Rainfall trends in the KwaZulu‐Natal Drakensberg region of South Africa during the twentieth century

Nel, Werner

doi:10.1002/joc.1814

Cited by 53 publications

(47 citation statements)

References 24 publications

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“…Seasonality of rainfall has been described through the monthly rainfall total as a percentage of the total annual rainfall (Nel and Sumner 2006;Nel 2009). Results indicate that annual rainfall in the Albert-Victoria area is seasonal, with 39 and 37 % of the annual rainfall occurring in MAM and SON seasons, respectively.…”

Section: Seasonal Rainfall Seriesmentioning

confidence: 99%

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

Nsubuga

Olwoch

Rautenbach

et al. 2013

Theor Appl Climatol

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A methodology has been applied to investigate the spatial variability and trends existent in a mid-twentieth century climatic time series (for the period recorded by 58 climatic stations in the Albert-Victoria water management area in Uganda. Data were subjected to quality checks before further processing. In the present work, temporal trends were analyzed using Mann-Kendall and linear regression methods. Heterogeneity of monthly rainfall was investigated using the precipitation concentration index (PCI). Results revealed that 53 % of stations have positive trends where 25 % are statistically significant and 45 % of stations have negative trends with 23 % being statistically significant. Very strong trends at 99 % significance level were revealed at 12 stations.

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Section: Seasonal Rainfall Seriesmentioning

confidence: 99%

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

Nsubuga

Olwoch

Rautenbach

et al. 2013

Theor Appl Climatol

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“…January was the only month that exhibited a statistically significant linear trend at 5% and Sen's estimator magnitude of change at a rate of 1.87 mm ( (Jury, 2013;Nel, 2009;Mason & Jury, 1997). Additionally, our results seemed to suggest that rainfall in this particular area may have been underestimated (in e.g., model simulations) in the past.…”

Section: Analysis Of Monthly and Seasonal Rainfall Trendsmentioning

confidence: 58%

“…Seasonality can be described through the monthly rainfall totals as percentages of the total annual rainfall (Nel & Sumner, 2006;Nel, 2009). In this study, seasonality analysis for 36 years was based on monthly averages for rainfall and temperature recorded during 1975 to 2011.…”

Section: Seasonality Delineationmentioning

confidence: 99%

“…Consequently, the average monthly rainfall total ( Figure 2 and Table 1) showed uneven distribution and variability in terms of trend (Figure 2), and magnitude of change (Table 1) varied between 1.87 (January) and -1.67 (September) across the study period. Generally, West Bank-East London area rainfall analysis showed large variability in magnitude (Table 1) The influence of ENSO events is strongest during the summer rainfall months of December to March when the El Niño/La Niña events have reached maturity (Mason & Jury, 1997;Nel, 2009). In addition, the southern oscillation influences rainfall variability in the southern hemisphere (Nel, 2009), and this could be as a result of the El Niño/La Niña phenomenon (Hyden & Sekoli, 2000).…”

Section: Analysis Of Monthly and Seasonal Rainfall Trendsmentioning

confidence: 99%

“…Therefore, any fluctuations in global sea surface temperatures could influence rainfall patterns in an area especially given the close proximity of the West Bank-East London area to the Indian Ocean. Furthermore, factors such as ENSO, cyclones and El Niño/La Niña occurrences have been found to influence rainfall in southern Africa (Jury, 2013;Nel 2009;Mason & Jury, 1997), and consequently could have had an effect on the observed rainfall variability over West Bank-East London area. Vol.…”

Section: Trend Analysis Of Annual Rainfall For Climatic Regimesmentioning

confidence: 99%

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Trend Analysis of Climate Variability over the West Bank - East London Area, South Africa (1975-2011)

Kalumba¹,

M²,

Aardt³

et al. 2013

JGG

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In recent years, climate change has received considerable attention by the scientific community at different scales concerning its potential impacts on Earth system processes. This study focused at local scale by analysing trends in rainfall and temperature data for the West Bank-East London area in South Africa, spanning 36 years from 1975-2011. Sen's and Man-Kendall non-parametric tests were performed on derived mean observed rainfall and temperature data to establish trends for monthly, seasonal, annual, and 30 year (1975-2005 and 1980-2011) climatic regimes. Results revealed that, 1977 recorded the highest annual rainfall (2272.9 mm) while the month of August received the highest total rainfall (493.8 mm) in 2002, whereas it never had rain in 1995. Seasonal and annual rainfall showed statistically no significant trend (at a = 0.10) while the magnitude of change varied between 1.87 mm (January) and -1.67 mm (September) across the study period. Rainfall decreased by 13.99 mm within the two climatic regimes. On the other hand, maximum and minimum annual mean temperature experienced an increasingly statistically significant trend (at a < 0.05) at 95% confidence level. February recorded the highest mean monthly temperature (21.8 °C) while July with the lowest (12.6 °C). Seasonal mean maximum temperature trends were statistically not significant (a = 0.10) while autumn minimum temperatures revealed a statistically significant trend (at a < 0.1). However, the period 1990-1999 predominantly experienced numerous extreme events. The seasonal trends showed substantial variability across the months and years during the study period. The significance of these findings lies in the linkage of rainfall and temperature to climate change and its potential impacts on vegetation in particular and changes in the ecology in general.

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Mechanisms of lateral and linear extension of gullies (dongas) in a subhumid grassland of South Africa

Podwojewski

Janeau

Caquineau

et al. 2020

Earth Surf Processes Landf

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The formation of deep gullies (called 'dongas' locally) in rangeland in KwaZulu-Natal Province in South Africa is a natural phenomenon. These U-shaped, very wide gullies have considerable lateral expansion due to the episodic collapse of sidewalls. The dongas have developed in duplex soils such as Luvisols and Lixisols formed on Permian sedimentary rocks or unconsolidated Quaternary colluvium. This study combined morphological, mineralogical and chemical characterization with measurements of grain-size content, structural stability and the complete shrinkage curve to detect changes in soil properties of the different horizons located in the gully banks. The different soil horizons present clear and sharp differences in physical and mineralogical properties. The topsoil with complete grass cover is very resistant to soil detachment. However, the leached E horizon and the BC horizon have low structural stability. The soil profile down to and including the Bt horizon contains exclusively illite in the clay fraction, while the BC colluvial layer and the C horizon (mudstone) contain expandable interstratified illite-smectite. The Bt horizon has a high water content at saturation and high shrinkage, while the BC and C horizons have a high residual shrinkage and a very low water content at saturation. Because this type of gully expansion is not significantly linked to slope value or the stream power index (SPI) at the gully head, to land-use change, high rainfall intensities or the threshold of concentrated runoff being exceeded at the gully head, other causes were investigated. It was concluded that the heterogeneity between horizons with different mineralogical properties and structural stabilities, soil types and parent material, anisotropic water-saturation and shrink-swell properties are of major importance. This heterogeneity between different soil horizon morphologies and their physical properties can explain why the relationship between the critical slope and the drainage area for gully initiation showed a threshold for gullying much lower than that found elsewhere.

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Rainfall trends in the KwaZulu‐Natal Drakensberg region of South Africa during the twentieth century

Cited by 53 publications

References 24 publications

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

Trend Analysis of Climate Variability over the West Bank - East London Area, South Africa (1975-2011)

Mechanisms of lateral and linear extension of gullies (dongas) in a subhumid grassland of South Africa

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