scholarly journals A Historical Analysis of Rainfall Trend in the Olifants Basin in South Africa

2016 ◽  
Vol 5 (1) ◽  
pp. 129 ◽  
Author(s):  
C. Gyamfi ◽  
J. M. Ndambuki ◽  
R. W. Salim
Keyword(s):  
South African ◽  
Historical Analysis ◽  
Climate Change Impacts ◽  
Test Methods ◽  
Annual Rainfall ◽  
Trend Test ◽  
Homogeneity Test ◽  
Rainfall Trend ◽  
Font Size ◽  
Spatio Temporal

<span style="font-size: 10.5pt; font-family: 'Times New Roman','serif'; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;" lang="EN-US">A set of homogeneity test methods and the Mann-Kendall trend test were applied on historical rainfall records of the Olifants Basin to detect changes in rainfall pattern under a changing climate. In total, historical rainfall records from 13 stations obtained from the South African Weather Service (SAWS) and the Department of Water Affairs (DWA) spanning the period 1975-2013 were used in the analysis. Results of the study indicate an insignificant declining rainfall trend in the Olifants Basin with a mean annual rainfall of 664 mm. Rainfall in the basin exhibits spatio–temporal variation with coefficient of variation of 24%. Inter-annual and seasonal variability is dominant in the records examined. Changes observed in rainfall over the years were therefore concluded to have resulted due to climate change impacts.</span>

scholarly journals Climate Change Impact in Flores Island, a Dry Region in Indonesia

2021 ◽  
Vol 23 (1) ◽  
pp. 20-27
Author(s):  
Cilcia Kusumastuti ◽  
Dicky Gode ◽  
Yobella Febe Kurnianto ◽  
Frederik Jones Syaranamual
Keyword(s):  
Climate Change ◽  
Climate Change Impacts ◽  
Annual Rainfall ◽  
Rainfall Trend ◽  
Simple Linear Regression ◽  
Adaptation Measures ◽  
Pattern Change ◽  
Increasing Trend ◽  
Change Impact ◽  
Potential Climate Change

Climate change impacts have gained great attention to be studied in various fields. In this paper, an investigation of rainfall pattern change is performed using three statistical methods, i.e., simple linear regression, t-test, and Mann-Kendall’s test. The analysis is performed at 10- and 20-year time scales of daily, monthly, and annual rainfall in Flores Island, a dry region in Indonesia. In general, an increasing monthly rainfall trend is detected in the rainy season (October – April) at a 20-year period, using all three methods. Specifically, a significant increasing trend in March 1989 – 2008 is observed, and it contributes to the significant increasing trend of annual rainfall.  The findings presented in this paper should be an alert for potential climate change impacts in the region. The positive consideration of having more rainfall in a dry region might turn into a negative reality when adaptation measures are not well-prepared.

scholarly journals Temporal Description of Annual Temperature and Rainfall in the Bawku Area of Ghana

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Yaw Asamoah ◽  
Kow Ansah-Mensah
Keyword(s):  
Temporal Variations ◽  
Significant Rise ◽  
The Other ◽  
Annual Rainfall ◽  
Trend Test ◽  
Homogeneity Test ◽  
Climate Data ◽  
Other Hand ◽  
Standardised Precipitation Index ◽  
Most Significant Change

With varied implications, Ghana’s temperature and rainfall are projected to rise and decline, respectively. A study exposing specific areas of concern for appropriate responses in this regard is a welcome one. This study sought to describe the temporal variations in temperature and rainfall in the Bawku Area of Ghana. A forty-year (1976–2015) daily climate data was collected on three meteorological stations from the Ghana Meteorological Agency. Normality test, homogeneity test, Standardised Precipitation Index (SPI) analysis, Mann–Kendall trend test, and One-way post hoc ANOVA were performed using XLSTAT and DrinC. Over the period under study, the mean annual rainfall pattern was generally erratic, fluctuating between 669.8 mm and 1339.4.6 mm with an annual average of 935.3 mm. The long-term (40-year period) average temperature of the three stations, on the other hand, was 28.7°C, varying between 26.9°C and 29.9°C annually. Whereas the SPI value of 2006 was ≥2.0, indicating extremely wet year with 2.3% probability of recurring once every 50 years, 1988 was the hottest year with temperature anomaly value of 1.2°C, while coolest years were 1979 (−1.8°C) and 1976 (−1.0°C). The Mann–Kendall trend test showed a rise in rainfall in Binduri, Garu-Tempane, and Manga, yet none of the rainfall changes were statistically significant (P>0.05). Mean temperature on the other hand experienced a significant rise (P<0.05). With an R-square of 34.7%, the rise in temperature in Manga witnessed the most significant change in annual temperature changes. There were statistically significant (P<0.05) differences in the interdecadal temperature over the 40-year period. Generally, it can be stated that both temperature and rainfall vary in the study area with various degrees of disparities, but temperature assumes an upward trend at a faster rate. We therefore recommend that stakeholders resort to the construction of dams and boreholes to ensure regular availability of water for both domestic and agricultural uses.

