cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/fdz8-5628
title: NOAA/WDS Paleoclimatology - Arctic Ostracode Rabilimis Population Data during the Quaternary

description: The Arctic Ocean has experienced orbital and millennial-scale climate oscillations over the last 500 kilo-annum (ka) involving massive changes in global sea level and components of the Arctic cryosphere, including sea-ice cover, land-based ice sheets and ice shelves. Although these climate events are only partially understood, micropaleontological studies utilizing ostracodes and benthic foraminifera have demonstrated that major changes in faunas have occurred at different timescales that signify ecosystem regime changes linked to sea-ice cover, surface productivity, bottom temperature and other factors. In addition to faunal changes characterizing glacial-interglacial cycles, Arctic sediments contain several unusual faunal events that cannot be explained by orbital-scale sea level and cryospheric changes. One indicator of such events involves the ostracode Rabilimis mirabilis (Brady, 1868), a shallow-water species that inhabits continental shelves in the modern Arctic. We conducted studies of the stratigraphic distribution of R. mirabilis in cores from the Northwind, Mendeleev, Lomonosov, and Alpha Ridges; the Siberian and North American (Beaufort Sea) continental margins; and the Lincoln Sea off North Greenland and in the northern Greenland Sherard Osborn Fjord. Evidence from these records suggests that this species occurs as a fossil in deeper water sediment cores on the upper parts of submarine ridges (mainly 700-900 meters water depth, mwd), in significant numbers (from 1% to 50% of total ostracodes) during Marine Isotope Stages (MIS) 5a (125-109 ka), MIS 4 (71-57 ka), and MIS 3 (57-29 ka). Furthermore, it occurs in cores from various depths on the Siberian margin, the Beaufort and Lincoln Seas during MIS 1 (the Holocene, ~11-0 ka). These occurrences involve well-preserved, stratigraphically consistent adult and juvenile populations, which are autochthonous in nature and not caused by downslope transport or ice rafting. Based on their age and associated paleoceanographic conditions in the Arctic, we interpret these R. mirabilis events as signifying basin-ward migration during abrupt changes in growth and decay of massive ice shelves and may be useful as biostratigraphic markers.
description: Provided Keywords: Paleoceanography, Paleoclimatology, Arctic Ocean, Ostracode, Rabilimis
DOI: 10.25921/ft0p-j151
title: NOAA/WDS Paleoclimatology - Marshall Islands 3,000 Year Grain Size Data and Tropical Cyclone Reconstruction

description: The instrumental record reveals that tropical cyclone activity is sensitive to oceanic and atmospheric variability on inter-annual and decadal scales. However, our understanding of the influence of climate on tropical cyclone behaviour is restricted by the short historical record and the sparseness of prehistorical reconstructions, particularly in the western North Pacific, where coastal communities suffer loss of life and livelihood from typhoons annually. Here, to explore past regional typhoon dynamics, we reconstruct three millennia of deep tropical North Pacific cyclogenesis. Combined with existing records, our reconstruction demonstrates that low-baseline typhoon activity prior to 1350 ce was followed by an interval of frequent storms during the Little Ice Age. This pattern, concurrent with hydroclimate proxy variability, suggests a centennial-scale link between Pacific hydroclimate and tropical cyclone climatology. An ensemble of global climate models demonstrates a migration of the Pacific Walker circulation and variability in two Pacific climate modes during the Little Ice Age, which probably contributed to enhanced tropical cyclone activity in the tropical western North Pacific. In the next century, projected changes to the Pacific Walker circulation and expansion of the tropics will invert these Little Ice Age hydroclimate trends, potentially reducing typhoon activity in the deep tropical Pacific.
description: Grain size analysis of a sediment core retrieved from the bottom of a 30m deep blue hole on the northwestern rim of Jaluit Atoll, Republic of the Marshall Islands. Coarse fraction >250 microns was used as a proxy indicator of storm event layers.
DOI: 10.25921/fpbz-rf96
title: NOAA/WDS Paleoclimatology - Minamihama Marsh, Northern Japan 4,400 Year Peat d18O Data

description: In Hokkaido, northern Japan, densely populated societies of hunter-fisher-gatherer cultures persisted over the Holocene until the 19th century. We used the cellulose δ18O values of Sphagnum and vascular plants in peat cores from Rishiri Island to understand paleoclimate changes in Hokkaido over the past 4400 years and discuss the impacts of climate changes on the development of the cultures. The cellulose δ18O values showed multi-centennial and millennial variations, reflecting the intensity of the Tsushima Warm Current and the summer position of the westerly jet. The marine hunter-fisher cultures responded to changes in the strength of Tsushima Warm Current and coastal primary production. In contrast, the inland cultures responded to changes in the latitudinal position of the summer westerlies. This implies that human societies of different lifestyles responded differently to climate changes.
description: Oxygen isotope (d18O) data from peat cores collected in Minamihama Marsh, Rishiri Island, northern Japan, for the past 4,400 years
DOI: 10.25921/fwgf-0s80
title: NOAA/WDS Paleoclimatology - Maxwell - Morgan Monroe Flux Tower Site - QUAL - ITRDB IN026

