Local-scale energy balances and microclimate in the desert ranges of central Australia

Direct observations of the surface energy balance and radiation budget are presented for a site within Australia’s semi-arid interior ranges. These observations are interpreted in terms of those processes contributing to the local-scale climate. Measured albedo is lower (18 per cent) than those values often quoted for desert albedos, yielding high surface temperatures and soil heat flows. Extreme ranges in diurnal surface and air temperatures result from this high absorption of solar radiation and the low thermal diffusivity of the soil with concentrates heating into a shallow layer. This heated layer is rapidly depleted at night through large radiative losses that result from the extreme dryness of the atmosphere. No latent heat fluxes (positive or negative) were recorded. The lack of dew-fall is supported by the dew-point temperatures which were always less than air temperatures. All radiative energy is thus partitioned between convective and conductive sensible heating, with the magnitude of the ratio being determined by wind speed. These observations provide an insight into those microclimatic processes operating within the semi-arid landscapes of central Australia.