scholarly journals Observational Validation of Parameterized Gravity Waves From Tropical Convection in the Whole Atmosphere Community Climate Model

2021 ◽  
Vol 126 (7) ◽  
Author(s):  
M. J. Alexander ◽  
C. C. Liu ◽  
J. Bacmeister ◽  
M. Bramberger ◽  
A. Hertzog ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Climate Model ◽  
Tropical Convection ◽  
Community Climate Model ◽  
Community Climate

Observational validation of parameterized gravity waves from tropical convection in the Whole Atmosphere Community Climate Model (WACCM)

2020 ◽  
Author(s):  
M. Joan Alexander ◽  
Chuntao Liu ◽  
Julio T. Bacmeister ◽  
Martina Bramberger ◽  
Albert Hertzog ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Climate Model ◽  
Tropical Convection ◽  
Community Climate Model ◽  
Community Climate

scholarly journals On the Momentum Budget of the Quasi-Biennial Oscillation in the Whole Atmosphere Community Climate Model

2018 ◽  
Vol 76 (1) ◽  
pp. 69-87 ◽  
Author(s):  
Rolando R. Garcia ◽  
Jadwiga H. Richter
Keyword(s):  
Gravity Waves ◽  
Climate Model ◽  
Equatorial Waves ◽  
Quasi Biennial Oscillation ◽  
Community Climate Model ◽  
Westerly Jet ◽  
Momentum Budget ◽  
Zonal Wavenumber ◽  
Biennial Oscillation ◽  
Community Climate

Abstract This study documents the contribution of equatorial waves and mesoscale gravity waves to the momentum budget of the quasi-biennial oscillation (QBO) in a 110-level version of the Whole Atmosphere Community Climate Model. The model has high vertical resolution, 500 m, above the boundary layer and through the lower and middle stratosphere, decreasing gradually to about 1.5 km near the stratopause. Parameterized mesoscale gravity waves and resolved equatorial waves contribute comparable easterly and westerly accelerations near the equator. Westerly acceleration by resolved waves is due mainly to Kelvin waves of zonal wavenumber in the range k = 1–15 and is broadly distributed about the equator. Easterly acceleration near the equator is due mainly to Rossby–gravity (RG) waves with zonal wavenumbers in the range k = 4–12. These RG waves appear to be generated in situ during both the easterly and westerly phases of the QBO, wherever the meridional curvature of the equatorial westerly jet is large enough to produce reversals of the zonal-mean barotropic vorticity gradient, suggesting that they are excited by the instability of the jet. The RG waves produce a characteristic pattern of Eliassen–Palm flux divergence that includes strong easterly acceleration close to the equator and westerly acceleration farther from the equator, suggesting that the role of the RG waves is to redistribute zonal-mean vorticity such as to neutralize the instability of the westerly jet. Insofar as unstable RG waves might be present in the real atmosphere, mixing due to these waves could have important implications for transport in the tropical stratosphere.

scholarly journals Gravity waves simulated by high-resolution Whole Atmosphere Community Climate Model

2014 ◽  
Vol 41 (24) ◽  
pp. 9106-9112 ◽  
Author(s):  
H.-L. Liu ◽  
J. M. McInerney ◽  
S. Santos ◽  
P. H. Lauritzen ◽  
M. A. Taylor ◽  
...  
Keyword(s):  
High Resolution ◽  
Gravity Waves ◽  
Climate Model ◽  
Community Climate Model ◽  
Community Climate

Modification of the Gravity Wave Parameterization in the Whole Atmosphere Community Climate Model: Motivation and Results

2017 ◽  
Vol 74 (1) ◽  
pp. 275-291 ◽  
Author(s):  
Rolando R. Garcia ◽  
Anne K. Smith ◽  
Douglas E. Kinnison ◽  
Álvaro de la Cámara ◽  
Damian J. Murphy
Keyword(s):  
Gravity Wave ◽  
Southern Hemisphere ◽  
Gravity Waves ◽  
Climate Model ◽  
Lower Thermosphere ◽  
Careful Examination ◽  
Control Analysis ◽  
Community Climate Model ◽  
The Impact ◽  
Community Climate