description: Several important environmental influences of tree growth and carbon sequestration have changed over the past several decades in eastern North America, specifically, more frequent pluvial conditions, increased carbon dioxide (CO2) concentrations, and decreased acidic deposition. These factors could lead to changes in the relationship between tree growth and water availability, and perhaps even decouple the two, having large implications on how future climate change will impact forest productivity and carbon sequestration. Here, we examine the concurrent influence of the climatic water balance (precipitation minus potential evapotranspiration), CO2 concentrations, and sulfate and nitrogen deposition on radial tree growth, carbon isotopes, and intrinsic water-use efficiency (iWUE) for several hardwood tree species in the Midwestern United States. We found that when considering the simultaneous influence of these factors, the climatic water balance is the dominant influence on annual growth. Therefore, the recent pluvial period is the primary cause of the weakening relationship between radial growth and water availability. Even during pluvial periods, water availability is the primary control on growth, with increasing CO2 concentrations and decreased SO4 deposition being secondary factors. Importantly, the weakening in the climate-growth relationship is species specific, with Acer species having stable relationships with the climatic water balance, Liriodendron tulipifera showing a strengthening relationship, and Quercus species and Populus grandidentata exhibiting weakening. Thus, interannual variations in soil moisture unevenly impact tree growth and carbon sequestration. Our findings suggest that, despite recent pluvial conditions, increasing CO2 concentrations and decreasing acidic deposition have not buffered the impact of water availability on tree growth and carbon sequestration.
description: NOAA Template Raw Measurements file added 2020-09-03.
DOI: 10.25921/ftg9-wq55
title: NOAA/WDS Paleoclimatology - Römer - Tartagine Valley - PINI - ITRDB FRAN052

description: Maximum latewood density (MXD) measurements from long-lived Black pines (Pinus nigra spp. laricio) growing at the upper treeline in Corsica are one of the few archives to reconstruct southern European summer temperatures at annual resolution back into medieval times. Here, we present a compilation of five MXD chronologies from Corsican pines that contain high-to-low frequency variability between 1168 and 2016 CE and correlate significantly (p < 0.01) with the instrumental April-July and September-October mean temperatures from 1901 to 1980 CE (r = 0.52-0.64). The growth-climate correlations, however, dropped to -0.13 to 0.02 afterward, and scaling the MXD data resulted in a divergence of >1.5 C between the colder reconstructed and warmer measured temperatures in the early-21st century. Our findings suggest a warming-induced shift from initially temperature-controlled to drought-prone MXD formation, and therefore question the suitability of using Corsican pine MXD data for climate reconstruction.
description: Maximum density, Pinus nigra ssp. laricio MAIRE (Corsican Pine) NOAA Template Raw Measurements file added 2021-08-05.
DOI: 10.25921/f82r-9929
title: NOAA/WDS Paleoclimatology - Peltier - Southwest Ecological Memory Project Site A7 - PPTR - ITRDB CO684

description: Trees are long-lived organisms that integrate climate conditions across years or decades to produce secondary growth. This integration process is sometimes referred to as 'climatic memory.' While widely perceived, the physiological processes underlying this temporal integration, such as the storage and remobilization of non-structural carbohydrates (NSC), are rarely explicitly studied. This is perhaps most apparent when considering drought legacies (perturbed post-drought growth responses to climate), and the physiological mechanisms underlying these lagged responses to climatic extremes. Yet, drought legacies are likely to become more common if warming climate brings more frequent drought. To quantify the linkages between drought legacies, climate memory and NSC, we measured tree growth (via tree ring widths) and NSC concentrations in three dominant species across the southwestern USA. We analyzed these data with a hierarchical mixed effects model to evaluate the time-scales of influence of past climate (memory) on tree growth. We then evaluated the role of climate memory and the degree to which variation in NSC concentrations were related to forward-predicted growth during the hot 2011-2012 drought and subsequent 4-year recovery period. Populus tremuloides exhibited longer climatic memory compared to either Pinus edulis or Juniperus osteosperma, but following the 2011-2012 drought, P. tremuloides trees with relatively longer memory of temperature conditions showed larger (more negative) drought legacies. Conversely, Pinus edulis trees with longer temperature memory had smaller (less negative) drought legacies. For both species, higher NSC concentrations followed more negative (larger) drought legacies, though the relevant NSC fraction differed between P. tremuloides and P. edulis. Our results suggest that differences in tree NSC are also imprinted upon tree growth responses to climate across long time scales, which also underlie tree resilience to increasingly frequent drought events under climate change.
description: These tree ring data were collected to assess the climate memory of tree growth around the southwestern US in "ecologically sampled" trees. Trees were from a range of size classes and vigors, but were all dominant or co-dominant. NOAA Template Raw Measurements file added 2022-04-04.
DOI: 10.25921/fedc-1441
title: NOAA/WDS Paleoclimatology - Rydval - Tři kopy - PISY - ITRDB SVK016

