cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/jdes-4077
title: NOAA/WDS Paleoclimatology - Central Vietnam 660 Year SPEI Index Reconstruction

description: We present the first crossdated tree ring record from central Vietnam, derived from the growth rings of the rare cypress Fokienia hodginsii from the mountains of Quang Nam Province near the Laos border. The Quang Nam Fokienia hodginsii time series (QNFH), based on the crossdated sequences of 71 increment core samples from 37 mature trees, is the third published dendrochronological record from this species. The record extends 667 years from AD 1347 to 2013 and exhibits a mean series intercorrelation of 0.526, similarly significant with the first two published Fokienia hodginsii records: 0.474 for Mu Cang Chai (MCFH) and 0.578 for Bidoup-Nui Ba National Park (BDFH) in the north and south of Vietnam, respectively. The Expressed Population Signal (EPS) for the QNFH record exceeds the generally accepted threshold of 0.85 back to AD 1567, but remains above 0.8 back to 1550. Similar to the MCFH and BDFH records, QNFH expresses statistically significant linkages to regional hydroclimate metrics and the El Niño-Southern Oscillation. Here we present a reconstruction of the Standardized Precipitation Evapotranspiration Index for the month of April, averaged over a large region of Southeast Asia. As with prior studies we demonstrate that cool phase (La Niña) and warm phase (El Niño) events are linked to regional wet and dry conditions, respectively, with linkages to modulation of the surface water temperature over the adjacent sea to the east of Vietnam as well as the Indian Ocean. A late eighteenth century megadrought that is expressed widely across South and Southeast Asia, and notably from the MCFH and BDFH records described above, is not as pronounced in Central Vietnam and we explore the reasons why.
description: Central Vietnam Standardized Precipitation Evapotranspiration Index (SPEI) for the month of April, 1347-2013 CE, based on Fokienia hodginsii tree rings from Quang Nam Province.
DOI: 10.25921/jgx6-2320
title: NOAA/WDS Paleoclimatology - Bruce Plateau, Antarctic Peninsula 100yr Ice Core d18O and Accumulation

description: A new ice core drilled in 2010 to bedrock from the Bruce Plateau (BP) on the Antarctic Peninsula (AP) provides a high temporal resolution record of environmental conditions in this region. The extremely high annual accumulation rate at this site facilitates analysis of the relationships between annual net accumulation An on the BP and large-scale atmospheric oscillations. Over the last ~45 years, An on the BP has been positively correlated with both the southern annular mode (SAM) and Southern Oscillation index (SOI). Extending this analysis back to 1900 reveals that these relationships are not temporally stable, and they exhibit major shifts in the late-1940s and the mid-1970s that are contemporaneous with phase changes in the Pacific decadal oscillation (PDO). These varying multidecadal characteristics of the An-oscillation relationships are not apparent when only data from the post-1970s era are employed. Analysis of the longer ice core record reveals that the influence of the SAM on An depends not only on the phase of the SAM and SOI but also on the phase of the PDO. When the SAM's influence on BP An is reduced, such as under negative PDO conditions, BP An is modulated by variability in the tropical and subtropical atmosphere through its impacts on the strength and position of the circumpolar westerlies in the AP region. These results demonstrate the importance of using longer-term ice core-derived proxy records to test conventional views of atmospheric circulation variability in the AP region.
description: Antarctic Peninsula oxygen isotope (d18O) and accumulation rate data from an ice core drilled on Bruce Plateau.
DOI: 10.25921/j0qn-qq37
title: NOAA/WDS Paleoclimatology - Sauchyn - Tamarack Bowl - LALY - ITRDB CANA528

