Location

Gaoqiao mangrove station locates in an estuary ((21º31'N~21º34'N; 109º44'E~109º47'E; altitude 0 ~ 5 m) southwest of Guangdong province, China, which belongs to Zhanjiang Mangrove National Nature Reserve. This flux tower was installed by Prof. Lin research groups at Tsinghua University and Xiamen University. The eddy flux system was at latitude 21°34'3.05" N, longitude 109°45'22.32" E, and base altitude 4 m. The Gaoqiao station represents a typical sub-tropical coastal mangrove ecosystem with regular diurnal tide inundation.

Climatic

The climate at the Gaoqiao station belongs to subtropical oceanic monsoonal climate, with mean annual temperature and precipitation of 23.2 °C and 1417 ~ 1802 mm, respectively. The coldest month is January, with average temperature of 15.5 °C and the hottest month, July, with average temperature of 28.9 °C. Cumulative sunshine hours range from 1864 to 2160 hours. The tides at this site are regular diurnal, and the high tides can reach up to 1.8 m above the sediment, with tidal water salinity ranging between 1 and 30 ppt.

Vegetation and soil

The Gaoqiao station contains mangrove forests, salt marshes and coastal psammophytic vegetation, and the dominating species include Avicennia marina, Aegiceras corniculatum, Rhizophora stylosa, Kandelia obovata and Bruguiera gymnorrhiza, and little mangrove trees in understory. The vegetation near the flux tower is a sub-tropical mangrove forest, with a canopy height of about 3 m. The soil at the site is muddy soil. The organic matter content in soil is 1.04 ~ 6.01%. and the nitrogen content is 0.056 ~ 0.284%. The soil composition are silt and loam, with PH from 3.7 to 5.9, and soil thickness is more than 1 m.

Observation system

The equipment of the flux observation system composed of CSAT3 three-dimensional sonic anemometer (Campbell Scientific, Inc., USA) and LI-7500 CO₂/H₂O infrared gas analyzer (Li-cor, Inc., USA). The height of the flux tower is 14 m, three-dimensional sonic anemometer and infrared analyzer installation height is 8m. The mount height of temperature and humidity sensors are 2.6 m, 8.6 m and 14.1 m. The mount height of four component, solar radiation and photosynthetic active radiation sensors is 8.6 m. The mount height of rain gauge is 15.1 m. The soil temperature sensor and soil heat flux plates were installed at 10 cm and 20 cm depths. Flux data sampling frequency is 10 Hz, the average time of flux is 30 min, meteorological data sampling frequency is 10 min, and the average time is 30min. The fluxes have been collected since September, 2009, and the system is still in operations.

Principal Investigator

Guanghui Lin

E-mail: lingh@tsinghua.edu.cn