scholarly journals Analysis of Historical Monthly, Seasonal and Annual Rainfall Variability (1990–2014) in Machakos Sub County, Kenya

2018 ◽  
Vol 6 (01) ◽  
Author(s):  
Christopher M. Indiatsy
Keyword(s):  
Rainwater Harvesting ◽  
Rainfall Variability ◽  
Climatic Conditions ◽  
Annual Rainfall ◽  
Correlation Technique ◽  
Precipitation Concentration Index ◽  
Considerable Uncertainty ◽  
Marginal Areas ◽  
Droughts And Floods ◽  
Central Kenya

Varying climatic conditions with increased uncertainty mainly in rainfall and temperature are salient features in marginal areas globally, adversely affecting farming activities particularly in Africa. Kenya experiences variations of annual rainfall with considerable uncertainty. These variations ranging from below 500mm to above 2000mm annually, cause droughts and floods respectively, affecting farming activities and yields. This study attempts to analyze historical monthly, seasonal and annual rainfall variability in Machakos sub County between 1990 – 2014. Studies on analysis of rainfall variability covered in Machakos have dwelt on broad and expansive areas of Eastern and South Eastern Kenya including Machakos, Kitui and Makueni Counties. Broad studies give generalized information which may not give true and adequate results for some specific areas. This has prompted the need to focus on a smaller area. This study focused on Machakos sub County, a semi arid area, East of Central Kenya highlands. Existing studies in the mentioned areas, mainly cover the period between 1930 - 1990. After this period, very scarce information exists. The main objective of the study was to establish the historical monthly, seasonal and annual rainfall variability in Machakos sub county between 1990 – 2014. Publications from Meteorological Department Nairobi and sub county Agricultural offices, provided rainfall data. Using SPSS, quantitative data was analyzed using descriptive statistics such as Means, Standard deviation and percentages. Inferential statistics using Pearson’s Correlation technique was used to determine relationships between variables. Coefficient of variability, Relative variability and Precipitation Concentration index measured Rainfall Variability. The study established that monthly, seasonal and annual rainfall distribution in Machakos sub County was highly variable, erratic and unpredictable over the 25 years with a CV of 24% and a PCI of 10. There is high temporal rainfall variability (CV of 24% and PCI of 10) in the sub County. Disseminating information on rainfall forecasts, rainwater harvesting for irrigation, proper cattle stocking, a forestation and reforestation programs were highly recommended.

scholarly journals Climatic information of Western Sahel (1535–1793 AD) in original documentary sources

2014 ◽  
Vol 10 (5) ◽  
pp. 3877-3900 ◽  
Author(s):  
V. Millán ◽  
F. S. Rodrigo
Keyword(s):  
18Th Century ◽  
Climatic Conditions ◽  
Ordinal Scale ◽  
Annual Rainfall ◽  
Minor Importance ◽  
Documentary Sources ◽  
Western Sahel ◽  
Dry Conditions ◽  
Droughts And Floods ◽  
Original Documentary

Abstract. The Sahel is the semi-arid transition zone between arid Sahara and humid tropical Africa, extending approximately 10–20° N from Mauritania in the West to Sudan in the East. The African continent, one of the most vulnerable regions to climate change, is subject to frequent droughts and famine. One climate challenge research is to isolate those aspects of climate variability that are natural from those that are related to human influences. Therefore, the study of climatic conditions before mid-19th century, when anthropogenic influence was of minor importance, is very interesting. In this work the frequency of extreme events, such as droughts and floods, in Western Sahel from the 16th to 18th centuries is investigated using documentary data. Original manuscripts with historical chronicles from Walata and Nema (Mauritania), Timbuktu and Arawan (Mali), and Agadez (Niger) have been analyzed. Information on droughts, intense rainfall, storms and floods, as well as socioeconomic aspects (famines, pests, scarcity, prosperity) has been codified in an ordinal scale ranging from −2 (drought and famines) to +2 (floods) to obtain a numerical index of the annual rainfall in the region. Results show wet conditions in the 17th century, as well as dry conditions in the 18th century (interrupted by a short wet period in the 1730s decade).

scholarly journals Recent Rainfall Variability Over a Dryland Ecosystem of North Western India

2021 ◽  
Author(s):  
DIVYA SAINI ◽  
PANKAJ BHARDWAJ ◽  
Omvir Singh
Keyword(s):  
Rainfall Variability ◽  
Climatic Conditions ◽  
Annual Rainfall ◽  
Western India ◽  
Positive Trend ◽  
North West ◽  
North East ◽  
Mean Annual Rainfall ◽  
The Mean ◽  
North Western

