cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/1yqs-0a24
title: NOAA/WDS Paleoclimatology - North America Past Two Millennia Diatom-inferred Lake Salinity Data

description: Six high-resolution climatic reconstructions, based on diatom analyses from lake sediment cores from the northern prairies of North America, show that shifts in drought conditions on decadal through multicentennial scales have prevailed in this region for at least the last two millennia. The predominant broad-scale pattern seen at all sites is a major shift in moisture regimes from wet to dry, or vice versa (depending on location), that occurred after a period of relative stability. These large-scale shifts at the different sites exhibit spatial coherence at regional scales. The three Canadian sites record this abrupt shift between anno Domini 500 and 800, and subsequently conditions become increasingly variable. All three U.S. sites underwent a pronounced change, but the timing of this change is between anno Domini 1000 and 1300, thus later than in all of the Canadian sites. The mechanisms behind these patterns are poorly understood, but they are likely related to changes in the shape and location of the jet stream and associated storm tracks. If the patterns seen at these sites are representative of the region, this observed pattern can have huge implications for future water availability in this region.

Drought is a recurring natural feature of climate that has had dramatic environmental, economic, and social impacts on modern (1) and ancient (2) civilizations. Decade- to century-scale episodes of prolonged drought or high rainfall have been recorded from North America in continental archives as diverse as tree rings (3), tree stumps (4), lake sediments (5), and river deposits (6, 7). The prairie region of North America is particularly susceptible to extreme droughts (8). However, few high-resolution proxy records of climate exist from the prairies. Tree-ring records on the prairies typically are spatially limited to wooded areas at the periphery of the prairies (9) and temporally limited to, at best, ≈500 years (10). Sediments from closed-basin lakes can provide high-temporal-resolution paleoclimatic information from prairie regions for much longer periods.

Here we provide evidence from high-resolution (subdecadal to decadal) sediment core records from six lakes on the Canadian and northern U.S. prairies (Fig. 1). All of the sites indicate that shifts in drought regimes have been a prevalent feature of this region, occurring on decadal through multicentennial scales. Inferred changes in climatic conditions over the past two millennia are based on analysis of diatom assemblages preserved in sediment cores, a commonly used technique for tracking past climatic conditions (11). Our focus here is on long-term dynamics and broad-scale similarities among the lake records. This approach is in part undertaken because of the inherent difficulties of comparing short-term dynamics across records constrained by carbon-dated chronologies.
DOI: 10.25921/1qf5-3r09
title: NOAA/WDS Paleoclimatology - Tropical Pacific Island Lakes 1,200 Year Biomarker Hydrogen Isotope Data

description: Tropical rainfall patterns control the subsistence lifestyle of more than one billion people. Seasonal changes in these rainfall patterns are associated with changes in the position of the intertropical convergence zone, which is characterized by deep convection causing heavy rainfall near 10N in boreal summer and 3N in boreal winter. Dynamic controls on the position of the intertropical convergence zone are debated, but palaeoclimatic evidence from continental Asia, Africa and the Americas suggests that it has shifted substantially during the past millennium, reaching its southernmost position some time during the Little Ice Age (AD 1400-1850). However, without records from the meteorological core of the intertropical convergence zone in the Pacific Ocean, quantitative constraints on its position are lacking. Here we report microbiological, molecular and hydrogen isotopic evidence from lake sediments in the Northern Line Islands, Galápagos and Palau indicating that the Pacific intertropical convergence zone was south of its modern position for most of the past millennium, by as much as 500 km during the Little Ice Age. A colder Northern Hemisphere at that time, possibly resulting from lower solar irradiance, may have driven the intertropical convergence zone south. We conclude that small changes in Earth's radiation budget may profoundly affect tropical rainfall.
description: Biomarker hydrogen isotope composition data from sediments collected in 3 Pacific island lakes for the past 1,200 years. Data were collected for the project "ICTZ Movement During the Little Ice Age in the Tropical Pacific".
DOI: 10.25921/1048-f979
title: NOAA/WDS Paleoclimatology - Azpeleta Tarancón fire data from Snow Canyon, south central New Mexico - IMPD USSC-001

