Characteristics of CO_2 flux over the alpine wetland in the Tibetan Plateau and its control factors
ZHANG Haihong;LI Lin;ZHOU Bingrong;XIAO Hongbin;Qinghai Institute of Meteorological Science;
Using the data observed by eddy-covariance flux in Longbao wetland,Yushu,in 2015,characteristics of CO_2 flux and its control factors were analyzed. The results show that daily change of CO_2 flux in Longbao wetland was inverted unimodal and was negative in daylight and positive at night. Daily range of CO_2 flux was maximum in July and minimum in January. From April to September there was a carbon sink in the alpine wetland ecosystem and a carbon source in other months. Annual CO_2 net absorption was 465 g·m~(-2). CO_2 flux decreased with photosynthetically active radiation increase in daylight. CO_2 emission was positively correlated with soil temperature and daily rangeability of air temperature. Alpine wetland soil moisture effected on CO_2 flux very weak. CO_2 emission increased in short order after rain event. CO_2 flux strongly correlated with photosynthetically active radiation,following by daily rangeability of air temperature and soil temperature. CO_2 flux weakly correlated with soil moisture.