cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/q9g1-zw44
title: NOAA/WDS Paleoclimatology - Mundo - Remeco - ARAR - ITRDB ARGE122

description: Seventeen tree-ring chronologies from the conifer Araucaria araucana (Molina) K. Koch have been analyzed across its range of distribution in Argentina. We studied the growth patterns and determined the main climatic factors influencing A. araucana radial growth. All the chronologies show a strong common signal observed by the high amount of variance explained by the first principal component (PC1) and the high mean correlation (r = 0.597) between the chronologies over the 1676-1974 interval. On this basis, we developed a regional chronology that is 866 years long (A.D. 1140-2006) and includes 621 tree-ring series. Based on the PC2 scores, chronologies were clearly separated by elevation in high- and low-elevation records. Regional tree growth is strongly negatively related to temperatures during summer and fall in the previous-growing season and spring in the current-growing season, respectively. A positive association of tree growth with precipitation is recorded during spring in the current growing season. These results suggest a close relationship between A. araucana tree growth and water availability on a regional scale. This observation is also consistent with a positive and significant correlation between our A. araucana regional record and a reconstruction of November-December rainfall for northern Patagonia inferred from the xeric Austrocedrus chilensis during the past 400 years. Negative correlations between A. araucana regional growth and the sea surface temperature in the Nino 3.4 region reflect the occurrence of above-mean summer temperatures in the region during positive tropical Pacific SST anomalies. The negative relationship with the Antarctic Oscillation (AAO) results from reduced precipitation in our study region during the positive phase of the AAO. The effect of elevation on water availability is consistent with significant correlations between ring-width variations at lower elevations and the Palmer Drought Severity Index during spring and summer in the current growing season. Our study emphasizes the high dendroclimatological potential of A. araucana chronologies for reconstructing past climate variations in northern Patagonia during the past millennium.
description: NOAA Template Raw Measurements file added 2019-04-29.
DOI: 10.25921/qqcn-kv13
title: NOAA/WDS Paleoclimatology - Conedera - Pian di Né Copera - PCAB - ITRDB SWIT226

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/q006-tx76
title: NOAA/WDS Paleoclimatology - Fennoscandia 1250 Year Height Increment Summer Temperature Reconstruction

description: New data have allowed us to extend a previous height-increment chronology of Scots pine (Pinus sylvestris L.) at the northern Fennoscandian timberline 817 years backwards in time, from 1561 to 745. Our final transfer model accounts for 31% of the dependent instrumental (mean June-August) temperature variance between 1908 and 2007. According to the 1263 yr long summer temperature proxy, the most severe summers were experienced in 1601, 1790 and 782. Correspondingly, the summers of 1689, 885 and 1123 were the most favourable for growth. Two drastic shifts in temperature variability were also found. The twentieth century experienced a multidecadal change as the cold 1905-1914 period was immediately followed by a warm period from 1915 to 1944. An even more prominent shift occurred in the Middle Ages, as the most severe cold spell during 1135-1164 was preceded by the warmest period only a decade earlier, during 1115-1124. The Fourier spectrum of the reconstruction shows significant concentrations of variance around 33.3, 23.3 and 11 years, and between 2.6 and 3.0 years. The wavelet spectrum was able to date several centres of fluctuating periodicities between 745 and 2007. Furthermore, daily temperature records allowed us to define the major growth forcing climatic factor in more detail than in previous response analyses. The mean temperature during a 53 day season from 14 June to 6 August produced the strongest positive growth response (r2 = 0.36).
description: 1250 year reconstruction of June - August temperature from height 
increment of Scots pine at the northern timberline in Fennoscandia. 
Annual height increments of 60 living Scots pine (Pinus sylvestris L.)
trees from the northern timberline were measured. Data collection,
preparation and measurement were carried out according to the
guidelines of Aalto and Jalkanen (1998). The Laanila site is 
located at 68°28' - 68°31'N, 27°16' - 27°24'E, 220-310 m a.s.l., 
North Finland, about 80 km south of the pine tree line.  
The Sodankylä meteorological station is located c. 140 km 
from the sampling site and provides a climate record from 
1908 to present.

Height-increment chronology was built from samples from 152 trees. 
Indexing by 33% splines. A 1-year lag is built into the data table, 
because current height growth responds strongly to temperature 
of the previous summer. Mean June - August temperature at Sodankylä 
meteorological station was used in simple linear regression models. 