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: This site was sampled to assess the spatiotemporal variability of fire regimes on Mescalero Apache lands and lands adjacent.
DOI: 10.25921/1dxn-sv15
title: NOAA/WDS Paleoclimatology - Hughes - Central Forest Nature Reserve - PISY - ITRDB RUSS270

description: We report new data on tree-ring growth in northern European Russia, a region with a hitherto relatively sparse tree-ring network. We explore its associations with climate variability. Areas, sampling locations and trees were selected for representativeness rather than climate sensitivity. Using tree rings from 651 conifers from six widely dispersed areas we show strong intercorrelation between trees within each major conifer species within and between areas. Regional composite tree-ring series for spruce and pine contain a major fraction of decadal and multidecadal variability. The most likely driver of this common variability is interannual to multidecadal climate variability. Gridded monthly instrumental climate data for the period 1902-2008, particularly mean temperature and total precipitation, were tested as predictors of each local species-specific tree-ring site chronology. The most consistent pattern emerged for spruce at all but the southernmost area. Cool and moist summers the year before growth were consistent drivers of spruce ring growth throughout the period, with no change in recent decades. Self-calibrating Palmer Drought Severity Index for prior summer was also a strong and consistent driver of spruce ring growth. For pine, there was a weaker but similarly stable association between larger rings and warm, moist conditions, in this case in the current summer. These associations were also identified at multidecadal time scales, particularly for spruce. On the other hand, the specific role of moisture variability in determining interannual to multidecadal variability in tree growth in this high latitude region raises questions about the relative vulnerability of spruce and pine there under global warming.
description: NOAA Template Raw Measurements file added 2020-01-15.
DOI: 10.25921/1xy4-ht08
title: NOAA/WDS Paleoclimatology - Kyoto, Japan 1,200 Year Cherry Tree Flowering Dates and March Temperature Reconstructions

description: We investigated documents and diaries from the ninth to the fourteenth centuries to supplement the phenological data series of the flowering of Japanese cherry (Prunus jamasakura) in Kyoto, Japan, to improve and fill gaps in temperature estimates based on previously reported phenological data. We then reconstructed a nearly continuous series of March mean temperatures based on 224 years of cherry flowering data, including 51 years of previously unused data, to clarify springtime climate changes. We also attempted to estimate cherry full-flowering dates from phenological records of other deciduous species, adding further data for 6 years in the tenth and eleventh centuries by using the flowering phenology of Japanese wisteria (Wisteria floribunda). The reconstructed tenth century March mean temperatures were around 7C, indicating warmer conditions than at present. Temperatures then fell until the 1180s, recovered gradually until the 1310s, and then declined again in the mid-fourteenth century.
description: Kyoto cherry blossom phenology data and March temperature reconstructions for the past 1,200 years. Latest updated versions (Aono 2012) are available on Yasuyuki Aono's website: http://atmenv.envi.osakafu-u.ac.jp/aono/kyophenotemp4/
DOI: 10.25921/1zgw-p940
title: NOAA/WDS Paleoclimatology - Manzanedo - Filabres - PINI - ITRDB SPAI079

description: Despite the importance of local adaptation and the extended literature that has addressed it, there are few methods available to explore local adaptation across large temporal scales. However, long-term patterns are likely to be essential to understanding adaptation in long-lived species, such as trees.
    Here, we propose a methodology named 'virtual transplant experiment' (VTE), which uses long-term climatic variability to explore local adaptation to climate in natural tree populations. VTEs evaluate the historical response of populations to their local climate and to climates representative of conditions in other populations. We tested our methodology using simulated data and applied it in two case studies on: (a) Pinus nigra populations at the edge of the species distribution, where previous research has suggested strong climate adaptation, and (b) Fagus sylvatica mesic populations, where parallel experiments showed no adaptation to macroclimate.
    VTE results from simulated and real-world data matched our expectations, suggesting that the method accurately identified the patterns of local adaptation to climate in tree populations. VTEs consistently discriminated locally adapted populations in synthetic data with a known degree of local adaptation. As expected, P. nigra populations showed adaptation to local climate in the VTE, while F. sylvatica populations showed no overall local advantage.
    Our method provides a new way to test for local adaptation over time scales encompassing the complete lifespan of trees. VTEs can complement current methods to study local adaptation by adding the ability to explore the long-term response to local climate in natural populations. The advantages and limitations of the different approaches to studying local adaptation stress the importance of combining multiple approaches to test for local adaptation in long‐lived organisms.
description: NOAA Template Raw Measurements file added 2020-01-15.
DOI: 10.25921/1f69-bn06
title: NOAA/WDS Paleoclimatology - Wilson - Mt. Mcintyre - PCGL - ITRDB CANA603