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/j3cy-vs63
title: NOAA/WDS Paleoclimatology - Porter - Old Crow River site OC50 - PCGL - ITRDB CANA542

description: We present a new 23-site network of white spruce ring-width chronologies near boreal treeline in Old Crow Flats, Yukon Territory, Canada. Most chronologies span the last 300 years and some reach the mid-16th century. The chronologies exhibit coherent growth patterns before the 1930s. However, since the 1930s, they diverge in trend and exhibit one of two contrasting, but well-replicated patterns we call Group 1 and Group 2. Over the instrumental period (1930-2007) Group 1 sites were inversely correlated with previous-year July temperatures while Group 2 sites were positively correlated with growth-year June temperatures. At the broader northwestern North America (NWNA) scale, we find that the Group 1 and Group 2 patterns are common to a number of white spruce chronologies, which we call NWNA 1 and NWNA 2 chronologies. The NWNA 1 and NWNA 2 chronologies also share a single coherent growth pattern prior to their divergence (ca. 1950s). Comparison of the NWNA 1/NWNA 2 chronologies against gridded 20th-century temperatures for NWNA and reconstructed northern hemisphere summer temperatures (ad 1300-2000) indicates that all sites responded positively to temperature prior to the mid-20th century (at least back to ad 1300), but that some changed to a negative response (NWNA 1) while others maintained a positive response (NWNA 2). The spatial extent of divergence implies a large-scale forcing. As the divergence appears to be restricted to the 20th century, we suggest that the temperature response shift represents a moisture stress caused by an anomalously warm, dry 20th-century climate in NWNA, as indicated by paleoclimatic records. However, because some sites do not diverge and are located within a few kilometres of divergent sites, we speculate that site-level factors have been important in determining the susceptibility of sites to the large-scale drivers of divergence.
description: NOAA Template Raw Measurements file added 2019-01-27. NOAA Template Raw Measurements file added 2019-02-04.
DOI: 10.25921/js4k-hk55
title: NOAA/WDS Paleoclimatology - Umbanhowar Fire Data from Crystal Lake, Eastern North America (Paleon) - IMPD USCRY001

description: Records of past fire occurrence from tree rings, charcoal found in lake sediments, and other 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.  Additional information on the International Multiproxy Database (IMPD) data set procedures are also available.

description: Provided Keywords: fire, paleoclimate, climate, charcoal
DOI: 10.25921/jvvs-jd17
title: NOAA/WDS Paleoclimatology - Paleo-pCO2 Database Wyoming Early Eocene Paleosol CO2 Data

description: The Early Eocene Climatic Optimum (EECO) has been characterized as a prolonged warm event indicated by increased atmospheric pCO2, temperatures, precipitation, and biological turnover. A new paleoenvironmental reconstruction using integrated pedological, geochemical, and isotopic data from the Green River Basin (Green River/Great Divide region) provides a high-resolution record of environmental and climatic change throughout the EECO. Our reconstruction indicates that this region, and likely much of the margin of paleolake Gosiute, was a stable, fluvially-controlled floodplain environment with evidence of large scale continuous soil development and features comparable with modern Alfisols (temperate forest soils). Regional climate data from multiple proxies indicates that the period was warm-temperate and semi-arid to sub-humid, with a peak interval from about 51.5-50.9 Ma that exhibits significantly warmer (~ 7C) and wetter (~ 750 mm yr-1) conditions, resulting in major changes to the local weathering regime. Isotopic analyses also indicate a rapid increase to high atmospheric pCO2 values (~ 1700 ppmV) and a shift in the d13C composition of pedogenic carbonates during this peak interval that appear to define and provide a cause for this significant regional response to global climatic change. The new data, when combined with foraminiferal d13C records, are consistent with CO2 ventilation from a deep marine reservoir source. This multi-proxy reconstruction suggests that the EECO may have had a superimposed "peak" of climatic and ecological change on land.
description: Paleo-CO2 derived from Eocene paleosols from the Wind River and Wasatch formations in Wyoming, USA, contributed to the Paleo-pCO2 Database.
DOI: 10.25921/j6gt-cq88
title: NOAA/WDS Paleoclimatology - Paleo-pCO2 Database Franks Method Stomata CO2 Data

