High-frequency water isotope variability in the WAIS Divide ice core
Abstract
One of the ways to deeply understand some aspect of the climate system is to understand its continuum of variability. In the case of the temperature continuum, the two extreme ends are primarily controlled by insolation. At ~10s to 100s of thousand year (kyr) timescales, temperature variations are controlled by Milankovitch cycles, which pace ice ages and affect tropical climate. At the other end, the annual cycle is strongly influenced by variations in seasonal insolation through time. At all other timescales, innumerable internal noise processes and additional solar variability combine to create the temperature continuum. Direct observations of the high-frequency portions of the temperature continuum (and climate variability in general) are difficult to obtain and represent one of the great challenges of paleoclimate studies. To obtain and understand such data requires a confluence of specialized technology, methodology, and modeling. In the case of ice core science, this confluence has recently become possible for water isotope records. Here, we discuss results from the West Antarctic Ice Sheet (WAIS) Divide ice core, including: 1) A continuous reconstruction of the annual signal throughout the Holocene and 2) Determination of the strength of interannual and decadal variability (3-15 yr) for the last 31 kyr. In this context, the water isotope record can be considered a hydrologic cycle proxy, forced primarily by local temperature and partly by atmospheric circulation. We use modeling (HadCM3 and Milankovitch) to explain changes in the strength of the variability through time. We also discuss where modeling deficiencies exist. As additional high-resolution ice core records become available (e.g. SPICE, Renland, EGRIP, DYE3, Hercules Dome, possibly GISP, etc.), the ability to analyze the high-frequency portions of the climate continuum across space and time will improve. As a result, our understanding of climate change on timescales that humans experience and relate to (annual to decadal) will also improve.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP21A..02J
- Keywords:
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- 3344 Paleoclimatology;
- ATMOSPHERIC PROCESSES;
- 1041 Stable isotope geochemistry;
- GEOCHEMISTRY;
- 1655 Water cycles;
- GLOBAL CHANGE;
- 1833 Hydroclimatology;
- HYDROLOGY