description: In north-western North America, the so-called divergence problem (DP) is expressed in tree ring width (RW) as an unstable temperature signal in recent decades. Maximum latewood density (MXD), from the same region, shows minimal evidence of DP. While MXD is a superior proxy for summer temperatures, there are very few long MXD records from North America. Latewood blue intensity (LWB) measures similar wood properties as MXD, expresses a similar climate response, is much cheaper to generate and thereby could provide the means to profoundly expand the extant network of temperature sensitive tree-ring (TR) chronologies in North America. In this study, LWB is measured from 17 white spruce sites (Picea glauca) in south-western Yukon to test whether LWB is immune to the temporal calibration instabilities observed in RW. A number of detrending methodologies are examined. The strongest calibration results for both RW and LWB are consistently returned using age-dependent spline (ADS) detrending within the signal-free (SF) framework. RW data calibrate best with June-July maximum temperatures (Tmax), explaining up to 28% variance, but all models fail validation and residual analysis. In comparison, LWB calibrates strongly (explaining 43-51% of May-August Tmax) and validates well. The reconstruction extends to 1337 CE, but uncertainties increase substantially before the early 17th century because of low replication. RW-, MXD- and LWB-based summer temperature reconstructions from the Gulf of Alaska, the Wrangell Mountains and Northern Alaska display good agreement at multi-decadal and higher frequencies, but the Yukon LWB reconstruction appears potentially limited in its expression of centennial-scale variation. While LWB improves dendroclimatic calibration, future work must focus on suitably preserved sub-fossil material to increase replication prior to 1650 CE.
description: NOAA Template Raw Measurements file added 2020-03-09.
DOI: 10.25921/1vaj-q854
title: NOAA/WDS Paleoclimatology - Touchan - Carpenter Ridge - ABMA - ITRDB CA691

description: The utility of a high-resolution snow-hydrologic model to derive climatological indices that describe the variability in radial growth of four conifer species in two Sierra Nevada sites is presented herein. Nine annual indices associated with radial growth were developed to represent the winter dormancy, characteristics of the snowpack and soil water content, and the duration of the seasons. Site chronologies of earlywood (EW) and latewood (LW) ring widths were developed for mountain hemlock (Tsuga mertensiana), red fir (Abies magnifica), white fir (Abies concolor), and ponderosa pine (Pinus ponderosa) at two sites on leeward and windward slopes. The signal strength for annual climatological indices derived from model output was tested with correlation and regression, in combination with principal components analysis. Results show significant snow-related climate signal in the tree-ring data, with substantial differences between species and between EW and LW. Dependence on previous year's snow and soil moisture (a lagged response) were found for EW of hemlock and red fir. The primary EW-LW signal contrast for those species is a shift toward dependence on current-year moisture conditions for LW, especially for red fir. Lagged climate response was less evident for white fir and ponderosa pine. Regression of tree-ring series on principal components of climatological indices showed a stronger average signal in EW (R2 = 0.48) than in LW (R2 = 0.35). Differences in tree-ring hydrologic signal at the two sites are attributed to microclimate and contrasts in snow regime. Results attest to the hydrologic model usefulness for investigating temporal relationships between tree rings and local climate.
description: Comments: Many logs fall down from snow, many new seedlings NOAA Template Raw Measurements file added 2020-03-09.
DOI: 10.25921/1xh8-d672
title: NOAA/WDS Paleoclimatology - Touchan - Truckee Ranger Station - ABCO - ITRDB CA693

description: The utility of a high-resolution snow-hydrologic model to derive climatological indices that describe the variability in radial growth of four conifer species in two Sierra Nevada sites is presented herein. Nine annual indices associated with radial growth were developed to represent the winter dormancy, characteristics of the snowpack and soil water content, and the duration of the seasons. Site chronologies of earlywood (EW) and latewood (LW) ring widths were developed for mountain hemlock (Tsuga mertensiana), red fir (Abies magnifica), white fir (Abies concolor), and ponderosa pine (Pinus ponderosa) at two sites on leeward and windward slopes. The signal strength for annual climatological indices derived from model output was tested with correlation and regression, in combination with principal components analysis. Results show significant snow-related climate signal in the tree-ring data, with substantial differences between species and between EW and LW. Dependence on previous year's snow and soil moisture (a lagged response) were found for EW of hemlock and red fir. The primary EW-LW signal contrast for those species is a shift toward dependence on current-year moisture conditions for LW, especially for red fir. Lagged climate response was less evident for white fir and ponderosa pine. Regression of tree-ring series on principal components of climatological indices showed a stronger average signal in EW (R2 = 0.48) than in LW (R2 = 0.35). Differences in tree-ring hydrologic signal at the two sites are attributed to microclimate and contrasts in snow regime. Results attest to the hydrologic model usefulness for investigating temporal relationships between tree rings and local climate.
description: Lots of needles, natural gap openings, regeneration, white fir 1 NOAA Template Raw Measurements file added 2020-03-09.
DOI: 10.25921/1e53-6h76
title: NOAA/WDS Paleoclimatology - Buma - Glacier Bay National Park and Preserve - PCSI - ITRDB AK173

