This dataset contains the flux measurements from the Daman superstation eddy covariance system (EC) at the highest layer in the flux observation matrix from 30 May to 15 September, 2012. The site (100.37223° E, 38.85551° N) was located in a cropland (maize surface) in Daman irrigation district, which is near Zhangye, Gansu Province. The elevation is 1556.06 m. The EC was installed at a height of 34 m; the sampling rate was 10 Hz. The sonic anemometer faced north, and the separation distance between the sonic anemometer and the CO2/H2O gas analyzer (CSAT3&Li7500A) was 0.17 m. Raw data acquired at 10 Hz were processed using the Edire post-processing software (University of Edinburgh, http://www.geos.ed.ac.uk/abs/research/micromet/EdiRe/), including spike detection, lag correction of H2O/CO2 relative to the vertical wind component, sonic virtual temperature correction, coordinate rotation (2-D rotation), corrections for density fluctuation (Webb-Pearman-Leuning correction), and frequency response correction. The EC data were subsequently averaged over 30 min periods. Moreover, the observation data quality was divided into three classes according to the quality assessment method of stationarity (Δst) and the integral turbulent characteristics test (ITC), which was proposed by Foken and Wichura [1996]: class 1 (level 0: Δst<30 and ITC<30), class 2 (level 1: Δst<100 and ITC<100), and class 3 (level 2: Δst>100 and ITC>100), representing high-, medium-, and low-quality data, respectively. In addition to the above processing steps, the half-hourly flux data were screened in a four-step procedure: (1) data from periods of sensor malfunction were rejected; (2) data before or after 1 h of precipitation were rejected; (3) incomplete 30 min data were rejected when the missing data constituted more than 3% of the 30 min raw record; and (4) data were rejected at night when the friction velocity (u*) was less than 0.1 m/s. There were 48 records per day; the missing data were replaced with -6999. Moreover, suspicious data were marked in red. The released data contained the following variables: data/time, wind direction (Wdir, °), wind speed (Wnd, m/s), the standard deviation of the lateral wind (Std_Uy, m/s), virtual temperature (Tv, ℃), H2O mass density (H2O, g/m^3), CO2 mass density (CO2, mg/m^3), friction velocity (ustar, m/s), stability (z/L), sensible heat flux (Hs, W/m^2), latent heat flux (LE, W/m^2), carbon dioxide flux (Fc, mg/ (m^2s)), quality assessment of the sensible heat flux (QA_Hs), quality assessment of the latent heat flux (QA_LE), and quality assessment of the carbon flux (QA_Fc). In this dataset, the time of 0:30 corresponds to the average data for the period between 0:00 and 0:30; the data were stored in *.xlsx format. For more information, please refer to Liu et al. (2016) (for multi-scale observation experiment or sites information), Xu et al. (2013) (for data processing) in the Citation section.
0 2019-09-15
The dataset is the ground verification point dataset of land cover and vegetation type in the Hoh Xil (in the northwest of Qinghai Province) which collected during August 2018. In the dataset, the homogeneous patches are considered as the main targets of this collection. They are easy to be recognized out and distinguished from other vegetation types. And these samples have high representativeness comparing with other land surface features. In each sample, the geographical references, longitude and latitude (degree, minute, second), time (24h) and elevation (0.1m) are recorded firstly according to GPS positioning. Vegetation types, constructive species, characteristics, land types and features, landmarks, etc. are recorded into the property table manually for checking in laboratory. At last, each sample place has been taken at least 1 photography. In this dataset, 90% or more samples have been taken 2 or more in field landscape photographs for land use type and vegetation classification examination. We have carefully examined the position accuracy of each sample in Google Earth. After 2 rounds of checking and examination, the accuracy and reliability of the property of each sample have been guaranteed.
0 2020-10-13
First, Data Description The data includes stable hydrogen and oxygen isotope data of snow melt water, river water and soil water from July 2013 to April 2014. Second, Sampling Sites The snowmelt water sampling point is located in the middle of the third area, with a latitude and longitude of 99°53′28.004′′E, 38°13′25.781′′N, and the number of acquisitions is 3 times; The river water sampling point is located at the exit of the Hulugou Basin, with a latitude and longitude of 99°52′47.7′′E, 38°16′11′′N, and the sampling frequency is once a week; The soil water sampling point is located in the middle and lower part of the Hongnigou catchment area, with a sampling depth of 90cm and 180cm underground, and a latitude and longitude of 99°52'25.98′′E, 38°15′36.11′′N. Third, Testing Method The samples were measured by L2130-i ultra-high precision liquid water and water vapor isotope analyzer.