description: Extreme tree growth reductions represent events of abrupt forest productivity decline and carbon sequestration reduction. An increase in their magnitude can represent an early warning signal of impending tree mortality. Yet the long-term trends in extreme growth reductions remain largely unknown. We analyzed the trends in the proportion of trees exhibiting extreme growth reductions in two Central-European conifer species - Pinus sylvestris (PISY) and Picea abies (PCAB) - between 1901 and 2018. We used a novel approach for extreme growth reduction quantification by relating their size to their mean recurrence interval. Twenty-eight sites throughout Czechia and Slovakia with 1120 ring width series representing high- and low-elevation forests were inspected for extreme growth reductions with recurrence intervals of 15 and 50 years along with their link to climatic drivers. Our results show the greatest growth reductions at low-elevation PCAB sites, indicating high vulnerability of PCAB to drought. The proportions of trees exhibiting extreme growth reductions increased over time at low-elevation PCAB, decreased recently following an abrupt increase in the 1970-1980s at high-elevation PCAB, and showed nonsignificant trends in high- and low-elevation PISY. Climatic drivers of extreme growth reductions, however, shifted over time for all site categories as the proportion of low-temperature-induced extreme growth reductions declined since the 1990s, whereas events caused by drought consistently increased in frequency during the same period. We observed higher growth volatility at the lower range of distribution compared with the upper range margin of PISY and PCAB. This will undoubtedly considerably impact tree growth and vitality as temperatures and incidence of drought in Central Europe are expected to further increase with ongoing climate change.
description: Extreme growth reductions in Central-European Pinus sylvestris (PISY) and Picea abies (PCAB). NOAA Template Raw Measurements file added 2021-12-29.
DOI: 10.25921/fx75-7d75
title: NOAA/WDS Paleoclimatology - Larson - Jablonowski - QUAL - ITRDB WI035

description: New and updated multi-century tree-ring chronologies from living oak trees, remnants, and archeological beams from across the Driftless Area of southwest Wisconsin and northeast Iowa, USA, were developed to fill a spatial gap in the network of available tree-ring chronologies. We produced a robust 303-year summer drought reconstruction (June-August Palmer's Modified Drought Index (PMDI): r2 = 0.45) that identified clusters of extreme droughts and pluvials (PMDI <= -4.0 or >= 4.0) in the early 1700s and more even distributions of drought conditions, with the exception of the post 1930s period when drought became relatively infrequent. Compared to the Living Blended Drought Atlas (LBDA) and the North American Drought Atlas (NADA), our reconstruction more accurately represented moderate moisture conditions across the Driftless Area, the NADA and LBDA more closely represented extreme pluvials, and our reconstruction and the LBDA better represented extreme drought years. The three reconstructions largely captured the same high-frequency variability in drought conditions and differed most at low frequencies. Significant correlations were identified between our reconstruction and corn (r = 0.30, n = 91, p = 0.002) and soybean (r = 0.25, n  = 81, p = 0.012) yields, with the strength of the correlations increasing over recent decades suggesting a tighter coupling of interannual climate variability and crop productivity in the region. Superposed epoch analyses indicated significantly wetter conditions in the Driftless Area two years after major volcanic eruptions. In the context of long-term climatic variability, the Driftless Oaks drought reconstruction demonstrated that drought and pluvial conditions more extreme than those experienced during the instrumental record have occurred in the past.
description: Oak ring width data from the Driftless Area of southwest Wisconsin and northeast Iowa, USA, sampled from living oak trees, remnants, and archeological beams. NOAA Template Raw Measurements file added 2021-10-19.
DOI: 10.25921/f2mf-gx89
title: NOAA/WDS Paleoclimatology - Treml - Letanovský mlýn - PISY - ITRDB SVK010

