黑河流域地表过程综合观测网（花寨子站涡动相关仪-2024）

该数据集包含了2024年1月1日至2024年12月31日的黑河流域地表过程综合观测网中游花寨子站涡动相关仪观测数据。站点位于甘肃省张掖市，下垫面是荒漠。观测点的经纬度是100.3201E，38.7659N，海拔1731m。涡动相关仪的架高4.5m，采样频率是10Hz，超声朝向是正北向，超声风速温度仪（CSAT3）与CO2/H2O分析仪（Li7500A）之间的距离是15cm。
涡动相关仪的原始观测数据为10Hz，发布的数据是采用Eddypro软件处理的30分钟数据，其处理的主要步骤包括：野点值剔除，延迟时间校正，坐标旋转（二次坐标旋转），频率响应修正，超声虚温修正和密度（WPL）修正等。同时对各通量值进行质量评价，主要是大气平稳性（Δst）和湍流相似性特征（ITC）的检验。对Eddypro软件输出的30min通量值也进行了筛选：（1）剔除仪器出错时的数据；（2）剔除降水前后1h的数据；（3）剔除10Hz原始数据中每30min内缺失率大于10%的数据。观测数据的平均周期为30分钟，一天48个数据，缺失数据标记为-9999。
发布的观测数据包括：日期/时间Date/Time，风向Wdir（°），水平风速Wnd（m/s），侧向风速标准差Std_Uy（m/s），超声虚温Tv（℃），水汽密度H2O（g/m3），二氧化碳浓度CO2（mg/m3），摩擦速度Ustar（m/s），奥布霍夫长度L（m），感热通量Hs（W/m2），潜热通量LE（W/m2），二氧化碳通量Fc（mg/(m2s)），感热通量的质量标识QA_Hs，潜热通量的质量标识QA_LE，二氧化碳通量的质量标识QA_Fc。感热、潜热、二氧化碳通量的质量标识分为九级（质量标识1-3数据质量好，4-6数据质量较好，7-8数据质量较差（较插补数据好）；9数据质量差））。数据时间的含义，如0:30代表0:00-0:30的平均；数据以*.xls格式存储。
黑河流域地表过程综合观测网或站点信息请参考Liu et al. (2018)和Liu et al. (2023)。

This dataset contains eddy covariance system observational data from the Huazhaizi Station of the middle reaches of the Heihe River Basin Surface Process Comprehensive Observation Network, spanning from January 1, 2024 to December 31, 2024. The station is located in Zhangye City, Gansu Province, with a desert underlying surface. The coordinates of the observation point are 100.3201°E, 38.7659°N, and the elevation is 1731 m. The eddy covariance system is installed at a height of 4.5 m, with a sampling frequency of 10 Hz. The sonic anemometer faces due north, and the distance between the sonic anemometer temperature sensor (CSAT3) and the CO2/H2O analyzer (Li7500A) is 15 cm.

The original observational data of the eddy covariance system is at 10 Hz, while the released data are 30-minute averaged data processed with EddyPro software. The main processing steps include: outlier removal, time lag correction, coordinate rotation (double coordinate rotation), frequency response correction, sonic virtual temperature correction, and density (WPL) correction, etc. Meanwhile, quality assessment was conducted for each flux value, mainly including tests of atmospheric stationarity (Δst) and turbulence similarity characteristics (ITC). Additionally, screening was performed on the 30-minute flux outputs from EddyPro software: (1) Remove data collected when the instrument malfunctioned; (2) Remove data within 1 hour before and after precipitation; (3) Remove data with a missing rate greater than 10% in each 30-minute 10Hz original dataset. The average period of the observational data is 30 minutes, with 48 data points per day. Missing data are marked as -9999.

The released observational data include: "Date/Time", wind direction Wdir (°), horizontal wind speed Wnd (m/s), lateral wind speed standard deviation Std_Uy (m/s), sonic virtual temperature Tv (℃), water vapor density H2O (g/m3), carbon dioxide concentration CO2 (mg/m3), friction velocity Ustar (m/s), Obukhov length L (m), sensible heat flux Hs (W/m2), latent heat flux LE (W/m2), carbon dioxide flux Fc (mg/(m2s)), quality flags of sensible heat flux QA_Hs, quality flags of latent heat flux QA_LE, and quality flags of carbon dioxide flux QA_Fc. The quality flags for sensible heat, latent heat, and carbon dioxide fluxes are divided into nine levels: quality levels 1–3 indicate good data quality, 4–6 indicate fair data quality, 7–8 indicate poor but better than interpolated data quality, and 9 indicates poor data quality. The meaning of the data timestamp: for example, 0:30 represents the average of 0:00–0:30; the data are stored in *.xls format.

For information on the Heihe River Basin Surface Process Comprehensive Observation Network or the station, please refer to Liu et al. (2018) and Liu et al. (2023).