Location

 The Damxung Alpine Wetland CO₂/H₂O Flux Station is located at Majilukuo village, approximately 5 km from the Damxung county, Tibet Autonomous Region. It is managed by Lhasa Plateau Ecosystem Research Station, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences. The CO₂/H₂O flux tower is situated at 30°28′08.50″N, 91°03′44.50″E，with altitude of 4286 m. This alpine wetland is the representative of the alpine Kobresia littledalei – Blysmus sinocompressus swamp meadow, mainly distributed in the river basin of higher altitudes (>4000 m a.s.l) in central Qinghai-Tibetan Plateau. The wetland provides winter (October–April) pasture for yaks and the Tibetan sheep. The marshes are usually mowed by herdsman in fall, but free from grazing during the growing season.

Climatic

 The Damxung alpine wetland CO₂/H₂O flux site was categorized as plateau semi-arid and semi-humid climate with characteristics of strong radiation, low air temperature, and short cool summers. Average annual air temperature is 1.3 ℃, with coldest monthly mean of -10.4 ℃ in January and the warmest of 10.7 ℃ in July. Average annual precipitation is 476.8 mm, over 80% of which concentrated in June through August, in phase with growing season. Vegetation starts to grow at the beginning of May, reaches a growth peak in mid-August, and then gradually begins to senescence at the end September.

Vegetation and soil

 The Damxung alpine wetland CO₂/H₂O flux station, is representative of the alpine Kobresia littledalei – Blysmus sinocompressus swamp meadow, distributed along the Dangqu River, one branch of the Lhasa River. Water depth is about 10 - 45cm in growing season. The wetland is dominated by Kobreisa littledalei and Blysmus sinocompressus with 20-35 cm of canopy height. The soil is swamp meadow soil. The wetland is water-logged during the growing season from May to September, and becomes frozen at the beginning of November, and gradually thaws in the following March.

Observation system

 The CO₂/H₂O flux system is consisted of one three-dimensional sonic anemometer (Model CSAT3, Campbell Scientific Inc., USA) and an open-path fast-response infrared gas analyzer (IRGA, Model LI7500, LI-Cor Inc., USA), the flux measurements were conducted at a height of 2.0 m. Standard meteorological parameters were measured using an array of sensors at 2m include photo synthetically active radiation(PAR), radiation balance of solar and far-infrared radiation, air temperature (Ta) and relative humidity (RH), wind direction (WD) and wind speed (WS), precipitation (PPT), Soil temperature and moisture was measured at depths of 5cm, 10cm, 15cm and 20cm. The data of CO₂/H₂O fluxwas measured at a rate of 10 Hz, calculations were carried out for each 30 min period by a data-logger (Model CR1000, Campbell Scientific Inc.). Starting time for the CO₂/H₂O flux observation was from May 2009.

Principal Investigator

Peili Shi

E-mail: shipl@igsnrr.ac.cn