中文摘要：

LI-7500分析仪仪器表面加热效应对开路式涡动相关系统CO2通量观测结果影响显著,利用Burba校正方法对提高观测站CO2通量观测精度、年净生态系统碳交换量（NEE）估算、全球CO2交换量估算和气候变化模拟等具有重要意义。基于临泽站绿洲玉米农田的开路式涡动相关系统和小气候观测系统所获得的一年数据,利用Burba校正方法分别对LI-7500分析仪光路中的感热通量、大气潜热通量、CO2通量以及NEE的季节变化过程进行了修正。结果表明,LI-7500分析仪底部窗口和支杆部分热量交换是光路中感热通量校正量的主要贡献者,平均分别为6.81W.m-2和2.68W.m-2,其加热效应主要来源于太阳辐射和电子元件运行产生的热量;加热效应对潜热通量影响最小,平均校正量仅为0.24W.m-2;Burba校正对CO2通量和NEE的季节变化影响显著,其平均校正量分别为19.14μg.CO2.m-2.s-1和313.21mg.C.m-2.d-1,而且气温越低加热效应对通量的影响越显著;除生长季空气中水汽浓度显著高于非生长季而导致潜热校正量较大外,生长季其他各通量的校正量明显小于非生长季,生长季光路中感热、周围大气潜热、CO2通量和NEE日校正量分别为6.94 W.m-2、0.33W.m-2、12.86μg.CO2.m-2.s-1和161.58mg.C.m-2.d-1,分别是非生长季的60.4%,220.0%,50.6%和37.4%。若未进行仪器表面加热效应的Burba校正,在生长季和非生长季累计高估的绿洲玉米农田生态系统碳吸收量分别为25.85g.C.m-2和88.47g.C.m-2。

英文摘要：

The instrument surface heating of LI--7500 analyzer has a significant impact on the meas- urement of CO2 flux from open-path eddy covariance system, and the Burba correction to CO2 flux is a most critical requirement for improving CO2 measurement, net ecosystem exchange （NEE） estimate, and global CO2 exchange and climate change modeling, etc. The sensible heat flux inside the optical path, la- tent heat flux and CO2 flux were corrected using Burba correction approach for one annual datasets of measurements from an open-path eddy covariance system and from an automatic meteorological observa- tion tower installed a maize field at Linze station. The results show that heat exchange from the bottom window and spars are the main contributor of the correction term of sensible heat flux inside the path with the mean values of 6.81 W · m-2 and 2.68 W · m-2 , respectively. For latent heat flux, the magnitude of the correction term is least and negligible, and the mean value is onlY about 0.24 W ·m-2. However, the measurements of CO2 flux and seasonal NEE are significantly affected by the Burba correction approach, and the mean values of the correction term are 19.14 μg· CO2 · m-2 · s-1 and 313.21 mg· C· m^-2 ·d-1 , respectively. Furthermore, with lower air temperature, the magnitude of the correction term is lar- ger expect for the latent heat flux. For instance, during the growing season, the corrected terms of sensi- ble heat flux inside the path, latent heat flux, CO2 flux and daily NEE are 6.94W. m 2, 0.33 W· m 2, 12.86 μg- CO2 · m-2 ·s 1 and 161.58 mg. C· m-2 · d 1 and are about 60.4%, 220.0%, 50.6% and 37.4% of the values of the coordinates during the non-growing season, respectively. Most of all, no-using the Burba correction procedure could let to overestimate the carbon uptake with value around 25.85 g· C · m-2 during the growing season, and underestimate the carbon emission from the agroecosystem with the value around 88.47 g · C · m 2 during the non-growing season.