By epitaxial layer structure design and key fabrication process optimization,a lattice-matched InP-based In0.53Ga0.47 As-In0.52Al0.48As HEMT with an ultra high maximum oscillation frequency （fmax） of 183GHz was fab-...By epitaxial layer structure design and key fabrication process optimization,a lattice-matched InP-based In0.53Ga0.47 As-In0.52Al0.48As HEMT with an ultra high maximum oscillation frequency （fmax） of 183GHz was fab- ricated. The fmax is the highest value for HEMTs in China. Also, the devices are reported, including the device structure, the fabrication process, and the DC and RF performances.展开更多
A zonal teleconnection has been found along the Asian jet over the Eurasian continent during summer. In this study, the authors investigated circulation anomalies in the extratropics, in particular for the zonal telec...A zonal teleconnection has been found along the Asian jet over the Eurasian continent during summer. In this study, the authors investigated circulation anomalies in the extratropics, in particular for the zonal teleconnection, under different combinations of subtropical convection anomalies over the northern Indian continent （IND） and the westem North Pacific （WNP）. The outof-phase configuration （i.e., stronger （weaker） IND convection and weaker （stronger） WNP convection） was found to be more common than the in-phase configuration （i.e., stronger （weaker） IND convection and stronger （weaker） WNP convection）, which is consistent with previous results. Composite results indicated that circulation anomalies for out-of-phase configurations of 30-60-day convection oscillations are much stronger in the middle latitudes than those for in-phase configurations. In addition, zonal teleconnection patterns are predominant for the out-of-phase configurations, particularly for the configuration of strong IND convection and weak WNP convec- tion; however, they are either weak or obscure for the in-phase configurations. These results suggest that the zonal teleconnection pattem along the Asian jet is dependent on different combinations of the 1ND and WNP subtropical convection anomalies.展开更多
The interdecadal circumglobal teleconnection （ID-CGT） pattern is the dominant circulation mode over the NH during boreal summer on the interdecadal time scale. Its temporal evolution is synchronous with that of the ...The interdecadal circumglobal teleconnection （ID-CGT） pattern is the dominant circulation mode over the NH during boreal summer on the interdecadal time scale. Its temporal evolution is synchronous with that of the Atlantic Multidecadal Oscillation （AMO）. In this study, through analyzing the results of sensitivity experiments using five AGCMs driven by specified AMO-related SST anomalies （SSTAs） in the North Atlantic, the authors investigate whether the ID-CGT is excited by the AMO. Two out of the five models simulate the barotropic stationary wave pattern located along the westerly jet, suggesting that the ID-CGT pattern should be excited, at least partially, by the AMO- related SSTAs. Model results suggest that the ID-CGT pattern plays a role in linking the AMO and NH summer land SAT perturbations on the interdecadal time scale.展开更多
Atmospheric physics is a very complicated natural phenomenon and needs to simplify its basic models for the sea-air oscillator. And it is solved by using the approximate method. The variational iteration method is a s...Atmospheric physics is a very complicated natural phenomenon and needs to simplify its basic models for the sea-air oscillator. And it is solved by using the approximate method. The variational iteration method is a simple and valid method. In this paper the coupled system for a sea-air oscillator model of interdecadal climate fluctuations is considered. Firstly, through introducing a set of functions, and computing the variations, the Lagrange multipliers are obtained. And then, the generalized expressions of variational iteration are constructed. Finally, through selecting appropriate initial iteration from the iteration expressions, the approximations of solution for the sea-air oscillator model are solved successively.展开更多