Abstract The current standard version of the Whole Atmosphere Community Climate Model (WACCM) simulates Southern Hemisphere winter and spring temperatures that are too cold compared with observations. This “cold-pole bias” leads to unrealistically low ozone column amounts in Antarctic spring. Here, the cold-pole problem is addressed by introducing additional mechanical forcing of the circulation via parameterized gravity waves. Insofar as observational guidance is ambiguous regarding the gravity waves that might be important in the Southern Hemisphere stratosphere, the impact of increasing the forcing by orographic gravity waves was investigated. This reduces the strength of the Antarctic polar vortex in WACCM, bringing it into closer agreement with observations, and accelerates the Brewer–Dobson circulation in the polar stratosphere, which warms the polar cap and improves substantially the simulation of Antarctic temperature. These improvements are achieved without degrading the performance of the model in the Northern Hemisphere stratosphere or in the mesosphere and lower thermosphere of either hemisphere. It is shown, finally, that other approaches that enhance gravity wave forcing can also reduce the cold-pole bias such that careful examination of observational evidence and model performance will be required to establish which gravity wave sources are dominant in the real atmosphere. This is especially important because a “downward control” analysis of these results suggests that the improvement of the cold-pole bias itself is not very sensitive to the details of how gravity wave drag is altered.

scholarly journals The seasonal cycle of atmospheric CO2: A study based on the NCAR Community Climate Model (CCM2)

1996 ◽  
Vol 101 (D10) ◽  
pp. 15079-15097 ◽  
Author(s):  
D. J. Erickson ◽  
P. J. Rasch ◽  
P. P. Tans ◽  
P. Friedlingstein ◽  
P. Ciais ◽  
...  
Keyword(s):  
Seasonal Cycle ◽  
Climate Model ◽  
Atmospheric Co2 ◽  
Community Climate Model ◽  
Community Climate

Structure of the migrating diurnal tide in the Whole Atmosphere Community Climate Model (WACCM)

2008 ◽  
Vol 41 (9) ◽  
pp. 1398-1407 ◽  
Author(s):  
Loren Chang ◽  
Scott Palo ◽  
Maura Hagan ◽  
Jadwiga Richter ◽  
Rolando Garcia ◽  
...  
Keyword(s):  
Climate Model ◽  
Diurnal Tide ◽  
Community Climate Model ◽  
Community Climate

Climate statistics from the National Center for Atmospheric Research community climate model CCM2

1994 ◽  
Vol 99 (D10) ◽  
pp. 20785 ◽  
Author(s):  
J. J. Hack ◽  
B. A. Boville ◽  
J. T. Kiehl ◽  
P. J. Rasch ◽  
D. L. Williamson
Keyword(s):  
Climate Model ◽  
Research Community ◽  
Atmospheric Research ◽  
Community Climate Model ◽  
Climate Statistics ◽  
Community Climate

scholarly journals Climatology of migrating and non-migrating tides observed by three meteor radars in the southern equatorial region

2021 ◽  
Author(s):  
Jianyuan Wang ◽  
Wen Yi ◽  
Jianfei Wu ◽  
Tingdi Chen ◽  
Xianghui Xue ◽  
...  
Keyword(s):  
Harmonic Analysis ◽  
Northern Hemisphere ◽  
Climate Model ◽  
Equatorial Region ◽  
Stratospheric Sudden Warming ◽  
Tidal Model ◽  
Community Climate Model ◽  
Zonal Wavenumber ◽  
Climatic Features ◽  
Community Climate

Abstract. We present a study of migrating and non-migrating tidal winds observed simultaneously by three meteor radars situated in the southern equatorial region. The radars are located at Cariri (7.4° S, 36.5° W), Brazil, Kototabang (0.2° S, 100.3° E), Indonesia and Darwin (12.3° S, 130.8° E), Australia. Harmonic analysis was used to obtain amplitudes and phases for diurnal and semidiurnal solar migrating and non-migrating tides between 80 and 100 km altitude during the period 2005 to 2008. They include the important tidal components of diurnal westward-propagating zonal wavenumber 1 (DW1), diurnal eastward-propagating zonal wavenumber 3 (DE3), semidiurnal westward-propagating zonal wavenumber 2 (SW2), and semidiurnal eastward-propagating zonal wavenumber 2 (SE2). In addition, we also present a climatology of these wind tides and analyze the reliability of the fitting through the reference to Whole Atmosphere Community Climate Model (WACCM) winds. The analysis suggests that the migrating tides could be well fitted by the three different radars, but the non-migrating tides might be overestimated. The results based on observations were also compared with the Climatological Tidal Model of the Thermosphere (CTMT). In general, climatic features between observations and model migrating tides were satisfactory in both wind components. However, the features of the DW1, DE3 and SW2 amplitudes in both wind components were slightly different from the results of the CTMT models. This result is probably because tides could be enhanced by the 2006 northern hemisphere stratospheric sudden warming (NH-SSW) event.

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