The Madden-Julian oscillation in the Canadian Climate Centre general circulation model

Sheng, Jian

doi:10.1007/bf00223725

Cited by 8 publications

(2 citation statements)

References 29 publications

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“…Maloney and Hartmann (2001) and Maloney (2002) found that the standard CCM3 employing the deep convection parameterization of Zhang and McFarlane (1995;hereafter ZM95) produced an MJO signal in zonal winds and precipitation with an amplitude much weaker than observed. A weak MJO is also produced in the Canadian Climate Center GCM with the same deep convective scheme (Sheng 1995). As shown by Maloney and Hartmann (2001) and Maloney (2002), the MJO in the CCM3 was markedly improved by implementing the relaxed Arakawa-Schubert (McRAS) scheme of Moorthi and Suarez (1992) as modified by Sud and Walker (1999).…”

Section: Introductionmentioning

confidence: 86%

MJO in the NCAR CAM2 with the Tiedtke Convective Scheme*

et al. 2005

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The boreal winter Madden–Julian oscillation (MJO) remains very weak and irregular in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model version 2 (CAM2) as in its direct predecessor, the Community Climate Model version 3 (CCM3). The standard version of CAM2 uses the deep convective scheme of Zhang and McFarlane, as in CCM3, with the closure dependent on convective available potential energy (CAPE). Here, sensitivity tests using several versions of the Tiedtke convective scheme are conducted. Typically, the Tiedtke convection scheme gives an improved mean state, intraseasonal variability, space–time power spectra, and eastward propagation compared to the standard version of the model. Coherent eastward propagation of MJO-related precipitation is also much improved, particularly over the Indian–western Pacific Oceans. A composite life cycle of the model MJO indicates that over the Indian Ocean wind-induced surface heat exchange (WISHE) functions, while over the western/central Pacific Ocean aspects of frictional moisture convergence are evident in the maintenance and eastward propagation of the oscillation.

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Section: Introductionmentioning

confidence: 86%

MJO in the NCAR CAM2 with the Tiedtke Convective Scheme*

et al. 2005

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“…For Kelvin and MRG waves, see Hayashi (1974), Tsay (1974), Hayashi and Golder (1978, 1980, Hayashi et al (1984), Itoh and Ghil (1988), Boville and Randel (1982), Hess et al (1993a,b), and Manzini and Hamilton (1993). For intraseasonal oscillations, see Hayashi and Golder (1986, 1988, Lau and Lau (1986), Hayashi and Sumi (1986), Neelin et al (1987), Pitcher and Geisler (1987), Lau et al (1988), Swinbank et al (1988), Kuma (1990Kuma ( , 1994, Tokioka et al (1988), Park et al (1990), Slingo and Madden (1991), Sumi (1992), Yip and North (1993), Chao and Lin (1994), Seager and Zebiak (1994), Brown and Bretherton (1995), Sheng (1996), and Slingo et al (1996). For superclusters, see Hayashi and Sumi (1986), Numaguti and Hayashi (1991a,b), Sumi (1992), Kuma (1994), Golder (1993, 1994), Chao and Lin (1994), Yano et al (1995), and Chao and Deng (1996).…”

Section: Introductionmentioning

confidence: 99%

United Mechanisms for the Generation of Low- and High-Frequency Tropical Waves. Part I: Control Experiments with Moist Convective Adjustment

Hayashi

Golder

1997

J. Atmos. Sci.

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To examine several mechanisms for the generation of low-and high-frequency tropical waves, numerical experiments are conducted using an idealized nine-level R21 spectral model with the original scheme of moist convective adjustment (MCA). The model prescribes globally uniform, time-independent distributions of sea surface temperatures and insolation, thereby excluding stationary waves and extratropical baroclinic waves. The idealized model, however, still produces tropical intraseasonal oscillations, superclusters, Kelvin waves, and mixed Rossby-gravity waves. When eliminating the wind fluctuations in the parameterized surface fluxes of latent and sensible heat, the intraseasonal oscillations are profoundly weakened while other waves are not substantially weakened. Subsequently, the MCA scheme is modified to neutralize any conditionally unstable stratification that would otherwise develop during periods of nonsaturation. This modification suppresses the part of the MCA process that neutralizes, upon saturation, any preexisting unstable stratification. In spite of the presence of moisture convergence, all tropical transient waves then disappear, in contrast to the wave-CISK (conditional instability of the second kind) mechanism. The above results are consistent with the united mechanisms proposed as follows. Intraseasonal oscillations are maintained primarily through the evaporation-wind feedback mechanism. Other waves are maintained primarily through the ''saturation-triggering mechanism'' and/or the lateral-triggering mechanism. The saturationtriggering mechanism hypothesizes that transient waves can be triggered by the intermittent onset of nonequilibrium moist convection, upon saturation, to neutralize any preexisting unstable stratification.

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