Factors controlling the position of the Intertropical Convergence Zone on an aquaplanet
By B. Möbis, Bjorn Stevens. 2012
163 citations recorded by the source corpus.
Aqua planet experiments performed with fixed sea surface temperatures (SST) using the ECHAM6 GCM are studied to understand properties that influence the position of the Intertropical Convergence Zone (ITCZ). A single ITCZ develops when using the Nordeng scheme and a double ITCZ when using the Tiedtke scheme. The position of the ITCZ is found to depend on a feedback loop process wherein convective heating drives pressure gradients and winds, which determine the rate of surface evaporation, which influences the boundary layer moist static energy, which finally couples back to the pattern of convective heating. This feedback loop process is sensitive to the SST profile and the choice of the convection scheme. However SSTs are only important in so far as they control the boundary layer moist static energy. The feed‐back loop can be broken by specifying the wind used to calculate surface fluxes, in so doing it is possible to control the magnitude of boundary layer moist static energy and hence the position of the ITCZ. The cloud top height and therefore the convective heating decisively depends on the entrainment rates and the free tropospheric humidity. In the double ITCZ case the humidity in the lower free troposphere is higher on the equatorward side of the double ITCZ compared to the poleward side. Therefore an increase of the entrainment rates favor convection on the equatorward side. This explains why the Nordeng scheme produces a single ITCZ, although the Tiedtke scheme produces a double ITCZ.
Subfields: Atmospheric Science, Global and Planetary Change, Oceanography
View Paper: https://www.semanticscholar.org/paper/dc0163c68000819a7241b75aa5c606279a457a4f
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Atmospheric Science
- Johann Jungclaus
- Jochem Marotzke
- E. Manzini
- Holger Pohlmann
- Helmuth Haak
- Martin Köhler
- T. Mauritsen
- Jin-Song von Storch
In Global and Planetary Change
- Jochem Marotzke
- Johann Jungclaus
- E. Manzini
- Helmuth Haak
- Holger Pohlmann
- M. Esch
- Martin Köhler
- T. Mauritsen
In Oceanography
- Jochem Marotzke
- Johann Jungclaus
- Jin-Song von Storch
- Helmuth Haak
- Holger Pohlmann
- E. Roeckner
- T. Mauritsen
- Aiko Voigt
Citations in the corpus
- Developments in the MPI‐M Earth System Model version 1.2 (MPI‐ESM1.2) and Its Response to Increasing CO2 (2019, background): “…aquaplanet configuration (Neale & Hoskins, 2001; Medeiros et al., 2008), which is regularly used to better understand fundamental differences between different models and to investigate how the model output depends on different parameterizations (e.g., Möbis & Stevens, 2012, Voigt et al., 2014).”
- ICON‐A, the Atmosphere Component of the ICON Earth System Model: I. Model Description (2018, methodology): “The implementation and characteristics of the scheme are as described in detail by Möbis and Stevens (2012) for the ECHAM 6.0 version, up to two differences.”