关键词: 相关长度-逐块筛选指数, 生态网络, 介数指数, 生态安全格局, 青岛市

Abstract: A quantitative relationship exists between leaf area index (LAI) and leaf inclination angle distribution (LAD), two important parameters in study of vegetation canopy structure. In this study, the quantitative relationship between LAI and LAD of Betula platyphylla pure forest was analyzed based on the data of single line, multi-angle measurement by TRAC, with Norman and Campbell’s linear least-square inversion technique (NC technique) and Campbell model. The NC technique received a very good inversion result of leaf inclination angle distribution, and its interpretation capacity to the measured leaf angle distribution was up to 90%. The leaf inclination probability density calculated by the NC technique was slightly higher than the real density, while the fitting result of Campbell model was relatively lower, especially in the interval of \[0°, 10°\]. Considering the complementary relationship between the results of the two techniques, the correlation between the mean values of the results of the two techniques and the measured results was up to 96%. Besides, when using the NC technique, it is best that the number of the leaf angle interval is half of the number of the solar zenith angle during multiangle measurements. Our study provides an algorithm for LAI and LAD and a theoretical basis for parameter optimization of quantitative remote sensing. Meanwhile, the quantitative inversion of LAI can provide strong authentication in a wide range of LAI measurements.

Key words: dynamic ecological security pattern, ecological network, betweenness centrality index, correlation length-percentage of importance of omitted patches, Qingdao City