Countervailing patterns in CESM-simulated regional Antarctic snowfall variability: spatial distribution and associated atmospheric circulation modes

Thursday, December 14, 2017 - 08:00
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Snowfall over Antarctica displays large regional heterogeneity in temporal variability patterns. This heterogeneity has the potential to dampen variability in integrated Antarctic surface mass trends by counteracting increases in snowfall in one location with decreases in another. Here we present an analysis of spatial patterns of regional Antarctic snowfall variability, their broader climate drivers and their impact on integrated Antarctic snowfall variability simulated as part of a preindustrial 1800 year equilibrated Earth System Model simulation. Correlation and composite analyses based on this output allow for a statistically robust exploration of Antarctic snowfall variability. We identify countervailing snowfall patterns across Antarctica that are corroborated by regional modelling and ice core records and consistent with previous findings. These countervailing patterns are driven by variability in regionally distinct large-scale atmospheric moisture transport patterns, and exert a dampening effect on overall Antarctic snowfall variability magnitude. We suggest that this dampening has implications for regulation of Antarctic-sourced sea level variability, detection of an emergent anthropogenic signal in Antarctic mass trends and identification of AIS mass loss accelerations.

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