scholarly journals Meridional atmospheric heat transport constrained by energetics and mediated by large-scale diffusion

2018 ◽  
Author(s):  
Kyle Armour ◽  
Nicholas Siler ◽  
Aaron Donohoe ◽  
Gerard Roe
Keyword(s):  
Heat Transport ◽  
Large Scale ◽  
Atmospheric Heat Transport ◽  
Atmospheric Heat

scholarly journals On the Spatial and Temporal Variability of Atmospheric Heat Transport in a Hierarchy of Models

2017 ◽  
Vol 74 (7) ◽  
pp. 2163-2189 ◽  
Author(s):  
G. Messori ◽  
R. Geen ◽  
A. Czaja
Keyword(s):  
Heat Transport ◽  
Temporal Variability ◽  
Large Scale ◽  
Storm Track ◽  
Spatial And Temporal Variability ◽  
Layer Model ◽  
Noise Component ◽  
Atmospheric Heat Transport ◽  
Two Layer Model ◽  
Atmospheric Heat

Abstract The present study analyzes the spatial and temporal variability of zonally integrated meridional atmospheric heat transport due to transient eddies in a hierarchy of datasets. These include a highly idealized two-layer model seeded with point geostrophic vortices, an intermediate complexity GCM, and the European Centre for Medium-Range Weather Forecasts interim reanalysis (ERA-Interim) data. The domain of interest is the extratropics. Both the two-layer model and the GCM display a pronounced temporal variability in the zonally integrated meridional transport, with the largest values (or pulses) of zonally integrated transport being associated with extended regions of anomalously strong local heat transport. In the two-layer model these large-scale coherent transport regions, termed “heat transport bands,” are linked to densely packed baroclinic vortex pairs and can be diagnosed as low-wavenumber streamfunction anomalies. In the GCM they are associated with both the warm and cold sectors of midlatitude weather systems. Both these features are also found in ERA-Interim: the heat transport bands match weather systems and occur primarily in the storm-track regions, which in turn correspond to planetary-scale climatological streamfunction anomalies. The authors hypothesize that the temporal variability of the zonally integrated heat transport is partly linked to oscillatory variations in the storm-track activity but also contains a background red noise component. The existence of a pronounced variability in the zonally integrated meridional heat transport can have important consequences for the interplay between midlatitude dynamics and the energy balance of the high latitudes.

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

2017 ◽  
Vol 30 (1) ◽  
pp. 189-201 ◽  
Author(s):  
Nicole Feldl ◽  
Simona Bordoni ◽  
Timothy M. Merlis
Keyword(s):  
Heat Transport ◽  
High Latitude ◽  
Surface Albedo ◽  
Hadley Cell ◽  
Lapse Rate ◽  
The Arctic ◽  
Albedo Feedback ◽  
Atmospheric Heat Transport ◽  
The Tropics ◽  
Atmospheric Heat

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.

scholarly journals Structural changes and variability of the ITCZ induced by radiation–cloud–convection–circulation interactions: inferences from the Goddard Multi-scale Modeling Framework (GMMF) experiments

2019 ◽  
Vol 54 (1-2) ◽  
pp. 211-229 ◽  
Author(s):  
William K. M. Lau ◽  
Kyu-Myong Kim ◽  
Jiun-Dar Chern ◽  
W. K. Tao ◽  
L. Ruby Leung
Keyword(s):  
Heat Transport ◽  
Structural Changes ◽  
Hadley Circulation ◽  
Modeling Framework ◽  
Multi Scale ◽  
Scale Modeling ◽  
Atmospheric Heat Transport ◽  
Multi Scale Modeling ◽  
Atmospheric Heat ◽  
High Clouds

