Location

 Zhangjiang Estuary is located in the Zhangjiang Estuary Mangrove National Nature Reserve, where is in the south of Fujian Province in Southeast China, about 95 km away from Xiamen, with the geographical location of 117°21'-117°30' E and 23°53'-23°57' N. It occupies 2360 hectares, covered mostly by mangrove forests (118 ha) and salt marshes (2142 ha) along the coastline of Zhangjiang Estuary. This flux tower was constructed by Prof. Guanghui Lin research groups at Tsinghua University and Xiamen University of China, which was installed at the latitude of 23°54'23.2″N, longitude of 117°24'10.1″ E, and base altitude of 4 m. Zhangjiang Estuary station stands for sub-tropical coastal mangrove ecosystem with irregular semidiurnal tides.

Climatic

 Zhangjiang Estuary station has a subtropical oceanic monsoon climate, and the mean annual evapotranspiration and precipitation are 1718.4 mm and 1714.5 mm, respectively, most of which occurs from April to September. The annual mean temperature is 21.2 °C, with the lowest of 0.2 °C in January, and the highest of 38.1 °C in August. Cumulative sunshine hours average around 2125.1 hours and relative humidity is about 79%. The tides at this site are irregular semidiurnal, and the high tides can reach up to 1.0 m above the sediment, with tidal water salinity ranging between 1 and 22 ppt.

Vegetation and soil

 The vegetation at Zhangjiang Estuary station includes mangrove forests, salt marsh and coastal psammophytic vegetation, and the dominating species are Kandelia obovata, Avicennia marina, Aegiceras corniculatum and Bruguiera gymnorrhiza, and Spartina alterniflora. The vegetation near the flux tower is a mangrove forest, with canopy height of 3 ~ 5 m. The soil is alluvial soil. The organic matter content in soil is 0.674 ~ 2.448%, and the nitrogen content is 0.069~ 0.208%. The mudflat soil is composed of the clay/silt sediments\, with pH from 4.8 to 7.0 and salinity from 5 to 27 ppt.

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 12.6 m, with three-dimensional sonic anemometer and infrared analyzer at 4 m. The mount heights for the temperature and humidity sensors are 3 m, 8.6 m and 12.6 m. The mount height for the solar radiation and photosynthetic active radiation sensors is 13.8 m, and the mount height for the rain gauge 14.7 m, The installation depth of soil temperature sensor and soil heat flux plate are 10, 20 and 30 cm. The flux was observed since August, 2008, but the observation system was ceased in July, 2014 because of fund limitation.

Principal Investigator

Guanghui Lin

E-mail: lingh@tsinghua.edu.cn