青海湖东北岸天然草地CO2 通量变化特征

采用涡度相关法对青海湖东北岸地区草甸化草原生态系统的CO₂ 通量进行了观测，结果表明：在生长季节(5~9 月)，就日变化，08:00~19:00 为CO₂ 净吸收，20:00~07:00 为CO₂ 净排放，CO₂ 通量净吸收峰值一般出现在12:00 时，7 月份12:00 时CO₂ 净吸收峰值为1.41 g·(m2·h)^-1；就月变化，7 月是生长季CO₂ 净吸收最高月份，月CO₂ 净吸收量达到162.70 g·m^-2，整个生长季CO₂ 净吸收的总量达468.07 g·m^-2。非生长季节(1~4 月及10~12 月)，CO₂ 通量日变化振幅极小，最大CO₂ 净排放通量出现在3 月，为0.29 g·(m2·h)^-1，除12 月和1 月各时段CO₂ 通量接近于零，其余月份各时段CO₂ 净排放在0.02~0.29 g·(m2·h)^-1；3 月是全年CO₂ 净排放的最高月份，全月CO₂ 净排放量为72.33 g·m^-2，整个非生长季CO₂ 净排放为319.78 g·m^-2。结果表明，无放牧条件下青海湖东北岸地区草甸化草原，全年CO₂净吸收量达148.30 g·m^-2，是显著的CO₂ 汇。

Natural grassland in Qinghai Lake in the northeastern coast of CO2 fluxes

With the eddy covariance method, CO₂ flux on the northeastern coast of the Qinghai Lakearea meadow steppe ecosystem was observed. The results showed that the growing season (May toSeptember) to diurnal variation, 08:00 to 19: 00 was a net absorption period of CO₂, from 20:00 to 07:00for the net emissions period of CO₂, net absorption peak of CO₂ flux usually occured at 12:00, at 12:00on July the net uptake peak of CO₂ was 1.41 g·(m2·h)^-1; to month variation, July was the highest monthof net uptake of CO₂ during the growing season, the monthly net absorption reached 162.70 g·m^-2, netabsorption of CO₂ throughout the growing season reached a total of 468.07 g·m^-2. Non-growing season(January to April and October to December), with the minimum amplitude of flux CO₂ , the maximumnet emissions of CO₂ fl uxes appeared in March, and was 0.29 g·(m2·h)^-1. Except December and January,the CO₂ fl ux of other months was close to zero, and the net CO₂ emissions of remaining months were0.02~0.29 g·(m2·h)^-1; March was the highest annual net emissions of CO₂, net emissions of full month was72.33 g·m^-2. Net CO₂ emissions during the non-growing season was 319.78 g·m^-2. The results showed thatunder the conditions of non-grazing area of Qinghai Lake meadow grasslands in the northeastern coast,the annual net CO₂ absorption capacity of 148.30 g·m^-2, is a signifi cant CO₂ sink.