description: A rise in atmospheric CO2 is believed to be necessary for the termination of large-scale glaciations. Although the Antarctic Ice Sheet is estimated to have melted from ~125% to ~50% its modern size, there is thus far no evidence for an increase in atmospheric CO2 associated with the Mi-1 glacial termination in the earliest Miocene. Here, we present evidence from a high-resolution terrestrial record of leaf physiological change in southern New Zealand for an abrupt increase in atmospheric CO2 coincident with the termination of the Mi-1 glaciation and lasting approximately 20 kyr. Quantitative pCO2 estimates, made using a leaf gas exchange model, suggest that atmospheric CO2 levels may have doubled during this period, from 516+/- 111 ppm to 1144+/-410 ppm, and subsequently returned back to 425 +/- 53 ppm. The 20-kyr interval with high pCO2 estimates is also associated with a period of increased moisture supply to southern New Zealand, inferred from carbon and hydrogen isotopes of terrestrial leaf waxes. The results provide the first high-resolution record of terrestrial environmental change at the Oligocene/Miocene boundary, document a ~20 kyr interval of elevated pCO2 and increased local moisture availability, and provide insight into ecosystem response to a major orbitally driven climatic transition.
description: Paleo-CO2 derived from fossil plant stomata utilizing the Franks method, contributed to the Paleo-pCO2 Database.
DOI: 10.25921/jz4r-sm15
title: NOAA/WDS Paleoclimatology - Marcinkowski - Thornton Lakes - TSME - ITRDB WA148

description: A stationary response of tree radial growth to climatic variables is assumed as a basis for climatic reconstructions and future growth projections in response to climate change. Mountain hemlock (Tsuga mertensiana (Bong.) Carriere) trees on the western slopes of the North Cascade Range (Washington, USA) were examined for stability in growth response to climatic influences at a small spatial scale. Moving correlation functions demonstrate that climate-growth interactions are nonstationary over time, alternating between periods of significant and nonsignificant responses. Correlations between growth and winter precipitation have weakened, becoming statistically insignificant in the last decade, but correlations with spring temperature and previous-year summer temperature have strengthened, becoming statistically significant. The Pacific Decadal Oscillation influences patterns in climate-growth correlations but does not seem to account for the most recent changes in correlation strength. At an interannual scale, growth differs between El Nino Southern Oscillation phases, specifically between El Nino and La Nina years and between La Nina and neutral phase years. The variability in growth response to climate at interannual and interdecadal time frames, especially with the climate changes emerging in recent decades, will challenge the reliability and accuracy of reconstruction and predictive models.
description: NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/j05v-pj47
title: NOAA/WDS Paleoclimatology - Heinrich - Atherton Tableland - TOCI - ITRDB AUSL051

description: In tropical Australia, palaeoclimatic proxies derived from tree rings are sought after sources for reconstructing climate variations. However, dendroclimatology has not been widely applied in tropical forests and even less so in the Australian tropics due to the extreme rarity of species producing anatomically distinct annual growth rings. Furthermore, most Australian tree species exhibit rather strong opportunistic growth with non-annual growth zones that are less suitable for dendrochronology. Recent studies on the Australian Red Cedar (Toona ciliata) in the Upper Kangaroo Valley near Sydney revealed that tree-ring based climate reconstructions are feasible with this species. This study moved 2500 km further north and concentrated on the tropical stands of T. ciliata because it is one of the few deciduous tree species in tropical Australia likely characterised by a dormant period of the cambium and thus annual tree rings. Although dendroclimatological studies indicate that some Australian tree species are suitable for reconstructing climate patterns, a well replicated tree-ring record from Far North Queensland has not been developed until now. Tree cores of T. ciliata were developed into a 140-year tree-ring widths index chronology. The analyses showed that the ring-widths indices correlate with March–June precipitation as recorded at Kairi research station. March–June precipitation was reconstructed using the tree-ring data with 35% of the variance explained. The reconstructed series contains both high- and low-frequency climate signals. This suggests that growth of T. ciliata is influenced by climate phenomena of different wave lengths which can be associated with El Niño Southern Oscillation (ENSO) and Interdecadal Pacific Oscillation (IPO).
description: NOAA Template Raw Measurements file added 2019-01-24. NOAA Template Raw Measurements file added 2019-02-01.
DOI: 10.25921/jchn-7617
title: NOAA/WDS Paleoclimatology - Mid-Pliocene Leaf Wax Data from the Bengal Fan