scholarly journals Spatio-temporal Variability and Trends in Rainfall and Temperature in Anger watershed, Southwestern Ethiopia

2021 ◽  
Vol 5 (1) ◽  
pp. 462-472
Author(s):  
Gemechu Yigezu Ofgeha ◽  
Muluneh Woldetsadik Abshire
Keyword(s):  
Temporal Trends ◽  
Kendall Test ◽  
Annual Rainfall ◽  
Small Scale ◽  
Rainfall Trend ◽  
High Rainfall ◽  
Southwestern Ethiopia ◽  
Spatio Temporal ◽  
Small Scale Farmers ◽  
Increasing Trends

Insights to broadly argued research gap on lack of climate studies at micro-scale considering unique features of an area, this paper intended to examine agro-ecological level spatio-temporal trends and variability in rainfall and temperature in Anger watershed of southwestern Ethiopia. The gridded data managed by the Ethiopia National Meteorological Services Agency (NMSA) for 1983-2018 were used. The Mann-Kendall test for trend analysis and different variability measures were used. Questionnaire and FGD data on community perceptions gathered from 214 households and elders were analysed descriptively and qualitatively. The study reveals the consistent increasing trends in temperature; and high variability and insignificant but increasing rainfall trend. The trends and variability show spatio-temporal differences along agro-ecologies. The watershed is characterized by moderate to high rainfall coefficient of variations, significant years of high rainfall concentration, and considerable negative annual rainfall anomalies; that the variability was severe in woinadega followed by kolla agro-ecology. Although, the perceptions on trends, variability and its implications show difference across agro-ecology, the propensity to increased temperature, unclear rainfall trend and significant inter-annual and seasonal variability were witnessed. Unpredictability of rainfall time, concentrations in kiremt, and unexpected rain during harvesting was major challenges resulting multifaceted impacts on the small-scale farmers’ livelihoods.

scholarly journals Cellular time series: a data structure for spatio-temporal analysis and management of geoscience information

2019 ◽  
Vol 21 (6) ◽  
pp. 999-1013
Author(s):  
Sina Nabaei ◽  
Bahram Saghafian
Keyword(s):  
Time Series ◽  
Data Structure ◽  
Temporal Analysis ◽  
Change Point Detection ◽  
Trend Test ◽  
Homogeneity Test ◽  
Monthly Precipitation ◽  
Detection Techniques ◽  
Standard Normal Homogeneity Test ◽  
Spatio Temporal

Abstract Geoscientists are continuously confronted by difficulties involved in handling varieties of data formats. Configuration of data only in time or space domains leads to the use of multiple stand-alone software in the spatio-temporal analysis which is a time-consuming approach. In this paper, the concept of cellular time series (CTS) and three types of meta data are introduced to improve the handling of CTS in the spatio-temporal analysis. The data structure was designed via Python programming language; however, the structure could also be implemented by other languages (e.g., R and MATLAB). We used this concept in the hydro-meteorological discipline. In our application, CTS of monthly precipitation was generated by employing data of 102 stations across Iran. The non-parametric Mann–Kendall trend test and change point detection techniques, including Pettitt's test, standard normal homogeneity test, and the Buishand range test were applied on the generated CTS. Results revealed a negative annual trend in the eastern parts, as well as being sporadically spread over the southern and western parts of the country. Furthermore, the year 1998 was detected as a significant change year in the eastern and southern regions of Iran. The proposed structure may be used by geoscientists and data providers for straightforward simultaneous spatio-temporal analysis.

‘Our passion for legality’: international law and imperialism in late nineteenth-century Britain

2008 ◽  
Vol 34 (3) ◽  
pp. 403-423 ◽  
Author(s):  
CASPER SYLVEST
Keyword(s):  
Nineteenth Century ◽  
International Law ◽  
South African ◽  
Historical Analysis ◽  
World Politics ◽  
Late Nineteenth Century ◽  
Contemporary World ◽  
Late Nineteenth ◽  
Congo Free State

AbstractThis article deploys a historical analysis of the relationship between law and imperialism to highlight questions about the character and role of international law in global politics. The involvement of two British international lawyers in practices of imperialism in Africa during the late nineteenth century is critically examined: the role of Travers Twiss (1809–1897) in the creation of the Congo Free State and John Westlake’s (1828–1913) support for the South African War. The analysis demonstrates the inescapably political character of international law and the dangers that follow from fusing a particular form of liberal moralism with notions of legal hierarchy. The historical cases raise ethico-political questions, the importance of which is only heightened by the character of contemporary world politics and the attention accorded to international law in recent years.

