cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/eddg-8879
title: NOAA/WDS Paleoclimatology - Central Arctic Sedimentary 231Pa/230Th Ratios from the Past 35,000 Years

description: The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deepwater exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of 231Pa and 230Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary 231Pa/230Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured 230Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in 231Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for 231Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export 231Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation.
description: U-series radionuclide records from seven Arctic sediment cores, with excess 231Pa/230Th ratios interpreted as indicators of 231Pa export in the water column. Age models are from calibrated radiocarbon measurements on polar foraminifer species N. pachyderma (sinistral).
DOI: 10.25921/ew93-1s89
title: NOAA/WDS Paleoclimatology - Paritsis - Rio Ragintuco 1 - NOPU - ITRDB ARGE134

description: In the temperate forests of the southern Andes, Nothofagus pumilio, the dominant species of the most extensive forest type, experiences severe defoliation caused by caterpillars of the Ormiscodes genus (Lepidoptera: Saturniidae). This study uses tree rings to reconstruct the history of Ormiscodes outbreaks for the 1850-2005 period and examines relationships between outbreaks and climate variability. We used local climate records to compare outbreak-climate relationships in the northern Patagonian Andes (c. 41°S) and the cooler southern Patagonian Andes (c. 49°S). We also examined relationships between outbreak events and regional climate variability driven by variability in the Southern Annular Mode (SAM) and the El Niño-Southern Oscillation. Although relationships between Ormiscodes outbreaks and climate proved to be complex, in northern Patagonia defoliation events are associated with drier and warmer than average growing seasons. Warming and drying trends in Patagonia during the latter part of the 20th century have been linked to a positive trend in SAM. During the post-1976 period of accelerated warming in Patagonia, widespread defoliation outbreaks have occurred in both northern and southern Patagonia but the increase in frequency of events has been greater in the south. In southern Patagonia the increases in frequency of outbreaks in the late 20th century appear to be unprecedented over the c. 150 year tree-ring record of reconstructed outbreaks. These results are consistent with the greater magnitude of recent warming in southern Patagonia, and suggest that under predicted warmer and drier climates in the 21st century, defoliator outbreaks may continue to increase in frequency. This study is the first systematic reconstruction of past insect outbreaks in South America and provides a preliminary understanding of how climate variability affects defoliator outbreaks in Patagonian Nothofagus forests.
description: Purpose of Collection:
# Ecology - insect outbreaks
# 
# Cores are stored at:
# Biogeography Lab, Geography Department, University of Colorado at Boulder
# 
# Notes:
# Most tree ring samples were collected during the growing season, so the most recent ring 
# is not a complete ring. The most recent ring was therefore not used in the analysis by 
# Paritsis and Veblen (2011). Two cores were collected per tree (desiginated with A & B sample codes). 
# Site names designated 1 and 2 are two stands located near each other, with one typically older 
# than the other.  These nearby site pairs were merged for the analysis by Paritsis and Veblen (2011). NOAA Template Raw Measurements file added 2019-04-29.
DOI: 10.25921/e2rk-zf96
title: NOAA/WDS Paleoclimatology - DeRose - Maguire Canyon - PSME - ITRDB UT536

description: Utah's Great Salt Lake (GSL) is a closed-basin remnant of the larger Pleistocene-age Lake Bonneville. The modern instrumental record of the GSL-level (i.e. elevation) change is strongly modulated by Pacific Ocean coupled ocean/atmospheric oscillations at low frequency, and therefore reflects the decadal-scale wet/dry cycles that characterize the region. A within-basin network of seven tree-ring chronologies was developed to reconstruct the GSL water year (September-August) level, based upon the instrumental record of GSL level from 1876 to 2005. The result was a 576-year reconstruction of the GSL level that extends from 1429 to 2005; all calibration-verification tests commonly used in dendroclimatology were passed. The reconstruction explains 48% of the variance in the instrumental GSL level and exhibits significant periodicity at sub-decadal scales over the past six centuries. Meanwhile, predominance of multi-decadal periodicity in the early half of the record shifted to quasi-decadal dominance in the latter half, and this is consistent with that of proxy reconstructions of the Pacific Decadal Oscillation. The GSL-level reconstruction is a crucial component to improving our insight into the possible controls of coupled ocean-atmosphere interactions on precipitation delivery.
description: NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/eyc5-fz81
title: NOAA/WDS Paleoclimatology - Colenutt - Lineham Lakes - LALY - ITRDB CANA412