Abstract In this study, an attempt has been made to examine the recent rainfall variability by means of daily rainfall data of 33 well spread stations over dryland ecosystem of Rajasthan in north western India during 1961-2017. For trend analysis, Mann-Kendall, Sen’s slope estimator and simple linear regression test have been used (at 95% confidence level). The results have shown a high interannual variability in rainfall occurrence varying from 277 mm (in year 2002) to 839 mm (in year 1975) with mean of 583 mm over this dryland ecosystem. Most of the rainfall deficit years have occurred with El-Nino years. The mean annual rainfall has shown a marginal non-significant upward trend over the ecosystem. The station-wise mean annual rainfall has revealed a significant rising trend over Barmer, Churu, Ganganagar, Jaisalmer and Pratapgarh stations. Interestingly, three year running average has shown a cyclic pattern of rainfall over dryland ecosystem under the changing climatic conditions. The spatial pattern has exhibited that the mean annual rainfall decreases from east and south east (more than 850 mm) to west and north west (less than 400 mm), which is mainly associated with the presence of Aravalli Mountains spreading north east to south west in central Rajasthan. Remarkably, majority of stations positioned in western parts of dryland ecosystem have shown increasing rainfall trends, whereas some stations located in eastern parts have recorded a non-significant declining trend. The magnitude of significant rising trend has varied from 5.34 mm/year (Pratapgarh station) to 2.17 mm/year (Jaisalmer station). Also, the frequency of heavy rainfall events has shown a positive trend with significant increasing trends over Bharatpur, Jaisalmer and Pratapgarh stations, whereas Bundi station has shown significant decreasing trend.

scholarly journals Analysis of spatial variability and temporal trends of rainfall in Amhara region, Ethiopia

2019 ◽  
Vol 11 (4) ◽  
pp. 1505-1520 ◽  
Author(s):  
Melkamu Meseret Alemu ◽  
Getnet Taye Bawoke
Keyword(s):  
Trend Analysis ◽  
Water Resource Management ◽  
Rainfall Variability ◽  
Temporal Trends ◽  
Amhara Region ◽  
Rainfall Distribution ◽  
Rainfall Events ◽  
Precipitation Concentration Index ◽  
Droughts And Floods ◽  
Seasonality Index

Abstract Understanding rainfall distribution in space and time is crucial for sustainable water resource management and agricultural productivity. This study investigated the spatial distribution and temporal trends of rainfall in Amhara region using time series rainfall data of Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) for the period 1981–2017. Coefficient of variation, standardized anomaly index (SAI), precipitation concentration index (PCI) and seasonality index (SI) were used to evaluate rainfall variability and seasonality. Mann–Kendall's test was also employed for rainfall trend analysis. Results showed that the region has been experiencing variable rainfall events that cause droughts and floods over different years. SAI also witnessed the presence of inter-annual variability of rainfall with negative and positive anomalies in 59.46% and 40.54% of the analyzed years, respectively. PCI and SI results implied that the area had irregular and strong irregular rainfall distribution. Trend analysis results showed an overall increase in the annual and seasonal rainfall (except winter) during the study period. The information obtained from this study could serve as a proxy for rainfall variability and trend in the study area which might be used as input for decision-makers to take appropriate adaptive measures in various agricultural and water resources sectors.

Spatiotemporal trend analysis of rainfall and temperature, and its implications for crop production

2018 ◽  
Vol 10 (4) ◽  
pp. 799-817 ◽  
Author(s):  
Tesfa Worku ◽  
Deepak Khare ◽  
S. K. Tripathi
Keyword(s):  
Correlation Analysis ◽  
Crop Production ◽  
Rainfall Variability ◽  
Pearson Correlation ◽  
Winter Season ◽  
Seasonal Rainfall ◽  
Annual Rainfall ◽  
Precipitation Concentration Index ◽  
Mk Test ◽  
The Impact