The SMRI-NIRS technology: development, validation and benefit

2021 ◽  
pp. 354-359
Author(s):  
Stephen N. Walford
Keyword(s):  
South African ◽  
Near Infrared ◽  
Technology Development ◽  
Correlation Coefficients ◽  
Test Methods ◽  
Analysis Method ◽  
Prediction Equations ◽  
Conventional Analysis ◽  
Methods Of Analysis ◽  
Conventional Methods

The Sugar Milling Research Institute NPC (SMRI) has developed a simple to use near-infrared spectroscopy (NIRS) transmission-based analysis method as an alternative to conventional methods for analysis of sugarcane factory stream samples. The technology provides rapid, simultaneous analysis of refractometric dry substance (rds), polarimetric sugar, sucrose, glucose, fructose, conductivity ash contents as well as colour and pH for all streams and additionally, dry solids for final molasses and eliminates the need for sample clarification chemicals. The analyte prediction equations were developed using conventional results of samples from 14 South African factories, analysed at SMRI using SANAS/ISO17025 accredited test methods, and NIRS scans of the same samples using up to 16 different NIRS instruments. The NIRS analyte prediction equations were validated against more than 1,500 independent factory samples that had been analysed by conventional methods of analysis, including samples from factories outside South Africa. The reproducibility of the NIRS results were equivalent to existing conventional analysis reproducibility values (juice and final molasses) and previously undocumented values determined for this study for conventional raw house analysis methods. Correlation coefficients of greater than 0.97 were recorded for all major analytes and greater than 0.9 for minor analytes when predicted results were compared against conventional results. A maintenance protocol was also developed to ensure that the prediction equations remain robust and can account for sample matrix variations that can occur from season to season. The SMRI-NIRS technology was installed at all 14 South African factories and found to be robust and give equivalent results to conventional methods of analysis.

How to assess the vulnerability and the risk of flooding of the most important catchment in the Republic of Djibouti?

2021 ◽  
Author(s):  
Golab Moussa Omar ◽  
Jean-Emmanuel Paturel ◽  
Christian Salles ◽  
Gil Mahe ◽  
Mohamed Jalludin
Keyword(s):  
Temporal Variability ◽  
Groundwater Resources ◽  
Annual Rainfall ◽  
Series Data ◽  
Boreal Summer ◽  
Precipitation Regime ◽  
Daily Data ◽  
Spatio Temporal ◽  
The Republic ◽  
Rainy Days

&lt;p&gt;&lt;span&gt;This study focus on the catchment of Ambouli wadi which is one of the country&amp;#8217;s largest watersheds covering 794 km&amp;#178; (3.5 % of the total area of the Republic of Djibouti). Because of its groundwater resources, this exoreic watershed is of major importance. Indeed, the aquifer is the main source of drinking water supply for the city of Djibouti-city. In addition, this wadi is also responsible for floods causing human suffering and severe economic damages. Despite the importance of the catchment for the development of Djibouti-city, Ambouli wadi has been the subject of few scientific studies. This partly explains the scarcity of rainfall stations and therefore data in this area. Analysis of the spatio-temporal variability of rainfall is required to assess the risk of flooding. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;In an arid country like the Republic of Djibouti flash floods are an important concern for the management of water resources systems and risk prevention and protection. The desertic climate of the country is characterized by high levels of temperature and evaporation, and also by very weak and irregular annual rainfall, distributed in two major seasons : a cooler season (from October to March) with high relative humidity and low temperatures comprised between 22&amp;#176;C and 30&amp;#176;C, and a hot and dry season (from June to September). &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;Rain data were collected from a network of 9 raingauge stations at different time scales, from monthly to hourly. These data are provided by the national meteorological agency (4 stations) and the early warning system of CERD National Research Center (5 stations).&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&amp;#160;&lt;/span&gt;&lt;span&gt;The spatio-temporal variability of rainfall, is characterized using the Standardized Precipitation Index (SPI) and the analysis of rainfall normals over 30 years (1951-1980 and 1961-1990). Long time series data were available from 4 of the 9 stations: (Djibouti-serpent, Djibouti-aeorodrome, Oueah and Arta). At annual scale, the variability is clearly described by a succession of dry and humid years. Also, the monthly rainfall clearly demonstrates the well-known bimodal precipitation regime of east Africa. It shows, two peaks corresponding to the &amp;#171;&amp;#160;long rain&amp;#160;&amp;#187; and the &amp;#171;&amp;#160;short rain&amp;#160;&amp;#187; rainy seasons, which correspond to the period of March-April-May and of October-November-December, respectively. On the other hand, we also observe a dry period which is characterized by a rainfall deficit (negative rainfall index for almost all the stations) corresponding to the boreal summer (June to September). &lt;/span&gt;&lt;span&gt;Daily data is currently collecting from the Djibouti-aerodrome station (1981-2017) for a better understanding of the precipitation regime. Rainy days are computed from daily data (rainfall &gt; 1 mm) and we find an annual average of 11 wet days with a minimum in 1988 (1 rainy day) and a maximum in 1993 (23 rainy days). &lt;/span&gt;&lt;/p&gt;