Final model: y = 9,4615 + 3,1389 x 

Calibration and verification statistics:
Calibration period:     1908 – 2007 (100 years)
Early period:           1908 – 1957 (50 years)
Late period:            1958 – 2007 (50 years)

RE = Reduction of error
CE = Coefficient of efficiency

     Early-calibration     Late-calibration       Whole period
    (late-verification)   (early-verification) 
R2         0.28                 0.35                 0.31    
RE         0.33                 0.219 
CE         0.32                 0.217
DOI: 10.25921/q9g2-nm90
title: NOAA/WDS Paleoclimatology - D'Arrigo - Ittyhauk Bay - PCGL - ITRDB CANA313

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 2019-01-27. NOAA Template Raw Measurements file added 2019-02-04.
DOI: 10.25921/qc0x-7r10
title: NOAA/WDS Paleoclimatology - Frank - Ketomella PT - PISY - ITRDB FINL073

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/qwm0-r254
title: NOAA/WDS Paleoclimatology - Seebergsee, Switzerland 1000 Year Chironomid Inferred Temperature

description: Determining if temperatures of the last century exceed natural variability necessitates the use of high-resolution paleo-reconstructions extending beyond the instrumental data (i.e. >150 years). Although syntheses using tree-ring, stalagmite, and borehole based reconstructions are available, biological proxies preserved in lake sediments have been neglected as a source of high-resolution information on climate change. Here, we present a decadal-scale mean July air temperature reconstruction covering the past millennium from varved Seebergsee, Switzerland. This reconstruction is compared to instrumental data at local, regional and European scales, to another high-resolution chironomid-inferred temperature reconstruction from Lake Silvaplana (Switzerland), to a composite of paleo-climate reconstructions from the Greater Alpine Region and to various millennial scale climate reconstructions from the northern hemisphere. When compared to local and regional instrumental records since ca 1760 AD significant (p < 0.01) relationships (rPearson > 0.5) are obtained, suggesting that chironomids accurately register the changes in temperature for the past ca 250 years. At European scale, the Seebergsee reconstruction correlates (rPearson = 0.40; p < 0.01) with instrumental and early instrumental data back to 1500 AD. On the millennial time scale, the chironomid reconstruction of Seebergsee provides a pattern of temperature changes mirrored by the chironomid reconstruction from Silvaplana (rPearson = 0.44; p < 0.01) and the Greater Alpine Region composite of reconstructions (rPearson = 0.40; p < 0.01). This includes warmer-than-the-last-century mean July air temperatures (+1.2 °C on average) during the end of the "Medieval Climate Anomaly" (MCA) and colder-than-the-last-century temperatures (-0.5 °C on average) during the "Little Ice Age". Both chironomid reconstructions inferred a warming during the last decades, but this chironomid-inferred warming does not exceed the MCA temperatures. This result is not singular as many millennial temperature reconstructions in the northern Hemisphere do not show unprecedented warming of the last century at local/regional scale. However, the chironomid assemblages found in Seebergsee and Silvaplana since ca 1950 AD seem to be unique (i.e. they show unprecedented assemblage compositions) for the past 1000 years.
description: Chironomid-inferred mean July temperature from Seebergsee, 
Switzerland for the last 1000 years. Data are presented 
with 11-year triangular filter (presented in fig 4). 

Seebergsee, Switzerland:  46°7'N, 7°28'E
DOI: 10.25921/qmte-tf60
title: NOAA/WDS Paleoclimatology - Boswijk - Hoanga Road - AGAU - ITRDB NEWZ099

description: It is not known how global warming will affect the El Niño/Southern Oscillation (ENSO). The instrumental record is too short to discern centennial-scale trends and modelling results are inconclusive1, 2, 3, 4, 5. Proxy reconstructions indicate that ENSO activity was relatively high during the late twentieth century6, 7, 8, 9, 10, but whether this was unusual in the millennial context remains uncertain. Here we present insights into these issues derived from rings of the kauri tree (Agathis australis), a rare long-lived conifer endemic to the forests of northern New Zealand. Our results indicate that the twentieth century was the most ‘ENSO-active’ century of the past 500 years, but may not be unique in the context of the past 700 years, and that ENSO activity comparable to or elevated above that experienced during the late twentieth century is plausible under warmer-than-present conditions. We also find evidence that there may have been significant changes in the ENSO teleconnection to the New Zealand region during the fourteenth and fifteenth centuries, and of multi-decadal fluctuations in ENSO-related activity building up to the present day. Although these two features may delay the expression of increased ENSO activity in the New Zealand region, our results indicate that New Zealand climate is likely to be more dominated by ENSO-related inter-annual variability as the world continues to warm.
description: NOAA Template Raw Measurements file added 2019-01-24. NOAA Template Raw Measurements file added 2019-02-01.
DOI: 10.25921/q64s-zm48
title: NOAA/WDS Paleoclimatology - King - Coyote Runs - PICO - ITRDB CA671

