涡度相关法和静态箱／气相色谱法在生态系统呼吸观测中的比较

Comparison of eddy covariance and static chamber/gas chromatogram methods in measuring ecosystem respiration

基于涡度相关法和静态箱/气相色谱法(箱式法)的碳通量观测数据,对比分析了两种方法在评价禹城冬小麦-夏玉米复种农田生态系统和海北高寒矮嵩草草甸生态系统呼吸中的差异.结果表明:在保证涡度相关法和箱式法观测数据质量的条件下,两种方法实时观测的夜间通量结果具有较好的一致性,相关系数达0.95～0.98;箱式法白天的观测结果与涡度相关法估算的白天生态系统呼吸值有较好的一致性,但前者普遍大于后者;两种方法测定生态系统呼吸日平均值的差异达极显著水平(P<0.01),但二者的季节变化趋势较一致.在整个观测期内,冬小麦-夏玉米复种农田观测箱内外平均温差为1.8℃,涡度相关法较箱式法测定的生态系统呼吸日平均值偏低30.3%;高寒矮嵩草草甸观测箱内外平均温差为1.9℃,涡度相关法较箱式法测定的生态系统呼吸日平均值偏低31.4%.两种方法对生态系统生长季呼吸日平均值测定结果的偏差高于非生长季.

Based on the measurement of carbon flux by the methods of eddy covariance and static chamber/gas ehromatogram, a comparison was made between the two methods in evaluating ecosystem respiration over winter wheat （ Triticum aestivum） - summer maize （Zea mays） double cropland and Kobresia humilis alpine meadow. The results showed that under the conditions of obtained data having good quality, nighttime ecosystem respiration from eddy eovarianee measurement was significantly agreed with that from static chamber/gas ehromatogram measurement, with the correlation eo- effieients ranging from 0. 95 to 0. 98, and the daytime ecosystem respiration from these two measurements also had a good consistency though the static chamber/gas ehromatogram measurement Often produced higher values. The daily mean value of ecosystem respiration was significantly different between these two measurements, but the seasonal pattern was similar. For winter wheat-summer maize double cropland, the difference of mean air temperature inside and outside the chamber was 1.8℃ , and the daily mean value of ecosystem respiration across the whole study period was 30. 3% lower in eddy eovarianee measurement than in static chamber/gas ehromatogram measurement; while for alpine meadow, the difference of the mean air temperature was 1.9 ℃, and the daily mean value of ecosystem respiration was 31.4% lower in eddy covariance measurement than in static chamber/gas chromatogram measurement. The variance between the daily mean values of ecosystem respiration obtained from the two measurements was higher in growing season than in dormant season.