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Abstract Summer temperatures across eastern North America (hereafter East) will soon reach a level consistently above any observation experienced during the instrumental period. Increasing temperatures will have negative impacts on natural (e.g., water, plant and animal communities) and human (e.g., health, infrastructure, economies) systems upon which the large and growing centres of human population across the region depend. Within the network of Northern Hemisphere tree‐ring temperature proxy records, one of the most obvious geographic holes is the East, where few temperature‐sensitive proxies exist. Here we present the first steps towards building a network of temperature‐sensitive proxy records across the East using blue light intensity (BI) methods applied to the tree rings of multiple temperature sensitive tree species situated from North Carolina to Maine, USA. Our overall objective is to report on the most viable species for BI analysis across different regions of the East (e.g., Southeast US, Midwest US, Northeast US/Canadian Maritimes) by exploring temporal (e.g., since ca. 1900) and spatial relationships between instrumental temperatures and BI metrics. We found BI to be a strong predictor of March–October mean air temperature (R2= 0.61) across the Northeast US/eastern Canada, and Sep‐Oct maximum air temperature (R2= 0.42) across the Southeast US. Of all species tested,Tsuga canadensisandPicea rubenscontained the strongest BI temperature signal. Adding more BI sites from these and potentially other species, as well as inclusion of other temperature proxies (e.g., ring widths) will allow for the development of a skilful broad‐scale and long‐term temperature field reconstruction across the East.
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A 561-yr (1461-2022 CE) summer temperature reconstruction for Mid-Atlantic-Northeast USA shows connections to volcanic forcing and atmospheric circulation
Abstract Contextualizing current increases in Northern Hemisphere temperatures is precluded by the short instrumental record of the pastca.120 years and the dearth of temperature-sensitive proxy records, particularly at lower latitudes south of <50 °N. We develop a network of 29 blue intensity chronologies derived from tree rings ofTsuga canadensis(L.) Carrière andPicea rubensSarg. trees distributed across the Mid-Atlantic and Northeast USA (MANE)—a region underrepresented by multi-centennial temperature records. We use this network to reconstruct mean March-September air temperatures back to 1461 CE based on a model that explains 62% of the instrumental temperature variance from 1901−1976 CE. Since 1998 CE, MANE summer temperatures are consistently the warmest within the context of the past 561 years exceeding the 1951−1980 mean of +1.3 °C. Cool summers across MANE were frequently volcanically forced, with significant (p<0.05) temperature departures associated with 80% of the largest tropical (n=13) and extratropical (n=15) eruptions since 1461 CE. Yet, we find that more of the identified cool events in the record were likely unforced by volcanism and either related to stochastic variability or atmospheric circulation via significant associations (p<0.05) to regional, coastal sea-surface temperatures, 500-hpa geopotential height, and 300-hpa meridional and zonal wind vectors. Expanding the MANE network to the west and south and combining it with existing temperature-sensitive proxies across North America is an important next step toward producing a gridded temperature reconstruction field for North America.
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- PAR ID:
- 10540076
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Climatic Change
- Volume:
- 177
- Issue:
- 9
- ISSN:
- 0165-0009
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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