兰州大学寒旱区科学观测网络CARN（寺大隆站气象要素梯度观测系统-2020）

该数据集包含了2020年1月1日至2020年12月31日兰州大学寒旱区科学观测网络寺大隆站气象要素梯度观测系统数据。站点位于甘肃张掖市肃南县康乐乡，下垫面是森林。观测点的经纬度是99.926E，38.428N，海拔3146m。二维超声风速/风向传感器和空气温湿度传感器分别架设在0.5m、3m、13m、24m、48m处，共5层；气压计安装在1.5m采集箱内；翻斗式雨量计安装在塔24m处；两个红外温度计分别安装在4m（冠层下）、24m（冠层下）处，探头朝向垂直向下；土壤热通量板（自校正式）（2块）依次埋设在植被下5cm和10cm处；土壤温/湿/电导率传感器和土壤水势传感器埋设在塔南侧植被下5cm、10cm、20cm、40cm、60cm处；光合有效辐射传感器分别安装在4m（冠层下）、24m（冠层下）处；日照时数传感器以及四分量辐射仪安装在24m处。 观测项目有：风速（WS_0.5m、WS_3m、WS_13m、WS_24m、WS_48m）(单位：米/秒)、风向（WD_0.5m、WD_3m、WD_13m、WD_24m、WD_48m）(单位：度)、空气温湿度（TA_0.5m、TA_3m、TA_13m、TA_24m、TA_48m和RH_0.5m、RH_3m、RH_13m、RH_24m、RH_48m）(单位：摄氏度、百分比)、气压（PA）(单位：百帕)、降水量（P）(单位：毫米)、四分量辐射（SWIN、SWOUT、LWIN、LWOUT、Rn）(单位：瓦/平方米)、地表辐射温度（TC）(单位：摄氏度)、土壤热通量（SHF）(单位：瓦/平方米)、土壤水分（SWC）(单位：百分比)、土壤温度（Ts）(单位：摄氏度) 、土壤水势（SWP）（单位：千帕）、土壤电导率（EC）（单位：微西门子/厘米）、光合有效辐射（PPFD）(单位：微摩尔/平方米秒)、日照时数（Sun_time）（单位：小时）。观测数据的处理与质量控制：（1）确保每天48个数据（每30min），缺失或异常数据以-6999代替（因SDI12通道总线故障，风速风向、土壤三参数、土壤水势等传感器较大范围缺失数据）；（2）剔除有重复记录的时刻；（3）删除了明显超出物理意义或超出仪器量程的数据；（4）数据中以红字标示的部分为有疑问的数据；（5）日期和时间的格式统一，并且日期、时间在同一列。如，时间为：2020-6-10 10:30。

This dataset contains meteorological element gradient observation system data from the Sidalong Station of the Cold and Arid Regions Science Observation Network of Lanzhou University, covering the period from January 1, 2020 to December 31, 2020. The station is located in Kangle Township, Sunan County, Zhangye City, Gansu Province, with forest as its underlying surface. The coordinates of the observation point are 99.926°E, 38.428°N, and the elevation is 3146 m. Two-dimensional ultrasonic wind speed/direction sensors and air temperature and humidity sensors are installed at five heights: 0.5 m, 3 m, 13 m, 24 m, and 48 m. The barometer is installed in a 1.5 m acquisition box. The tipping bucket rain gauge is installed at 24 m on the observation tower. Two infrared thermometers are installed at 4 m (under canopy) and 24 m (under canopy), with their probes facing vertically downward. Two self-calibrating soil heat flux plates are buried at 5 cm and 10 cm below the vegetation, respectively. Soil temperature, moisture and electrical conductivity sensors as well as soil water potential sensors are buried at 5 cm, 10 cm, 20 cm, 40 cm and 60 cm below the vegetation on the south side of the tower. Photosynthetically active radiation sensors are installed at 4 m (under canopy) and 24 m (under canopy). The sunshine duration sensor and four-component radiometer are installed at 24 m.

Observation items include: wind speed (WS_0.5m, WS_3m, WS_13m, WS_24m, WS_48m) (unit: m/s), wind direction (WD_0.5m, WD_3m, WD_13m, WD_24m, WD_48m) (unit: degree), air temperature and humidity (TA_0.5m, TA_3m, TA_13m, TA_24m, TA_48m and RH_0.5m, RH_3m, RH_13m, RH_24m, RH_48m) (unit: ℃, %), barometric pressure (PA) (unit: hPa), precipitation (P) (unit: mm), four-component radiation (SWIN, SWOUT, LWIN, LWOUT, Rn) (unit: W/m²), surface radiation temperature (TC) (unit: ℃), soil heat flux (SHF) (unit: W/m²), soil moisture (SWC) (unit: %), soil temperature (Ts) (unit: ℃), soil water potential (SWP) (unit: kPa), soil electrical conductivity (EC) (unit: μS/cm), photosynthetically active radiation (PPFD) (unit: μmol/(m²·s)), and sunshine duration (Sun_time) (unit: h).

Data processing and quality control of the observed data are conducted as follows: (1) Ensure 48 data records per day (one record every 30 minutes), missing or abnormal data are replaced with -6999 (a large range of data from wind speed and direction sensors, soil three-parameter sensors, soil water potential sensors, etc. is missing due to SDI12 channel bus failure); (2) Remove duplicate timestamp records; (3) Delete data that obviously exceeds physical significance or instrument measurement range; (4) Data marked in red are considered questionable; (5) Unify the date and time formats, and place date and time in the same column. For example, the time format is: 2020-6-10 10:30.