Much of the Eastern Cape province in South Africa has been experiencing a severe drought since 2015. This drought has had major socio-economic effects particularly on the large impoverished rural population as well as on some urban areas where supplied water services have broken down in several cases. The region is influenced by both midlatitude and tropical systems leading to a complex regional meteorology that hitherto has not been much studied compared to other parts of South Africa. Here, the ongoing drought is examined in the context of long-term trends and the interannual rainfall variability of the region. Although the region has experienced drought in all seasons since 2015, focus here is placed on the spring (September–November) which shows the most consistent and robust signal. On average, this season contributes between about 25–35% of the annual rainfall total. Based on CHIRPS data, it is found that this season shows a significant decreasing trend in both rainfall totals as well as the number of rainfall days (but not heavy rainfall days) for spring over most of the province since 1981. On interannual time scales, the results indicate that dry (wet) springs over the Eastern Cape are associated with a cyclonic (anticyclonic) anomaly southeast of South Africa as part of a shift in the zonal wavenumber 3 pattern in the midlatitudes. Over the landmass, a stronger (weaker) Botswana High is also apparent with increased (decreased) subsidence over and near the Eastern Cape which is less (more) favourable for cloud band development and hence reduced (enhanced) rainfall during dry (wet) springs. Analysis of mid-century (2040–2060) CMIP5 rainfall projections suggests that there may be a flattening of the annual cycle over the Eastern Cape with the winter becoming wetter and the summer drier. For the spring season of interest here, the multi-model projections also indicate drying but less pronounced than that projected for the summer.

自 2015 年以来，南非东开普省的大部分地区一直在经历严重的干旱。这场干旱对社会经济产生了重大影响，特别是对大量贫困的农村人口以及一些供水服务在几个地区中断的城市地区造成了重大影响。案例。该地区受到中纬度和热带系统的影响，导致复杂的区域气象学与南非其他地区相比迄今尚未得到太多研究。在这里，在长期趋势和该地区年际降雨变化的背景下，对持续干旱进行了研究。尽管该地区自 2015 年以来在所有季节都经历了干旱，但这里的重点是春季（9 月至 11 月），这是最一致和最强劲的信号。一般，这个季节贡献了大约 25-35% 的年降雨量。根据 CHIRPS 数据发现，自 1981 年以来，该季节在全省大部分地区的春季降雨总量和降雨天数（但不是强降雨天数）均呈现显着下降趋势。在年际时间尺度上，结果表明，东开普省的干（湿）泉与南非东南部的气旋（反气旋）异常有关，这是中纬度纬向波数 3 模式转变的一部分。在陆地上，较强（较弱）的博茨瓦纳高压也很明显，东开普省及其附近的沉降增加（减少），这对云带的发展不太有利，因此在干（湿）春季降雨量减少（增强） . 对本世纪中叶（2040-2060 年）CMIP5 降雨预测的分析表明，东开普省的年周期可能会趋于平缓，冬季变得更加潮湿，夏季更加干燥。对于这里感兴趣的春季，多模型预测也表明干燥，但不如夏季预测的那么明显。