Is the summer season losing potential for solar energy applications in South Africa?

Abstract

Seasonal trends using in situ sunshine duration (SD)

Integrated climatology and trends in the subtropical Hadley cell, sunshine duration and cloud cover over South Africa

“…Positive trends are evident during SON (Figure d) from both the ECMWF and SAWS observations. This is consistent with findings by Singh and Kruger (), who, although using point observations from weather stations across South Africa, use a similar period and found a general decrease in sunshine duration trends, mostly in DJF and MAM, while a maximum increase is recorded in SON. Trends between cloud cover and sunshine duration are largely consistent, with some areas of disagreement.…”

“…A decrease in sunshine duration from the equator to the subtropics (around latitude 29°S) is evident in DJF (Figure b); however, in JJA (Figure b) a decrease in sunshine duration is evident from the equator to latitude 19°S, thereafter an increase is evident for all lower latitudes. A clear correspondence between trends over the different latitudes compares well with results from Singh and Kruger (), for example, positive trend in sunshine duration south of 30°S but turning negative northwards in DJF and negative trends south of 30°S in JJA.…”

“…Trends in cloud cover, solar radiation and sunshine duration for various regions have been documented in a number of studies (e.g., Liepert, ; Groisman et al, ; Wang and Key, ). A recent study (Singh and Kruger, ) on sunshine duration trends using point observations from 22 sunshine recording stations across South Africa identified a general decreasing trend for all seasons. However, the decrease was most prominently observed for the summer season.…”

The Ångström-Prescott Regression Coefficients for Six Climatic Zones in South Africa

“…Hourly sunshine duration data was obtained by determining the burn made by the sun on a coated card in a Campbell-Stokes sunshine recorder [8]. Hourly data was then summed to get total daily sunshine duration (n).…”

“…The data collected from SAWS network help in the validation of satellites as well as the development and verification of empirical models [7]. SAWS also manage a very dense sunshine duration recording network over South Africa to the extent that sunshine duration data has been continuously measured for several years [8]. SAWS GHI stations are sparse, according to [1,2,3,4,5,9].…”