The quasi-biennial oscillation(QBO),a dominant mode of the equatorial stratospheric(~100–1 hPa)variability,is known to impact tropospheric circulation in the middle and high latitudes.Yet,its realistic simulation in ...The quasi-biennial oscillation(QBO),a dominant mode of the equatorial stratospheric(~100–1 hPa)variability,is known to impact tropospheric circulation in the middle and high latitudes.Yet,its realistic simulation in general circulation models remains a challenge.The authors examine the simulated QBO in the 69-layer version of the Institute of Atmospheric Physics Atmospheric General Circulation Model(IAP-AGCML69)and analyze its momentum budget.The authors find that the QBO is primarily caused by parameterized gravity-wave forcing due to tropospheric convection,but the downward propagation of the momentum source is significantly offset by the upward advection of zonal wind by the equatorial upwelling in the stratosphere.Resolved-scale waves act as a positive contribution to the total zonal wind tendency of the QBO over the equator with comparable magnitude to the gravity-wave forcing in the upper stratosphere.Results provide insights into the mechanism of the QBO and possible causes of differences in models.展开更多
This paper has been addressed to the well-known problem of energy in gravitational waves. We have investigated the energy of cylindrical gravitational waves in the context of General Relativity and teleparallel theory...This paper has been addressed to the well-known problem of energy in gravitational waves. We have investigated the energy of cylindrical gravitational waves in the context of General Relativity and teleparallel theory of gravity. For this purpose, the prescriptions of Einstein, Landau-Lifshitz, Bergmann-Thomson, and Moeller are used in both the theories. It is shown that these energy-momentum complexes do not provide equivalent results in the two theories. However, these turn out to be constant for all the prescriptions except Moeller in both the theories at large distances.展开更多
An exact de Sitter solution of scalar-tensor gravity is found in our recent work, in which the non-minimal coupling scalar is rolling along a non-constant potential. Based on this solution, a dust-filled FRW universe ...An exact de Sitter solution of scalar-tensor gravity is found in our recent work, in which the non-minimal coupling scalar is rolling along a non-constant potential. Based on this solution, a dust-filled FRW universe is explored in frame of scalar-tensor gravity in this article. The effective dark energy induced by the sole non-minimal scalar can be quintessence-like, phantom-like, and more significantly, can cross the phantom divide. The rich and varied properties of scalar-tensor gravity even with only one scalar is shown.展开更多
基金This research was supported by the National Major Research High Performance Computing Program of China[grant number 2016YFB0200800]the National Natural Science Foundation of China[grant numbers 41630530 and 41706036]the National Key Scientific and Technological Infrastructure project“Earth System Science Numerical Simulator Facility”(EarthLab).
文摘The quasi-biennial oscillation(QBO),a dominant mode of the equatorial stratospheric(~100–1 hPa)variability,is known to impact tropospheric circulation in the middle and high latitudes.Yet,its realistic simulation in general circulation models remains a challenge.The authors examine the simulated QBO in the 69-layer version of the Institute of Atmospheric Physics Atmospheric General Circulation Model(IAP-AGCML69)and analyze its momentum budget.The authors find that the QBO is primarily caused by parameterized gravity-wave forcing due to tropospheric convection,but the downward propagation of the momentum source is significantly offset by the upward advection of zonal wind by the equatorial upwelling in the stratosphere.Resolved-scale waves act as a positive contribution to the total zonal wind tendency of the QBO over the equator with comparable magnitude to the gravity-wave forcing in the upper stratosphere.Results provide insights into the mechanism of the QBO and possible causes of differences in models.
文摘This paper has been addressed to the well-known problem of energy in gravitational waves. We have investigated the energy of cylindrical gravitational waves in the context of General Relativity and teleparallel theory of gravity. For this purpose, the prescriptions of Einstein, Landau-Lifshitz, Bergmann-Thomson, and Moeller are used in both the theories. It is shown that these energy-momentum complexes do not provide equivalent results in the two theories. However, these turn out to be constant for all the prescriptions except Moeller in both the theories at large distances.
基金supported by the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learningthe National Education Foundation of China(Grant No.200931271104)+2 种基金the National Natural Science Foundation of China(Grant Nos.11075106,11275128,11203006 and 11303003)Shandong Provincial Natural Science Foundation of China(Grant Nos.ZR2012AQ029 and ZR2013AM002)Nature Science Foundation of Zhejiang Province(Grant No.Y6110778)
文摘An exact de Sitter solution of scalar-tensor gravity is found in our recent work, in which the non-minimal coupling scalar is rolling along a non-constant potential. Based on this solution, a dust-filled FRW universe is explored in frame of scalar-tensor gravity in this article. The effective dark energy induced by the sole non-minimal scalar can be quintessence-like, phantom-like, and more significantly, can cross the phantom divide. The rich and varied properties of scalar-tensor gravity even with only one scalar is shown.
