Location
Daman Superstation is a farmland flux observation station and affiliated to Heihe Remote Sensing Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences(CAREERI,CAS). It is located in Daman irrigation farmland of Zhangye city, GanSu province and belongs to the administrative divisions of five-star village, Xiaoman town, Zhangye city. There is a gradient meteorological tower of 40 m height in the observation field, Flux observation is located in the tower. The observation coordinate is 100°22'20.2"E, 38°51'20.0" N, 1556m, and the underlying surface of flux station is farmland and the main crop type is maize. The station represents seed maize type in the middle latitude hinterland of mainland, which belongs to the Zhangye Oasis in the middle basin of Heihe river.
Climatic
Daman Superstation is located in mid-latitudes mainland hinterland, affected by the atmospheric circulation and the Qinghai Tibet Plateau, Inner Mongolia plateau. The climate regionalization belongs to the temperate continental arid climate. The area is rich in light and heat, large wind and sand enough, dry and little rain, sunny, strong solar radiation, temperature difference rapidly between day and night,the uneven distribution of rainfall characteristics. There is stong wind and stand storm in spring in the station in Ganzhou district, annual average temperature is 7.3 ℃, extreme maximum temperature is 38.6 ℃, extreme minimum temperature is -28.2 ℃, annual average relative humidity is 52%, the average annual rainfall of 130.4 mm, surface evaporation 2002.5 mm, annual average sunshine hours-3065.6 hours, sunshine percentage is 69%, 12.3 day were windy days, sandstorm days to 11.8 days, frost-free period between138 and 179 days.
Vegetation and soil
The irrigation zone grow crop once a year, which is priority to maize seed production, between wheat and maize interpolating of wheat. The underlying surface vegetation in flux tower and source region is seed maize.
The station area is located in the Zhangye basin of the alluvial plain which fine soil in Oasis irrigation silting soil primarily in Ganzhou district, the thickness of the soil is above 160cm, the soil nutrient content average as shown in the table：
Observation system
The Daman Superstation have set up a weather station(40m), open-path eddy-covariance flux measurement system. The eddy-covariance flux system is composed of three dimensional sonic anemometer(CSAT3, Campbell, USA）and open path CO2/H2O gas analyzer(Li7500A, Li-cor, USA). The instrument mount-height was 4.5m, the ultrasound direction was at an azimuth angle of 0°, the distance between Li7500 and CSAT3 was 17cm and sampling frequency was 10Hz. Output Flux data are 30-minutes cycle. Observation start from Sep. 15, 2012.
The installation heights and orientations of different sensors and measured quantities were as follows: air temperature and humidity profile (3, 5, 10, 15, 20, 30, and 40 m, towards north), wind speed and direction profile (3, 5, 10, 15, 20, 30, and 40 m, towards north), CO2 and H2O density profile (3, 5, 10, 15, 20, 30, and 40 m, towards north), air pressure (2 m), rain gauge (2.5 m, 8 m in west of tower), four-component radiometer (12 m, towards south), two infrared temperature sensors (12 m, towards south, vertically downward), photosynthetically active radiation (12 m, towards south, vertically upward; another four photosynthetically active radiation were installed on Jul. 28, 2013, two above the plants (12 m) and two below the plants (0.3m), towards south, each with one vertically downward and one vertically upward), soil heat flux (3 duplicates with G1 below the vegetation; G2 and G3 between plants, -0.06 m), a TCAV averaging soil thermocouple probe (-0.02, -0.04 m), soil temperature profile (0, -0.02, -0.04, -0.1, -0.2, -0.4, -0.8, -1.2, and -1.6 m), soil moisture profile (-0.02, -0.04, -0.1, -0.2, -0.4, -0.8, -1.2, and -1.6 m).
Principal Investigator
Mingguo Ma
E-mail: mmg@lzb.ac.cn