants, shellfish, animals, and raw materials. We report our progress in using the Extreme Science and Engineering Discovery Environment (XSEDE) to realize the paleoscape model, which consists of four components: a climate model, correlative and dynamic vegetation models, and agent-based models. We adopt a workflow-based approach that combines modeling and data analytics to couple these four modeling components using XSEDE. We have made significant progress in scaling climate and agent-based models on XSEDE. Our next steps will be to couple these models to the vegetation models to complete the workflow, which will require overcoming multiple theoretical, methodological, and technical challenges.

The Impacts of Climate Change on African Cities

Changes in the frequency and intensity of extreme events have significant impacts and are one of the most serious challenges faced by society in coping with a changing climate.

An atmospheric inversion over the city of Cape Town: sensitivityanalyses

An atmospheric inversion was performed for the city of Cape Town for the period of March 2012 to June 2013, making use of in situ measurements of CO2 concentrations at temporary measurement sites located to the north-east and south-west of Cape Town. This paper presents results of sensitivity analyses that tested assumptions regarding the prior information and the uncertainty covariance matrices associated with the prior fluxes and with the observations. Alternative prior products were considered in the form of a carbon assessment analysis to provide biogenic fluxes and the ODIAC (Open-source Data Inventory for Anthropogenic CO2 product) fossil fuel product. These were used in place of the reference inversion’s biogenic fluxes from CABLE (Community Atmosphere Biosphere Land Exchange model) and fossil fuel emissions from a bespoke inventory analysis carried out specifically for the Cape Town inversion. Our results confirmed that the inversion solution was strongly dependent on the prior information, but by using independent alternative prior products to run multiple inversions, we were able to infer limits for the true domain flux. Where the reference inversion had aggregated prior flux estimates that were made more positive by the inversion – suggesting that CABLE was overestimating the amount of CO2 biogenic uptake – the carbon assessment prior fluxes were made more negative by the inversion. As the posterior estimates tended towards the same point, we could infer that the best estimate was located somewhere between these two posterior fluxes. The inversion was shown to be sensitive to the spatial error correlation length in the biogenic fluxes – even a short correlation length – influencing the spatial distribution of the posterior fluxes, the size of the aggregated flux across the domain, and the uncertainty reduction achieved by the inversion. Taking advantage of expected spatial correlations in the fluxes is key to maximizing the use of a limited observation network. Changes to the temporal correlations in the observation errors had a very minor effect on the inversion. The control vector in the original version consisted of separate daytime and night-time weekly fluxes for fossil fuel and biogenic fluxes over a 4-week inversion period. When we considered solving for mean weekly fluxes over each 4week period – i.e. assuming the flux remained constant over the month – larger changes to the prior fossil fuel and biogenic fluxes were possible, as well as further changes to the spatial distribution of the fluxes compared with the reference. The uncertainty reduction achieved in the estimation of the overall flux increased from 25.6 % for the reference inversion to 47.2 % for the mean weekly flux inversion. This demonstrates that if flux components that change slowly can be solved for separately in the inversion, where these fluxes are assumed to be constant over long periods of time, the posterior estimates of these fluxes substantially benefit from the additional observational constraint. In summary, estimates of Cape Town fluxes can be improved by using better and multiple prior information sources, and particularly on biogenic fluxes. Fossil fuel and Published by Copernicus Publications on behalf of the European Geosciences Union. 7790 A. Nickless et al.: Cape Town atmospheric inversion: sensitivity analyses biogenic fluxes should be broken down into components, building in knowledge of spatial and temporal consistency in these components into the control vector and uncertainties specified for the sources for the inversion. This would allow the limited observations to provide maximum constraint on the flux estimates.

High-resolution dynamic downscaling of future climate over key cities in west and East Africa