description: Records of past climate and ocean circulation derived from marine sediments. 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.
DOI: 10.25921/jkp9-7765
title: NOAA/WDS Paleoclimatology - Lake Nyamogusingiri, Uganda 800 Year Multiproxy Lake Sediment Data

description: The exploitation of lakes has led to large-scale contemporary impacts on freshwater systems, largely in response to catchment clearance. Such clearance is causing changes to carbon dynamics in tropical lakes which may have significance for wider carbon budgets, depending on the changes in carbon sequestration and mineralisation driven by changing roles of terrestrial and aquatic carbon in lakes over time. Despite increasing awareness of the pivotal role of carbon source in carbon dynamics, discriminating the source of carbon from a palaeolimnological record is rarely undertaken. Here we use novel geochemical techniques (brGDGTs, n-alkanes, Rock-Eval pyrolysis), paired with traditional analyses (diatoms, pollen), to elucidate changing sources of carbon through time and ecosystem response.

Environmental changes at Lake Nyamogusingiri can be divided into three phases: Phase I (CE 1150-1275), a shallow and productive lake, where a diverse terrestrial environment is, initially, the main carbon source, before switching to an aquatic source; Phase II (CE 1275-1900), variable lake levels (generally in decline) with increasing productivity, and carbon is autochthonous in source; Phase III (CE 1900-2007), lake level declines, and the carbon is of a mixed source, though the terrestrially derived carbon is from a less diverse source.

The organic geochemical analyses provide a wealth of data regarding the complexity of aquatic response to catchment and with-in lake changes. These data demonstrate that small, tropical lake systems have the potential to bury high quantities of carbon, which has implications for the disruption of local biogeochemical cycles (C, P, N, and Si) both in the past, and the future as human and climate pressures increase.
description: Geochemical, isotope, and physical properties data plus pollen data from sediments collected in Lake Nyamogusingiri, Uganda, for the past 800 years.
DOI: 10.25921/jrqz-x388
title: NOAA/WDS Paleoclimatology - Leviathan Chronology v2, Nevada 174KYr Stalagmite d18O Data

description: Although Great Basin paleoclimate history has been examined for more than a century, the orbital-scale paleoclimate forcings remain poorly understood. Here we show - by a detailed phasing analysis of a well-dated stalagmite d18O time series - that Great Basin paleoclimate is linearly related to, but lagged, the 23,000yr precession cycle in northern hemisphere summer insolation by an average of 3240 years (-900 to 6600yr range) over the last two glacial cycles. We interpret these lags as indicating that Great Basin climate is sensitive to and indirectly forced by changes in the cryosphere, as evidenced by fast and strong linkages to global ice volume and Arctic paleoclimate indicators. Mid-latitude atmospheric circulation was likely impacted by a northward shifted storm track and higher pressure over the region arising from decreased sea ice and snow cover. Because anthropogenic warming is expected to reduce northern hemisphere snow and ice cover, continued increase in atmospheric greenhouse gases is likely to result in warming and drying over coming centuries that will amplify a warming trend that began ~2400 years ago.
description: Stalagmite d18O values from Leviathan Cave and Devils Hole, Nevada, known as the Leviathan Chronology v2.  The original 2014 Leviathan Chronology is archived at: https://www.ncdc.noaa.gov/paleo/study/16517
DOI: 10.25921/jdk7-tw97
title: NOAA/WDS Paleoclimatology - Walker Lake, Nevada, USA d18O lake sediment Data from -567 to 2000 CE

