Global Warming and Changing Temperature Patterns over Mauritius

This paper discusses the changing temperature pattern over Mauritius. We observe an increase of the annual mean temperature at Pamplemousses since 1876 with an average rate of 0.009oC per year with a significant correlation coefficient of 0.67. Compared to the mean temperature for the period of 1951 to 1960, we find that there is a shift in time (decadal) in the warming from northwest to other regions over the island. The temperature deviations are more marked in winter than in summer. Moreover, the number of hot days per year is increasing and the number of cold days is decreasing.Keywords: Temperature spatial variation, trend, hot and cold days, kriggin

A Water Accumulation Flooding Potentiality Index (WAFPI) for rating the risk of flooding– A case study of Mauritius Island

The Water Accumulation Flooding Potentiality Index (WAFPI) is a qualitative risk assessment method based on a factorial scoring system that is aimed at dividing the land into classes that are similar in their susceptibility to flooding due to accumulating water. Such an assessment precedes quantitative flood modeling work, the overall results that are used for planning flood mitigation measures. WAFPI takes the form of an equation with five parameters as input, namely, rainfall amount; topographic slope angle; permeability of geology strata; soil infiltration capacity & land cover imperviousness. The output is a map with indices ranging from 1 to 10, with 1 being the lowest risk and 10 the highest risk of flooding. The assessment has been carried for Mauritius for the rainiest month of February. Results show that the assessment method succeeds in qualitatively evaluating the geospatial potentiality and the geospatial distribution of flooding due to water accumulation.Keywords: flooding, risk assessment, potentiality mapping, GIS, factorial scoring, Mauritius

AUTOMATED TRAFFIC ROUTING BASED ON THE RIP AND EIGRP ALGORITHMS USING CELLULAR AUTOMATA

The Routing Information Protocol (RIP) and Enhanced Interior Gateway Routing Protocol (EIGRP) algorithms are widely used in the field of telecommunications for transmission of data over computer networks. Traffic Cellular Automata (TCA) is a technique that has proved to be very efficient in simulating large-scale road traffic networks. In this paper a multicell TCA model that includes anticipation and probability randomization has been hybridized with the RIP and EIGRP algorithms. Simulation was performed on a small network and the performance of these two algorithms compared and analyzed. The results show that the EIGRP algorithm, through an adaptive routing of vehicles, achieves reduced travel times, more space-headway and lower traffic densities. </jats:p

OVERCOMING THE PIGOU–DOWNS PARADOX USING ADVANCED TRAFFIC SIGNAL CONTROL

Expansion of a road network has often been observed to cause more congestion and has led researchers to the formulation of traffic paradoxes such as the Pigou–Downs and the Braess paradoxes. In this paper, we present an application of advanced traffic signal control (ATSC) to overcome the Pigou–Downs paradox. Port Louis, the capital city of Mauritius is used to investigate the effect of using a harbor bridge to by-pass the city center. Using traffic cellular automata (TCA) simulations it has been shown how, if traffic is only gradually deviated along the by-pass, an overall longer travel time and decreased flux would result. By making use of ATSC, which involves traffic lights that sense the number of vehicles accumulated in the queue, better travel times and fluxes are achieved. </jats:p

Mangrove biomass productivity and sediment carbon storage assessment at selected sites in Mauritius: the effect of tidal inundation, forest age and mineral availability

Carbon dioxide is the most abundant anthropogenic greenhouse gas released in the environment and is considered as one of the main drivers of global warming and ensuing climate change. Mangals, recognised as key ‘blue carbon’ ecosystems, are amongst the world’s most carbon-dense ecosystems and can sequester a considerable amount of carbon through biological carbon sequestration in their biomass and soils. In this work, five Rhizophora mucronata natural and planted forests in Mauritius were studied with the aims at evaluating the carbon storage potential and the effect of tidal inundation, forest age, and mineral availability on biomass productivity and sediment carbon storage. Using 25m x 25m quadrats and a simple random sampling technique, plant height and diameter at breast height (DBH) were measured in situ with the GLOBE Observer application (The Globe Program, NASA-sponsored) and a measuring tape, respectively. The rate of canopy coverage over the past twenty years was assessed using historical Landsat 7 and 8 images available on Google Earth Pro. Rhizophora allometric equations were used to estimate the above-ground biomass (AGB), below-ground biomass (BGB), and total biomass (TB). Total organic carbon (TOC), sediment carbon storage, and all essential nutrients for plant growth were analysed using standard methods. Soil texture was determined using granulometric analysis. Our findings show that in both natural and planted forests, the zones that were more inundated were first established. However, tree and sapling density, as well as biomass, were negatively correlated with sodium (density: r = −0.830; AGB: r = −0.880). Positive correlations between AGB and nitrate nitrogen (NO _3 -N) (r = 0.686), ammonium nitrogen (NH _4 -N) (r = 0.706), phosphate (r = 0.618), and manganese (r = 0.776) suggest that these minerals were limiting factors. Nevertheless, the combination of forest age and salinity was found to play key roles on the AGB and therefore on total organic carbon (TOC), which is linked to materials originating from the mangroves. High correlations of TOC with NH _4 -N (r = 0.822) and magnesium (r = 0.831) indicate the greater availability of these essential nutrients in older forests. It is noteworthy that the Ferney forest with a relatively lower salinity (5–15 ppt) and the only forest that had already reached a steady state in 2010, had a relatively much higher AGB (326.2 ± 26.3 t ha ^−1 ) than the global average for Rhizophora mucronata (94.8 t ha ^−1 ), let alone Rhizophora spp. (281 t ha ^−1 ). The TOC registered at Ferney (47.34%) was also higher than the global values reported (2.00 ± 2.20% to 40.00 ± 2.20%)