Extent of Hadley circulations in dry atmospheres

Korty, Robert; Schneider, Tapio

doi:10.1029/2008gl035847

Cited by 55 publications

(82 citation statements)

References 16 publications

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“…The high-albedo experiment has the strongest mean tropical circulation and also weakens most. The Hadley cell does expand under increased CO 2 , consistent with theory and modeling (Held and Hou 1980;Korty and Schneider 2008;Levine and Schneider 2015;Lu et al 2007); however, the widening is the same in all four experiments (28 latitude). Hence, the experimental setup induces variability in strength but not position of the Hadley cell.…”

supporting

confidence: 52%

Coupled High-Latitude Climate Feedbacks and Their Impact on Atmospheric Heat Transport

2017

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The response of atmospheric heat transport to anthropogenic warming is determined by the anomalous meridional energy gradient. Feedback analysis offers a characterization of that gradient and hence reveals how uncertainty in physical processes may translate into uncertainty in the circulation response. However, individual feedbacks do not act in isolation. Anomalies associated with one feedback may be compensated by another, as is the case for the positive water vapor and negative lapse rate feedbacks in the tropics. Here a set of idealized experiments are performed in an aquaplanet model to evaluate the coupling between the surface albedo feedback and other feedbacks, including the impact on atmospheric heat transport. In the tropics, the dynamical response manifests as changes in the intensity and structure of the overturning Hadley circulation. Only half of the range of Hadley cell weakening exhibited in these experiments is found to be attributable to imposed, systematic variations in the surface albedo feedback. Changes in extratropical clouds that accompany the albedo changes explain the remaining spread. The feedback-driven circulation changes are compensated by eddy energy flux changes, which reduce the overall spread among experiments. These findings have implications for the efficiency with which the climate system, including tropical circulation and the hydrological cycle, adjusts to high-latitude feedbacks over climate states that range from perennial or seasonal ice to ice-free conditions in the Arctic.

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supporting

confidence: 52%

Coupled High-Latitude Climate Feedbacks and Their Impact on Atmospheric Heat Transport

2017

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“…Frierson et al (2007) also found a poleward expansion with increased mean temperature. Korty and Schneider (2008) and Walker and Schneider (2006) found a poleward expansion with a prescribed increased dry static stability. A smaller increase in width of the Hadley cells with increased meridional temperature gradient was also found by Korty and Schneider (2008), Walker and Schneider (2006), and Frierson et al (2007).…”

Section: Hadley Circulationmentioning

confidence: 99%

“…Furthermore, recent studies using idealized simulations emphasized that the dry static stability increase in subtropics is especially crucial for the poleward expansion of the Hadley cells Walker and Schneider 2006;Korty and Schneider 2008). Therefore, to study the impact of the SST changes on the large-scale circulation, the dry static stability has been computed with the static stability parameter S p , defined as…”

Section: A Midtropospheric Vertical Velocitymentioning

confidence: 99%

The Hadley and Walker Circulation Changes in Global Warming Conditions Described by Idealized Atmospheric Simulations

Gastineau

Treut

2009

Journal of Climate

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Sea surface temperature (SST) changes constitute a major indicator and driver of climate changes induced by greenhouse gas increases. The objective of the present study is to investigate the role played by the detailed structure of the SST change on the large-scale atmospheric circulation and the distribution of precipitation. For that purpose, simulations from the Institut Pierre-Simon Laplace Coupled Model, version 4 (IPSL-CM4) are used where the carbon dioxide (CO 2 ) concentration is doubled. The response of IPSL-CM4 is characterized by the same robust mechanisms affecting the other coupled models in global warming simulations, that is, an increase of the hydrological cycle accompanied by a global weakening of the largescale circulation. First, purely atmospheric simulations are performed to mimic the results of the coupled model. Then, specific simulations are set up to further study the underlying atmospheric mechanisms. These simulations use different prescribed SST anomalies, which correspond to a linear decomposition of the IPSL-CM4 SST changes in global, longitudinal, and latitudinal components. The simulation using a globally uniform increase of the SST is able to reproduce the modifications in the intensity of the hydrological cycle or in the mean upward mass flux, which also characterize the double CO 2 simulation with the coupled model. But it is necessary (and largely sufficient) to also take into account the zonal-mean meridional structure of the SST changes to represent correctly the changes in the Hadley circulation strength or the zonal-mean precipitation changes simulated by the coupled model, even if these meridional changes by themselves do not change the mean thermodynamical state of the tropical atmosphere. The longitudinal SST anomalies of IPSL-CM4 also have an impact on the precipitation and large-scale tropical circulation and tend to introduce different changes over the Pacific and Atlantic Oceans. The longitudinal SST changes are demonstrated to have a smaller but opposite effect from that of the meridional anomalies on the Hadley cell circulations. Results indicate that the uncertainties in the simulated meridional patterns of the SST warming may have major consequences on the assessment of the changes of the Hadley circulation and zonal-mean precipitation in future climate projections.

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“…This widening tendency is in qualitative agreement with Sobel and Neelin (2006), who found that increasing the horizontal moisture diffusivity in an axisymmetric model (analogous to increasing the transient-eddy moisture flux) resulted in a wider ITCZ. Transient eddies have previously been shown to modulate the strength of the Hadley circulation through their effect on the both the angular momentum and energy budgets (Singh and Kuang 2016) of the tropics, and are also important for the extent of the Hadley circulation (Korty and Schneider 2008;Levine and Schneider 2015). Although MSE divergence by transient eddies has been found to be an important term in the energy budgets of the eastern Pacific (Peters et al 2008) and the ITCZ in an idealized model (Nolan et al 2010), the quantitative relationship between transient eddies and the size of the ITCZ has not been demonstrated previously.…”

Section: ) Transient-eddy Component Deddymentioning

confidence: 99%

Energetic Constraints on the Width of the Intertropical Convergence Zone

Byrne

Schneider

2016

Journal of Climate

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The intertropical convergence zone (ITCZ) has been the focus of considerable research in recent years, with much of this work concerned with how the latitude of maximum tropical precipitation responds to natural climate variability and to radiative forcing. The width of the ITCZ, however, has received little attention despite its importance for regional climate and for understanding the general circulation of the atmosphere. This paper investigates the ITCZ width in simulations with an idealized general circulation model over a wide range of climates. The ITCZ, defined as the tropical region where there is time-mean ascent, displays rich behavior as the climate varies, widening with warming in cool climates, narrowing in temperate climates, and maintaining a relatively constant width in hot climates. The mass and energy budgets of the Hadley circulation are used to derive expressions for the area of the ITCZ relative to the area of the neighboring descent region, and for the sensitivity of the ITCZ area to changes in climate. The ITCZ width depends primarily on four quantities: the net energy input to the tropical atmosphere, the advection of moist static energy by the Hadley circulation, the transport of moist static energy by transient eddies, and the gross moist stability. Different processes are important for the ITCZ width in different climates, with changes in gross moist stability generally having a weak influence relative to the other processes. The results are likely to be useful for analyzing the ITCZ width in complex climate models and for understanding past and future climate change in the tropics.

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Extent of Hadley circulations in dry atmospheres

Cited by 55 publications

References 16 publications

Coupled High-Latitude Climate Feedbacks and Their Impact on Atmospheric Heat Transport

Coupled High-Latitude Climate Feedbacks and Their Impact on Atmospheric Heat Transport

The Hadley and Walker Circulation Changes in Global Warming Conditions Described by Idealized Atmospheric Simulations

Energetic Constraints on the Width of the Intertropical Convergence Zone

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