Abstract Global warming is a significant global environmental problem in the 21st century. The problem is high in developing countries, particularly sub-Saharan countries in which the majority of the population live on rainfed agriculture. The present study aimed to undertake spatiotemporal analysis of seasonal and annual rainfall and temperature and its implications. The MK test, Sen's slope and precipitation concentration index (PCI) were applied. Finally, Pearson correlation analysis between climatic variables and crop production was analysed. The Mann–Kendall test results showed that the annual and seasonal rainfall trend was highly variable. The minimum and maximum temperatures have increased by 0.8 and 1.1 °C/year, respectively. Based on PCI results, rainfall during the summer and spring seasons is moderately distributed as compared to annual and winter season rainfall. Based on these observations, the rainfall pattern and distribution of the area could be classified as irregular and erratic distribution. Results of correlation analysis between monthly and seasonal rainfall with crop production were insufficient to conclude the impact of rainfall and temperature on crop production. In view of this, the incidence of food shortage is a common occurrence. Therefore, depending on the historical trend of rainfall variability and prolonged temperature increase, appropriate coping and adaptation strategies need to be encouraged.

scholarly journals Climate Change Impact on Rainfall: How will Threaten Wheat Yield?

2018 ◽  
Vol 37 ◽  
pp. 03001
Author(s):  
K. Tafoughalti ◽  
E.M. El Faleh ◽  
Y. Moujahid ◽  
F. Ouargaga
Keyword(s):  
Climate Change ◽  
Rainfall Variability ◽  
Wheat Yield ◽  
Annual Rainfall ◽  
Strongly Correlated ◽  
Rainfall Distribution ◽  
Precipitation Concentration Index ◽  
Agrarian Economy ◽  
Cumulative Rainfall ◽  
Change Impact

Climate change has a significant impact on the environmental condition of the agricultural region. Meknes has an agrarian economy and wheat production is of paramount importance. As most arable area are under rainfed system, Meknes is one of the sensitive regions to rainfall variability and consequently to climate change. Therefore, the use of changes in rainfall is vital for detecting the influence of climate system on agricultural productivity. This article identifies rainfall temporal variability and its impact on wheat yields. We used monthly rainfall records for three decades and wheat yields records of fifteen years. Rainfall variability is assessed utilizing the precipitation concentration index and the variation coefficient. The association between wheat yields and cumulative rainfall amounts of different scales was calculated based on a regression model. The analysis shown moderate seasonal and irregular annual rainfall distribution. Yields fluctuated from 210 to 4500 Kg/ha with 52% of coefficient of variation. The correlation results shows that wheat yields are strongly correlated with rainfall of the period January to March. This investigation concluded that climate change is altering wheat yield and it is crucial to adept the necessary adaptation to challenge the risk.

scholarly journals Complex Valuation of Energy from Agricultural Crops including Local Conditions

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1415
Author(s):  
Václav Voltr ◽  
Martin Hruška ◽  
Luboš Nobilis
Keyword(s):  
Soil Quality ◽  
Environmental Impacts ◽  
Climatic Conditions ◽  
Energy Crops ◽  
Co2 Production ◽  
Low Carbon ◽  
Local Conditions ◽  
Low Carbon Economy ◽  
Silage Maize ◽  
Marginal Areas

This paper provides values of economic, energy and environmental assessments of 20 crops and assesses the relationships of soil-climatic conditions in the example of the Czech Republic. The comparison of main soil quality indicators according to the configuration of land and climate regions is performed on the basis of energy and economic efficiency as well as a comparison of the level of environmental impacts. The environmental impacts are identified based on the assessment of emissions from production and also in the form of soil compaction as an indicator of the relationship to soil quality. As concerns soil properties, of major importance is soil skeleton, slope of land and the depth of soil, which cause an increase in emissions from the energy produced. Substantially better emission parameters per 1 MJ through energy crops, the cultivation of perennial crops and silage maize has been supported. Among energy crops, a positive relationship with the quality of soil is seen in alfalfa, with a significant reduction in soil penetrometric resistance; energy crops are also politically justifiable in competition with other crops intended for nutrition of population. The main advantage of energy crops for the low-carbon economy is their CO2 production to MJ, which is almost half, especially in marginal areas with lower soil depths, slopes and stoniness, which can be included in the new agricultural policy.

