Environmental and gross primary production observations for a mature black spruce site located in central Saskatchewan, Canada

Observations are presented here for the late winter / early summer period (March 20 to June 26) for 2019 and 2020 at a mature black spruce site located in central Saskatchewan, Canada. Daily means and standard deviations of the diurnal variability are reported for photosynthetically active radiation (PAR), soil volumetric water content (VWC), soil temperature, air temperature, vapour pressure deficit (VPD) and gross primary production (GPP). The site is equipped with a walk-up scaffold tower, 25m in height. PAR was measured with a Li-COR LI190R installed at the top of the tower; air temperature and relative humidity were measured at 6m height with a Vaisala HMP45C probe housed in a 12-plate Gill radiation shield; soil temperature at 10 cm depth was measured at two locations with Type-T (copper-constantan) thermocouples and averaged; soil VWC at 7.5 cm depth was measured at two locations with Campbell Scientific CS615 probes and averaged; VPD was calculated from air temperature and relative humidity. GPP was calculated from eddy covariance measurements of net ecosystem exchange (NEE) using a Campbell Scientific CSAT3 sonic anemometer in combination with a Li-Cor LI7200 infrared gas analyzer installed at the top of the tower. NEE was then partitioned into GPP and total ecosystem respiration (Re). The eddy covariance system was not operational in 2019, so GPP is only reported for 2020. PAR data were recorded at 1 second resolution and averaged into 30-minute time bins to compare with other environmental variables, then averaged for daily resolution. All other variables were recorded at a 30-minute time resolution and averaged for daily resolution.

本数据集收录了加拿大萨斯喀彻温省中部成熟黑云杉样地在2019年与2020年冬末至初夏时段（3月20日至6月26日）的观测数据。报告了光合有效辐射（photosynthetically active radiation, PAR）、土壤体积含水量（soil volumetric water content, VWC）、土壤温度、空气温度、水汽压差（vapour pressure deficit, VPD）以及总初级生产力（gross primary production, GPP）的日变化序列的日均值与标准差。该样地架设了一座高度25米的可步行脚手架塔：光合有效辐射由安装于塔顶的Li-COR LI190R传感器测定；空气温度与相对湿度由安装于6米高度、置于12板Gill辐射防护罩内的Vaisala HMP45C探头测定；10厘米深度的土壤温度通过两处布设的T型（铜-康铜）热电偶测量后取平均值；7.5厘米深度的土壤体积含水量通过两处Campbell Scientific CS615探头测量后取平均值；水汽压差由空气温度与相对湿度计算得到。总初级生产力通过基于涡度协方差法测定的净生态系统交换（net ecosystem exchange, NEE）计算得到，所用设备为安装于塔顶的Campbell Scientific CSAT3超声风速仪与Li-Cor LI7200红外气体分析仪。后续将净生态系统交换划分为总初级生产力与总生态系统呼吸（total ecosystem respiration, Re）。因2019年涡度协方差系统无法正常运行，故仅报告2020年的总初级生产力数据。光合有效辐射数据以1秒分辨率记录，先平均至30分钟时间窗口以匹配其他环境变量的时间尺度，随后进一步平均得到日分辨率数据集。其余所有变量均以30分钟时间分辨率记录，并平均得到日分辨率数据集。