Links between observed micro - meteorological 5 variability and land use patterns in the Highveld 6 Priority Area of South Africa

26 Links between spatial and temporal variability of Planetary Boundary Layer (PBL) 27 meteorological quantities and existing land use patterns are still poorly understood due to 28 the non-linearity of air-land interaction processes. This study describes the results of a 29 statistical analysis of meteorological observations collected by a network of ten 30 Automatic Weather Stations (AWSs). The stations were in operation in the Highveld 31 Priority Area (HPA) of the Republic of South Africa during 2008 – 2010. The analysis 32 revealed localization, enhancement and homogenization in the inter-station variability of 33 observed meteorological quantities (temperature, relative humidity and wind speed) over 34 diurnal and seasonal cycles. Enhancement of the meteorological spatial variability was 35 found on a broad range of scales from 20 to 50 km during morning hours and in the dry 36 winter season. These spatial scales are comparable to scales of observed land use 37 heterogeneity, which suggests links between atmospheric variability and land use patterns 38 through excitation of horizontal meso-scale circulations. Convective motions 39 homogenized and synchronized meteorological variability during afternoon hours in the 40 winter seasons, and during large parts of the day during the moist summer season. The 41 analysis also revealed that turbulent convection overwhelms horizontal meso-scale 42 circulations in the study area during extensive parts of the annual cycle. 43 44