Location

Dongting Lake station, located in the south of Caisanghu (29°29′59.06″N, 112°47′50.50″E; altitude: 28 m), belongs to Institute of Subtropical Agriculture, The Chinese Academy of Sciences. A flux tower exists in a Phragmites australis and Miscanthus sacchariflorus marshland (29°29′15.94″N, 113°03′08.06″E, altitude: 29 m), which is the sample area for Dongting Lake station. This station stands for a typical river-connected lake wetland ecosystem in subtropical region.

Climatic

Dongting Lake station belongs to the humid north-subtropical monsoon climate. The average annual temperature is 16.6—16.8℃, and the extreme maximum or minimum temperature is 40.4℃ or -11.8℃, respectively. The annual relative humidity is 79%. The annual precipitation is 1320 mm. The annual sunshine duration is 1722.1-1816.5 hours, and the frost-free days are 258-278 days.

Vegetation and soil

The vegetation of Dongting Lake station is dominated by Carex spp., Phragmites australis, Miscanthus sacchariflorus, Phalaris arundinacea, Polygonum hydropiper and poplar populations. The underlying vegetation of the flux tower is the mix-community of P. australis and M. sacchariflorus. The soil is azonal and includes lake soil, paddy soil and boggy soil. The soil organic matter content is 2.3%, and the total soil nitrogen is 0.15%. The soil particle compositions are clay (10.9%), silt (53.5%) and sand (35.6%).

Observation system

This flux observation system consists of an ultrasonic anemometer (CSAT3, Campbell, USA) and a CO₂/H₂O infrared gas analyser (Li7500A, Li-cor, USA). The flux tower is 8.5 m in height. The ultrasonic anemometer, gas analyser, the air temperature and humidity meter and radiation meter are installed at 6.5 m. the soil temperature and humidity meters are installed at the depth of 20cm/40cm/60cm. The data sampling frequency is 10 HZ, and the flux results are averaged every half an hour. The flux observation was started on July 1st, 2014.

Principal Investigator

Zhengmiao Deng

E-mail: dengzm@isa.ac.cn