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).
Eucalyptus obliqua forests dominate the vegetation below 650 m where they exist as fire-maintained communities. On fertile soils these forests attain mature heights in excess of 55 m: the tallest E. obliqua reaches a height of 90 m. The flux station is installed in a stand of tall, mixed-aged E. obliqua forest (77 and >250 years-old) with a rainforest understorey and a dense man-fern (Dicksonia antarctica) ground-layer, on a small flat of elevation 100 m adjacent to the Huon River. The understorey vegetation progresses from wet sclerophyll (dominated by Pomaderris apatala and Acacia dealbata) to rainforest (dominated by Nothofagus cunninghamii, Atherosperma moschatum, Eucryphia lucida and Phyllocladus aspleniifolius) with increasing time intervals between fire events. The site supports prodigous quantities of coarse woody debris as is characteristic of these fire-maintained eucalypt forests on fertile sites in southern Tasmania. The soil at the flux site is derived from Permian mudstone and has a gradational profile with a dark brown organic clayey silt topsoil overlying a yellow brown clay. The climate is classified as temperate with a mild summer and no dry season. Mean annual precipitation is 1700 mm with a relatively uniform seasonal distribution. Summer temperatures peak in January (8.4 °C to 19.2 °C) with winter temperatures reaching their lowest in July (2.6 °C to 8.4 °C).
The instruments are mounted at the top of an 80 m tall guyed steel lattice tower. Supplementary measurements above the canopy include temperature, humidity, windspeed, wind direction, rainfall, incoming and reflected shortwave radiation and net radiation. An open-path gas analyser (EC150) was replaced by a closed-path gas analyser (EC155) at the end of January 2015. Soil moisture content is measured using time domain reflectometry. Soil heat fluxes and temperature are also measured. Micro-meteorology (CO2, H2O, energy fluxes) and meteorology (temperature, humidity, wind speed and direction, rainfall) were measured from 2013 to late 2016, but the dataset is incomplete due to ongoing problems since changing the open-path IRGA to a closed path system (CPEC200) during 2015. Soil data (moisture, heat flux, temperature) are complete for the time period.
Credit
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 site is managed by the University of Tasmania and funded by TERN.
Purpose
The purpose of the Warra flux station is to:
- study the ecophysiological processes and rates of carbon accumulation and decomposition in a mixed-aged, tall, wet Eucalyptus obliqua forest that experienced natual wildfires
- measure the exchanges of carbon dioxide, water vapour and energy between the forest and the atmosphere using micrometeorological techniques
- link ecophysiological processes and rates of carbon accumulations and decomposition with the biota
- utilise the measurements in combination with remote sensing data and land surface models to upscale the estimate of net exchanges of carbon and water at regional scale.
Data Processing
File 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).
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