C rays, produced by high-energy extra-solar events, ionize the earth’s atmosphere. Ionized aerosol particles can combine and form “seed” particles for cloud formation. In addition, cosmic-ray ionization increases the atmospheric conductivity. Variations of these quantities would be expected to have an effect on climate, and they do vary. The solar corona has a temperature of one million degrees and is continually “boiling off,” producing “the solar wind.” The solar wind is plasma that fills the solar system to a distance of about 90 times the earth-sun distance. The cosmic rays that fill the galaxy must do work against the solar wind to reach the earth’s orbit and hence lose intensity. The work done is measured in hundreds of megavolts. The intensity of the solar wind, and hence the intensity of cosmic-rays at earth orbit varies irregularly over an approximately 11-year cycle and sometimes, falls to deep minima. The 17th century “Maunder Minimum,” when solar modulation, the energy necessary to reach earth orbit, fell nearly to zero, was accompanied by what has been known as the “Little Ice Age,” causing much hardship in Europe. This is evidence that changes in cosmic-rays intensity can be associated with an impact on climate. Another important climatological consideration due to cosmic-ray impacts on the terrestrial atmosphere is the production of 1.5 million-year Be-10 by the spallation process. Radioactive Be-10 is used to date sections of Greenland and Antarctic ice cores to analyze past climates. Calculations of these quantities from basic principles are presented.Floods are becoming increasingly common in Nepal resulting in a huge loss of life and damage to settlements, agriculture land and infrastructures in various parts of the country. Most recent research findings suggest that climate change has accelerated the intensity and frequency of flood hazards in most parts of the country. Communities are however, making use of options that increase their preparedness for these flood hazards. The random sampling (for household survey), focus group discussion, key informant interviews and field observations were employed for data collection. Based on field data, this paper intends to assess the indigenous knowledge on flood forecasting and flood management practices at the community level those are being in practiced in the plain region of West Rapti River Basin of Nepal and its relevance under climate change induced flood disaster. The research findings indicate that there are some very effective local flood forecasting practices such as identifying the position of clouds; monitoring the extent of rainfall in upper catchments; analyzing the mobility of ants; analyzing the magnitude of thunderstorms and wind blows; analyzing the magnitude of hotness; and hearing strange sounds from river/torrents. Synthesis and analysis of these indicators helps communities to prepare for potential flood events. These include preparation of search and rescue related materials; the creation of small drainage structures in each plot of land and storage of the valuable material at a safer location; and being psychologically prepared for floods. This paper argues that these indigenous flood forecasting and management practices could be particularly useful for migrants, who are in flood prone areas but are not familiar with those practices.T of past earth system states are preserved in an array of biogeochemical archives. Extracting information from these archives produces valuable data that reveal time progression of environmental conditions. Covarying measurements entice cause-effect explanations, but establishing causal relationships from observational studies requires a rigorous epistemology. Correlation is necessary for hypothesizing a causal relationship, but insufficient for forming conclusions. Common-cause explanations, such as independent orbital forcing of correlated measurements, must be rejected based on characteristics of the data. Determining amplitude and phase response over a range of frequencies provides a test of cause-effect scenarios: measured cause must precede proportionate effect in a manner consistent with direct forcing theory. Amplitude and phase persistence (coherence) through time provides a method for quantifying probabilistic confidence in a cause-effect conclusion. In this presentation, methods are described, and then applied to ice core proxies for air temperature and atmospheric carbon dioxide concentration.T ‘100ky problem’ (1ky=1000 years) of the astronomical theory of the ice ages questions how the almost negligible ~100ky eccentricity forcing could power the ten massive glaciations of the last million years while the stronger ~400ky eccentricity forcing is nearly absent from the proxy records. Further, the astronomical theory does not explain how, without change in forcing, climatic oscillations switched from 41ky to 100ky at the mid-Pleistocene transition (MPT) 1.2 million years ago (1.2 Ma), or what caused the strong climatic response at the marine isotope stage (MIS) 11, the presence of power at frequencies absent in the external forcing, or the timing of glacial terminations. To resolve these inconsistencies many explanations have been put forward, from internal climatic oscillations without external forcing to external forcing other than the Milankovitch cycles, but the ultimate cause(s) remain elusive. I will introduce a unifying explanation that resolves all the above inconsistencies through a single process: nonlinear synchronization of the climate system’s internal oscillations to the eccentricity forcing. Synchronization is a fundamental nonlinear phenomenon and one basic mechanism of self-organization in complex system. The evidence suggests that after at least four million years of slow evolution, the climate system first synchronized to eccentricity at ~1.2Ma and has remained synchronized ever since. Synchronization powered the late Pleistocene glaciations, forced the frequency switch at the MPT, and caused the strong short-lived response at the MIS11 (~400ka).The study was conducted in July 2011 to June 2012 at the Isabela State University watershed experimental. Primary goal is to evaluate the performance and adaptability of the Water Erosion Prediction Project (WEPP) model in estimating the rate of soil erosion and run-off under upland rice cultivation. The research involves establishment of automatic weather station, small farm reservoir and erosion plots with three conservation management as treatments. Analysis was undertaken to characterize rainfall events in terms of amount, intensity, duration and frequency in relation to erosion data. Comparison of actual and simulated data and sensitivity analysis of scenarios for different types of rainfall, slope, and conservation practices were made. Validation