Drought is a slow onset, recurring and inevitable feature of South Africa's climate. This research deconstructs the meteorological processes underlying drought and its impacts on surface temperature and vegetation in the more productive eastern half of South Africa. We use an index area 22–31°S, 22–32°E and extract monthly satellite and reanalysis data in the period 1979–2019. Drought intensity is determined by i) vegetation color, ii) soil moisture, iii) maximum air temperature and iv) net outgoing longwave radiation. Global drivers are represented by tropical Pacific and Indian Ocean sea temperatures. Composite and regression analysis of drought reveals a mid-tropospheric anticyclone over Namibia induces equatorward flow and subsidence that drives away atmospheric moisture. This feature is associated with the Pacific El Niño, positive Indian Ocean Dipole and an accelerated westerly jet stream. Ocean warming east of Madagascar draws NW-cloud bands there. The advection of anticyclonic vorticity from the South Atlantic and standing atmospheric Rossby wave-trains are key features of South African drought. Dry spells in the summers of 2015, 2016 and 2019 were more intense than 1983 and 1992, as reflected by S-pan potential evaporation measurements >14 mm/day. Despite water deficits, maize yields and river discharge appear stable, due to the uptake of scientific advice and innovative engineering.

干旱是南非气候的一个缓慢发作、反复出现和不可避免的特征。这项研究解构了干旱背后的气象过程及其对南非东半部生产力更高的地表温度和植被的影响。我们使用 22-31°S、22-32°E 的指数区域，并提取 1979-2019 年期间的月度卫星和再分析数据。干旱强度由 i) 植被颜色、ii) 土壤湿度、iii) 最高气温和 iv) 净输出长波辐射决定。全球驱动因素以热带太平洋和印度洋海水温度为代表。干旱的复合和回归分析表明，纳米比亚上空的对流层中层反气旋引起赤道流动和下沉，从而驱散大气水分。该特征与太平洋厄尔尼诺现象有关，正印度洋偶极子和加速的西风急流。马达加斯加以东的海洋变暖在那里吸引了西北云带。来自南大西洋的反气旋涡旋平流和常设大气罗斯比波列是南非干旱的关键特征。2015 年、2016 年和 2019 年夏季的干旱期比 1983 年和 1992 年更加强烈，这反映在 S-pan 潜在蒸发测量值 >14 毫米/天。尽管缺水，但由于采纳了科学建议和创新工程，玉米产量和河流流量似乎很稳定。2015 年、2016 年和 2019 年夏季的干旱期比 1983 年和 1992 年更加强烈，这反映在 S-pan 潜在蒸发测量值 >14 毫米/天。尽管缺水，但由于采纳了科学建议和创新工程，玉米产量和河流流量似乎很稳定。2015 年、2016 年和 2019 年夏季的干旱期比 1983 年和 1992 年更加强烈，这反映在 S-pan 潜在蒸发测量值 >14 毫米/天。尽管缺水，但由于采纳了科学建议和创新工程，玉米产量和河流流量似乎很稳定。