Alice Springs Mulga Flux Data Release 2023_v2 

This release consists of flux tower measurements of the exchange of energy and mass between the surface and the atmospheric boundary-layer using eddy covariance techniques. Data were processed using PyFluxPro (v3.4.15) as described by Isaac et al. (2017). PyFluxPro produces a final, gap-filled product with Net Ecosystem Exchange (NEE) partitioned into Gross Primary Productivity (GPP) and Ecosystem Respiration (ER).

Alice Springs Mulga flux station is located on Pine Hill cattle station, near Alice Springs in the Northern Territory. The woodland is characterized by the Acacia aneura canopy, which is 6.5 m tall on average. Elevation of the site is 606 m above sea level, and the terrain is flat. Mean annual precipitation at the nearby (45 km distant) Bureau of Meteorology station is 305.9 mm but ranges between 100 mm in 2009 to 750 mm in 2010. Predominant wind directions are from the southeast and east. The extent of the woodland is 11 km to the east of the flux station and 16 km to the south. The soil is red sandy clay (50:50 sand:clay) overlying a 49 m deep water table. Pine Hill Station is a functioning cattle station that has been in operation for longer than 50 years. The instrument mast is 13.7 m tall. Fluxes of heat, water vapour and carbon are measured using the open-path eddy covariance technique at 11.6 m. Supplementary measurements above the canopy include temperature and humidity (11.6 m), windspeed and wind direction (9.25 m), downwelling and upwelling shortwave and longwave radiation (12.2 m). Precipitation is monitored in a canopy gap (2.5 m). Supplementary measurements within and below the canopy include barometric pressure (1 m), wind speed (2 m, 4.25 m and 6.5 m), and temperature and humidity (2 m, 4.25 m and 6 m). Below ground soil measurements are made in bare soil, mulga, and understory habitats and include ground heat flux (0.08 m), soil temperature (0.02 m – 0.06 m) and soil moisture (0 – 0.1 m, 0.1 – 0.3 m, 0.6 – 0.8 m and 1.0 – 1.2 m). Ancillary measurements include soil water and carbon fluxes, leaf water potential, leaf gas exchange, stem basal area, stem growth, litter production, leaf area index, stem hydraulic conductance, and carbon and water stable isotope ratios. 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. The TERN Alice Springs Mulga site is managed by the University of Technology Sydney, and is funded by TERN. 

The purpose of the Alice Springs Mulga flux station is to:

• measure the exchanges of carbon dioxide, water vapour and energy between a semi-arid mulga (Acacia aneura) ecosystem and the atmosphere using micrometeorological techniques
• study ecosystem, hydrologic and ecophysiologic responses to rainfall variability
• evaluate the evapotranspiratory cost of assimilation
• study the partitioning of ecosystem metabolism between the mulga canopy, a seasonal mixed understory (C₃ and C₄, grass and shrub) and soil components
• utilise the measurements for paramterising a Soil-Vegetation-Atmosphere Transfer (SVAT) model to evaluate climate change scenarios in North-Central Australia
• utilise the measurements for parameterising and validating remote sensing measurements over semi-arid mulga ecosystems
• utilise the measurements for parmaterising and validating the Community Atmosphere-Biosphere Land Exchange (CABLE) model.

 

All flux raw data is subject to the quality control process OzFlux QA/QC to generate data from L1 to L6. Levels 3 to 6 are available for re-use. Datasets contain Quality Controls flags which will indicate when data quality is poor and has been filled from alternative sources. For more details, refer to Isaac et al. (2017).