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 Chronology file added 2018-12-20. NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/qtt5-te55
title: NOAA/WDS Paleoclimatology - Kuroshio Extension Oxygen Isotope Data During the Pliocene-Pleistocene Climate Transition

description: The Pliocene–Pleistocene climate transition offers an opportunity to study the effect of glaciation on the ocean–climate system. We present a Globigerinoides ruber δ18O record from Ocean Drilling Program Site 1208 (Kuroshio Current Extension; KCE). This exclusively (sub)tropical foraminifer, a summer/fall mixed-layer dweller at the KCE, affords the first long (3.0 Ma to 1.8 Ma) orbital-scale (2.5-kyr time step) account of the sea surface in this area. The section's temperature-corrected benthic foraminiferal δ18O record constrains global changes in ice volume, yielding a Δδ18O record that primarily reflects summer/fall KCE hydrography (temperature and salinity). A 0.3‰ decrease in Δδ18O values at 2.7 Ma coincides with the onset of Northern Hemisphere glaciation, indicating as much as 1.5°C warming during the summer/fall to suggest that the subtropical North Pacific sea surface provided heat and moisture for expanding ice sheets. On the orbital scale, the 41-kyr cycle that dominates high-latitude climate is absent from the Δδ18O record, indicating a stable surface water hydrographic regime on this time scale. Rather, the Δδ18O record varies at and is coherent with the 19-kyr precessional component of the regional insolation curve, supporting a direct response to subtropical insolation and insensitivity to extra-regional forcing factors, such as ice sheets.
description: Oxygen isotope measurements of Globigerinoides ruber span the Plio-Pleistocene boundary (3.0 to 1.76 Ma) at 2500-year time step. Stable-isotope analyses were conducted at the University of Delaware with the GV Instruments IsoPrime dual-inlet mass spectrometer. Oxygen isotopic values have been corrected to the Peedee Belemnite standard using NBS-19 and Carrara Marble as an in-house standard.
DOI: 10.25921/q0a2-rt10
title: NOAA/WDS Paleoclimatology - South Atlantic GeoB2107-3 30KYr Glacial Silicon Isotope Data

description: The supply of nutrients to the low-latitude thermocline is largely controlled by intermediate-depth waters formed at the surface in the high southern latitudes. Silicic acid is an essential macronutrient for diatoms, which are responsible for a significant portion of marine carbon export production. Changes in ocean circulation, such as those observed during the last deglaciation, would influence the nutrient composition of the thermocline and, therefore, the relative abundance of diatoms in the low latitudes. Here we present the first record of the silicic acid content of the Atlantic over the last glacial cycle. Our results show that at intermediate depths of the South Atlantic, the silicic acid concentration was the same at the Last Glacial Maximum (LGM) as it is today, overprinted by high silicic acid pulses that coincided with abrupt changes in ocean and atmospheric circulation during Heinrich Stadials and the Younger Dryas. We suggest these pulses were caused by changes in intermediate water formation resulting from shifts in the subpolar hydrological cycle, with fundamental implications for the nutrient supply to the Atlantic.
description: This file contains the silicon isotope compositions 
(denoted by d30Si relative to NBS28) of sponge spicules 
extracted from GeoB2107-3. The spicules were cleaned 
using hydrogen peroxide and dissolved in sodium hydroxide 
solution; the solutions were purified by passing through 
a cation exchange resin. Analysis was carried out using 
the Neptune MC-ICP-MS at Woods Hole Oceanographic Institution. 
Reproducibility is plus/minus 0.16 per mil (2sd). 
Age model is based on radiocarbon dates, and tuned to 
the Antarctic deuterium record.
DOI: 10.25921/qpxy-zh18
title: NOAA/WDS Paleoclimatology - Touchan - Dahllia - PIHA - ITRDB TUNI002

description: Changes in precipitation patterns and the frequency and duration of drought are likely to be the feature of anthropogenic climate change that will have the most direct and most immediate consequences for human populations. The latest generation of state-of-the-art climate models project future widespread drying in the subtropics. Here, we reconstruct spatially-complete gridded Palmer drought severity index values back to A.D. 1179 over Morocco, Algeria, and Tunisia. The reconstructions provide long-term context for northwest African hydroclimatology, revealing large-scale regional droughts prior to the sixteenth century, as well as more heterogeneous patterns in sixteenth, eighteenth, and twentieth century. Over the most recent decades a shift toward dry conditions over the region is observed, which is consistent with general circulation model projections of greenhouse gas forced enhanced regional subtropical drought.
description: NOAA Template Chronology file added 2018-12-13. NOAA Template Raw Measurements file added 2019-05-01.
DOI: 10.25921/qps2-8w14
title: NOAA/WDS Paleoclimatology - Reuter et al. 2009 Cascayunga Cave, Peru 1000 Year d18O Data

