Spatial patterns of Hydroclimate in the Alaska-Yukon region from late Holocene proxy evidence that includes elevation gradients
Abstract
Major mountain ranges in Alaska and the southwest Yukon Territory cause dramatic elevation climate gradients. They also cause prominent differences in regional hydroclimate due to their interaction with atmospheric flow. These effects also lead to more complex spatial patterns indicated by Alaska-Yukon proxy records and to overlook regional and elevation differences between proxy records will result in erroneous interpretations. Yet proxy record patterns are particularly important for the region because current isotope enabled GCMs lack the spatial resolution to accurately simulate topographic effects. With careful analyses, however, they also offer the opportunity to obtain more detailed information about additional paleoclimatic parameters such as changes in seasonality, boundary layer dynamics, and rain shadow aridity related to atmospheric flow patterns and multidecadal ocean atmosphere dynamics. These points are illustrated by examples of 10 hydroclimatic proxy record comparisons in northern, interior and coastal regions that span from 4 ka to present, which represents the time period before, during and after neo-glaciation. In the Brooks Range of Northern Alaska, neo-glacial advances by 1ka at upper elevations is coincident with a trend to more arid conditions at low elevations in the Yukon Flats of northeast interior Alaska. Whereas similar patterns are evident in the low elevations of central and southwest interior Yukon, data from the Alaska Range, with sensitivity to winter precipitation, indicates more arid conditions before 2ka with moisture increases thereafter. In south-central Alaska, records of effective moisture indicate drier conditions during the onset of neo-glaciation but with more variations during the neo-glacial than the other regions. Conclusions will highlight regional differences and their possible interpretations and emphasize the potential for new paleoclimatic insights to be gained.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP21B..06A
- Keywords:
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- 3335 North American Monsoon;
- ATMOSPHERIC PROCESSESDE: 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCESDE: 4914 Continental climate records;
- PALEOCEANOGRAPHYDE: 4938 Interhemispheric phasing;
- PALEOCEANOGRAPHY