Impact of ITCZ width on global climate: ITCZ-MIP
Abstract. The width of the Inter-Tropical Convergence Zone (ITCZ) affects tropical rainfall, Earth's albedo, large-scale circulation and climate sensitivity; yet we do not understand what controls it. To better understand the ITCZ width and its effects on global climate, we present a protocol to force changes in ITCZ width in climate models. Starting from an aquaplanet configuration with a slab ocean, adding surface heat fluxes in the deep tropics forces the ITCZ to narrow, and subtracting them causes it to widen. The protocol successfully generates changes in ITCZ width in four climate models; within each model, ITCZ width responds linearly to forcing magnitude and sign. Comparing across the four climate models, a response to varying ITCZ width that is remarkably consistent among models is the ITCZ strength, which is greater the narrower the ITCZ. On the other hand, the effect of varying ITCZ width on climate sensitivity is divergent among our four models, varying even in sign. These results indicate that idealized model experiments have the potential to increase our understanding of ITCZ width.
Status: open (until 03 Apr 2024)
Model output https://doi.org/10.5281/zenodo.10558341
Interactive computing environment
Jupyter notebook https://doi.org/10.5281/zenodo.10558341
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