Alice Springs Mulga Flux Data Release 2022_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 (v3.4.7) 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).

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.

本次发布的数据集包含采用涡度协方差技术（eddy covariance techniques）开展的地表与大气边界层间能量与物质交换通量塔观测数据。数据按照Isaac等人（2017）所述方法，使用PyFluxPro（v3.4.7）进行处理。PyFluxPro可生成最终的间隙填补数据集，将净生态系统交换量（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）两部分。

爱丽丝斯普林斯穆尔加通量站位于北领地爱丽丝斯普林斯附近的派恩希尔畜牧场。该林地以穆尔加金合欢（Acacia aneura）冠层为特征，平均株高6.5米。站点海拔为606米，地形平坦。附近（距站点45公里）的澳大利亚气象局（Bureau of Meteorology）站点年均降水量为305.9毫米，年际降水量波动范围为2009年的100毫米至2010年的750毫米。主导风向为东南风和东风。该林地分布于通量站东侧11公里、南侧16公里范围内。土壤为红砂质黏土（砂粒与黏土占比各50%），下伏49米深的地下水位。派恩希尔畜牧场为运营时长超过50年的商业化畜牧场。观测塔高13.7米。热通量、水汽通量与碳通量采用开路式涡度协方差技术（open-path eddy covariance technique）在11.6米高度处观测。冠层上方的补充观测项目包括：11.6米高度处的气温与湿度、9.25米高度处的风速与风向、12.2米高度处的下行与上行短波辐射及长波辐射。降水在冠层间隙（2.5米高度）处进行监测。冠层内及冠层下方的补充观测项目包括：1米高度处的气压、2米、4.25米及6.5米高度处的风速，以及2米、4.25米及6米高度处的气温与湿度。地下土壤观测在裸地、穆尔加金合欢林地及林下生境开展，观测指标包括：0.08米深度的土壤热通量、0.02米至0.06米深度的土壤温度、0–0.1米、0.1–0.3米、0.6–0.8米及1.0–1.2米深度的土壤含水率。辅助观测还包括土壤水与碳通量、叶片水势、叶片气体交换、茎干基面积、茎干生长、凋落物产量、叶面积指数、茎干水力导度，以及碳与水的稳定同位素比值。