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Doctoral Degrees (Agrometeorology)

Permanent URI for this collectionhttps://hdl.handle.net/10413/6564

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Browsing Doctoral Degrees (Agrometeorology) by Subject "Drought characterization."

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    Observed and projected climate change effects on localized drought events: a case study for sugarbelt within KwaZulu-Natal Midlands, South Africa.
    (2021) Ncoyini-Manciya, Zoleka.; Savage, Michael John.
    The projected increase of air temperature across the globe has been associated the increased vulnerability of resource-poor farming communities to climate variability. Past and possible changes in climate trends for the study area within the KwaZulu-Natal (KZN) midlands sugarcane belt are presented in this study. An analysis of the climatic trend for two time-periods (1966-1994 and 1997-2017) is undertaken. Various analytical tools which include Expert Team on Climate Change Detection and Indices (ETCCDI), the Penman-Monteith model, linear regression and Man-Kendall (MK) test, the de-trended method, surface humidity index (SHI), Run’s theory, statistical downscaling method (SDSM), drought indices and a survey through questionnaires were applied. The ETCCDI analysis showed that air temperatures during day-time have become warmer resulting in a decrease in the number of cool days. with night-time air temperatures showing an opposite trend. The Penman-Monteith model results showed a statistically insignificant decreasing short-grass reference evapotranspiration (ETo) trend for the study site for the 1966 to 2017. The statistical downscaling results indicated an increasing trend for both minimum and maximum air temperature for the period of 2011-2099. Except for the results of extreme minimum air temperature, the results of the study are consistent with other climate studies conducted worldwide. Nevertheless, the findings of this study provide evidence that despite the general global warming observation across the world, there are areas that experience a paradoxical minimum air temperature trend that is often overlooked in global and national studies. The study also emphasizes the possible influence of microclimate on climate trends. Most importantly, the study results highlight the critical role that individual local weather stations play in informing local farming communities and relevant stakeholders that are less knowledgeable about local climate change. Descriptive analysis based on the survey data for the study area found that the majority of the small-scale sugarcane farmers (69%) in the study area are poorly informed about the accessibility, availability and possible use of climate information. A large number of the participants (> 50%) have never used either seasonal climate information or climate warnings in their decision making. The few individuals (31%) who have received the information from different sources highlighted the delayed delivery of the information. Despite significant progress on climate modelling and possible information dissemination channels, access to climate information by small-scale farmers still has not improved and many have not captured the substance of climate change. This finding needs a further investigation. The study is useful in informing land-use planning decisions based on the observed and projected climate trends. Through identification of possible impacts of increased extreme rainfall and decrease in short grass reference evapotranspiration as well as projected changes in air temperature and precipitation, the sugarcane farming community can determine whether sugarcane farming will be commercially viable under climate change conditions or determine sugarcane varieties that align with the detected and projected climate changes of the study area.