Brief description
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 (v3.5.0) 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).
Ti Tree East site was established in July 2012 and is managed by the University of Technology Sydney. Pine Hill Station is a functioning cattle station that has been in operation for longer than 50 years. However, the east side has not been stocked in over three years. The site is a mosaic of the primary semi-arid biomes of central Australia: grassy mulga woodland and Corymbia/Triodia savanna.The woodland is characterised by a mulga (Acacia aneura) canopy, which is 4.85 m tall on average. The soil is red sand overlying an 8 m deep water table. Elevation of the site is 553 m above sea level, and the terrain is flat. Mean annual precipitation at the nearby (30 km to the south) 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 instrument mast is 10 m tall. Fluxes of heat, water vapour and carbon are measured using the open-path eddy covariance technique at 9.81 m. Supplementary measurements above the canopy include temperature and humidity (9.81 m), windspeed and wind direction (8.28 m), downwelling and upwelling shortwave and longwave radiation (9.9 m). Precipitation is monitored in the savanna (2.5 m). Supplementary measurements within and below the canopy include barometric pressure (2 m). Below ground soil measurements are made beneath Triodia, mulga and grassy understorey 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).
Notes
Data ProcessingFile naming convention
The NetCDF files follow the naming convention below:
SiteName_ProcessingLevel_FromDate_ToDate_Type.nc
- SiteName: short name of the site
- ProcessingLevel: file processing level (L3, L4, L5, L6)
- FromDate: temporal interval (start), YYYYMMDD
- ToDate: temporal interval (end), YYYYMMDD
- Type (Level 6 only): Summary, Monthly, Daily, Cumulative, Annual
- Summary: This file is a summary of the L6 data for daily, monthly, annual and cumulative data. The files Monthly to Annual below are combined together in one file.
- Monthly: This file shows L6 monthly averages of the respective variables, e.g. AH, Fc, NEE, etc.
- Daily: same as Monthly but with daily averages.
- Cumulative: File showing cumulative values for ecosystem respiration, evapo-transpiration, gross primary productivity, net ecosystem exchange and production as well as precipitation.
- Annual: same as Monthly but with annual averages.
Lineage
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).
Notes
CreditWe 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.
Ti Tree East flux station is managed by the University of Technology Sydney. It is established in conjunction with the TERN Alice Springs Supersite, the Alice Springs OzFlux site and the Woodforde River NGCRT Superscience Site.
The purpose of Ti Tree East flux station is to:
- measure the exchanges of carbon dioxide, water vapour and energy in a semi-arid ecosystem with potential access to groundwater
- identify flux footprints associated with contributions by mulga versus Corymbia savannas
- compare water use efficiency, GPP and ecosystem respiration between adjacent semi-arid ecosystems (Alice Springs mulga)
- identify relationships between groundwater, soil moisture, rainfall and evapotranspiration
- identify phenological trends and to relate phenology to flux footprints and remote sensing of water and carbon fluxes.
Data Quality Assessment Scope
local :
dataset
<br>Processing levels</br>
<br>Under each of the data release directories, the netcdf files are organised by processing levels (L3, L4, L5 and L6):<ul style="list-style-type: disc;">
<li>L3 (Level 3) processing applies a range of quality assurance/quality control measures (QA/QC) to the L1 data. The variable names are mapped to the standard variable names (CF 1.8) as part of this step. The L3 netCDF file is then the starting point for all further processing stages.</li>
<li>L4 (Level 4) processing fills gaps in the radiation, meteorological and soil quantities utilising AWS (automated weather station), ACCESS-G (Australian Community Climate and Earth-System Simulator) and ERA5 (the fifth generation ECMWF atmospheric reanalysis of the global climate).</li>
<li>L5 (Level 5) processing fills gaps in the flux data employing the artificial neural network SOLO (self-organising linear output map).</li>
<li>L6 (Level 6) processing partitions the gap-filled NEE into GPP and ER.</li></ul>
Each processing level has two sub-folders ‘default’ and ‘site_pi’:<ul style="list-style-type: disc;">
<li>default: contains files processed using PyFluxPro</li>
<li>site_pi: contains files processed by the principal investigators of the site.</li></ul>
If the data quality is poor, the data is filled from alternative sources. Filled data can be identified by the Quality Controls flags in the dataset. Quality control checks include: <ul style="list-style-type: disc;">
<li>range checks for plausible limits</li>
<li>spike detection</li>
<li>dependency on other variables</li>
<li>manual rejection of date ranges</li></ul>
Specific checks applied to the sonic and IRGA data include rejection of points based on the sonic and IRGA diagnostic values and on either automatic gain control (AGC) or CO<sub>2</sub> and H<sub>2</sub>O signal strength, depending upon the configuration of the IRGA.</br>
Isaac P., Cleverly J., McHugh I., van Gorsel E., Ewenz C. and Beringer, J. (2017). OzFlux data: network integration from collection to curation, Biogeosciences, 14: 2903-2928
doi :
https://doi.org/10.5194/bg-14-2903-2017
Created: 2023-03-31
Issued: 2023-05-04
Modified: 2024-05-12
Data time period: 2012-07-18
text: Pine Hill cattle station, Northern Territory.
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Point-of-truth metadata URL
Isaac P., Cleverly J., McHugh I., van Gorsel E., Ewenz C. and Beringer, J. (2017). OzFlux data: network integration from collection to curation, Biogeosciences, 14: 2903-2928
doi :
https://doi.org/10.5194/bg-14-2903-2017
PyFluxPro
- URI : geonetwork.tern.org.au/geonetwork/srv/eng/catalog.search#/metadata/bf80347d-1c02-46b4-af97-111c66451d8f
- global : bf80347d-1c02-46b4-af97-111c66451d8f