description: Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives.  Most data sets include raw treering measurements (most are annual ring width, with some collections of earlywood or latewood width or wood density), plus chronologies (standardized growth indices for a site compiled from multiple treering samples). Reconstructions of climate variables are included with some of these data sets.  Each data type is stored in a separate data file; the data type is coded into the file name. For details please see: http://www.ncdc.noaa.gov/paleo/treeinfo.htmll
description: Cores are stored at:
# # University of Western Ontario
# # 
# # 
# # Reference:
# # Colenutt M.  2000.  
# # Climate reconstruction in the southern Canadian Rockies using tree-ring data from alpine larch.  
# # PhD dissertation, University of Western Ontario, London, Ontario. NOAA Template Raw Measurements file added 2019-01-27. NOAA Template Raw Measurements file added 2019-02-04.
DOI: 10.25921/en0n-jj52
title: NOAA/WDS Paleoclimatology - Finnish Lakeland 1241 Year May-September Temperature Reconstruction

description: X-ray based tree-ring data of maximum latewood densities (MXD) was combined for south-eastern Finland. This data originated from subfossil and modern pine (Pinus sylvestris L.) materials comprising a continuous dendroclimatic record over the past millennium. Calibrating and verifying the MXD chronologies against the instrumental temperature data showed a promising opportunity to reconstruct warm-season (May through September) temperature variability. A new palaeotemperature record correlated statistically significantly with the long instrumental temperature records in the region and adjacent areas since the 1740s. Comparisons with tree-ring based (MXD and tree-ring width) reconstructions from northern Fennoscandia and northern Finland exhibited consistent summer temperature variations through the Medieval Climate Anomaly, Little Ice Age, and the 20th century warmth. A culmination of the LIA cooling during the early 18th century appeared consistently with the Maunder Minimum, when the solar activity was drastically reduced. A number of coolest reconstructed events between AD 1407 and 1902 were coeval to years of crop failure and famine as documented in the agro-historical chronicles. Results indicate an encouraging possibility of warm-season temperature reconstructions using middle/south boreal tree-ring archives to detail and enhance the understanding of past interactions between humans, ecosystems and the earth.
description: Finnish Lakeland summer temperature reconstruction over the last millennium based on a maximum latewood density of subfossil and modern tree rings.
DOI: 10.25921/eeqz-re12
title: NOAA/WDS Paleoclimatology - Paritsis - Veranada Catarata 2 - NOPU - ITRDB ARGE138

description: In the temperate forests of the southern Andes, Nothofagus pumilio, the dominant species of the most extensive forest type, experiences severe defoliation caused by caterpillars of the Ormiscodes genus (Lepidoptera: Saturniidae). This study uses tree rings to reconstruct the history of Ormiscodes outbreaks for the 1850-2005 period and examines relationships between outbreaks and climate variability. We used local climate records to compare outbreak-climate relationships in the northern Patagonian Andes (c. 41°S) and the cooler southern Patagonian Andes (c. 49°S). We also examined relationships between outbreak events and regional climate variability driven by variability in the Southern Annular Mode (SAM) and the El Niño-Southern Oscillation. Although relationships between Ormiscodes outbreaks and climate proved to be complex, in northern Patagonia defoliation events are associated with drier and warmer than average growing seasons. Warming and drying trends in Patagonia during the latter part of the 20th century have been linked to a positive trend in SAM. During the post-1976 period of accelerated warming in Patagonia, widespread defoliation outbreaks have occurred in both northern and southern Patagonia but the increase in frequency of events has been greater in the south. In southern Patagonia the increases in frequency of outbreaks in the late 20th century appear to be unprecedented over the c. 150 year tree-ring record of reconstructed outbreaks. These results are consistent with the greater magnitude of recent warming in southern Patagonia, and suggest that under predicted warmer and drier climates in the 21st century, defoliator outbreaks may continue to increase in frequency. This study is the first systematic reconstruction of past insect outbreaks in South America and provides a preliminary understanding of how climate variability affects defoliator outbreaks in Patagonian Nothofagus forests.
description: Purpose of Collection:
# Ecology - insect outbreaks
# 
# Cores are stored at:
# Biogeography Lab, Geography Department, University of Colorado at Boulder
# 
# Notes:
# Most tree ring samples were collected during the growing season, so the most recent ring 
# is not a complete ring. The most recent ring was therefore not used in the analysis by 
# Paritsis and Veblen (2011). Two cores were collected per tree (desiginated with A & B sample codes). 
# Site names designated 1 and 2 are two stands located near each other, with one typically older 
# than the other.  These nearby site pairs were merged for the analysis by Paritsis and Veblen (2011). NOAA Template Raw Measurements file added 2019-04-29.
DOI: 10.25921/e7g5-cm62
title: NOAA/WDS Paleoclimatology - Bräker - Stockmatthubel - ABAL - ITRDB SWIT349

