Warra Flux Data Release 2024_v1

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 (v3.4.17) 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.本数据集发布内容为采用涡度协方差（eddy covariance）技术获取的地表与大气边界层间能量与物质交换的通量塔观测数据。数据处理使用PyFluxPro（v3.4.17），处理流程参照Isaac等人（2017）的研究成果。PyFluxPro可生成最终的间隙填充数据集，并将生态系统净交换（Net Ecosystem Exchange, NEE）划分为总初级生产力（Gross Primary Productivity, GPP）与生态系统呼吸（Ecosystem Respiration, ER）。 海拔650米以下的原生植被以斜叶桉（Eucalyptus obliqua）林为主，该类森林为火维持群落。在肥沃土壤上，此类林分的成熟高度可达55米以上，现存最高斜叶桉株高可达90米。通量观测站设置于一片高龄混龄的斜叶桉林分中，林龄分别为77年及250年以上，林下为雨林植被，地表覆盖密集的澳洲黑桫椤（Dicksonia antarctica）。站点位于毗邻侯恩河（Huon River）的一处海拔100米的小型平坦区域。随着火灾间隔周期延长，林下植被由以亮叶鼠李（Pomaderris apatala）和银叶金合欢（Acacia dealbata）为主的湿硬叶林，逐步演替为以假山毛榉（Nothofagus cunninghamii）、香皮檫（Atherosperma moschatum）、亮叶银香桃木（Eucryphia lucida）及塔斯曼尼亚芹叶松（Phyllocladus aspleniifolius）为主的雨林群落。该样地存在大量粗木质残体，这是塔斯马尼亚南部肥沃生境下此类火维持桉树林的典型特征。通量站点所在土壤源自二叠纪泥岩，剖面呈渐变型，表层为暗棕色有机黏土质粉砂，下伏黄棕色黏土。气候类型为温带气候，夏季温和无酷暑，无明显旱季。年平均降水量为1700毫米，季节分布相对均匀。夏季气温于1月达到峰值（8.4℃至19.2℃），冬季气温则于7月降至最低（2.6℃至8.4℃）。 观测仪器安装于一座80米高的拉线式钢制格构塔塔顶。冠层上方的补充观测项目包括气温、空气湿度、风速、风向、降雨量、入射与反射短波辐射以及净辐射。2015年1月末，开放式气体分析仪（EC150）被封闭式气体分析仪（EC155）替换。土壤含水率采用时域反射仪（time domain reflectometry）进行测定，同时同步观测土壤热通量与土壤温度。微气象观测（CO₂、H₂O、能量通量）与气象观测（气温、湿度、风速、风向、降雨量）的观测时段为2013年至2016年末，但由于2015年将开放式红外气体分析仪（IRGA）更换为封闭式系统（CPEC200）后出现持续故障，导致该数据集存在缺失。而土壤相关观测数据（含水率、热通量、温度）在对应时段内完整无缺。