Long-Term Trends of Carbon Monoxide Total Columnar Amount in Urban Areas and Background Regions:Ground-and Satellite-based Spectroscopic Measurements

A comparative study was carried out to explore carbon monoxide total columnar amount（CO TC） in background and polluted atmosphere, including the stations of ZSS（Zvenigorod）, ZOTTO（Central Siberia）, Peterhof, Beijing, and Moscow,during 1998–2014, on the basis of ground-and satellite-based spectroscopic measurements. Interannual variations of CO TC in different regions of Eurasia were obtained from ground-based spectroscopic observations, combined with satellite data from the sensors MOPITT（2001–14）, AIRS（2003–14）, and IASI Met Op-A（2010–13）. A decreasing trend in CO TC（1998–2014） was found at the urban site of Beijing, where CO TC decreased by 1.14% ± 0.87% yr^（-1）. Meanwhile, at the Moscow site, CO TC decreased remarkably by 3.73% ± 0.39% yr^（-1）. In the background regions（ZSS, ZOTTO, Peterhof）, the reduction was 0.9%–1.7% yr^（-1） during the same period. Based on the AIRSv6 satellite data for the period 2003–14, a slight decrease（0.4%–0.6% yr^（-1）） of CO TC was detected over the midlatitudes of Eurasia, while a reduction of 0.9%–1.2% yr^（-1） was found in Southeast Asia. The degree of correlation between the CO TC derived from satellite products（MOPITTv6 Joint, AIRSv6 and IASI Met Op-A） and ground-based measurements was calculated, revealing significant correlation in unpolluted regions.While in polluted areas, IASI Met Op-A and AIRSv6 data underestimated CO TC by a factor of 1.5–2.8. On average, the correlation coefficient between ground-and satellite-based data increased significantly for cases with PBL heights greater than 500 m.

Spectroscopic measurement approaches in evaluation of dry rubber content of cup lump rubber using machine learning techniques

Dry rubber content(DRC)is an important factor to be considered in evaluating the quality of cup lump rubber.The DRC analysis requires prolonged laboratory validation.To develop fast and effective DRC determination methods,this study proposed methods to evaluate the DRC of cup lump rubber using different spectroscopic measurement approaches.This involved a complete fundamental analysis leading to an efficient measurement method based on either point-based measurement using NIR reflectance spectrometer or area-based measurement using hyperspectral imaging.A dataset was prepared that 120 samples were randomly divided into a calibration set of 90 samples and a validation set of 30 samples.To obtain an average spectrum to represent a cup lump rubber sample,the spectral data were collected by locating and scanning for point-based and area-based measurement,respectively.The spectral data were calibrated using partial least squares regression(PLSR)and the least-squares support vector machine(LS-SVM)methods against the reference values.The experiments showed that the area-based measurement approach with both algorithms performed outstandingly in predicting the DRC of cup lump rubber and was clearly better than the point-based measurement approach.The best predictions of PLSR represented by the coefficient of determination(R2),the root mean square error of prediction(RMSEP)and the residual predictive deviation(RPD)were 0.99,0.72%and 15.17,while the best prediction of LS-SVM were 0.99,0.64%and 16.83,respectively.In summary,the area-based measurement based on the LS-SVM prediction model provided a highly accurate estimate of the DRC of cup lump rubber.

The Spectroscopic Systems for the Study of Light Impurity Particle Transport in the HT-7 Tokamak

Three spectroscopic systems have been developed for the study of light impurity particle transport in the HT-7 tokamak. A visible multi-channel spectroscopic system （VIS） is used to obtain the brightness distribution of the line emission from ionized light impurities. The profile of Zeff（r） has been obtained from the visible multi-channel bremsstrahlung measurement （VB）. The system with a rotating hexahedral mirror for space-time resolved spectroscopy measurement from ultraviolet to visible （UV） can provide the brightness distribution of two different emission lines of the light impurities simultaneously. The emissivities by these multi-channel measurements can be obtained by Abel inversion. The measurement was performed in typical OH discharges in the HT-7 tokamak. The carbon particle transport was analyzed. The feasibility of these diagnostic systems for the impurity particle transport study is clearly demonstrated.