基于有限样点和大尺度模型的区域土壤呼吸模型研究

Regional Soil Respiration Modelling Based on the Finite Sample Points and the Large-Scale Model

  • 摘要: 预测森林土壤呼吸对研究陆地生态系统的碳循环和气候变化有重要意义,而不同尺度(全球、国家和区域)的预测模型作用不同。由于样点数量有限,区域尺度的土壤呼吸模型研究较少。本文提出一种区域建模的新思路:基于有限样点建立线性模型实现对大尺度森林土壤呼吸模型的预测值进行修正。结果表明,直接应用全球、全国尺度模型于广西和广东省,其精度相比原模型精度分别下降40%和53%。而基于两广内32个实测样点值,通过选取不同分区参数(森林类型、温度和降水)分别建立线性模型实现对两个大尺度模型的预测值进行修正,其中,降水分区参数得到的线性模型效果最好,使修正后的精度分别提高11% ~ 38%。因此,本文的建模方法可以解决区域内样点数量不足以建模的问题,较好的实现大尺度模型的区域化应用和优化,同时线性模型参数简单易于移植到其他的地区。

     

    Abstract: Prediction of forest soil respiration is of great significance to study carbon cycling and climate change in terrestrial ecosystems. The prediction models of different scales (global, national and regional) have different functions. Due to the limited number of sample points, researches on soil respiration models of regional scale are less. In this paper, a new idea of regional modeling was proposed, that was a linear model based on the finite sample points established to modify the predicted values of large-scale forest soil respiration model. The results showed that the accuracies of the global- and national- scale models applied in Guangxi Province and Guangdong Province were decreased by 40% and 53%, respectively compared with the original models. To modify the predicted data of the two large scale models, the parameters (such as the forest type, temperature and precipitation) with different categories were selected respectively to build linear models based on the 32 sample points in this two provinces. Among the parameters, the best linear model was built by the precipitation, which improved the modification accuracy by 11%-38%. Therefore, the modeling method in this study could solve the problem that the number of sample points in the region was not enough to model. Moreover, it also better realized the regional application and optimization of large-scale mode, which was applied simply and easily for other regions base on the linear model parameters.

     

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