Abstract In this paper, we have investigated the impact of radiation–cloud–convection–circulation interaction (RC3I) on structural changes and variability of the Inter-tropical Convergence Zone (ITCZ) using the Goddard Multi-scale Modeling Framework, where cloud processes are super-parameterized, i.e., explicitly resolved with 2-D cloud resolving models embedded in each coarse grid of the host Goddard Earth Observing System-Version 5 global climate model. Experiments have been conducted under prescribed sea surface temperature conditions for 10 years (2007–2016), with and without cloud radiation feedback in the atmosphere, respectively. Diagnostic analyses separately for January and July show that RC3I leads to an enhanced and expanded Hadley Circulation characterized by (1) a quasi-uniform warming and moistening of the tropical atmosphere and a sharpening of the ITCZ with enhanced deep convection, more intense precipitation and higher clouds, (2) extended drying of the tropical marginal convective zones, and extratropical mid- to lower troposphere, and (3) a cooling of the polar regions, with increased baroclinicity and midlatitude storm track activities. Computations based on the zonal mean thermodynamic energy balance equation show that the radiative warming and cooling are strongly balanced by local adiabatic processes associated with changes in large-scale vertical motions, as well as horizontal atmospheric heat transport. In the tropics, enhanced short-wave absorption and longwave water vapor greenhouse effects by high clouds play key roles in providing strong positive feedback to the tropospheric warming. In the extratropics, increased atmospheric heat transport associated with changes in the Hadley circulation is balanced by strong longwave cooling above, and warming below due to increased high clouds. We also find a strong positive correlation between daily and pentad heavy rain in the ITCZ core, and expansion of the drier zones coupled to a contraction of the highly convective zones in the ITCZ, indicating a strong tendency RC3I-induced convective aggregation in tropical clouds i.e., wet-regions-get-wetter and contracted, and dry-areas-get-drier and expanded.

Polar amplification: is atmospheric heat transport important?

2012 ◽  
Vol 41 (2) ◽  
pp. 533-547 ◽  
Author(s):  
Vladimir A. Alexeev ◽  
Craig H. Jackson
Keyword(s):  
Heat Transport ◽  
Polar Amplification ◽  
Atmospheric Heat Transport ◽  
Atmospheric Heat

scholarly journals Impacts of Oceanic and Atmospheric Heat Transports on Sea Ice Extent

2020 ◽  
Vol 33 (16) ◽  
pp. 7197-7215
Author(s):  
Jake Aylmer ◽  
David Ferreira ◽  
Daniel Feltham
Keyword(s):  
Sea Ice ◽  
Heat Transport ◽  
Climate Model ◽  
Balance Model ◽  
Sea Ice Extent ◽  
Transport Component ◽  
Atmospheric Heat Transport ◽  
Ice Edge ◽  
Atmospheric Heat ◽  
The Impact

AbstractClimate-model biases in ocean heat transport (OHT) have been proposed as a major contributor to uncertainties in projections of sea ice extent. To better understand the impact of OHT on sea ice extent and compare it to that of atmospheric heat transport (AHT), an idealized, zonally averaged energy balance model (EBM) is developed. This is distinguished from previous EBM work by coupling a diffusive mixed layer OHT and a prescribed OHT contribution, with an atmospheric EBM and a reduced-complexity sea ice model. The ice-edge latitude is roughly linearly related to the convergence of each heat transport component, with different sensitivities depending on whether the ice cover is perennial or seasonal. In both regimes, Bjerknes compensation (BC) occurs such that the response of AHT partially offsets the impact of changing OHT. As a result, the effective sensitivity of ice-edge retreat to increasing OHT is only ~2/3 of the actual sensitivity (i.e., eliminating the BC effect). In the perennial regime, the sensitivity of the ice edge to OHT is about twice that to AHT, while in the seasonal regime they are similar. The ratio of sensitivities is, to leading order, determined by atmospheric longwave feedback parameters in the perennial regime. Here, there is no parameter range in which the ice edge is more sensitive to AHT than OHT.

scholarly journals Erratum to: Polar amplification: is atmospheric heat transport important?

2013 ◽  
Vol 41 (2) ◽  
pp. 549-549 ◽  
Author(s):  
Vladimir A. Alexeev ◽  
Craig H. Jackson
Keyword(s):  
Heat Transport ◽  
Polar Amplification ◽  
Atmospheric Heat Transport ◽  
Atmospheric Heat
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