An exceptionally prolonged heavy snow event(PHSE)occurred in southern China from 10 January to 3 February 2008,which caused considerable economic losses and many casualties.To what extent any dynamical model can predi...An exceptionally prolonged heavy snow event(PHSE)occurred in southern China from 10 January to 3 February 2008,which caused considerable economic losses and many casualties.To what extent any dynamical model can predict such an extreme event is crucial for disaster prevention and mitigation.Here,we found the three S2S models(ECMWF,CMA1.0 and CMA2.0)can predict the distribution and intensity of precipitation and surface air temperature(SAT)associated with the PHSE at 10-day lead and 10−15-day lead,respectively.The success is attributed to the models’capability in forecasting the evolution of two important low-frequency systems in the tropics and mid-latitudes[the persistent Siberian High and the suppressed phase of the Madden−Julian Oscillation(MJO)],especially in the ECMWF model.However,beyond the 15-day lead,the three models show almost no skill in forecasting this PHSE.The bias in capturing the two critical circulation systems is responsible for the low skill in forecasting the 2008 PHSE beyond the 15-day lead.On one hand,the models cannot reproduce the persistence of the Siberian High,which results in the underestimation of negative SAT anomalies over southern China.On the other hand,the models cannot accurately capture the suppressed convection of the MJO,leading to weak anomalous southerly and moisture transport,and therefore the underestimation of precipitation over southern China.The Singular Value Decomposition(SVD)analyses between the critical circulation systems and SAT/precipitation over southern China shows a robust historical relation,indicating the fidelity of the predictability sources for both regular events and extreme events(e.g.,the 2008 PHSE).展开更多
Substantial development has been achieved in snow cover delineations through binary mapping techniques. Continuous efforts for development and institution of methodologies in fractional snow cover mapping are steadily...Substantial development has been achieved in snow cover delineations through binary mapping techniques. Continuous efforts for development and institution of methodologies in fractional snow cover mapping are steadily conducted by the research communities. In this work, the attempts are driven towards the attainment of the same. MODIS (Moderate Resolution Imaging Spectroradiometer) images are worked upon Landsat 8 images under multivariate polynomial regression schemes utilizing corresponding count of pixels in a test region of Himachal Pradesh. 11.00 μm centered waveband is employed to develop a scheme for snow mapping followed by a qualitative and quantitative comparison with NDSI and S3 snow index where the values of correlation coefficient between fractional snow cover and index values have been obtained as 77.04%, 78.82% and 85.15% for NDSI, S3 and our scheme respectively. Exponential empirical relationships have been tried to be employed to attain improvements in prediction of snow cover followed by a test of correlation between true and theoretical fractional snow cover values. An improvement in degree of correlation is obtained over the conventional methodologies which serves for the verification of scheme employed and empirical relationship defined, collectively. The results provide a scope for improvements and investigations in the subject of fractional snow cover mapping.展开更多
In this study, mitochondrial 16S rRNA sequences of snow leopard, gray wolf, domestic horse and Bactrian camel inhabited or domesticated in Mongolian territory were obtained by using polymerase chain reaction （PCR） b...In this study, mitochondrial 16S rRNA sequences of snow leopard, gray wolf, domestic horse and Bactrian camel inhabited or domesticated in Mongolian territory were obtained by using polymerase chain reaction （PCR） based on universal primers for 16S rRNA （F-5＇-AACGAGCCTGGTGATA-3＇ and R-5＇-CTCCGGTCTGAACTCAGATCACGTA-3＇）. The 16S rRNA sequence was 1,048 bp to 1,086 bp in length, and each sequence was compared to other related species （Felidae, Camelidae, Equidae and Canidae） by using NCBI Basic Local Alignment Search Tool （BLAST）. Results showed that sequences were highly similar to sequences in GenBank database （93%-99%）. Then phylogenetic analysis was performed based on about 1,100 bp sequence of 16S rRNA for Panthera uncia, Canis lupus, Equus caballus, Camelus bactrianus and other related species. The result revealed that P. uncia and P. leo were sister species, C. bactrianus and C. ferus were more closely related species, and wolf and dog were the almost similar species. This finding could be important for designing species specific primers for PCR based analysis of animal species identification and forensic veterinary medicine.展开更多
＂Snow＇s proposition＂ points out the contradictions and conflicts between ＂scientific culture＂ and ＂literary culture＂ and the dilemma of the development of the ＂two cultures.＂ In the positive sense, Snow＇s pr...＂Snow＇s proposition＂ points out the contradictions and conflicts between ＂scientific culture＂ and ＂literary culture＂ and the dilemma of the development of the ＂two cultures.＂ In the positive sense, Snow＇s proposition concerns the contradictions between the integrity of the research subject and the particularity of established disciplines, as well as the trend toward division and isolation in subdivisions of the humanities and social sciences. The key to solving Snow＇s proposition is to take an inter-disciplinary path that pays particular attention to combining discipline-centered with issue-centered research and individual work with teamwork, giving full play to individual endowment, social orientation and environmental orientation and to the optimization of evaluation systems and mechanisms.展开更多
基金The authors greatly appreciate the professional and earnest review made by the anonymous reviewers which for sure improved the quality of our manuscript.This work was supported by the National Key R&D Program of China(Grant Nos.2018YFC1505905&2018YFC1505803)the National Natural Science Foundation of China(Grant Nos.42088101,41805048 and 41875069)Tim LI was supported by NSF AGS-1643297 and NOAA Grant NA18OAR4310298.
