The data set contains the eddy correlator observation data of bare ground stations downstream of Heihe hydrometeorological observation network from July 10, 2013 to December 31, 2013. The station is located in sidaoqiao, Ejina Banner, Inner Mongolia, with bare land underlying. The longitude and latitude of the observation point are 101.1326e, 41.9993n and the altitude is 878m. The frame height of eddy correlator is 3.5m, the sampling frequency is 10Hz, the ultrasonic direction is due north, and the distance between ultrasonic anemometer and CO2 / H2O analyzer is 15cm

  The original observation data of eddy correlator is 10Hz, and the released data is the 30 minute data processed by edire software. The main steps of processing include:

  Field value elimination, delay time correction, coordinate rotation (quadratic coordinate rotation), frequency response correction, ultrasonic virtual temperature correction and density (WPL) correction. At the same time, the quality of each flux value is evaluated, mainly the atmospheric stability（ Δ St) and turbulence similarity characteristics (ITC). The 30 min flux value output by edire software is also screened:

 （ 1) Eliminate the data in case of instrument error

 （ 2) Eliminate the data 1H before and after precipitation

 （ 3) Eliminate the data with deletion rate greater than 3% every 30min in the 10Hz original data

 （ 4) Eliminate the observation data of weak turbulence at night (U < EM > less than 0.1M / s)

  The average period of observation data is 30 minutes, 48 data a day, and the missing data is marked as - 6999. Suspicious data caused by instrument drift and other reasons shall be identified in red font. The CO2 / H2O analyzer was repaired from July 17 to September 13. There was a problem in the collector storage from December 6 to December 11, and the data was missing during this period

  The published observation data include: date / time, wind direction WDIR (°), horizontal wind speed wnd (M / s), standard deviation of lateral wind speed 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), stability Z / L (dimensionless), sensible heat flux HS (w / m2), latent heat flux Le (w / m2), carbon dioxide flux FC (mg / (M2S)), quality identification QA of sensible heat flux_ HS, quality identification of latent heat flux QA_ Le, quality identification QA of carbon dioxide flux_ Fc。 The quality identification of sensible heat, latent heat and carbon dioxide flux is divided into three levels (quality identification 0:（ Δ st < 30, ITC< 30）; 1: （ Δ st < 100, ITC< 100）; The rest are 2). The meaning of data time, for example, 0:30 represents the average of 0:00-0:30; The data is stored in < / EM >. XLS format. For hydrometeorological network or station information, please refer to Li et al. (2013), and for observation data processing, please refer to Liu et al. (2011)