Conference proceeding
Climate factors leading to asymmetrical extreme capture in the tree-ring record
American Geophysical Union Fall Meeting, Vol.2018
American Geophysical Union 2018 fall meeting
12/2018
Abstract
The frequency and severity of extreme events are likely to change in a warming climate, and paleoclimate data play a critical role in placing recent hydroclimate extremes within a longer-term context. Asymmetries in proxy responses to extreme climatic conditions remain a largely unaddressed challenge for the reconstruction and interpretation of past climate. Here, we establish the extent to which the existing tree-ring record captures precipitation extremes across seasons in western North America and evaluate climate conditions hypothesized to lead to asymmetrical extreme capture, including timing of precipitation, seasonal temperatures, snowpack, and amount of water delivered through atmospheric river events. We find that approximately half of western North American sites better capture low precipitation extremes than high extremes. These asymmetries vary by latitude, season, and extreme threshold: the most extreme dry-bias is found at lower latitudes, in the cool season, and with more stringent extreme thresholds. Years in which low water-year precipitation was not adequately reflected in the tree-ring record had relatively more precipitation in the autumn season, when moisture is less likely to contribute to tree growth in the current or following year. Factors contributing to poor capture of high precipitation extremes included more intense precipitation from a smaller number of events, as well as a cool winter and spring followed by high summer potential evapotranspiration. Overall, poor capture of both dry and wet extremes were linked to the form (high-intensity summer convective storms and autumn atmospheric rivers) and timing (mismatch between periods of tree growth and precipitation) of moisture delivery. Understanding the mechanisms leading to asymmetric extreme value capture in proxy records can aid our interpretation of past climate and help identify alternative tree-ring metrics and complementary proxies to improve future reconstructions.
Details
- Title: Subtitle
- Climate factors leading to asymmetrical extreme capture in the tree-ring record
- Creators
- E. Wise - University of North Carolina at Chapel HillM. P. Dannenberg - University of Iowa
- Resource Type
- Conference proceeding
- Publication Details
- American Geophysical Union Fall Meeting, Vol.2018
- Conference
- American Geophysical Union 2018 fall meeting
- Publisher
- American Geophysical Union
- Alternative title
- AGU 2018 fall meeting
- Language
- English
- Date published
- 12/2018
- Academic Unit
- Geographical and Sustainability Sciences
- Record Identifier
- 9984264390202771
Metrics
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