Sensitivity of northwest Australian tropical cyclone activity to ITCZ migration since 500 CE

Rhawn F Denniston; Caroline C Ummenhofer; Kerry Emanuel; Roberto Ingrosso; Francesco S R Pausata; Alan D Wanamaker; Matthew S Lachniet; Kenneth T Carr; Yemane Asmerom; Victor J Polyak; Jonathan Nott; Wei Zhang; Gabriele Villarini; John Cugley; Darren Brooks; David Woods; William F Humphreys

doi:10.1126/sciadv.add9832

Sensitivity of northwest Australian tropical cyclone activity to ITCZ migration since 500 CE

Sci Adv. 2023 Jan 13;9(2):eadd9832. doi: 10.1126/sciadv.add9832. Epub 2023 Jan 11.

Authors

Rhawn F Denniston¹, Caroline C Ummenhofer^{2

3}, Kerry Emanuel⁴, Roberto Ingrosso⁵, Francesco S R Pausata⁵, Alan D Wanamaker⁶, Matthew S Lachniet⁷, Kenneth T Carr^{2

8

9}, Yemane Asmerom^{9

10}, Victor J Polyak¹⁰, Jonathan Nott¹¹, Wei Zhang^{12

13}, Gabriele Villarini¹², John Cugley¹⁴, Darren Brooks¹⁴, David Woods¹⁵, William F Humphreys^{16

17}

Affiliations

¹ Department of Geology, Cornell College, Mount Vernon, IA, USA.
² Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
³ ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, NSW, Australia.
⁴ Lorenz Center, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁵ Centres ESCER (Étude et la Simulation du Climat à l'Échelle RÉgionale) and GEOTOP, Department of Earth and Atmospheric Sciences, University of Quebec in Montreal, Montreal, Canada.
⁶ Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, USA.
⁷ Department of Geoscience, University of Nevada Las Vegas, Las Vegas, NV, USA.
⁸ Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁹ MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering, Cambridge and Woods Hole, MA, USA.
¹⁰ Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, USA.
¹¹ College of Science and Engineering, James Cook University, Cairns, QLD, Australia.
¹² IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, IA, USA.
¹³ Department of Plants, Soils and Climate, Utah State University, Logan, UT, USA.
¹⁴ Australian Speleological Federation, Perth, WA, Australia.
¹⁵ Department of Environment and Science, Queensland Parks and Wildlife Service, Townsville, QLD, Australia.
¹⁶ School of Biological Sciences, University of Western Australia, Perth, WA, Australia.
¹⁷ Department of Terrestrial Zoology, Western Australian Museum, Welshpool, DC, WA, Australia.

Abstract

Tropical cyclones (TCs) regularly form in association with the intertropical convergence zone (ITCZ), and thus, its positioning has implications for global TC activity. While the poleward extent of the ITCZ has varied markedly over past centuries, the sensitivity with which TCs responded remains poorly understood from the proxy record, particularly in the Southern Hemisphere. Here, we present a high-resolution, composite stalagmite record of ITCZ migrations over tropical Australia for the past 1500 years. When integrated with a TC reconstruction from the Australian subtropics, this time series, along with downscaled climate model simulations, provides an unprecedented examination of the dependence of subtropical TC activity on meridional shifts in the ITCZ. TCs tracked the ITCZ at multidecadal to centennial scales, with a more southward position enhancing TC-derived rainfall in the subtropics. TCs may play an increasingly important role in Western Australia's moisture budgets as subtropical aridity increases due to anthropogenic warming.