针对目前近红外光谱分析中模型传递现有方法的局限性,文章介绍了一种简便的近红外光谱标准化方法,并构造了一种新的光谱标准化误差指标(spectra standard error,SSE)作为评价传递结果的指标。SSE为J2和J1的比值,这里,J2表示同一样本在...针对目前近红外光谱分析中模型传递现有方法的局限性,文章介绍了一种简便的近红外光谱标准化方法,并构造了一种新的光谱标准化误差指标(spectra standard error,SSE)作为评价传递结果的指标。SSE为J2和J1的比值,这里,J2表示同一样本在不同仪器上测得的谱线的距离,J1表示目标机的不同样本相对中心谱线的平均距离。文章首先对不同光谱仪所测得的吸光度谱图进行多项式卷积平滑处理以去除基线,接着采用标准归一法以实现谱图的标准化,并采用多项式卷积滤波以去除噪声。为使SSE达到最小,在处理过程中可进行波长范围和卷积窗口宽度的优化。经过上述处理后的标准化谱图可用于光谱建模分析。该方法不需要预先获得大量样本,也不需要将同一样本在不同光谱仪上测得的谱图进行比较。针对一批汽油样本的试验结果表明,借助于此方法可使SSE从1.418下降至0.167,谱图标准化效果令人满意。展开更多
Based on daily mean temperature records from 1961 to 2007 at 20 meteorological sites in Southwest Yunnan, and the surface temperature simulated by IPCC AR4 Climate Models, a quantitative examination was undertaken int...Based on daily mean temperature records from 1961 to 2007 at 20 meteorological sites in Southwest Yunnan, and the surface temperature simulated by IPCC AR4 Climate Models, a quantitative examination was undertaken into the characteristics of multi-timescale temperature （AMT, DMT and WMT） variation in Southwest Yunnan. The simulation abilities of the models were also evaluated with the normalized root mean square error （NRMSE） and Mann-Kendal test statistic methods. Temperatures show remarkable increasing trend from 1961 to 2007, with the Mann-Kendall test statistic passing 95% confidence verification. The result of the NRMSE analysis shows that the simulated temperature anomaly variations are more similar to observed ones especially for AMT and DMT, and the projected result （anomalies） of IPCC AR4 climate models can be used for predicting the trends in multi-timescale temperature variation in Southwest Yunnan in the next 40 years under the three emission scenarios, which has better simulating effect on AMT and DMT than WMT. Over the next 40 years the temperature will continue to rise, with annual mean temperature showing a more remarkable rising trend than that of the dry and wet seasons. Temperature anomalies exhibit different increasing rates under different emission scenarios： During the 2020s the rising rates of multi-timescale temperature anomalies in a high greenhouse gases emissions scenario （SRESA2） are smaller than those under a low emission scenario （SRESB1）. Except that, the rate of increase in temperature anomalies are the highest in the intermediate emissions scenario （SRESA1B）, followed by those in SRESA2, and those in low emissions scenario （SRESB1） are the lowest. The reason of different simulating effects on WMT from AMT and DMT was also discussed.展开更多
文摘针对目前近红外光谱分析中模型传递现有方法的局限性,文章介绍了一种简便的近红外光谱标准化方法,并构造了一种新的光谱标准化误差指标(spectra standard error,SSE)作为评价传递结果的指标。SSE为J2和J1的比值,这里,J2表示同一样本在不同仪器上测得的谱线的距离,J1表示目标机的不同样本相对中心谱线的平均距离。文章首先对不同光谱仪所测得的吸光度谱图进行多项式卷积平滑处理以去除基线,接着采用标准归一法以实现谱图的标准化,并采用多项式卷积滤波以去除噪声。为使SSE达到最小,在处理过程中可进行波长范围和卷积窗口宽度的优化。经过上述处理后的标准化谱图可用于光谱建模分析。该方法不需要预先获得大量样本,也不需要将同一样本在不同光谱仪上测得的谱图进行比较。针对一批汽油样本的试验结果表明,借助于此方法可使SSE从1.418下降至0.167,谱图标准化效果令人满意。
基金National Natural Science Foundation of China (40901050), National Basic Research Program of China (No. 2012CB955903)Scientific Research Fund Project of Yunnan Provincial Department of Education (No. 09Y0284, "Technology Research of Adaptation and Mitigation to Yunnan Climate Change")
文摘Based on daily mean temperature records from 1961 to 2007 at 20 meteorological sites in Southwest Yunnan, and the surface temperature simulated by IPCC AR4 Climate Models, a quantitative examination was undertaken into the characteristics of multi-timescale temperature （AMT, DMT and WMT） variation in Southwest Yunnan. The simulation abilities of the models were also evaluated with the normalized root mean square error （NRMSE） and Mann-Kendal test statistic methods. Temperatures show remarkable increasing trend from 1961 to 2007, with the Mann-Kendall test statistic passing 95% confidence verification. The result of the NRMSE analysis shows that the simulated temperature anomaly variations are more similar to observed ones especially for AMT and DMT, and the projected result （anomalies） of IPCC AR4 climate models can be used for predicting the trends in multi-timescale temperature variation in Southwest Yunnan in the next 40 years under the three emission scenarios, which has better simulating effect on AMT and DMT than WMT. Over the next 40 years the temperature will continue to rise, with annual mean temperature showing a more remarkable rising trend than that of the dry and wet seasons. Temperature anomalies exhibit different increasing rates under different emission scenarios： During the 2020s the rising rates of multi-timescale temperature anomalies in a high greenhouse gases emissions scenario （SRESA2） are smaller than those under a low emission scenario （SRESB1）. Except that, the rate of increase in temperature anomalies are the highest in the intermediate emissions scenario （SRESA1B）, followed by those in SRESA2, and those in low emissions scenario （SRESB1） are the lowest. The reason of different simulating effects on WMT from AMT and DMT was also discussed.
