Location

Flux tower locates at Plot 1 in the Forest Ecosystem Open Research Station of Changbai Mountains( Erdaobaihe, Antu county, Jilin province 42°24′9″N，128°05′45″E，asl 738m ), Institute of Applied ecology, Chinese Academy of Sciences. the measurement describes the fluxes characteristics of mixed forest in temperate forests in China.

Climatic

Changbai mountain flux tower affected by the monsoon temperate continental climate, with remarkable climatic characteristics of mid-latitude mountains, dry and windy spring, hot summers and rainy and cold winters. Annual average temperature is 3.6 degrees Celsius, average annual rainfall is 713 mm, mainly concentrated in June-August. Annual sunshine hours is 2271 ~ 2503 h, The frost-free period is about 109 ~141 days.

Vegetation and soil

The area surrounding the site was covered by a mixed forest consisting of over 200 uneven-aged species including Korean pine (Pinus koraiensis), Amur linden (Tilia amurensis), Mono maple (Acer mono), Manchurian ash (Fraxinus mandshurica) and Mongolian oak (Quercus mongolica). The mean canopy height was 26 m. A dense understory, consisting of broad-leaved shrubs, was 0.5 -- 2 m tall. The soil is classified as dark brown forest soil originating from volcanic ashes. Surface soil organic matter content is about 10%, the nitrogen content is about 0.3%, Clay content is about 31%.

Observation system

Flux observations at this site have continued since 2002 (Zhang et al., 2006a; Zhang et al., 2006b). An EC system was installed at the height of 40 m above the ground on a 62.8 m tower. CO2, H2O, wind and temperature fluctuations were measured with an open-path CO2/H2O sensor (model Li7500, Li-Cor, USA) and a 3D ultrasonic anemometer (model CSAT3, Campbell Scientific, USA) at a rate of 10 Hz. Supporting meteorological variables were sampled every 2 s and stored as half-hourly statistics on a datalogger (model CR23X, Campbell Scientific, USA); They included air temperature and relative humidity (model HMP45C, Vaisala, Finland), wind speed (model A100R, Vector, UK), downward/upward solar radiation and net radiation (model CNR1, Kipp and Zonen, The Netherlands), barometric pressure (model CS105, Campbell Scientific, USA) and PAR (model Li190SB, Li-Cor, USA) at the 40-m height, and precipitation (model 52203, Young, USA) at the height of 62.8 m.

Principal Investigator

Shijie Han

E-mail: hansj@iae.ac.cn