description: The study of community succession is one of the oldest pursuits in ecology. Challenges remain in terms of evaluating the predictability of succession and the reliability of the chronosequence methods typically used to study community development. The research of William S. Cooper in Glacier Bay National Park is an early and well-known example of successional ecology that provides a long-term observational data set to test hypotheses derived from space-for-time substitutions. It also provides a unique opportunity to explore the importance of historical contingencies and as an example of a revitalized historical study system. We test the textbook successional trajectory in Glacier Bay and evaluate long-term plant community development via primary succession through extensive fieldwork, remote sensing, dendrochronological methods, and newly discovered data that fills in data gaps (1940s to late 1980s) in continuous measurement over 100+ years. To date, Cooper's quadrats do not support the classic facilitation model of succession in which a sequence of species interacts to form predictable successional trajectories. Rather, stochastic early community assembly and subsequent inhibition have dominated; most species arrived shortly after deglaciation and have remained stable for 50+ years. Chronosequence studies assuming prior composition are thus questionable, as no predictable species sequence or timeline was observed. This underscores the significance of assumptions about early conditions in chronosequences and the need to defend such assumptions. Furthermore, this work brings a classic study system in ecology up to date via a plot size expansion, new baseline biogeochemical data, and spatial mapping for future researchers for its second century of observation.
description: NOAA Template Chronology file added 2020-05-12.
DOI: 10.25921/16wj-bx68
title: NOAA/WDS Paleoclimatology - Western Equatorial Pacific Sea Surface and Subsurface Temperature and Mg/Ca Data over the last 4 million years

description: The Western Equatorial Pacific (WEP) warm pool, with surface temperatures >28 °C and a deep thermocline, is an important source of latent and sensible heat for the global climate system. Because the tropics are not sensitive to ice‐albedo feedbacks, the WEP's response to radiative forcing can be used to constrain a minimum estimate of Earth system sensitivity. Climate modeling of pCO2-radiative warming projections shows little change in WEP variability; here we use temperature distributions of individual surface and subsurface dwelling fossil foraminifera to evaluate past variability and possible radiative and dynamic climate forcing over the Plio-Pleistocene. We investigate WEP warm pool variability within paired glacial-interglacial (G-IG) intervals for four times: the Holocene-Last Glacial Maximum, ~2, ~3, and ~4 Ma. Our results show that these surface and subsurface temperature distributions are similar for all G-IG pairs, indicating no change in variability, even as pCO2-radiative forcing and other boundary conditions changed on G-IG timescales. Plio-Pleistocene sea surface temperature (SST) distributions are similar to those from the Holocene, indicating WEP SSTs respond to pCO2-radiative forcing and associated feedbacks. In contrast, Plio-Pleistocene subsurface temperature distributions suggest subsurface temperatures respond to changes in thermocline temperature and depth. We estimate tropical temperature sensitivity for the mid-Pliocene (~3 Ma) using our individual foraminifera SST data set and a previously published high-resolution boron isotope-based pCO2 reconstruction. We find tropical temperature sensitivity was equal to, or less than, that of the Late Pleistocene.
description: Provided Keywords: T. sacculifer, G. tumida, sea surface temperature, subsurface temperature
DOI: 10.25921/1frg-zk64
title: NOAA/WDS Paleoclimatology - Bakker - Kellett Bluff - PSME - ITRDB WA149

description: Fire is a common disturbance in many forests. We conducted a fire history study on 40 Douglas-fir (Pseudotsuga menziesii) trees from two sites, Kellett Bluff and Turn Point, in the San Juan Islands of Washington state, USA. In total, 146 fire scars were identified and dated, representing 34-35 fires per site. Fires occurred between 1565 and 1964. Individual trees recorded up to 10 fires. The composite mean fire interval (MFI) was 11-13 years over the entire study period and 6 years in the historical period (1780-1895). These sites were structured by frequent, low-severity fires, yet supported a tree component for centuries - the oldest tree in this study was more than 500 years old. A program of frequent, low-severity fire may be critical for their long-term persistence. Comparisons of fire history data among these and five other local sites indicate frequent fires but little synchronicity; the MFI was 4 years but most fires were only recorded at single sites. Although forests west of the Cascade Mountains are often described as subject to infrequent, high-severity fires, these results highlight the need for a more refined understanding of historical fire regimes in this region.
description: Fire History data for this site also available in the IMPD, site code USWKB001. NOAA Template Raw Measurements file added 2019-08-22.
DOI: 10.25921/1t3d-d130
title: NOAA/WDS Paleoclimatology - Sauchyn - Beaver Creek - PSME - ITRDB CANA562

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: Upper Missouri River Basin Streamflow project NOAA Template Raw Measurements file added 2020-01-15.
DOI: 10.25921/16n4-ts45
title: NOAA/WDS Paleoclimatology - Woodhouse - Chokecherry Canyon Update - PIED - ITRDB CO660

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: Upper Missouri River Basin Streamflow project NOAA Template Raw Measurements file added 2020-01-15.