The Brewer-Dobson Circulation in a Changing Climate: Impact of the Model Configuration

Bunzel, Felix; Schmidt, Hauke
May 2013
Journal of the Atmospheric Sciences;May2013, Vol. 70 Issue 5, p1437
Academic Journal
Most climate models simulate a strengthening of the Brewer-Dobson circulation (BDC) under a changing climate. However, the magnitude of the trend as well as the underlying mechanisms varies significantly among the models. In this work the impact of both vertical resolution and vertical extent of a model on the simulated BDC change is investigated by analyzing sensitivity simulations performed with the general circulation model ECHAM6 in three different model configurations for three different climate states. Tropical upwelling velocities and age of stratospheric air are used as measures for the strength of the BDC. Both consistently show a BDC strengthening from the preindustrial to the future climate state for all configurations of the model. However, the amplitude and origin of this change vary between the different setups. Analyses of the tropical upward mass flux indicate that in the model with a lid at 10 hPa the BDC strengthening at 70 hPa is primarily produced by resolved wave drag, while in the model with a higher lid (0.01 hPa) the parameterized wave drag yields the main contribution to the BDC increase. This implies that consistent changes in the BDC originate from different causes when the stratosphere is not sufficiently resolved in a model. Furthermore, the effect of enhancing the horizontal diffusion in the upper model layers to avoid resolved wave reflection at the model lid is quantified, and a possible link to the different behavior of the low-top model with regard to the origin of the BDC change is identified.


Related Articles

  • Climatology and Forcing of the Quasi-Biennial Oscillation in the MAECHAM5 Model. Giorgetta, M. A.; Manzini, E.; Roeckner, E.; Esch, M.; Bengtsson, L. // Journal of Climate;Aug2006, Vol. 19 Issue 16, p3882 

    The quasi-biennial oscillation (QBO) in the equatorial zonal wind is an outstanding phenomenon of the atmosphere. The QBO is driven by a broad spectrum of waves excited in the tropical troposphere and modulates transport and mixing of chemical compounds in the whole middle atmosphere. Therefore,...

  • Regional climate change experiments over southern South America. I: present climate. Solman, Silvina A.; Nu�ez, Mario N.; Cabr�, Mar�a Fernanda // Climate Dynamics;May2008, Vol. 30 Issue 5, p533 

    We present an analysis of a regional simulation of present-day climate (1981�1990) over southern South America. The regional model MM5 was nested within time-slice global atmospheric model experiments conducted by the HadAM3H model. We evaluate the capability of the model in simulating the...

  • The simulation of medicanes in a high-resolution regional climate model. Cavicchia, Leone; Storch, Hans // Climate Dynamics;Nov2012, Vol. 39 Issue 9/10, p2273 

    Medicanes, strong mesoscale cyclones with tropical-like features, develop occasionally over the Mediterranean Sea. Due to the scarcity of observations over sea and the coarse resolution of the long-term reanalysis datasets, it is difficult to study systematically the multidecadal statistics of...

  • Sensitivity of seasonal precipitation extremes to model configuration of the Canadian Regional Climate Model over eastern Canada using historical simulations. Roy, Philippe; Gachon, Philippe; Laprise, René // Climate Dynamics;Nov2014, Vol. 43 Issue 9/10, p2431 

    This study analyzes the uncertainty of seasonal (winter and summer) precipitation extremes as simulated by a recent version of the Canadian Regional Climate Model (CRCM) using 16 simulations (1961-1990), considering four sources of uncertainty from: (a) the domain size, (b) the driving...

  • Tropospheric temperature response to stratospheric ozone recovery in the 21st century. Hu, Y.; Xia, Y.; Fu, Q. // Atmospheric Chemistry & Physics;2011, Vol. 11 Issue 15, p7687 

    Recent simulations predicted that the stratospheric ozone layer will likely return to pre-1980 levels in the middle of the 21st century, as a result of the decline of ozone depleting substances under the Montreal Protocol. Since the ozone layer is an important component in determining...

  • Last Millennium Climate Simulations Still Falling Short of Reality.  // CO2 Science;8/7/2013, Vol. 16 Issue 32, p5 

    The article discusses a study led by L. Landrum published in a 2013 issue of "Journal of Climate" on the Last Millenium (LM) simulation of the Community Climate System Model, version 4 (CCSM4). Researchers compared LM simulations to actual temperature data reconstructions, hydrologic cycles and...

  • Twentieth-Century Surface Air Temperature over China and the Globe Simulated by Coupled Climate Models. Tianjun Zhou; Rucong Yu // Journal of Climate;Nov2006, Vol. 19 Issue 22, p5843 

    This paper examines variations of the surface air temperature (SAT) over China and the globe in the twentieth century simulated by 19 coupled climate models driven by historical natural and anthropogenic forcings. Most models perform well in simulating both the global and the Northern...

  • A Simulated Climatology of Spectrally Decomposed Atmospheric Infrared Radiation. Huang, Yi // Journal of Climate;Mar2013, Vol. 26 Issue 5, p1702 

    A simulation experiment is conducted to inquire into the mean climate state and likely trends in atmospheric infrared radiation spectra. Upwelling and downwelling spectra at five vertical levels from the surface to the top of the atmosphere (TOA) are rigorously calculated from a...

  • A high-resolution ocean-atmosphere coupled downscaling of the present climate over California. Li, Haiqin; Kanamitsu, Masao; Hong, Song-You; Yoshimura, Kei; Cayan, Daniel; Misra, Vasubandhu // Climate Dynamics;Feb2014, Vol. 42 Issue 3/4, p701 

    A fully coupled regional ocean-atmosphere model system that consists of the regional spectral model and the regional ocean modeling system for atmosphere and ocean components, respectively, is applied to downscale the present climate (1985-1994) over California from a global simulation of the...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics