cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/4w48-p306
title: NOAA/WDS Paleoclimatology - Peltier - Southwest Ecological Memory Project Site P11 - PIED - ITRDB UT562

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: 10.25921/4ejd-q214
title: NOAA/WDS Paleoclimatology - European Alps Paleoflood Data during the Holocene

description: Flooding is a pervasive natural hazard—costly in both human and economic terms—and climate change will probably exacerbate risks around the world. Mountainous areas, such as the densely populated European Alps, are of particular concern as topography and atmospheric conditions can result in large and sudden floods. In addition, the Alps are experiencing a high warming rate, which is probably leading to more heavy rainfall events. Here, we compile palaeoflood records to test the still uncertain impact these climatic trends might have on flood frequency and magnitude in the European Alps. We demonstrate that a warming of 0.5–1.2°C, whether naturally or anthropogenically forced, led to a 25–50% decrease in the frequency of large (≥10 yr return period) floods. This decreasing trend is not conclusive in records covering less than 200 years but persistent in those ranging from 200 to 9,000 years. By contrast, extreme (>100 yr) floods may increase with a similar degree of warming in certain small alpine catchments impacted by local intensification of extreme rainfall. Our results show how long, continuous palaeoflood records can be used to disentangle complex climate–flooding relationships and assist in improving risk assessment and management at a regional scale.
description: Synthesis of paleoflood records from lake sediment sequences of the European Alps covering the last centuries to the Holocene.
    Provided Keywords: Paleoflood, lake sediments European Alps, MCA, LIA, Holocene
DOI: 10.25921/4hc9-0170
title: NOAA/WDS Paleoclimatology - Arctic and North Atlantic 1979-2015 Coralline Red Algae Annual Growth and Mg/Ca Data

description: Arctic sea ice cover has been steeply declining since the onset of satellite observations in the late 1970s. However, the available annually resolved sea ice data before this time are limited. Here, we evaluated the suitability of annual trace element (Mg/Ca) ratios and growth increments from the long-lived annual increment-forming benthic coralline red alga, Clathromorphum compactum, as high-resolution sea ice cover archive. It has previously been shown that the growth of C. compactum is strongly light controlled and therefore greatly limited during the polar night and underneath sea ice cover. We compare algal data from 11 sites collected throughout the Canadian Arctic, Greenland, and Svalbard, with satellite sea ice data. Our results suggested that algal growth anomalies most often produced better correlations to sea ice concentration than Mg/Ca ratios or when averaging growth and Mg/Ca anomalies. High Arctic regions with persistently higher sea ice concentrations and shorter ice-free seasons showed the strongest correlations between algal growth anomalies and satellite sea ice concentration over the study period (1979-2015). At sites where ice breakup took place before the return of sufficient solar irradiance, algal growth was most strongly tied to a combination of solar irradiance and other factors such as temperature, suspended sediments, phytoplankton blooms, and cloud cover. These data are the only annually resolved in situ marine proxy data known to date and are of utmost importance to gain a better understanding of the sea ice system and to project future sea ice conditions.
description: Annual growth increments and Mg/Ca ratios of the coralline red algae Clathromorphum compactum in the Arctic and North Atlantic Oceans from 1979 to 2015.
DOI: 10.25921/4ybn-6660
title: NOAA/WDS Paleoclimatology - Jinchuan Peat Bog, NE China Mid- to Late-Holocene Temperature Reconstruction

description: There has been an increasing need to reconstruct past climate from proxy records quantitatively and mechanistically. The inverse proxy modeling method stands out as a novel approach to quantitative palaeoclimate reconstructions through integrating process-based models and proxy records, representing a major progress in quantitative palaeoclimatology. It has been proposed to incorporate multiple proxy records to produce a more robust constraint on the climate parameters sought for estimation, and most of the work has been conducted using pollen records in conjunction with vegetation models. Here, I show a worked example of using paired stable oxygen and carbon isotope records of peat cellulose from one single core to infer the climate history in NE China for the last 6000 years through solving a well-posed inverse problem using Bayesian statistics. The quantitative palaeoclimate data obtained in this study may deepen our insight into the dynamics of the East Asian summer monsoon. Mean growing season temperature and relative humidity show millennial-scale fluctuations prior to c. 4000 cal. yr BP; thereafter, centennial-scale fluctuations prevailed, revealing the relative importance of solar activity over tropical ocean-atmosphere interactions in regulating the variability of regional climate during the late Holocene. It appears that there was a prominent out-of-phase relationship between temperature and relative humidity, due probably to the different response of these climate elements to orbital forcing and land cover. This worked example demonstrates the potential of using model-data fusion techniques to produce physically meaningful, mathematically optimal, and geologically sound results.
description: This dataset was contributed as part of the Temperature-12k project (https://doi.org/10.25921/4RY2-G808). Data were contributed to the project from the original data generators, who are listed in the Investigator field of this template file. Additional notes regarding the use of these data in the Temperature-12k project can be found in the LiPD file listed as an Online_Resource of this template file.
DOI: 10.25921/44d0-d377
title: NOAA/WDS Paleoclimatology - Allen - El Sharana - CAIN - ITRDB AUSL056

description: An understanding of tropical hydroclimate variability, the associated drivers and how it is likely to change is a major scientific and societal challenge that is acutely hampered by short instrumental records. We present a 246-year tree-ring drought reconstruction of the Standardised Precipitation Evaporation Index (SPEI) for monsoonal northern Australia for the end of the wet season (March-May; MAM). This reconstruction extends the instrumental record back by 150 years. Around one third of total annual rainfall falls during MAM, making it a crucial component of the monsoonal cycle. MAM is also the season most impacted by the differential decay process of Central Pacific (as opposed to Western Pacific) El Nino events that are linked with dry conditions over northern and northwestern Australia more generally. Our reconstruction therefore provides an opportunity to consider how central Pacific variability has modulated MAM hydroclimate in Australia's monsoonal north over the past two and a half centuries. We found that MAM hydroclimate extremes in the region have a strong, but asymmetric relationship with central Pacific sea surface temperatures (SSTs) and ENSO indices. Extremely wet MAMs in monsoonal north Australia were associated with cooler SSTs, above average rainfall across much of Australia, and often coincided with La Nina events. The spatial relationship between dry extremes and Pacific SSTs during dry events was generally, but weakly, consistent with the SST signature of central Pacific El Nino events. The association between reconstructed dry extremes in the monsoonal north and dry conditions across the rest of Australia is also less extensive and weaker than for wet events. Results suggest that more extreme wet events in the Australian monsoonal north likely reflect cool central Pacific SSTs and later termination of the Australian monsoon. Consecutive years with extremely dry MAMs became more frequent over the latter part of the 20th Century while the probability of an extreme dry MAM followed by an extreme wet MAM the next year peaked in the mid 20th Century and has since declined.
description: Callitris intratropica ring-width data used for drought reconstruction, monsoonal north Australia. NOAA Template Raw Measurements file added 2020-11-18.
DOI: 10.25921/44x2-bp73
title: NOAA/WDS Paleoclimatology - Vanoni - Berguen - ABAL - ITRDB SWIT407

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: Reference: 
# Vanoni M. 2012. Klimatische Einflusse auf die Wachstumsvariabilitat von Weisstanne und Fichte entlang des Weisstannen-Ausbreitungsgradienten. Master thesis. ETH Zurich, Zurich. NOAA Template Raw Measurements file added 2021-05-03.
DOI: 10.25921/4zd6-x681
title: NOAA/WDS Paleoclimatology - Lake N3, Greenland 7,800 Year Chironomid d18O Data

description: The Arctic hydrological cycle is predicted to intensify as the Arctic warms, due to increased poleward moisture transport during summer and increased evaporation from seas once ice-covered during winter. Records of past Arctic precipitation seasonality are important because they provide a context for these ongoing changes. In some Arctic lakes, stable isotopes of oxygen and hydrogen (d18O and d2H, respectively) vary seasonally, due to seasonal changes in precipitation d18O and d2H. We reconstruct precipitation seasonality from Lake N3, a well-dated lake sediment archive in Disko Bugt, western Greenland, by generating Holocene records of two proxies that are produced at different times of the year, and therefore record different lake water seasonal isotopic compositions. Aquatic plants synthesize waxes throughout the summer, and their d2H reflects winter-biased precipitation d2H at Lake N3, whereas chironomids synthesize their head capsules between late summer and winter, and their d18O reflects summer-biased precipitation d18O at Lake N3. During the middle Holocene at Lake N3, aquatic plant leaf wax was strongly 2H-depleted, while chironomid chitin was 18O-enriched. We guide interpretations of these records using sensitivity tests of a lake water and energy balance model, where we change precipitation amount and isotope seasonality inputs. The sensitivity tests suggest that the contrasting trends between proxies were likely caused by an increase in precipitation amount during all seasons and an increase in precipitation isotope seasonality, in addition to proxy-specific mechanisms, highlighting the importance of understanding lake- and proxy-specific systematics when interpreting records from sediment archives.
description: Oxygen isotope (d18O) data from chironomids in sediments collected in Lake N3, Greenland for the past 7,800 years (Corcoran et al. 2021). Previously archived Thomas et al. 2016 Lake N3 leaf Wax d2H and geochemical data can be found at: https://www.ncdc.noaa.gov/paleo/study/20126
DOI: 10.25921/410y-ep42
title: NOAA/WDS Paleoclimatology - Searles Valley, California Latest Pleistocene Plant Wax and Salinity Data and Modern Plant Wax Data

description: This study aims to evaluate whether machine learning techniques can be successfully applied to process the complex information contained within the molecular abundance distributions of plant wax n-alkane and n-alkanoic acid homologous series. We trained five vegetation identification models using plant wax chain length distributions from modern plants in the Mojave Desert (hyperarid) and the San Bernardino Mountains (conifer forest) and previously published data for macrophytes from Blood Pond (USA) and Mt Kenya (Kenya). All vegetation identification models proved accurate (mean classification accuracy = 0.81) at classifying the modern plant wax chain length distributions into desert plants, conifer and macrophyte categories. We then applied the models to fossil waxes extracted from a 76 m lacustrine sediment core drilled in Searles Valley, CA with an approximate age range of 10 to 150 kyrs (SLAPP-SRLS17) to reconstruct the proportion of desert plants, conifer woodland and lake vegetation. We compared our machine learning models with a previously published linear mixing model and validated our modelled plant type distributions by comparing the results with the archaeol caldarchaeol ecometric (ACE), a proxy for lake salinity, measured in the same core. We found a moderate positive correlation (r = 0.40) between the modelled desert plant proportion and high lake salinity in our models as well as a negative correlation (r = -0.45) between modelled macrophyte plants and ACE, validating the ability of the machine learning techniques to detect both xeric and macrophyte plant communities. Our results suggest that machine learning of plant wax molecular abundance distributions has potential to reconstruct past plant communities, given information from two compound classes and highly differentiated vegetation types.
description: Lake sediment and modern plant wax data (n-alkanes and n-alkanoic acids), and Archeol Caldarcheol Ecometric salinity indicator, from Searles Valley, California, USA, for the past 200,000 years.
DOI: 10.25921/492s-mq43
title: NOAA/WDS Paleoclimatology - Maxwell - Babler State Park - ACSH - ITRDB MO081

description: While forest communities are changing as a result of global environmental change, the impacts of tree species shifts on ecosystem services such as carbon storage are poorly quantified. In many parts of the eastern United States (US), more xeric-adapted oak-hickory dominated stands are being replaced with mesic beech-maple assemblages. To examine the possible impacts of this ongoing change in forest composition, we investigated how two wide-ranging and co-occurring eastern US species - Acer saccharum (sugar maple) and Quercus alba (white oak) - respond to interannual climate variability. Using 781 tree cores from 418 individual trees at 18 locations, we found late-growing season drought reduced A. saccharum growth more than that of Q. alba. A gradient in the growth reduction across latitude was also found in A. saccharum, where southern populations of A. saccharum experienced greater reductions in growth during drought. Drought had a legacy effect on growth for both species, with drought occurring later in the growing season having a larger legacy effect. Consequently, as forests shift from oak to maple dominance, drought in the later part of the growing season is likely to become an increasingly important control on forest productivity. Thus, our findings suggest that co-occurring species are responding to environmental conditions during different times in the growing season and, therefore, the timing of drought conditions will play an important role in forest productivity and carbon sequestration as forest species composition changes. These findings are particularly important because the projected increases in potential evapotranspiration, combined with possible changes in the seasonality of precipitation could have a substantial impact on how tree growth responds to future climatic change.
description: Sugar Maple and White Oak comparisons 1901-2016 (analyses period) NOAA Template Raw Measurements file added 2021-12-29.
DOI: 10.25921/4np7-dr30
title: NOAA/WDS Paleoclimatology - Campbell Island Air Temperature Reconstructions during the Holocene

