Abstract:
Links between spatial and temporal variability of Planetary Boundary Layer (PBL)
meteorological quantities and existing land use patterns are still poorly understood due to
the non-linearity of air-land interaction processes. This study describes the results of a
statistical analysis of meteorological observations collected by a network of ten
Automatic Weather Stations (AWSs). The stations were in operation in the Highveld
Priority Area (HPA) of the Republic of South Africa during 2008 – 2010. The analysis
revealed localization, enhancement and homogenization in the inter-station variability of
observed meteorological quantities (temperature, relative humidity and wind speed) over
diurnal and seasonal cycles. Enhancement of the meteorological spatial variability was
found on a broad range of scales from 20 to 50 km during morning hours and in the dry
winter season. These spatial scales are comparable to scales of observed land use
heterogeneity, which suggests links between atmospheric variability and land use patterns
through excitation of horizontal meso-scale circulations. Convective motions
homogenized and synchronized meteorological variability during afternoon hours in the
winter seasons, and during large parts of the day during the moist summer season. The
analysis also revealed that turbulent convection overwhelms horizontal meso-scale
circulations in the study area during extensive parts of the annual cycle.