description: Extreme tree growth reductions represent events of abrupt forest productivity decline and carbon sequestration reduction. An increase in their magnitude can represent an early warning signal of impending tree mortality. Yet the long-term trends in extreme growth reductions remain largely unknown. We analyzed the trends in the proportion of trees exhibiting extreme growth reductions in two Central-European conifer species - Pinus sylvestris (PISY) and Picea abies (PCAB) - between 1901 and 2018. We used a novel approach for extreme growth reduction quantification by relating their size to their mean recurrence interval. Twenty-eight sites throughout Czechia and Slovakia with 1120 ring width series representing high- and low-elevation forests were inspected for extreme growth reductions with recurrence intervals of 15 and 50 years along with their link to climatic drivers. Our results show the greatest growth reductions at low-elevation PCAB sites, indicating high vulnerability of PCAB to drought. The proportions of trees exhibiting extreme growth reductions increased over time at low-elevation PCAB, decreased recently following an abrupt increase in the 1970-1980s at high-elevation PCAB, and showed nonsignificant trends in high- and low-elevation PISY. Climatic drivers of extreme growth reductions, however, shifted over time for all site categories as the proportion of low-temperature-induced extreme growth reductions declined since the 1990s, whereas events caused by drought consistently increased in frequency during the same period. We observed higher growth volatility at the lower range of distribution compared with the upper range margin of PISY and PCAB. This will undoubtedly considerably impact tree growth and vitality as temperatures and incidence of drought in Central Europe are expected to further increase with ongoing climate change.
description: Extreme growth reductions in Central-European Pinus sylvestris (PISY) and Picea abies (PCAB). NOAA Template Raw Measurements file added 2021-12-29.
DOI: 10.6084/m9.figshare.29916745
title: Correspondence Analysis on Sparse Bipartite Graphs with Hyperspecialization

description: Correspondence analysis (CA) and its covariate-based counterpart, canonical correspondence analysis (CCA), are classic yet popular scaling methods in the natural, social, and biomedical sciences to estimate latent gradients that drive the formation of edges in a bipartite graph. However, these methods struggle to identify latent gradients when they exist in sparse graphs where small subsets of nodes are hyperspecialized to each other. This article proposes a new computational method to prevent hyperspecialized nodes from obscuring latent gradient solutions based on a Markov chain interpretation of the CA eigenvalue problem. This approach identifies small subsets of hyperspecialized nodes with greater precision than traditional graph clustering techniques, and outperforms existing regularization techniques at identifying a latent gradient on a real-world political fundraising network of candidates for U.S. federal office, which spans three decades and includes nearly 20,000 candidates for federal office and 3 million of their donors. Supplementary materials for this article are available online.
DOI: 10.6084/m9.figshare.29916745.v2
title: Correspondence Analysis on Sparse Bipartite Graphs with Hyperspecialization

description: Correspondence analysis (CA) and its covariate-based counterpart, canonical correspondence analysis (CCA), are classic yet popular scaling methods in the natural, social, and biomedical sciences to estimate latent gradients that drive the formation of edges in a bipartite graph. However, these methods struggle to identify latent gradients when they exist in sparse graphs where small subsets of nodes are hyperspecialized to each other. This article proposes a new computational method to prevent hyperspecialized nodes from obscuring latent gradient solutions based on a Markov chain interpretation of the CA eigenvalue problem. This approach identifies small subsets of hyperspecialized nodes with greater precision than traditional graph clustering techniques, and outperforms existing regularization techniques at identifying a latent gradient on a real-world political fundraising network of candidates for U.S. federal office, which spans three decades and includes nearly 20,000 candidates for federal office and 3 million of their donors. Supplementary materials for this article are available online.
DOI: 10.25921/f9gg-wt91
title: NOAA/WDS Paleoclimatology - Margolis fire data from Rowe Mesa northeast, northern New Mexico - IMPD USROW004

description: Pinon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at >2 sites. Tree establishment was negatively correlated with fire frequency (r = -0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean = 881 trees/ha) that is>600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.
description: Description: This site was sampled as part of a project to reconstruct the fire history of the PJ dominated landscape of Rowe Mesa in northern New Mexico. 

Sample_storage_location: University of Arizona Laboratory of Tree-Ring Research, 1215 E Lowell St., Tucson, Arizona, 85721
Dating_method: crossdated
Area_sampled [hectares]: 3.5

FHX File Header: For additional information, see the header of this datasets FHX file, usrow004.fhx, located in the same folder as this file. 

Fire History Graphs: Fire History Graphs illustrate specific years when fires occurred and how many trees were scarred. They are available in both PDF and PNG formats. The graphs consist of 2 parts, both of which show the X axis (time line) at the bottom with the earliest year of information on the left and the latest on the right. The Fire Index Plot is the topmost plot, and shows two variables: sample depth (the number of recording trees in each year) as a blue line along the left Y axis, compared with the percent trees scarred shown as gray bars along the right Y axis. Below, the Fire Chronology Plot consists of horizontal lines representing injuries by year on individual sampled trees. Symbols are overlain that denote the years containing the dendrochronologically-dated fire scars or injuries. The sample ID of each tree is displayed to the right of each line. The Composite Axis below represents the composite information from all individual series. The symbols used to represent the fire scars or injuries, and the filters used to determine the composite information, are shown in the legend. These graphs were created using the Fire History Analysis and Exploration System (FHAES). See https://www.fhaes.org/ for more information.