The modulation of winter intraseasonal variability(ISV)by the Atlantic Multidecadal Oscillation(AMO)is investigated through three sets of reanalysis data and numerical experiments with the NCEP’s atmospheric general ...The modulation of winter intraseasonal variability(ISV)by the Atlantic Multidecadal Oscillation(AMO)is investigated through three sets of reanalysis data and numerical experiments with the NCEP’s atmospheric general circulation model(AGCM).Results show that the positive phase of the AMO tends to intensify ISV activity over the northern Atlantic and shift ISV activity over the Ural Mountains toward the south,causing weakened ISV activity at 200 hPa in the north to the Urals and intensified activity in the south.The modulation of ISV activity by the AMO over the Urals is then explored through comparison of the composite evolution of anomalous ISV cases for the different AMO phases.Fewer ISV cases are found in the AMO positive phase than the negative phase,but no substantial difference in the temporal evolution of anomalous ISV events between the two opposing phases of the AMO.Thus,the AMO exerts its modulation through influencing the occurrence frequency of ISV events,rather than their development or evolution processes.A similar result is seen in the AGCM sensitivity experiments.展开更多
Using the low-resolution （T31, equivalent to 3.75°× 3.75°） version of the Community Earth System Model （CESM） from the National Center for Atmospheric Research （NCAR）, a global climate simulation ...Using the low-resolution （T31, equivalent to 3.75°× 3.75°） version of the Community Earth System Model （CESM） from the National Center for Atmospheric Research （NCAR）, a global climate simulation was carried out with fixed external forcing factors （1850 Common Era. （C.E.） conditions） for the past 2000 years. Based on the simulated results, spatio-temporal structures of surface air temperature, precipitation and internal variability, such as the E1 Nifio-Southem Oscillation （ENSO）, the Atlantic Multi-decadal Oscilla- tion （AMO）, the Pacific Decadal Oscillation （PDO）, and the North Atlantic Oscillation （NAO）, were compared with reanalysis datasets to evaluate the model performance. The results are as follows： 1） CESM showed a good performance in the long-term simulation and no significant climate drift over the past 2000 years; 2） climatological patterns of global and regional climate changes simulated by the CESM were reasonable compared with the reanalysis datasets; and 3） the CESM simulated internal natural variability of the climate system performs very well. The model not only reproduced the periodicity of ENSO, AMO and PDO events but also the 3-8 years vari- ability of the ENSO. The spatial distribution of the CESM-simulated NAO was also similar to the observed. However, because of weaker total irradiation and greenhouse gas concentration forcing in the simulation than the present, the model performances had some differences from the observations. Generally, the CESM showed a good performance in simulating the global climate and internal natu- ral variability of the climate system. This paves the way for other forced climate simulations for the past 2000 years by using the CESM.展开更多
文摘By epitaxial layer structure design and key fabrication process optimization,a lattice-matched InP-based In0.53Ga0.47 As-In0.52Al0.48As HEMT with an ultra high maximum oscillation frequency （fmax） of 183GHz was fab- ricated. The fmax is the highest value for HEMTs in China. Also, the devices are reported, including the device structure, the fabrication process, and the DC and RF performances.
基金supported by the Chinese Academy of Sciences (Grant No. KZCX2-YW-220)the National Basic Research Program of China (Grant No. 2006CB403601)the National Natural Science Foundation of China (Grant No. 40725016)
文摘A zonal teleconnection has been found along the Asian jet over the Eurasian continent during summer. In this study, the authors investigated circulation anomalies in the extratropics, in particular for the zonal teleconnection, under different combinations of subtropical convection anomalies over the northern Indian continent （IND） and the westem North Pacific （WNP）. The outof-phase configuration （i.e., stronger （weaker） IND convection and weaker （stronger） WNP convection） was found to be more common than the in-phase configuration （i.e., stronger （weaker） IND convection and stronger （weaker） WNP convection）, which is consistent with previous results. Composite results indicated that circulation anomalies for out-of-phase configurations of 30-60-day convection oscillations are much stronger in the middle latitudes than those for in-phase configurations. In addition, zonal teleconnection patterns are predominant for the out-of-phase configurations, particularly for the configuration of strong IND convection and weak WNP convec- tion; however, they are either weak or obscure for the in-phase configurations. These results suggest that the zonal teleconnection pattem along the Asian jet is dependent on different combinations of the 1ND and WNP subtropical convection anomalies.
