A Source–Receptor Perspective on the Polar Hydrologic Cycle: Sources, Seasonality, and Arctic–Antarctic Parity in the Hydrologic Cycle Response to CO ₂ Doubling

Journal Article · 30 November 2017 · Journal of Climate

DOI: https://doi.org/10.1175/JCLI-D-16-0917.1 · OSTI ID:1409718

Singh, Hansi K. A. ^[1]; Bitz, Cecilia M. ^[2]; Donohoe, Aaron ^[3]; Rasch, Philip J. ^[1]

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1. Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington
2. Department of Atmospheric Sciences, University of Washington, Seattle, Washington
3. Applied Physics Laboratory, University of Washington, Seattle, Washington

Numerical water tracers implemented in a global climate model are used to study how polar hydroclimate responds to CO ₂ -induced warming from a source–receptor perspective. Although remote moisture sources contribute substantially more to polar precipitation year-round in the mean state, an increase in locally sourced moisture is crucial to the winter season polar precipitation response to greenhouse gas forcing. In general, the polar hydroclimate response to CO ₂ -induced warming is strongly seasonal: over both the Arctic and Antarctic, locally sourced moisture constitutes a larger fraction of the precipitation in winter, while remote sources become even more dominant in summer. Increased local evaporation in fall and winter is coincident with sea ice retreat, which greatly augments local moisture sources in these seasons. In summer, however, larger contributions from more remote moisture source regions are consistent with an increase in moisture residence times and a longer moisture transport length scale, which produces a robust hydrologic cycle response to CO ₂ -induced warming globally. The critical role of locally sourced moisture in the hydrologic cycle response of both the Arctic and Antarctic is distinct from controlling factors elsewhere on the globe; for this reason, great care should be taken in interpreting polar isotopic proxy records from climate states unlike the present.

• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• OSTI ID: 1409718
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 24 Vol. 30; ISSN 0894-8755
• Publisher: American Meteorological SocietyCopyright Statement
• Country of Publication: United States
• Language: English