Nkamisa Melezwa, Ndhleve Simbarashe, Nakin Motebang D V, Mngeni Asabonga, Kabiti Hlekani M
Department of Biological and Environmental Science, Faculty of Natural Sciences, Walter Sisulu University, Mthatha, South Africa.
Risk and Vulnerability Science Centre, Walter Sisulu University, Mthatha, South Africa.
Jamba. 2022 Feb 25;14(1):1147. doi: 10.4102/jamba.v14i1.1147. eCollection 2022.
South Africa is susceptible to droughts. However, little documentation exists on drought occurrence in South Africa at national, provincial and municipal administrative boundaries. This study profiles hydrological drought in OR Tambo District Municipality from 1998 to 2018, computing frequency, severity and intensity in order to show areas of high vulnerability. Data used were obtained from South African Weather Services. Standardised precipitation index (SPI) was calculated using the Meteorological Drought Monitor (MDM) software. Results showed a wide variation in monthly precipitation throughout the year. Coastal areas receive higher rainfall than inland municipalities. The study revealed that Nyandeni experienced the highest drought frequency of 62%, Mhlontlo (58%), King Sabatha Dalindyebo Municipality (57%), Ngquza Hill (55%) and Port St Johns Municipality showing the least at 52%. Hydrological drought severity frequency and duration varied between seven days and nine weeks. Drought intensity class exposed the annual average intensity for the five local municipalities represented as follows: KSDM (-0.71), PSJM (-0.99), Ngquza Hill (-0.81), Nyandeni (-0.71) and Mhlontlo (-0.62). The longest drought duration across OR Tambo was experienced in 2014 with durations varying from 3 to 11 weeks across the municipalities. OR Tambo District Municipality is susceptible to hydrological droughts and the extent varies across local municipalities. Results could be used for both adaptation planning and mitigating the impacts of future droughts. In addition, they could assist in guiding allocation of drought relief resources in ways that prioritise drought prone and vulnerable municipality.
南非易受干旱影响。然而，关于南非在国家、省和市行政边界发生干旱的记录很少。本研究分析了1998年至2018年奥·坦博区市的水文干旱情况，计算了频率、严重程度和强度，以显示高脆弱性地区。所使用的数据来自南非气象局。使用气象干旱监测（MDM）软件计算标准化降水指数（SPI）。结果显示，全年月降水量变化很大。沿海地区的降雨量高于内陆市。研究表明，尼扬德尼经历的干旱频率最高，为62%，姆隆特洛为58%，萨巴萨·达林德耶博国王市为57%，恩古扎山为55%，圣约翰斯港市最低，为52%。水文干旱的严重程度、频率和持续时间在7天至9周之间变化。干旱强度等级显示了五个当地市的年平均强度，如下所示：萨巴萨·达林德耶博国王市（-0.71）、圣约翰斯港市（-0.99）、恩古扎山（-0.81）、尼扬德尼（-0.71）和姆隆特洛（-0.62）。2014年，奥·坦博全区经历了最长的干旱期，各市的干旱持续时间从3周至11周不等。奥·坦博区市易受水文干旱影响，不同当地市的受影响程度各不相同。研究结果可用于适应规划和减轻未来干旱的影响。此外，它们还可以帮助指导干旱救济资源的分配，优先考虑干旱多发和脆弱的市。