Climate change could intensify Sahel conflicts

2022 ◽  
Keyword(s):  
Climate Change ◽  
Security Policy ◽  
Rainfall Variability ◽  
Political Stability ◽  
Climate Impacts ◽  
Small Scale ◽  
Content Type ◽  
Droughts And Floods ◽  
Political Conditions ◽  
Small Scale Irrigation

Significance It will increase rainfall variability and extreme events such as droughts and floods, as well as raising temperatures. These effects may trigger cascading risks to economic, social and political stability. Impacts The EU could play a key role in moderating climate effects as it shapes migration and security policy in the Sahel. The likelihood and severity of climate impacts will depend on socio-economic and political conditions in the region. Small-scale irrigation, climate-adapted seeds and traditional soil conservation techniques can help increase resilience to climate change.

scholarly journals China's water sustainability in the 21st century: a climate-informed water risk assessment covering multi-sector water demands

2014 ◽  
Vol 18 (5) ◽  
pp. 1653-1662 ◽  
Author(s):  
X. Chen ◽  
D. Naresh ◽  
L. Upmanu ◽  
Z. Hao ◽  
L. Dong ◽  
...  
Keyword(s):  
Water Stress ◽  
Risk Measures ◽  
Rainfall Variability ◽  
Political Process ◽  
Temporal Distribution ◽  
High Water ◽  
Annual Rainfall ◽  
Water Sustainability ◽  
Domestic Water ◽  
Water Demands

Abstract. China is facing a water resources crisis with growing concerns as to the reliable supply of water for agricultural, industrial and domestic needs. High inter-annual rainfall variability and increasing consumptive use across the country exacerbates the situation further and is a constraint on future development. For water sustainability, it is necessary to examine the differences in water demand and supply and their spatio-temporal distribution in order to quantify the dimensions of the water risk. Here, a detailed quantitative assessment of water risk as measured by the spatial distribution of cumulated deficits for China is presented. Considering daily precipitation and temperature variability over fifty years and the current water demands, risk measures are developed to inform county level water deficits that account for both within-year and across-year variations in climate. We choose political rather than watershed boundaries since economic activity and water use are organized by county and the political process is best informed through that unit. As expected, the risk measures highlight North China Plain counties as highly water stressed. Regions with high water stress have high inter-annual variability in rainfall and now have depleted groundwater aquifers. The stress components due to agricultural, industrial and domestic water demands are illustrated separately to assess the vulnerability of particular sectors within the country to provide a basis for targeted policy analysis for reducing water stress.

No bush foods without people: the essential human dimension to the sustainability of trade in native plant products from desert Australia

2011 ◽  
Vol 33 (4) ◽  
pp. 395 ◽  
Author(s):  
Fiona Walsh ◽  
Josie Douglas
Keyword(s):  
Research And Development ◽  
Reference Group ◽  
Rainfall Variability ◽  
Forest Products ◽  
Annual Rainfall ◽  
Ecological Sustainability ◽  
Small Scale ◽  
Native Plant ◽  
Plant Products ◽  
Trade Offs

Improvement in Aboriginal people’s livelihoods and economic opportunities has been a major aim of increased research and development on bush foods over the past decade. But worldwide the development of trade in non-timber forest products from natural populations has raised questions about the ecological sustainability of harvest. Trade-offs and tensions between commercialisation and cultural values have also been found. We investigated the sustainability of the small-scale commercial harvest and trade in native plant products sourced from central Australian rangelands (including Solanum centrale J.M. Black, Acacia Mill. spp.). We used semi-structured interviews with traders and Aboriginal harvesters, participant observation of trading and harvesting trips, and analysis of species and trader records. An expert Aboriginal reference group guided the project. We found no evidence of either taxa being vulnerable to over-harvest. S. centrale production is enhanced by harvesting when it co-occurs with patch-burning. Extreme fluctuations in productivity of both taxa, due to inter-annual rainfall variability, have a much greater impact on supply than harvest effects. Landscape-scale degradation (including cattle grazing and wildfire) affected ecological sustainability according to participants. By contrast, we found that sustainability of bush food trade is more strongly impacted by social and economic factors. The relationship-based links between harvesters and traders are critical to monetary trade. Harvesters and traders identified access to productive lands and narrow economic margins between costs and returns as issues for the future sustainability of harvest and trade. Harvesters and the reference group emphasised that sustaining bush harvest relies on future generations having necessary knowledge and skills; these are extremely vulnerable to loss. Aboriginal people derive multiple livelihood benefits from harvest and trade. Aboriginal custodians and harvester groups involved in recent trade are more likely to benefit from research and development investment to inter-generational knowledge and skill transfer than from investments in plant breeding and commercial horticultural development. In an inductive comparison, our study found there to be strong alignment between key findings about the strategies used by harvesters and traders in bush produce and the ‘desert system’..

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.

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