description: Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives.  Most data sets include raw treering measurements (most are annual ring width, with some collections of earlywood or latewood width or wood density), plus chronologies (standardized growth indices for a site compiled from multiple treering samples). Reconstructions of climate variables are included with some of these data sets.  Each data type is stored in a separate data file; the data type is coded into the file name. For details please see: http://www.ncdc.noaa.gov/paleo/treeinfo.htmll
description: NOAA Template Raw Measurements file added 2019-02-05.
DOI: 10.25921/e94c-9t66
title: NOAA/WDS Paleoclimatology - Stahle - Mancos River - PSME - ITRDB CO651

description: Old Rocky Mountain Douglas-fir (Pseudotsuga menziesii) trees and remnant "subfossil" logs have been found on the outcrop of a mafic igneous intrusion above the Mancos River Valley near Mesa Verde National Park. These trees and logs have been used to develop earlywood (EW), latewood (LW), and total ring width (TRW) chronologies dating from AD 722-2011. The new chronologies include good series replication during the former chronological "gap" from AD 1250 to 1400, which was so problematic for the initial development of the "Central Pueblo" chronology by A. E. Douglas. Discrete reconstructions of the cool-season (September-May) and early warm-season (June-July) moisture balance for Mesa Verde have been derived from the EW and adjusted LW width chronologies from the Mancos Valley. Cool-season drought is estimated to have been more severe and sustained than early warm-season conditions during the "Great Drought" of the late-13th Century when southwestern Colorado was depopulated. The combined archaeological, subfossil, and living tree chronologies of EW, LW, and TRW for the Mancos River and Mesa Verde Douglas-fir now date from AD 480-2011.
description: NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/e92b-h788
title: NOAA/WDS Paleoclimatology - Palestina Cave, Peru 1,600 Year Stalagmite Stable Isotope Data

description: In this paper we explore a speleothem d18O record from Palestina cave, northwestern Peru, at a site on the eastern side of the Andes cordillera, in the upper Amazon Basin. The d18O record is interpreted as a proxy for South American Summer Monsoon (SASM) intensity and allows the reconstruction of its variability during the last 1600 years. Two periods of anomalous changes in the climate mean state corresponding to the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) periods identified in the Northern Hemisphere are recognized in the record, in which decreased and increased SASM activity, respectively, have been documented. Variations in SASM activity between the MCA and the LIA seem to be larger over the northern part of the continent, suggesting a latitudinal dependence of the MCA footprint. Our results, based on time series, composite and wavelet analyses, suggest that the Atlantic Multidecadal Oscillation (AMO) plays an relevant role for SASM modulation on multidecadal scales (~65 years), especially during dry periods such as the MCA. Composite analyses, applied to evaluate the influence of the AMO on the Palestina cave d18O and other d18O-derived SASM reconstructions, allow insight into the spatial footprints of the AMO over tropical South America and highlight differences between records during key studied periods. This work also reveals that replicating regional climate signals from different sites, and using different proxies is absolutely essential for a comprehensive understanding of past changes in SASM activity.
description: Stable Oxygen isotope record (d18O and d13C) of PAL3 and PAL4 speleothems from the palestina Cave in north western Andes of Peru.  The composite record of Palestina spans the period between 421 to 1921 A.D.
DOI: 10.25921/e63s-1m07
title: NOAA/WDS Paleoclimatology - Mica Lake, Alaska 9,000 Year Diatom Isotope Data

description: The oxygen isotope ratios of diatoms (d18Odiatom), and the oxygen and hydrogen isotope ratios of lake water (dW) of lakes in south Alaska provide insight into past changes in atmospheric circulation. Lake water was collected from 31 lakes along an elevation transect 
and diatoms were isolated from lake sediment from one lake (Mica Lake) in south Alaska. In general, dW values from coastal lakes overlap the global meteoric water line (GMWL). dW values from interior lakes do not lie on the GMWL; they fall on a local evaporation line trajectory suggesting source isotopes are depleted with respect to maritime lakes. Sediment cores were recovered from 58 m depth in Mica Lake (60.96N, 148.15W; 100 m asl), an evaporation-insensitive lake in the western Prince William Sound. Thirteen calibrated 14C ages on terrestrial macrofossil samples were used to construct an age-depth model for core MC-2, which spans 9910 cal years. Diatoms from 46, 0.5-cm-thick samples were isolated and analyzed for their oxygen isotope ratios. The analyses employed a newly designed, stepwise fluorination technique, which uses a CO2 laser-ablation system, coupled to a mass spectrometer, and has an external reproducibility of 0.2%. d18Odiatom values from Mica Lake sediment range between 25.2 and 29.8%. d18Odiatom values are relatively uniform between 9.6 and 2.6 ka, but exhibit a four-fold increase in variability since 2.6 ka.  High-resolution sampling and analyses of the top 100 cm of our lake cores suggest large climate variability during the last 2000 years. The 20th century shows a +4.0% increase of d18Odiatom values. Shifts of d18Odiatom values are likely not related to changes in diatom taxa or dissolution effects. Late Holocene excursions to lower d18Odiatom values suggest a reduction of south-to-north storm trajectories delivered by meridional flow, which likely corresponds to prolonged intervals when the Aleutian Low pressure system weakened. Comparisons with isotope records of precipitation (dP) from the region support the storm-track hypothesis, and add to evidence for variability in North Pacific atmospheric circulation during the Holocene.
description: d18O diatom, biogenic silica, and organic matter from Mica Lake, Alaska, USA
DOI: 10.25921/epgp-m695
title: NOAA/WDS Paleoclimatology - Speer - Greene-Sullivan State Forest - QUVE - ITRDB IN002

