Spokas K, Graff C, Morcet M, Aran C
University of Minnesota, Department of Soil, Water, and Climate, 1991 Upper Buford Circle, 439 Borlaug Hall, St. Paul, MN 55108, USA.
Waste Manag. 2003;23(7):599-607. doi: 10.1016/S0956-053X(03)00102-8.
Accurate methods quantifying whole landfill surface flux of methane are important for regulatory and research purposes. This paper presents the results from the analysis of chamber measurements utilizing geospatial techniques [kriging and inverse distance weighting (IDW)] to arrive at an estimation of the whole landfill surface flux from the spatially distributed chamber measurement points. The difficulties in utilizing these methods will be discussed. Methane flux was determined on approximately 20 m grid spacing and variogram analysis was performed in order to model spatial structure, which was used to estimate methane flux at unsampled locations through kriging. Our analysis indicates that while the semi-variogram model showed some spatial structure, IDW was a more accurate interpolation method for this particular site. This was seen in the comparison of the resulting contour maps. IDW, coupled with surface area algorithms to extract the total area of user defined contour intervals, provides a superior estimate of the methane flux as confirmed through the methane balance. It is critical that the results of the emissions estimates be viewed in light of the whole cell methane balance; otherwise, there is no rational check and balance system to validate the results.
准确量化整个垃圾填埋场甲烷表面通量的方法对于监管和研究目的而言至关重要。本文展示了利用地理空间技术（克里金法和反距离加权法（IDW））对气室测量结果进行分析的成果，以便根据空间分布的气室测量点估算整个垃圾填埋场的表面通量。文中将讨论使用这些方法时遇到的困难。甲烷通量是在大约20米的网格间距上测定的，并进行了变异函数分析以模拟空间结构，该结构用于通过克里金法估算未采样位置的甲烷通量。我们的分析表明，虽然半变异函数模型显示出一定的空间结构，但对于该特定场地，IDW是一种更准确的插值方法。这在所得等值线图的比较中可见一斑。IDW与表面积算法相结合以提取用户定义的等值线间隔的总面积，通过甲烷平衡证实，其对甲烷通量的估算更为优越。必须根据整个单元的甲烷平衡来审视排放估算结果；否则，就没有合理的制衡系统来验证结果。