description: Over the past 18,000 years, sea surface temperatures for the Southern Ocean do not align with those of the adjacent, high-latitude landmasses. During the late glacial period, the ocean surface warmed rapidly to present-day temperatures1, whereas the land warmed only slowly, as evidenced by the lagged response of forest and glaciers2,3. However, in the Holocene epoch, land-based records suggest strong warming whereas marine records indicate that ocean surface temperatures cooled. Here we present reconstructions of summer temperature for Campbell Island, in the Southern Ocean, over the past 16,500 years based on fossil pollen. We find a pronounced warming 12,500–11,000 years ago, a cooling until 9,200 years ago, and a rapid warming to a peak between 6,000 and 5,000 years ago, followed by minor cool intervals from 5,200–4,000, 3,000–1,700 and 700–100 years ago. As expected, our temperature reconstructions show a late glacial lag behind nearby records of sea surface temperature6,7, and opposing trends in the Holocene. We suggest that this discrepancy arises because land-based reconstructions record summer temperatures, whereas marine proxies generally reflect annual temperatures. We conclude that the divergence of the records therefore reflects changes in the seasonality of atmospheric heat transport. As atmospheric heat transport is tied to the Southern Hemisphere westerly winds, we attribute our observed changes to shifts in the position and intensity of the southern westerlies.
description: This dataset was contributed as part of the Temperature-12k project (https://doi.org/10.25921/4RY2-G808). Data were contributed to the project from the original data generators, who are listed in the Investigator field of this template file. Additional notes regarding the use of these data in the Temperature-12k project can be found in the LiPD file listed as an Online_Resource of this template file.
DOI: 10.25921/4153-fz04
title: NOAA/WDS Paleoclimatology - South Pole Ice Core 52,000 Year SP19 Gas Age Chronology and Methane Data

description: A new ice core drilled at the South Pole provides a 54 000-year paleoenvironmental record including the composition of the past atmosphere. This paper describes the SP19 chronology for the South Pole atmospheric gas record and complements a previous paper (Winski et al., 2019) describing the SP19 ice chronology. The gas chronology is based on a discrete methane (CH4) record with 20- to 190-year resolution. To construct the gas timescale, abrupt changes in atmospheric CH4 during the glacial period and centennial CH4 variability during the Holocene were used to synchronize the South Pole gas record with analogous data from the West Antarctic Ice Sheet Divide ice core. Stratigraphic matching based on visual optimization was verified using an automated matching algorithm. The South Pole ice core recovers all expected changes in CH4 based on previous records. Gas transport in the firn results in smoothing of the atmospheric gas record with a smoothing function spectral width that ranges from 30 to 78 years, equal to 3 % of the gas-age–ice-age difference, or Δage. The new gas chronology, in combination with the existing ice age scale from Winski et al. (2019), allows a model-independent reconstruction of the gas-age–ice-age difference through the whole record, which will be useful for testing firn densification models.
description: The SP19 gas age chronology for the South Pole Ice Core, plus atmospheric methane concentration data, for the past 52,000 years
DOI: 10.25921/4kp0-q894
title: NOAA/WDS Paleoclimatology - Equatorial Pacific Foram-Bound N Isotopes from the Pliocene to the Pleistocene

description: Upwelling generates a nutrient-rich "cold tongue" in the eastern equatorial Pacific Ocean (EEP), with impacts on global climate, oceanic biological productivity, and the carbon cycle. The cold tongue was reduced during the Pliocene Epoch, a feature attributed to weaker upwelling and an associated deepening of the surface mixed layer in the EEP. Here we report nitrogen isotope evidence that modern-like upwelling occurred in the EEP during the Pliocene and persisted over the last 5 million years. We explain the reduced Pliocene cold tongue as an expression of the reduced temperature difference between surface and subsurface waters in the tropical Pacific. The attendant reduction in the vertical density gradient may have maintained EEP upwelling despite the expected slackening of the trade winds under Pliocene warmth.
description: 29-Jul-2025: Unpublished data updated with data published in 2025 Science paper. ODP 806 (0.318
333 N, 159.361667 E, -2520 m); ODP 849 (0.18 N, -110.52 W, -3839 m); RNDB 74P (0.3333 N, 159.3667 E, -2547 m)