The mesoscale convection life cycle: Building block or prototype for large-scale tropical waves?

Mapes, Brian E.; Tulich, Stefan N.; Zuidema, Paquita

doi:10.1016/j.dynatmoce.2006.03.003

Cited by 325 publications

(322 citation statements)

References 66 publications

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“…9c). Similar evidence for a rapid growth of convection in large-scale tropical waves (as well as individual mesoscale convective systems) can be found in the independent observational/model analyses of Mapes et al (2006). Presumably, the pronounced suppression of observed rainfall and convection at negative lags in the range -60 to -24 h is due in part to strong dryness in the lower to middle troposphere (cf.…”

Section: Vertical Dynamical Structuressupporting

confidence: 53%

Convectively coupled Kelvin and easterly waves in a regional climate simulation of the tropics

2009

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This study evaluates the performance of a regional climate model in simulating two types of synoptic tropical weather disturbances: convectively-coupled Kelvin and easterly waves. Interest in these two wave modes stems from their potential predictability out to several weeks in advance, as well as a strong observed linkage between easterly waves and tropical cyclogenesis. The model is a recent version of the weather research and forecast (WRF) system with 36-km horizontal grid spacing and convection parameterized using a scheme that accounts for key convective triggering and inhibition processes. The domain spans the entire tropical belt between 45°S and 45°N with periodic boundary conditions in the east-west direction, and conditions at the meridional/lower boundaries specified based on observations. The simulation covers 6 years from 2000 to 2005, which is long enough to establish a statistical depiction of the waves through space-time spectral filtering of rainfall data, together with simple lagged-linear regression. Results show that both the horizontal phase speeds and three-dimensional structures of the waves are qualitatively well captured by the model in comparison to observations. However, significant biases in wave activity are seen, with generally overactive easterly waves and underactive Kelvin waves. Evidence is presented to suggest that these biases in wave activity (which are also correlated with biases in time-mean rainfall, as well as biases in the model's tropical cyclone climatology) stem in part from convection in the model coupling too strongly to rotational circulation anomalies. Nevertheless, the model is seen to do a reasonable job at capturing the genesis of tropical cyclones from easterly waves, with evidence for both wave accumulation and critical layer processes being importantly involved.

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Section: Vertical Dynamical Structuressupporting

confidence: 53%

Convectively coupled Kelvin and easterly waves in a regional climate simulation of the tropics

2009

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“…Mapes et al(2006) considered why patterns in cloudiness associated with large-scale waves evolve in a similar way to mesoscale convective systems, with shallow convection developing first, followed by deep convection and then by upper level stratus. They suggested that the waves are associated with patterns of anomalous density (controlled by temperature and humidity) that tilt in the vertical in a manner that modifies the life cycles of mesoscale convective systems embedded within.…”

Section: Additional Insights From Solutionsmentioning

confidence: 99%

Analysis of vertically propagating convectively coupled equatorial waves using observations and a non‐hydrostatic Boussinesq model on the equatorial beta‐plane

Roundy

Janiga

2011

Quart J Royal Meteoro Soc

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“…The strategy in this paper is to exploit the observed statistical self-similarity of tropical convection (37) and study the multicloud models for superclusters in a parameter regime appropriate for intraseasonal variability.…”

Section: The Strategy For Producing An Mjo Analogmentioning

confidence: 99%

“…In earlier work (31)(32)(33)(34), the parameters c , conv , and s were used in the range of 1-3 h to parameterize the unresolved effects of convective wave packets from smaller scales on the equatorial synoptic supercluster scales. Here, by exploiting the observed statistical self-similarity of tropical convection (37), the multicloud models are studied with the parameters c , conv , and s in an intraseasonal planetary regime:…”

Section: The Strategy For Producing An Mjo Analogmentioning

confidence: 99%

Madden–Julian Oscillation analog and intraseasonal variability in a multicloud model above the equator

Majda

Stechmann

Khouider

2007

Proc. Natl. Acad. Sci. U.S.A.

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The Madden-Julian Oscillation (MJO) is the dominant component of tropical intraseasonal variability, and a theory explaining its structure and successful numerical simulation remains a major challenge. A successful model for the MJO should have a propagation speed of 4 -7 m/s predicted by theory; a wavenumber-2 or -3 structure for the planetary-scale, low-frequency envelope with distinct active and inactive phases of deep convection; an intermittent turbulent chaotic multiscale structure within the planetary envelope involving embedded westward-and eastward-propagating deep convection events; and qualitative features of the low-frequency envelope from the observational record regarding, e.g., its zonal flow structure and heating. Here, such an MJO analog is produced by using the recent multicloud model of Khouider and Majda in an appropriate intraseasonal parameter regime for flows above the equator so that rotation is ignored. Key features of the multicloud model are (i) systematic low-level moisture convergence with retained conservation of vertically integrated moist static energy, and (ii) the use of three cumulus cloud types (congestus, stratiform, and deep convective) together with their differing vertical heating structures. Besides all of the above structure in the MJO analog waves, there are accurate predictions of the phase speed from linear theory and transitions from weak, regular MJO analog waves to strong, multiscale MJO analog waves as climatological parameters vary. With all of this structure in a simplified context, these models should be useful for MJO predictability studies in a fashion akin to the Lorenz 96 model for the midlatitude atmosphere.coherent planetary intraseasonal variability ͉ multiscale structure ͉ intermittency in convection ͉ nonlinear analog model T he dominant component of intraseasonal variability in theTropics is the 40-to 50-day tropical intraseasonal oscillation, often called the Madden-Julian Oscillation (MJO) after its discoverers (1). In the troposphere, the MJO is an equatorial planetary-scale wave envelope of complex multiscale convective processes that begins as a standing wave in the Indian Ocean and propagates across the western Pacific at a speed of Ϸ5 m⅐s Ϫ1 (2-5). The planetary-scale circulation anomalies associated with the MJO significantly affect monsoon development and intraseasonal predictability in midlatitudes and the development of the El Niño southern oscillation in the Pacific Ocean, which is one of the most important components of seasonal prediction (6, 7). Present-day computer general circulation models typically poorly represent the MJO (8, 9). One conjectured reason for the poor performance of general circulation models is the inadequate treatment across multiple spatial scales of the interaction of the hierarchy of organized structures that generate the MJO as their envelope.There have been a large number of theories attempting to explain the MJO through a specific linearized mechanism, such as evaporation-wind feedback (10, 11), boundary layer...

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The mesoscale convection life cycle: Building block or prototype for large-scale tropical waves?

Cited by 325 publications

References 66 publications

Convectively coupled Kelvin and easterly waves in a regional climate simulation of the tropics

Convectively coupled Kelvin and easterly waves in a regional climate simulation of the tropics

Analysis of vertically propagating convectively coupled equatorial waves using observations and a non‐hydrostatic Boussinesq model on the equatorial beta‐plane

Madden–Julian Oscillation analog and intraseasonal variability in a multicloud model above the equator

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