description: Measurements of the oxygen isotopic composition (δ18O) of the total inorganic carbon (TIC) fraction from cored sediments of Walker Lake, Nevada, were conducted at an average resolution of ~3 years per sample over the last 1200 years. On the basis of radiocarbon analysis on the total organic carbon (TOC) fraction, a δ18O time series was created to reconstruct changes in hydrologic conditions back to AD 800. The timings of variations in the TIC δ18O record are generally consistent with the tree ring‐based Sacramento River flow record spanning AD 869 to 1977, indicating that Walker Lake δ18O contains information about past changes in at least regional hydrologic conditions. Comparison with the δ18O record from Pyramid Lake sediments indicates that both basins have recorded five century‐scale oscillations in regional hydrologic conditions since AD 800. Several of these changes in hydrologic conditions appear synchronous with century‐scale California Current water temperature changes derived from analysis of sediment cores from the Santa Barbara Basin also attesting to the regional extent of these climatic fluctuations. Nearly synchronous oscillations in the Sierra wetness and the California Current suggest that regional changes in atmospheric circulation may have played an important role in century-scale climate variability over the last millennium.
description: Contributed to NOAA Paleoclimatology as part of Rodysill et al. 2018 synthesis study (https://www.ncdc.noaa.gov/paleo/study/24910).
DOI: 10.25921/j0m7-td42
title: NOAA/WDS Paleoclimatology - South Atlantic Ocean Deep Sea Temperature Reconstruction and Mg/Ca Data during the Last 12 Million Years

description: Published benthic foraminiferal Mg/Ca records have been compiled that span the latest Oligocene through Miocene, including new data for the South Atlantic. This synthesis, the first such of Mg/Ca data, necessitates consideration of uncertainties and limitations and provides a general perspective on the evolution of deep-sea temperatures over this period. Published Mg/Ca records show temperature patterns through the Miocene that are consistent with those first synthesized by Kennett (1985) utilizing isotope and other data. Accordingly, the early Miocene was an interval of relative warmth culminating in a climatic optimum at ~16 Ma that was characterized by the warmest (Mg-derived) temperatures of the past 20 million years. After the climatic optimum, palaeotemperatures dropped by 3–4°C during the second major advance of Antarctic ice between ~15Ma and 13 Ma. For the late Miocene, between 11-8.5 Ma, a distinct increase in benthic foraminiferal Mg/Ca ratios at two Atlantic sites provides evidence for deep to intermediate water circulation changes. Thereafter, temperatures close to modern are recorded at all sites. Assuming constant seawater Mg/Ca ratios through time, it can be concluded that the early Miocene climate was generally warmer than today and that by the late Miocene temperatures approached modern values.
description: Age model is based on the age model described by Billups (2002) with the ages of the epoch boundaries updated to the Gradstein et al (2004) time scale
      Provided Keywords: benthic foraminfera, stable isotopes, Mg/Ca ratios
DOI: 10.25921/j2wq-p403
title: NOAA/WDS Paleoclimatology - Gutiérrez - Lochwood - QURO - ITRDB BRIT072

description: Aim

The aim was to decipher Europe‐wide spatio-temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming.
Location

Europe and North Africa (30-70 N, 10 W-35 E).
Time period

1901-2003.
Major taxa studied

Temperate and Euro-Siberian trees.
Methods

We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree-ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic, boreal, cold continental, Mediterranean and temperate). We also examine whether TRWi shows variable coupling with leaf-level gas exchange, inferred from indexed carbon isotope discrimination of tree-ring cellulose (Delta13Ci).

Results

We find spatial autocorrelation for TRWi and Delta13Ci extending over a maximum of 1,000 km among forest stands. However, growth synchrony is not uniform across Europe, but increases along a latitudinal gradient concurrent with decreasing temperature and evapotranspiration. Latitudinal relationships between TRWi and Delta13Ci (changing from negative to positive southwards) point to drought impairing carbon uptake via stomatal regulation for water saving occurring at forests below 60 N in continental Europe. An increase in forest growth synchrony over the 20th century together with increasingly positive relationships between TRWi and Delta13Ci indicate intensifying impacts of drought on tree performance. These effects are noticeable in drought-prone biomes (Mediterranean, temperate and cold continental).
Main conclusions

At the turn of this century, convergence in growth synchrony across European forest ecosystems is coupled with coordinated warming-induced effects of drought on leaf physiology and tree growth spreading northwards. Such a tendency towards exacerbated moisture-sensitive growth and physiology could override positive effects of enhanced leaf intercellular CO2 concentrations, possibly resulting in Europe‐wide declines of forest carbon gain in the coming decades.
description: NOAA Template Raw Measurements file added 2020-01-15.