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 (v3.4.7) 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).
The Loxton site was established in August 2008 and decommissioned in June 2009. The orchard was divided into 10 ha blocks (200 m by 500 m with the long axis aligned north–south) and the flux tower was situated at 34.47035 °S and 140.65512 °E near the middle of the northern half of a block of trees. The topography of the site was slightly undulating and the area around the tower had a slope of less than 1.5 °. The orchard was planted in 2000 with an inter-row spacing of 7 m and a within row spacing of 5 m. Tree height in August 2008 was 5.5 m. The study block consists of producers, Nonpareil, planted every other row, and pollinators planted as alternating rows of Carmel, Carmel and Peerless, and Carmel and Price. All varieties were planted on Nemaguard rootstock. All but 31 ha of the surrounding orchard was planted between 1999 and 2002. Nutrients were applied via fertigation. Dosing occurred between September and November and in April with KNO3, Urea, KCl, and NH4NO3 applied at annual rates of 551, 484, 647, and 113 kg/ha, respectively. The growth of ground cover along the tree line was suppressed with herbicides throughout the year. Growth in the mid-row began in late winter and persisted until herbicide application in late November. The research was supported with funds from the National Action Plan for Salinity via the Centre for Natural Resource Management, and the River Murray Levy.
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 product, 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.
The research was supported with funds from the National Action Plan for Salinity via the Centre for Natural Resource Management, and the River Murray Levy.
The purpose of the Loxton flux station is to:
- measure the water use of about 4 ha of mature high-yielding almond trees.
- collect ancillary measures of orchard canopy size, water, nutrient and salinity status, and climate in the study area.
- address two of the weaknesses in this approach by calculating monthly flux footprints and deriving ET from fluxes which have been adjusted to close the energy balance.
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><br>
Loxton Flux Tower was established in 2008, and stopped measuring in 2009. The processed data release is currently ongoing, biannually.“
Created: 2008-08-19
Issued: 2024-05-03
Modified: 2024-05-03
Data time period: 2008-08-19 to 2009-09-06
text: Riverland, South Australia.
User Contributed Tags
Login to tag this record with meaningful keywords to make it easier to discover
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/e1ec2ed3-9cc2-4eb3-829e-fc5187ec127f
- global : e1ec2ed3-9cc2-4eb3-829e-fc5187ec127f