0 2019-09-13
On 25 August 2012, a RCD30 camera of Leica Company boarded on the Y-12 aircraft was utilized to obtain the optical remote sensing data. RCD30 camera has a focal length of 80 mm and four bands including red, green, blue and near-infrared bands. The absolute flight altitude is 5200 m and ground sample distance is 6-19 cm. The product includes TIF images and exterior orientation elements.
0 2019-09-11
The data set contains cosmic ray instrument (CRS) observations from January 1, 2016 to December 31, 2016.The station is located in gansu province zhangye city da man irrigated area farmland, under the surface is corn field.The longitude and latitude of the observation point are 100.3722e, 38.8555n, and 1556m above sea level. The bottom of the instrument probe is 0.5m from the ground, and the sampling frequency is 1 hour. Original observations of cosmic ray instruments include: voltage Batt (V), temperature T (c), relative humidity RH (%), pressure P (hPa), fast neutron number N1C (hr), thermal neutron number N2C (hr), fast neutron sampling time N1ET (s) and thermal neutron sampling time N2ET (s).The data published are processed and calculated. The data headers include Date Time, P (pressure hPa), N1C (fast neutron number/hour), N1C_cor (fast neutron number/hour with revised pressure) and VWC (soil volume moisture content %). The main processing steps include: 1) data filtering There are four criteria for data screening :(1) data with voltage less than and equal to 11.8 volts are excluded;(2) remove the data of air relative humidity greater than and equal to 80%;(3) data whose sampling interval is not within 60±1 minute are excluded;(4) the number of fast neutrons removed changed by more than 200 in one hour compared with that before and after.In addition, the missing data was supplemented by -6999. 2) air pressure correction According to the fast neutron pressure correction formula mentioned in the instrument instruction manual, the original data were revised to obtain the revised fast neutron number N1C_cor. 3) instrument calibration In the process of calculating soil moisture, N0 in the calculation formula should be calibrated.N0 is the number of fast neutrons under the condition of soil drying. The measured soil moisture (or through relatively dense soil moisture wireless sensor) m (Zreda et al. Here, according to Soilnet soil water data in the source area of the instrument, the instrument was calibrated to establish the relationship between soil volumetric water content v and fast neutrons.Selection of dry and wet conditions are the obvious difference of June 26, 2012-27 and July 16-17, four days of data, including June 26-27 rate data showed that soil moisture is small, so the selection of 4 cm, 10 and 20 cm as the rate of the three values of average data, its range is 22% 30%, and July 16-17 rate data showed that soil moisture is bigger, so select 4 cm and 10 cm as two value average rate data, the range of 28% - 39%, final N0 an average of 3597. 4) soil moisture calculation According to the formula, the hourly soil water content data were calculated. Please refer to Liu et al. (2018) for information of hydrometeorological network or site, and Zhu et al. (2015) for observation data processing.
0 2020-04-10
On 29 June 2012, CASI sensor carried by the Harbin Y-12 aircraft was used in a visible near Infrared hyperspectral airborne remote sensing experiment, which is located in the observation experimental area (30×30 km). The land cover pattern product in the middle reaches of the Heihe River Basin were obtained at a spatial resolution of 1 m, using CASI aerial data with high spatial and spectral resolution．A hierarchical classification structure integrated by pixel-based classification and object-based classification is used to obtain production．According to surveyed reference data about land cover and visual interpretation from high resolution imagery，the accuracy of the classification result of land cover was evaluated，and the result showed that overall accuracy was 84.61 %，Kappa coefficient was 0.8262．
0 2019-09-15
Since the formation of Heihe River, sporopollen data samples have been collected from the drilling strata of Da'ao well in the middle reaches of Heihe River. Drilling location: 39.491 n, 99.605 E. The drilling depth is 140 meters. 128 samples of sporopollen are collected from top to bottom. At present, there are 19 data of sporopollen results, which are distributed in each sedimentary facies from top to bottom. The sporopollen samples were removed from carbonate, organic matter, silicate and other impurities in the laboratory, and the species and data of sporopollen were identified under the microscope. Sporopollen results mainly include the percentage content and number of trees, shrubs, herbs, aquatic, ferns and other families and genera.
