Koppen Climatic Zonation

When hydrological landscapes, or climatic drivers of hydrological processes, are in a state of flux, baselines of climate and climatic zones are important, because these baselines are the references against which hydrological response comparisons may be made, for example, of possible changes in the climate regime. The hydrological responses to perturbations of climate include changes in total streamflows and their seasonal distributions. Baselines against which climate impacts may be assessed are all the more important in water resources management because hydrological responses, especially to changes in rainfall, are non-linear.

In order determination of Köppen climate zones over South Africa, Lesotho and Swaziland, the 1` x 1` latitude/longitude raster (i.e.1.7 x 1.7 km) of median monthly precipitation from Lynch (2004) was used, while for monthly means of daily average temperatures the 1` x 1` gridded values, derived from Schulze and Maharaj (2004), were used. A computer program was written to identify the Koppen class at each of the 429 700 grid points covering southern Africa.

当水文景观或水文过程的气候驱动因子处于动态变化状态时，气候及气候带的基准基线具有重要意义——此类基线可作为参照，用于开展水文响应的对比分析（例如针对气候态可能出现的变化）。气候扰动所引发的水文响应，涵盖总径流量及其季节分布的变化。在水资源管理工作中，用于评估气候影响的基准基线尤为关键，这是由于水文响应（尤其是对降雨变化的响应）具备非线性特征。

为确定南非、莱索托及斯威士兰的柯本（Köppen）气候分区，本研究采用了Lynch（2004）发布的1′×1′经纬度栅格数据集（即分辨率约1.7×1.7公里）的月均降水量数据；而针对日平均气温的月均值数据集，则采用了Schulze与Maharaj（2004）生成的1′×1′网格化数据。本研究编写了计算机程序，对覆盖南部非洲的429700个栅格点逐一识别其所属的柯本气候分类。