基金supported by the National Basic Research Program of China[grant number 2012CB955202]the National Natural Science Foundation of China[grant numbers 41005040 and 41023002]the R&D Special Fund for Public Welfare Industry(Meteorology)[grant number GYHY201506012]
文摘The interdecadal circumglobal teleconnection （ID-CGT） pattern is the dominant circulation mode over the NH during boreal summer on the interdecadal time scale. Its temporal evolution is synchronous with that of the Atlantic Multidecadal Oscillation （AMO）. In this study, through analyzing the results of sensitivity experiments using five AGCMs driven by specified AMO-related SST anomalies （SSTAs） in the North Atlantic, the authors investigate whether the ID-CGT is excited by the AMO. Two out of the five models simulate the barotropic stationary wave pattern located along the westerly jet, suggesting that the ID-CGT pattern should be excited, at least partially, by the AMO- related SSTAs. Model results suggest that the ID-CGT pattern plays a role in linking the AMO and NH summer land SAT perturbations on the interdecadal time scale.
文摘Atmospheric physics is a very complicated natural phenomenon and needs to simplify its basic models for the sea-air oscillator. And it is solved by using the approximate method. The variational iteration method is a simple and valid method. In this paper the coupled system for a sea-air oscillator model of interdecadal climate fluctuations is considered. Firstly, through introducing a set of functions, and computing the variations, the Lagrange multipliers are obtained. And then, the generalized expressions of variational iteration are constructed. Finally, through selecting appropriate initial iteration from the iteration expressions, the approximations of solution for the sea-air oscillator model are solved successively.
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA19070401]the National Natural Science Foundation of China[grant numbers 41790473 and41421004]the Fundamental Research Funds for the Central Universities
文摘The modulation of winter intraseasonal variability(ISV)by the Atlantic Multidecadal Oscillation(AMO)is investigated through three sets of reanalysis data and numerical experiments with the NCEP’s atmospheric general circulation model(AGCM).Results show that the positive phase of the AMO tends to intensify ISV activity over the northern Atlantic and shift ISV activity over the Ural Mountains toward the south,causing weakened ISV activity at 200 hPa in the north to the Urals and intensified activity in the south.The modulation of ISV activity by the AMO over the Urals is then explored through comparison of the composite evolution of anomalous ISV cases for the different AMO phases.Fewer ISV cases are found in the AMO positive phase than the negative phase,but no substantial difference in the temporal evolution of anomalous ISV events between the two opposing phases of the AMO.Thus,the AMO exerts its modulation through influencing the occurrence frequency of ISV events,rather than their development or evolution processes.A similar result is seen in the AGCM sensitivity experiments.
基金Under the auspices of National Basic Research Program of China(No.2010CB950102)Strategic and Special Frontier Project of Science and Technology of Chinese Academy of Sciences(No.XDA05080800)+3 种基金National Natural Science Foundation of China(No.41371209,41420104002)Special Research Fund for Doctoral Discipline of Higher Education Institutions(No.20133207110015)Natural Science Foundation of Jiangsu Higher Education Institutions(No.14KJA170002)Priority Academic Program Development of Jiangsu Higher Education Institutions(No.164320H101)
文摘Using the low-resolution （T31, equivalent to 3.75°× 3.75°） version of the Community Earth System Model （CESM） from the National Center for Atmospheric Research （NCAR）, a global climate simulation was carried out with fixed external forcing factors （1850 Common Era. （C.E.） conditions） for the past 2000 years. Based on the simulated results, spatio-temporal structures of surface air temperature, precipitation and internal variability, such as the E1 Nifio-Southem Oscillation （ENSO）, the Atlantic Multi-decadal Oscilla- tion （AMO）, the Pacific Decadal Oscillation （PDO）, and the North Atlantic Oscillation （NAO）, were compared with reanalysis datasets to evaluate the model performance. The results are as follows： 1） CESM showed a good performance in the long-term simulation and no significant climate drift over the past 2000 years; 2） climatological patterns of global and regional climate changes simulated by the CESM were reasonable compared with the reanalysis datasets; and 3） the CESM simulated internal natural variability of the climate system performs very well. The model not only reproduced the periodicity of ENSO, AMO and PDO events but also the 3-8 years vari- ability of the ENSO. The spatial distribution of the CESM-simulated NAO was also similar to the observed. However, because of weaker total irradiation and greenhouse gas concentration forcing in the simulation than the present, the model performances had some differences from the observations. Generally, the CESM showed a good performance in simulating the global climate and internal natu- ral variability of the climate system. This paves the way for other forced climate simulations for the past 2000 years by using the CESM.
