Evaluation of Polar MM5 Simulations of Antarctic Atmospheric Circulation

Guo, Zhichang; Bromwich, David H.; Cassano, John J.
February 2003
Monthly Weather Review;Feb2003, Vol. 131 Issue 2, p384
Academic Journal
Evaluation of a complete annual cycle of nonhydrostatic mesoscale model simulations of the Antarctic atmospheric circulation is presented. The year-long time series are compiled from a series of overlapping short-duration (72 h) simulations of the atmospheric state with the first 24 h being discarded for spinup reasons, and the 24-72-h periods used for model evaluation. The simulations are generated with the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5), which is modified for polar applications, and is referred to as the Polar MM5. With a horizontal resolution of 60 km, the Polar MM5 has been run for the period of January 1993-December 1993, creating short-term simulations from initial and boundary conditions provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) Tropical Ocean Global Atmosphere (TOGA) operational analyses. The model output is compared with observations from automatic weather stations, upper-air data, and global atmospheric analyses as well as climatological maps over timescales from diurnal to annual. In comparison with the observations, the evaluation shows that simulations with the Polar MM5 capture both the large- and regional-scale circulation features with generally small bias in the modeled variables. For example, the differences between the observations and simulations at the 500-hPa level are usually less than 2°C for temperature and dewpoint temperature, and 20 m for geopotential height. On the annual timescale the largest errors in the model simulations are the deficient total cloud cover and precipitation, and the colder near-surface temperature over the interior of the Antarctic plateau. The deficiencies in the cloud prediction and precipitation simulation follow from low-level dry biases found in the Polar MM5 simulations, and the cold bias is related to the low predicted downward longwave radiation under clear skies in the radiation...


Related Articles

  • Summer Circulation and Temperature Structure of Lake Kinneret. Pan, Hai; Avissar, Roni; Haidvogel, Dale B. // Journal of Physical Oceanography;Jan2002, Vol. 32 Issue 1, p295 

    A three-dimensional lake model driven by wind stress and heat flux fields derived from an atmospheric model is applied to Lake Kinneret, Israel. The summer wind field over the lake has a strong diurnal and large spatial variation due to complex terrain surrounding the lake, the sharp temperature...

  • The Impact of ENSO on Extratropical Low-Frequency Noise in Seasonal Forecasts. Schubert; Suarez, Max J.; Yehui Chang // Journal of Climate;5/15/2001, Vol. 14 Issue 10, p2351 

    This study examines the variability in forecasts of the January-February-March (JFM) mean extratropical circulation and how that variability is modulated by the El Niño-Southern Oscillation. The analysis is based on ensembles of seasonal simulations made with an atmospheric general...

  • Regional mountain torque estimates over the Rocky Mountains in lee cyclones. Czarnetzki, Alan C. // Journal of the Atmospheric Sciences;8/1/97, Vol. 54 Issue 15, p1986 

    Presents a study which examined the earth-atmosphere exchange of atmospheric angular momentum over a portion of the Rocky Mountains for three lee cyclones, highlighting the distribution of the mountain torque. Importance of the mountain torque to the regional balance of atmospheric angular...

  • Cloud-level penetrative compressible convection in the Venus atmosphere. Jones, Philip W.; Baker, R. David; Schubert, Gerald // Journal of the Atmospheric Sciences;1/1/98, Vol. 55 Issue 1, p3 

    Examines the role of convection in the cloud region of the Venus atmosphere. Indepth look at cellular convection; Methodology used in the examination; Implications of the results for the atmosphere of Venus.

  • Maintenance of circulation anomalies during the 1998 drought and 1993 floods over the United States. Liu, Alan Z.; Ting, Mingfang; Wang, Hailan // Journal of the Atmospheric Sciences;9/1/98, Vol. 55 Issue 17, p2810 

    Analyzes large-scale circulation anomalies associated with the 1988 drought and the 1993 floods in the United States. Description of research methodology used; Examination of differences in monthly climates; In-depth look at the stationary wave anomalies for 1988 and 1993.

  • Preferred and unpreferred circulation types in the Northern Hemisphere wintertime phase space. Toth, Zoltan // Journal of the Atmospheric Sciences;9/1/93, Vol. 50 Issue 17, p2868 

    Investigates local density maxima and minima in the Northern Hemisphere extratropical wintertime circulation phase. Twenty-eight out of 273 circulation maps showing higher local density than that expected from a multinormal distribution; Existence of multiple flow regimes in the hemispheric...

  • A mechanism of scale selection in tropical circulation at observed intraseasonal frequencies. Goswami, Prashant; Mathew, Vincent // Journal of the Atmospheric Sciences;11/1/94, Vol. 51 Issue 21, p3155 

    Presents a mechanism of scale selection in tropical circulation at observed intraseasonal frequencies. Intraseasonal oscillations of the tropical atmosphere; Dynamics of the moisture variable; Moist feedbacks in the presence of a moisture relaxation timescale.

  • Orographically induced stationary waves: Dependence on latitude. Ringler, T.D.; Cook, K.H. // Journal of the Atmospheric Sciences;7/15/95, Vol. 52 Issue 14, p2548 

    Examines the effects of a mountain's latitudinal position on the stationary wave response by using a general circulation model (GCM) with idealized boundary conditions. GCM and model experiments; Stationary wave response in the GCM; Linear model justification; Reversal of weak easterly flow on...

  • The impact of tropical forcing on extratropical predictability in a simple global model. Jianchun Qin; Robinson, Walter A. // Journal of the Atmospheric Sciences;11/15/95, Vol. 52 Issue 22, p3895 

    Studies the impact of tropical forcing on the predictability of the extratropical atmosphere. Two-layer spectral model; Enhancement of predictability from the knowledge of tropical forcing; Relation of robust response to tropical forcing on extratropical predictions.


Read the Article


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

Try another library?
Sign out of this library

Other Topics