文摘An exceptionally prolonged heavy snow event(PHSE)occurred in southern China from 10 January to 3 February 2008,which caused considerable economic losses and many casualties.To what extent any dynamical model can predict such an extreme event is crucial for disaster prevention and mitigation.Here,we found the three S2S models(ECMWF,CMA1.0 and CMA2.0)can predict the distribution and intensity of precipitation and surface air temperature(SAT)associated with the PHSE at 10-day lead and 10−15-day lead,respectively.The success is attributed to the models’capability in forecasting the evolution of two important low-frequency systems in the tropics and mid-latitudes[the persistent Siberian High and the suppressed phase of the Madden−Julian Oscillation(MJO)],especially in the ECMWF model.However,beyond the 15-day lead,the three models show almost no skill in forecasting this PHSE.The bias in capturing the two critical circulation systems is responsible for the low skill in forecasting the 2008 PHSE beyond the 15-day lead.On one hand,the models cannot reproduce the persistence of the Siberian High,which results in the underestimation of negative SAT anomalies over southern China.On the other hand,the models cannot accurately capture the suppressed convection of the MJO,leading to weak anomalous southerly and moisture transport,and therefore the underestimation of precipitation over southern China.The Singular Value Decomposition(SVD)analyses between the critical circulation systems and SAT/precipitation over southern China shows a robust historical relation,indicating the fidelity of the predictability sources for both regular events and extreme events(e.g.,the 2008 PHSE).
文摘Substantial development has been achieved in snow cover delineations through binary mapping techniques. Continuous efforts for development and institution of methodologies in fractional snow cover mapping are steadily conducted by the research communities. In this work, the attempts are driven towards the attainment of the same. MODIS (Moderate Resolution Imaging Spectroradiometer) images are worked upon Landsat 8 images under multivariate polynomial regression schemes utilizing corresponding count of pixels in a test region of Himachal Pradesh. 11.00 μm centered waveband is employed to develop a scheme for snow mapping followed by a qualitative and quantitative comparison with NDSI and S3 snow index where the values of correlation coefficient between fractional snow cover and index values have been obtained as 77.04%, 78.82% and 85.15% for NDSI, S3 and our scheme respectively. Exponential empirical relationships have been tried to be employed to attain improvements in prediction of snow cover followed by a test of correlation between true and theoretical fractional snow cover values. An improvement in degree of correlation is obtained over the conventional methodologies which serves for the verification of scheme employed and empirical relationship defined, collectively. The results provide a scope for improvements and investigations in the subject of fractional snow cover mapping.
文摘In this study, mitochondrial 16S rRNA sequences of snow leopard, gray wolf, domestic horse and Bactrian camel inhabited or domesticated in Mongolian territory were obtained by using polymerase chain reaction （PCR） based on universal primers for 16S rRNA （F-5＇-AACGAGCCTGGTGATA-3＇ and R-5＇-CTCCGGTCTGAACTCAGATCACGTA-3＇）. The 16S rRNA sequence was 1,048 bp to 1,086 bp in length, and each sequence was compared to other related species （Felidae, Camelidae, Equidae and Canidae） by using NCBI Basic Local Alignment Search Tool （BLAST）. Results showed that sequences were highly similar to sequences in GenBank database （93%-99%）. Then phylogenetic analysis was performed based on about 1,100 bp sequence of 16S rRNA for Panthera uncia, Canis lupus, Equus caballus, Camelus bactrianus and other related species. The result revealed that P. uncia and P. leo were sister species, C. bactrianus and C. ferus were more closely related species, and wolf and dog were the almost similar species. This finding could be important for designing species specific primers for PCR based analysis of animal species identification and forensic veterinary medicine.
文摘＂Snow＇s proposition＂ points out the contradictions and conflicts between ＂scientific culture＂ and ＂literary culture＂ and the dilemma of the development of the ＂two cultures.＂ In the positive sense, Snow＇s proposition concerns the contradictions between the integrity of the research subject and the particularity of established disciplines, as well as the trend toward division and isolation in subdivisions of the humanities and social sciences. The key to solving Snow＇s proposition is to take an inter-disciplinary path that pays particular attention to combining discipline-centered with issue-centered research and individual work with teamwork, giving full play to individual endowment, social orientation and environmental orientation and to the optimization of evaluation systems and mechanisms.
