Temporal and spatial variability analysis of the solar radiation in a region affected by the intertropical convergence zone

Abstract

Abstract The first aim of this work was to obtain temporal variability patterns for satellite‐derived solar radiation estimations in Zambia. A principal component analysis, in Zambia and the surrounding zones, was performed and from this analysis the physical phenomena associated with these patterns were established. According to the results, two temporal variability patterns stand out: the first is associated with the regional global climate characteristics, including both the deterministic and non‐deterministic components of solar radiation, and the other is strictly associated with the influence of the intertropical convergence zone (ITCZ) responsible for the behaviour of solar radiation during October–March. The second aim of the work was to analyse the spatial variability of the irradiance in the study area. For this aim, a clustering analysis based on the interquartile range of the data was performed. The analysis leads to a spatial distribution of the radiation in agreement with the influence of the ITCZ on the territory. Indeed, those stations less affected by the ITCZ, in the south and east of the territory, show a clear diminution of the radiation around June. However, the stations of the northwest zone, the most affected by the belt of low pressure during November–April, do not present this diminution.

Keywords

• clustering analysis
• interquartile range
• intertropical convergence zone
• principal component analysis