祁连山综合观测网：黑河流域地表过程综合观测网（垭口站涡动相关仪-2018）

该数据集包含了2018年1月1日至2018年12月31日的黑河流域地表过程综合观测网上游垭口站涡动相关仪观测数据。站点位于青海省祁连县，下垫面是高寒草甸。观测点的经纬度是100.2421, 38.0142N，海拔4148 m。涡动相关仪的架高3.2m，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-6999。该站缺电现象比较严重，导致数据出现较多的缺失，在5月24-6月21日间由于供电不足数据缺失。
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)，观测数据处理请参考Liu et al. (2011)。

This dataset contains eddy covariance observations collected at the Yakou Station (the upstream station of the Heihe River Basin Comprehensive Observation Network for Surface Processes) between January 1, 2018 and December 31, 2018. The station is situated in Qilian County, Qinghai Province, with an underlying surface of alpine meadow. The observation coordinates are 100.2421, 38.0142°N, at an altitude of 4148 m.

The eddy covariance system is installed at a height of 3.2 m, with a sampling frequency of 10 Hz. The ultrasonic sensor faces due north, and the separation distance between the ultrasonic anemometer-temperature unit (CSAT3) and the CO2/H2O gas analyzer (Li7500A) is 15 cm.

The raw eddy covariance data is recorded at 10 Hz, while the publicly released dataset consists of 30-minute averaged data processed with EddyPro software. The primary processing workflow includes: outlier removal, time lag correction, double coordinate rotation, frequency response correction, ultrasonic virtual temperature correction, and density correction (WPL correction), among other steps. Quality assessments were performed for all flux products, primarily via tests of atmospheric stationarity (Δst) and turbulence similarity characteristics (ITC). We further screened the 30-minute flux outputs from EddyPro using the following criteria: (1) removing data collected during instrument malfunctions; (2) excluding data within 1 hour before and after precipitation events; (3) discarding data with a missing rate exceeding 10% within each 30-minute window of the 10 Hz raw dataset.

The observation data has an average interval of 30 minutes, yielding 48 data points per day. Missing data is marked with the value -6999. This station frequently experienced power outages, resulting in extensive data gaps; specifically, no valid data was available between May 24 and June 21 due to insufficient power supply.

The released dataset includes the following variables: Date/Time, wind direction (Wdir, °), horizontal wind speed (Wnd, m/s), lateral wind speed standard deviation (Std_Uy, m/s), ultrasonic 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 flag for sensible heat flux (QA_Hs), quality flag for latent heat flux (QA_LE), and quality flag for carbon dioxide flux (QA_Fc). The quality flags for sensible heat, latent heat, and carbon dioxide fluxes are graded into nine levels: levels 1–3 denote good data quality, levels 4–6 denote relatively good data quality, levels 7–8 denote relatively poor data quality (better than interpolated data), and level 9 denotes poor data quality. The timestamp convention is as follows: for example, 0:30 represents the average value over the period 0:00–0:30. All data are stored in *.xls format.

For more information about the Heihe River Basin Comprehensive Observation Network for Surface Processes or the Yakou Station, please refer to Liu et al. (2018). For details on the data processing procedures, please refer to Liu et al. (2011).

搜集汇总

背景与挑战

背景概述

该数据集包含2018年黑河流域垭口站涡动相关仪观测的30分钟平均数据，涵盖风向、风速、温度、水汽密度、二氧化碳浓度及通量等参数，数据质量经过严格检验，但因供电问题存在部分缺失。