0 2020-07-28
Heihe river basin is the second largest inland river basin in China. In the past 30 years, a relatively perfect drainage observation system has been established in heihe river basin, which has become an important inland river research base in China.River basin is an important natural research unit, but the boundary of heihe river basin is not unified. In order to facilitate the use of data by users, we collected and sorted out 5 kinds of heihe river basin boundaries commonly seen in the literature: 1) from 1985 to 1986, China began to conduct systematic research on the heihe river basin as a whole. On the basis of basic investigation and a large number of data mastered, the early heihe river basin map was drawn with an area of 138,900 km ^ 2.The whole basin is divided into three hydrologic balance zones, which are: the balance zone of heihe main stream system, the balance zone of beida river main stream system and the balance zone of ma ying - feng leshan front water system. 2) sub project national key scientific research project of the ninth five-year plan "in heihe river basin water resources reasonable use and the economic society and ecological environment coordinated development research", considering the integrity of the county-level administrative units, on the basis of the first basin boundary using the administrative boundary of basin boundary was revised, formed the "digital heihe" published information system (http://heihe.westgis.ac.cn) of the heihe river basin boundary, watershed area of 128700 km ^ 2.The division of hydrological unit inherits the original idea and is divided into three river systems, namely the eastern river system, the central river system and the western river system. 3) in the comprehensive control plan of heihe river basin of the ministry of water resources, the area of heihe river basin is determined as 142,900 km ^ 2, and the hydrologic unit is divided into two independent water systems in the central and western regions and the east, with an area of 27,000 km2 and 116,000 km ^ 2 respectively. 4) in 2002-2006 in the national integrated water resources planning, "the Yellow River" (piece of) integrated water resources planning working group in 2005, the establishment "the northwest rivers and water resources and its exploitation and utilization of investigation evaluation report, briefly, to the secondary and tertiary area as the unit of water resources, to complete a series of natural geography and social economy statistical tables, maps and other data.In this comprehensive plan, the area of heihe river basin is about 151,700 km ^ 2, and the plan does not give a more detailed sub-watershed division plan. 5) based on the high-precision digital elevation model (SRTM and ASTER GDEM), the boundary of heihe river basin was determined by using the GIS hydrologic analysis method.The boundary has been verified by remote sensing and field investigation, and the present situation of modern water resources utilization is considered in the process of basin boundary determination and sub-basin division.
0 2020-06-05
The data set contains the flux observation data of large aperture scintillator from daman station in the middle reaches of heihe hydrometeorological observation network.The large aperture scintiometer of German BLS450_NQ and Dutch Kipp&zonen models has been installed at the dameng station in the middle reaches. The north tower is the receiving end of Kipp&zonen and the transmitting end of BLS450_NQ, and the south tower is the transmitting end of Kipp&zonen and the receiving end of BLS450_NQ.The observation period of BLS450_NQ is from January 1, 2014 to December 31, 2014, and the observation period of Kipp&zonen is from January 1, 2014 to March 1, 2014.The station is located in dazman irrigation district, zhangye city, gansu province. The underlying surface involves corn, orchards and greenhouses, but mainly corn.The latitude and longitude of the north tower is 100.379 E, 38.861 N, and the latitude and longitude of the south tower is 100.369 E, 38.847 N, with an altitude of about 1556m.The effective height of the large aperture scintillator is 22.45m, the optical diameter length is 1854m, and the sampling frequency is 1min. Large aperture flicker meter raw observation data for 1 min, data released for 30 min after processing and quality control of data, including sensible heat flux is mainly combined with the automatic meteorological station observation data, based on similarity theory alonzo mourning - Mr. Hoff is obtained by iterative calculation, the quality control of the main steps include: (1) excluding Cn2 reach saturation data (BLS450_NQ: Cn2 > 1.43 e-13, Kipp&zonen: Cn2 e-13 > 1.54);(2) data with weak demodulation signal strength were eliminated (BLS450_NQ: Mininum X<50, Kipp&zonen: Demod>-20mv);(3) data at the time of precipitation were excluded;(4) data of weak turbulence under stable conditions were excluded (u* < 0.1m/s).In the iterative calculation process, for BLS450_NQ, the stability universal function of Thiermann and Grassl, 1992 was selected.For Kipp&zonen, take Andreas 1988's stability universal function.Please refer to Liu et al.(2011, 2013) for detailed introduction. Some notes on the released data :(1) the data of mid-range LAS is mainly BLS450_NQ, the missing moment is supplemented by Kipp&zonen observation, and the missing of both is marked by -6999.(2) missing period: on June 21, 2014, solstice, 27, due to the lack of data from the automatic meteorological station, the sensible heat flux H_LAS observed at LAS during this period could not be calculated;On June 29, 2014, solstice on July 2, July 21, solstice 22, September 24, solstice 25, and December 21, solstice 30, data was missing due to LAS instrument failure.(3) data table head: Date/Time: Date/Time (format: yyyy-m-d h:mm), Cn2: structural parameters of air refraction index (unit: m-2/3), H_LAS: sensible heat flux (unit: W/m2).The meaning of data time, such as 0:30 represents the average between 0:00 and 0:30;The data is stored in *.xls format. Please refer to Li et al.(2013) for hydrometeorological network or site information, and Liu et al.(2011) for observation data processing.
0 2020-03-05
The runoff record of Pailugou watershed in the upper reaches of Heihe River, dated from January 2011 to September 2012. The data measuring device is the measuring weir at the exit of the small watershed, the unit of the data is m³/day.
0 2020-03-31
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