Cloud radiative effects （CREs） at the top of the atmosphere （TOA） in three reanalysis datasets （the Eur- opean Center for Medium-Range Weather Forecasts In- terim Reanalysis （ERA-Interim）, the Japanese 55-yr Re...Cloud radiative effects （CREs） at the top of the atmosphere （TOA） in three reanalysis datasets （the Eur- opean Center for Medium-Range Weather Forecasts In- terim Reanalysis （ERA-Interim）, the Japanese 55-yr Re- analysis Project （JRA-55）, and the Modem-Era Retro- spective Analysis for Research and Applications （MERRA）） are evaluated using recent satellite-based observations. The reanalyses can basically capture the spatial pattern of the annual mean shortwave CRE, but the global mean longwave CRE in ERA-interim and JRA55 is weaker than observed, leading to overestimations of the net CRE. Moreover, distinct CRE biases of the reanalyses occur in the Intertropical Convergence Zone （ITCZ）, coastal Pa- cific and Atlantic regions, and East Asia. Quantitative examination further indicates that the spatial correlations of CREs and TOA upward radiation fluxes with corre- sponding observations in ERA-Interim are better than in the other two reanalyses. Although MERRA has certain abilities in producing the magnitudes of global mean CREs, its performance in terms of spatial correlations in winter and summer are worse than for the other two re- analyses. The ability of JRA55 in reflecting CREs lies between the other two datasets. Compared to the global mean results, the spatial correlations of shortwave CRE in East Asia decrease and the biases of regional mean CREs increase in the three reanalyses. This implies that, cur- rently, it is still difficult to reproduce East Asian CREs based on these reanalyses. Relatively, ERA-Interim de- scribes the seasonal variation of East Asian CREs well, albeit weaker than observed. The present study also sug- gests that in-depth exploration of the ability of reanalysis data to describe aspects relating to cloud properties and rad- iation is needed usin~ more comprehensive observations.展开更多
Well logging technology in coalbed methane （CBM） exploration may develop in two directions： one is the novel well logging methods; the other is the new interpretation methods for the conventional logging data, on w...Well logging technology in coalbed methane （CBM） exploration may develop in two directions： one is the novel well logging methods; the other is the new interpretation methods for the conventional logging data, on which the authors of this paper concentrated mainly. The paper introduced several methods in calculating with well logs such important parameters as porosity, permeability and gas content of CBM reservoir and evaluated their effectiveness. A new method of well logging data interpretation was put forward for coalbed recognition, i.e., the combination of the principal component analysis and the wavelet transform. The authors find that the second principal component （PCA2） contains much more information of coalbed in the coal-bearing series and the reconstruction signal from the detailed wavelet coefficients at level 4 （PCA24） and 5 （PCA25） highlights the signature ofcoalbeds. In terms of the characteristics of CBM reservoir in China, the authors summarized the key points in the application of well logging technique to CBM exploration, and gave a guideline for further related research work.展开更多
基金supported jointly by the National Basic Research Program of China(Grant Nos.2012CB955303 and 2013CB955803)the Chinese Academy of Sciences Ocean Project(Grant No.XDA11010402)+1 种基金the National Natural Science Foundation of China(Grant Nos.41175059 and 41375087)the Key Laboratory of Meteorological Disaster of Ministry of Education(Nanjing University of Information Science and Technology)(Grant No.KLME1409)
文摘Cloud radiative effects （CREs） at the top of the atmosphere （TOA） in three reanalysis datasets （the Eur- opean Center for Medium-Range Weather Forecasts In- terim Reanalysis （ERA-Interim）, the Japanese 55-yr Re- analysis Project （JRA-55）, and the Modem-Era Retro- spective Analysis for Research and Applications （MERRA）） are evaluated using recent satellite-based observations. The reanalyses can basically capture the spatial pattern of the annual mean shortwave CRE, but the global mean longwave CRE in ERA-interim and JRA55 is weaker than observed, leading to overestimations of the net CRE. Moreover, distinct CRE biases of the reanalyses occur in the Intertropical Convergence Zone （ITCZ）, coastal Pa- cific and Atlantic regions, and East Asia. Quantitative examination further indicates that the spatial correlations of CREs and TOA upward radiation fluxes with corre- sponding observations in ERA-Interim are better than in the other two reanalyses. Although MERRA has certain abilities in producing the magnitudes of global mean CREs, its performance in terms of spatial correlations in winter and summer are worse than for the other two re- analyses. The ability of JRA55 in reflecting CREs lies between the other two datasets. Compared to the global mean results, the spatial correlations of shortwave CRE in East Asia decrease and the biases of regional mean CREs increase in the three reanalyses. This implies that, cur- rently, it is still difficult to reproduce East Asian CREs based on these reanalyses. Relatively, ERA-Interim de- scribes the seasonal variation of East Asian CREs well, albeit weaker than observed. The present study also sug- gests that in-depth exploration of the ability of reanalysis data to describe aspects relating to cloud properties and rad- iation is needed usin~ more comprehensive observations.
基金This work was supported by Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry （2006331）, China Postdoctoral Science Foundation （20070411106） and Open Fund of Key Laboratory of Depositional Mineralization ＆ Sedimentary Mineral, Shandong Province （DMSM200802）.
文摘Well logging technology in coalbed methane （CBM） exploration may develop in two directions： one is the novel well logging methods; the other is the new interpretation methods for the conventional logging data, on which the authors of this paper concentrated mainly. The paper introduced several methods in calculating with well logs such important parameters as porosity, permeability and gas content of CBM reservoir and evaluated their effectiveness. A new method of well logging data interpretation was put forward for coalbed recognition, i.e., the combination of the principal component analysis and the wavelet transform. The authors find that the second principal component （PCA2） contains much more information of coalbed in the coal-bearing series and the reconstruction signal from the detailed wavelet coefficients at level 4 （PCA24） and 5 （PCA25） highlights the signature ofcoalbeds. In terms of the characteristics of CBM reservoir in China, the authors summarized the key points in the application of well logging technique to CBM exploration, and gave a guideline for further related research work.