description: Periodical cicada emergences in the eastern United States are one of the largest biomass fluctuations in the world, providing a unique opportunity to study if a root parasite can affect broad-scale patterns of forest growth and succession. We used dendrochronology to examine the direct effect of Brood X (17 y cicada) and Brood XXIII (13 y cicada) periodical cicadas on 89 individual trees from five species (Acer saccharum, Fraxinus americana, Quercus palustris, Q. velutina and Sassafras albidum) in Indiana. Standard dendrochronological techniques were used to date the tree-ring samples and our chronologies ranged from 63-98 y in age, spanning from four to eight cicada emergences. We removed the main climate variable from each species chronology by conducting a regression analysis and using the residuals for the remainder of the analysis. Significant climate models were developed for all five species. Acer saccharum growth correlated highest with Jun. temperature (r  =  -0.392), Fraxinus americana growth correlated with summer Palmer Drought Severity Index (PDSI) (r  =  0.338), Quercus palustris growth correlated with summer precipitation (r  =  0.366), Q. velutina growth correlated with Jul. PDSI (r  =  0.527) and Sassafras albidum growth correlated the highest with Jun. precipitation (r  =  0.406). A superposed epoch analysis was used to examine the effect of periodical cicadas on each tree species before, during and after multiple emergences on the stand level. No effect from root parasitism prior to emergence was evident in any of the species, but three of the species chronologies showed a significant reduction in growth the year of or the year after the emergence year. Three chronologies showed an increase in growth 5 y following the cicada emergence event.
description:  NOAA Template Chronology file added 2018-12-20. NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/e0jv-bn26
title: NOAA/WDS Paleoclimatology - Soulé - Paine Gulch - PIPO - ITRDB MT135

description: Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives.  Most data sets include raw treering measurements (most are annual ring width, with some collections of earlywood or latewood width or wood density), plus chronologies (standardized growth indices for a site compiled from multiple treering samples). Reconstructions of climate variables are included with some of these data sets.  Each data type is stored in a separate data file; the data type is coded into the file name. For details please see: http://www.ncdc.noaa.gov/paleo/treeinfo.htmll
description: NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/eq97-ec68
title: NOAA/WDS Paleoclimatology - Central Nova Scotia Pollen Temperature and Precipitation Reconstructions during the Late Holocene

description: The interaction between climate change and disturbances affects forest composition and dynamics, but most of our empirical knowledge comes from short-term studies of the past century. Pollen and charcoal analyses of lake sediment cores retrieved from three sites in Nova Scotia were used to produce a landscape-level analysis of long-term forest cover dynamics and fire disturbances of the past ~2500 years. The present-day forests had been established by that time, although a long-term increase in Picea at the expense of northern hardwoods was seen at all sites, consistent with other pollen records found across New England and Eastern Canada. The driving influences of forest change prior to European settlement were a combination of climate and disturbance, acting on site characteristics of each region. Fires were relatively infrequent in this region and did not have a major impact on the evolution of the forests of central Nova Scotia. Changes in the relative abundances of the tree taxa occurred in response to long-term cooling during the past 3000 years and century-scale climate variability such as the Little Ice Age (ce 1450–1850) and Medieval Warm Period (ce 800–1300). The impact of climate variability on the fire regime depends on the landscape and vegetation type. “Borealization” of the Acadian Forest, noted during the period of European colonization, has been occurring for millennia.
description: High-resolution sampling; lake sediment charcoal and pollen; paleoclimate reconstruction using modern analogue technique. Lake locations: Chase Lake (45.732 N, -63.963 W, 65m), Rees Lake (44.749 N, -63.937 W, 92m), Susie's Lake (45.353 N, -61.676 W, 68m)