result demonstrated statistical acceptability of the WEPP model. Actual and simulated data indicated that 50% soil loss is reduced when contour planting with hedgerow are practiced. The rate of sedimentation is linearly affected by increasing slopes and length, such that, the rate of soil removal ranges 1.2 t/ha to 48.46 t/ha across treatments at 10%-50% slope and 10 m-40 m slope length. The model can be use to develop decision support tools for conservation, optimization and utilization of farm resources in agricultural watershed units to improved productivity of upland areas in sustainable way.E though anomalous behaviors of liquid water around 4oC have long been studied by many different authors up to now, it is not still cleared what thermodynamic mechanisms induce them. The thermodynamic properties of substances are determined by inter-particle interactions. We analyze what characteristics of pair potential cause density anomaly using a thermodynamically Self-Consistent Ornstein-Zernike Approximation (SCOZA). The SCOZA is known to provide a very good description of the overall thermodynamics and a remarkably accurate critical point and coexistence curve. We consider a fluid of spherical particles with a pair potential given by a hard-core repulsion plus a Lennard-Jones type tail (HC-LJ system). We show that the soft-repulsion near the hard-core contact determines the behavior of excess internal energy which plays a crucial role in the anomalous behaviors of the system. Our results show that even though such models as second critical point hypothesis, a twostate model, liquid-liquid phase transition model, clathrate model, network model, and orientation-dependent potential would be important to some properties of water, those are not the immediate cause of the density anomaly in liquid water. We present also a core-softened potential which reproduces experimentally measured density-temperature curve in the wide temperature range much better compared to other models presented up to now. Although our study is restricted to liquid phases of water, it provides us with important insights into the thermodynamic properties of solid water. Makoto Yasutomi, J Earth Sci Climate Change 2013, 4:4 http://dx.doi.org/10.4172/2157-7617.S1.009S green tea (GT) and Peppermint (PM) teabags were used as adsorbents of dyes to purify aqueous solutions. Basic Yellow 57 (BY) and Crystal Violet (CV) were chosen as model dyes due to their widespread use in the scientific and cosmetics industries. Equilibrium parameters such as pH, mass of adsorbent, initial dye concentration, salinity and presence of heavy metals were studied to maximize the adsorption of the dyes from aqueous solution in discontinuous experiments at room temperature. Experimental data indicate that adsorption of BY is maximized at pH 6, with optimum adsorbent masses of 100 mg and 75 mg for GT and PM respectively. The adsorbents also reached their highest adsorption in the absence of salts and heavy metal with maximum initial concentrations of 0.085 g/L and 0.2 g/L for GT and PM, respectively. On the other hand, CV was greatly adsorbed at pH 4 with adsorbent masses of 75 mg and 25 mg of GT and PM, respectively. Both adsorbents were able to adsorb CV dye concentrations of up to 0.075 g/L. The presence of salts and heavy metals also had negative effects on the adsorption. Finally, desorption of the dyes were studied to recycle the adsorbents in repetitive adsorption cycles. BY was surprisingly desorbed by using diluted HCl and ethanol solutions, while CV showed better desorption in front of ethanol and acetone solutions. We believe this “clean” technology will educate us to take advantage of inexpensive waste materials to improve water quality.Sulphur is essential in healthy plant and crop yields. Rapidly, largely due to emission controls, soils are becoming depleted in sulphur. Soils also act as a significant carbon sink but suggest that soil carbon is largely released back into the atmosphere. Here we examine the potential of soil microorganisms in the sequestration of atmospheric CO2 whilst examining the role sulphur has to play on the fixation of CO2. Agricultural soils were incubated in a carbon dioxide incubation chamber (ECIC) for 12 weeks where CO2 or CO2 was added at 400 ppm. One sample-soil A-had elemental sulphur added as a supplement. Total microbial DNA obtained from CO2 and CO2 experiments were subjected to Isopycnic centrifugation. Labelled DNA fractions and total microbial DNA extractsfollowing incubationwere subjected to Pyrosequencing. RubisCO genes were quantified by qPCR over the course of the experiment. Phospholipid fatty acid analysis and DGGE was used to monitor the microbial community structure over the duration of the experiment. To track the fate of labelled carbon into the soil throughout the incubation NMR analysis was performed on soil samples at defined time points. We established that the addition of sulphur to soil, as a fertilizer, has a significant impact on the microbial community structure. The sequestration of atmospheric CO2 by soil microorganisms was stimulated through the addition of sulphur whilst Rubis CO gene copy numbers increased significantly following its addition to soil.This project aims at detecting variabilities and trends in outputs of a three dimensional hydro dynamical numerical model based on a version of the Princeton Ocean Model (POM), covering the region between 85°S-30°N and 70°W-25°E, with 0.5° x 0.5° resolution. Surface data of temperature and salinity, from Climate Forecast System Reanalysis (CFSR), together with meteorological data of winds and surface fluxes, generated by reanalyzes of NCEP / NCAR global model, were analyzed and used as model forcing. The temperature salinity data, meteorological data and the model results cover the period from 1980 to 2009 (30 years). The model was validated through comparisons of outputs with oceanic buoy data from the project PIRATA. Model results and sea surface temperature data from PIRATA display strong correlations, both in the annual and higher frequencies signals. Harmonic and statistical analyses of selected points, applied to meteorological parameters, sea surface elevation, temperature, salinity and currents provide information on the variabilities and trends in the Tropical and South Atlantic Ocean, in the period 1980-2009. Biography Joseph Harari has completed his M.Sc. in Physical Oceanography in 1978, Ph.D. in Meteorology in 1985 and postdoctoral studies in Physical Oceanography in 1991, from the University of Sao Paulo (SP, Brazil). His research is on Numerical Modeling applied to the ocean dynamics and he is an Associate Professor in the Postgraduate Programs in Oceanography and in the Post Graduate Program in Environmental Sciences, at the University of Sao Paulo (SP, Brazil).