scholarly journals Adaptive genetic variation at three loci in South African vervet monkeys (Chlorocebus pygerythrus) and the role of selection within Primates

2018 ◽  
Author(s):  
Willem G Coetzer ◽  
Trudy R Turner ◽  
Christopher A Schmitt ◽  
J Paul Grobler
Keyword(s):  
Genetic Variation ◽  
South African ◽  
Vervet Monkey ◽  
Climatic Conditions ◽  
Primate Species ◽  
Annual Rainfall ◽  
Future Research ◽  
Vervet Monkeys ◽  
Adaptive Genetic Variation ◽  
Chlorocebus Pygerythrus

Vervet monkeys (Chlorocebus pygerythrus) are one of the most widely distributed non-human primate species found in South Africa. They occur across all the South African provinces, inhabiting a large variety of habitats. These habitats vary sufficiently that it can be assumed that various factors such as pathogen diversity could influence populations in different ways. In turn, these factors could lead to varied levels of selection at specific fitness linked loci. The Toll-like Receptor (TLR) gene family, which play an integral role in vertebrate innate immunity, is a group of fitness linked loci which has been the focus of much research. In this study, we assessed the level of genetic variation at partial sequences of two TLR loci (TLR4 and 7) and a reproductively linked gene, acrosin (ACR), across the different habitat types within the vervet monkey distribution range. Gene variation and selection estimates were also made among 11 – 21 primate species. Low levels of genetic variation for all three gene regions were observed within vervet monkeys , with only two polymorphic sites identified for TLR4, three sites for TLR7 and one site for ACR . TLR7 variation was positively correlated with high mean annual rainfall, which was linked to increased pathogen abundance. The observed genetic variation at TLR4 might have been influenced by numerous factors including pathogens and climatic conditions. The ACR exonic regions showed no variation in vervet monkeys, which could point to the occurrence of a selective sweep. The TLR4 and TLR7 results for the among primate analyses was mostly in line with previous studies, indicating a higher rate of evolution for TLR4. Within primates, ACR also showed signs of positive selection, which was congruent with previous reports on mammals. Important additional information to the already existing vervet monkey knowledge base was gained from this study, which can guide future research projects on this highly researched taxon as well as help conservation agencies with future management planning involving possible translocations of this species.

scholarly journals Fine-grained, spatio-temporal datasets measuring 200 years of land development in the United States

2020 ◽  
Author(s):  
Johannes H. Uhl ◽  
Stefan Leyk ◽  
Caitlin M. McShane ◽  
Anna E. Braswell ◽  
Dylan S. Connor ◽  
...  
Keyword(s):  
United States ◽  
Temporal Resolution ◽  
Data Extraction ◽  
Historical Analysis ◽  
Land Development ◽  
Remote Sensing Data ◽  
The United States ◽  
Building Stock ◽  
Fine Grained ◽  
Spatio Temporal

Abstract. The collection, processing and analysis of remote sensing data since the early 1970s has rapidly improved our understanding of change on the Earth’s surface. While satellite-based earth observation has proven to be of vast scientific value, these data are typically confined to recent decades of observation and often lack important thematic detail. Here, we advance in this arena by constructing new spatially-explicit settlement data for the United States that extend back to the early nineteenth century, and is consistently enumerated at fine spatial and temporal granularity (i.e., 250 m spatial, and 5 a temporal resolution). We create these time series using a large, novel building stock database to extract and map retrospective, fine-grained spatial distributions of built-up properties in the conterminous United States from 1810 to 2015. From our data extraction, we analyse and publish a series of gridded geospatial datasets that enable novel retrospective historical analysis of the built environment at unprecedented spatial and temporal resolution. The datasets are available at https://dataverse.harvard.edu/dataverse/hisdacus (Uhl and Leyk, 2020a, b, c, d).

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