description: An absolute dated speleothem oxygen isotope (d18O) record 
from northeastern Peru documents monsoon precipitation 
variability over northern South America during the past 
that 1000 years and indicates the annual precipitation 
in the 15th through the 18th centuries, the so-called 
Little Ice Age (LIA), was on average ~10% higher than 
during the 20th century. Over the 20th century recurrent 
modes of seasonal rainfall variability across northern 
South America were associated with discrete sea surface 
temperature anomaly patterns within the Atlantic and 
Pacific Oceans. Calling upon these SST-rainfall 
teleconnectivity patterns, and paleo-SST reconstructions 
that span the past 8 centuries, higher annual rainfall 
across northern South America during the LIA is attributed 
to cooler boreal spring SSTs in the tropical North Atlantic.
Weaker co-variance between north Atlantic SSTs and the 
South American Monsoon System (SAMS) rainfall during 
the 20th century suggests that ENSO has become a more
dominant influence than it was during the LIA.
DOI: 10.25921/qpst-s398
title: NOAA/WDS Paleoclimatology - Bradtmiller et al. 2009 Pacific SO Composition/Radionuclide Data

description: The silicic acid leakage hypothesis (SALH) predicts that during glacial periods excess silicic acid was transported from the Southern Ocean to lower latitudes, which favored diatom production over coccolithophorid production and caused a drawdown of atmospheric CO2. Downcore records of 230Th-normalized opal (biogenic silica) fluxes from 31 cores in the Pacific sector of the Southern Ocean were used to compare diatom productivity during the last glacial period to that of the Holocene and to examine the evidence for increased glacial Si export to the tropics. Average glacial opal fluxes south of the modern Antarctic Polar Front (APF) were less than during the Holocene, while average glacial opal fluxes north of the APF were greater than during the Holocene. However, the magnitude of the increase north of the APF was not enough to offset decreased fluxes to the south, resulting in a decrease in opal burial in the Pacific sector of the Southern Ocean during the last glacial period, equivalent to approximately 15 Gt opal ka−1. This is consistent with the work of Chase et al. (2003a), and satisfies the primary requirement of the SALH, assuming that the upwelled supply of Si was approximately equivalent during the Holocene and the glacial period. However, previous results from the equatorial oceans are inconsistent with the other predictions of the SALH, namely that either the Corg:CaCO3 ratio or the rate of opal burial should have increased during glacial periods. We compare the magnitudes of changes in the Southern Ocean and the tropics and suggest that Si escaping the glacial Southern Ocean must have had an alternate destination, possibly the continental margins. There is currently insufficient data to test this hypothesis, but the existence of this sink and its potential impact on glacial pCO2 remain interesting topics for future study.
DOI: 10.25921/qbbh-1v29
title: NOAA/WDS Paleoclimatology - Wilson 2007 Gulf of Alaska 1300 Year Temperature Reconstruction

description: The Gulf of Alaska (GOA) is highly sensitive to shifts in North Pacific climate variability. Here we present an extended tree-ring record of January–September GOA coastal surface air temperatures using tree-ring width data from coniferous trees growing in the mountain ranges along the GOA. The reconstruction (1514–1999), based on living trees, explains 44% of the temperature variance, although, as the number of chronologies decreases back in time, this value decreases to, and remains around ∼30% before 1840. Verification of the calibrated models is, however, robust. Utilizing sub-fossil wood, we extend the GOA reconstruction back to the early eighth century. The GOA reconstruction correlates significantly (95% CL) with both the Pacific Decadal Oscillation Index (0.53) and North Pacific Index (−0.42) and therefore likely yields important information on past climate variability in the North Pacific region. Intervention analysis on the GOA reconstruction identifies the known twentieth century climate shifts around the 1940s and 1970s, although the mid-1920s shift is only weakly expressed. In the context of the full 1,300 years record, the well studied 1976 shift is not unique. Multi-taper method spectral analysis shows that the spectral properties of the living and sub-fossil data are similar, with both records showing significant (95% CL) spectral peaks at ∼9–11, 13–14 and 18–19 years. Singular spectrum analysis identifies (in order of importance) significant oscillatory modes at 18.7, 50.4, 38.0, 91.8, 24.4, 15.3 and 14.1 years. The amplitude of these modes varies through time. It has been suggested (Minobe in Geophys Res Lett 26:855–858, 1999) that the regime shifts during the twentieth century can be explained by the interaction between pentadecadal (50.4 years) and bidecadal (18.7 years) oscillatory modes. Removal of these two modes of variance from our GOA time series does indeed remove the twentieth century shifts, but many are still identified prior to the twentieth century. Our analysis suggests that climate variability of the GOA is very complex, and that much more work is required to understand the underlying oscillatory behavior that is observed in instrumental and proxy records from the North Pacific region.
DOI: 10.25921/q42v-m283
title: NOAA/WDS Paleoclimatology - Clark and Huybers 2009 Interglacial and Future Sea Level

description: Records of past temperature, precipitation, and other climate variables derived from paleoclimate proxies.  Parameter keywords describe what was measured in this data set.  Additional summary information can be found in the abstracts of papers listed in the data set citations.