cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.25921/jg7k-6z41
title: NOAA/WDS Paleoclimatology - Chipman fire data from Upper Capsule Lake, North Slope, Alaska - IMPD USUP-001

description: Anthropogenic climate change has altered many ecosystem processes in the Arctic tundra and may have resulted in unprecedented fire activity. Evaluating the significance of recent fires requires knowledge from the paleofire record because observational data in the Arctic span only several decades, much shorter than the natural fire rotation in Arctic tundra regions. Here we report results of charcoal analysis on lake sediments from four Alaskan lakes to infer the broad spatial and temporal patterns of tundra-fire occurrence over the past 35 000 years. Background charcoal accumulation rates are low in all records (0-0.05 pieces cm-2 yr-1), suggesting minimal biomass burning across our study areas. Charcoal peak analysis reveals that the mean fire-return interval (FRI; years between consecutive fire events) ranged from ca. 1650 to 6050 years at our sites, and that the most recent fire events occurred from ca. 880 to 7030 years ago, except for the CE 2007 Anaktuvuk River Fire. These mean FRI estimates are longer than the fire rotation periods estimated for the past 63 years in the areas surrounding three of the four study lakes. This result suggests that the frequency of tundra burning was higher over the recent past compared to the late Quaternary in some tundra regions. However, the ranges of FRI estimates from our paleofire records overlap with the expected values based on fire-rotation-period estimates from the observational fire data, and the differences are statistically insignificant. Together with previous tundra-fire reconstructions, these data suggest that the rate of tundra burning was spatially variable and that fires were extremely rare in our study areas throughout the late Quaternary. Given the rarity of tundra burning over multiple millennia in our study areas and the pronounced effects of fire on tundra ecosystem processes such as carbon cycling, dramatic tundra ecosystem changes are expected if anthropogenic climate change leads to more frequent tundra fires.
description: Chronology and macroscopic charcoal counts (number of pieces >125 microns) from lake sediments, Upper Capsule Lake, North Slope, Alaska.

Provided Keywords: tundra fire-regimes, Arctic, Alaska

Additional Information:
Contact person:	Feng Sheng Hu
Sample storage location:	University of Illinois, Urbana.
Sampling date:	1997
Site size(ha):	1.1
Location description:	Tussock-sedge, dwarf shrub tundra
State/Province:	Alaska
Water depth(cm):	5.7
Sampling device:	All cores were taken with a combination of 7.5 cm livingstone, 5 cm livingstone, and 7.5 cm polycarbonate tube;	
Analysis method:	Macroscopic charcoal counts (>125 microns). Please see Chipman et al. 2015 for details
DOI: 10.25921/jt28-3y15
title: NOAA/WDS Paleoclimatology - Umbanhowar fire data from Tsagaan Nuur, western Mongolia - IMPD MNTGN001

description: Fires are common in grassland regions of the world, and the frequency and severity of fire is linked to climate-driven changes in fuel loads. Western Mongolia is dominated by grasslands but the fire history of this region is largely unknown. We reconstructed modern fire (48 lakes) and historical fires (9 lakes) using sediment charcoal. Modern fuel loads were estimated using a combination of clipped plots, satellite-based estimates of annual aboveground net primary productivity (NPP) and NPP modeled from annual temperature and precipitation. Loss-on-ignition and environmental magnetics of lake sediments were analyzed as proxies for climate. We found little evidence for modern or historical fire in the landscape, as charcoal was absent from the surface sediments of 34 of 48 lakes. Charcoal influxes were uniformly low, averaging from 0.002 to 0.028 mm2/cm2 per yr, over the past 1200 years at nine lakes, and the past 6000-5000 years at two of the lakes with longer sediment records. In the modern landscape, livestock grazing has eliminated most of the fuels necessary to carry a fire, as measured fuel loads (27.3+-4.9 g/m2) were only ~20% of aboveground annual NPP estimated using MODIS Imagery or modeled from climate data. The historical absence of fire may indicate a longer history of intensive grazing than sometimes assumed, and cultural prohibitions against burning may also play a role. Regional summary indicated a >50% decrease in charcoal influxes since AD 1600 at most sites which may be related to lower temperatures or greater aridity during the 'Little Ice Age'. Alternatively this decrease in charcoal influxes may reflect increases in livestock numbers or increased local concentrations because of restrictions on the movement of animals coincident with the establishment of Manchu rule in the late seventeenth century.
DOI: 10.15468/dl.8tmxyv
title: Occurrence Download

description: A dataset listing the 30 species recorded in GBIF matching the query:
{
 "and" : [
 "Geometry POLYGON((-82.38578 21.63575,-82.42516 21.61387,-82.40474 21.56501,-82.40401 21.54824,-82.37046 21.54095,-82.32015 21.54605,-82.28879 21.50303,-82.24212 21.48407,-81.86729 21.5796,-81.77613 21.55043,-81.78051 21.71159,-81.82645 21.72399,-81.9373 21.72545,-82.06564 21.67148,-82.24285 21.65325,-82.38578 21.63575))",
 "OccurrenceStatus is Present",
 "TaxonKey is Aves"
 ]
}

 The dataset's 30 records were derived from 3 constituent datasets; see https://api.gbif.org/v1/occurrence/download/0021038-251009101135966/datasets/export for details.
 
Data from some individual datasets included in this download may be licensed under less restrictive terms.
DOI: 10.25921/jkpm-pm05
title: NOAA/WDS Paleoclimatology - Greenland Ice Core (GICC05) and Radiocarbon (IntCal13) Holocene Timescale Differences

description: Investigations of past climate dynamics rely on accurate and precise chronologies of the employed climate reconstructions. The radiocarbon dating calibration curve (IntCal13) and the Greenland ice core chronology (GICC05) represent two of the most widely used chronological frameworks in paleoclimatology of the past ~50,000 years. However, comparisons of climate records anchored on these chronologies are hampered by the precision and accuracy of both timescales. Here we use common variations in the production rates of 14C and 10Be recorded in tree-rings and ice cores, respectively, to assess the differences between both timescales during the Holocene. Compared to earlier work, we employ a novel statistical approach which leads to strongly reduced and yet, more robust, uncertainty estimates. Furthermore, we demonstrate that the inferred timescale differences are robust independent of (i) the applied ice core 10Be records, (ii) assumptions of the mode of 10Be deposition, as well as (iii) carbon cycle effects on 14C, and (iv) in agreement with independent estimates of the timescale differences. Our results imply that the GICC05 counting error is likely underestimated during the most recent 2000 years leading to a dating bias that propagates throughout large parts of the Holocene. Nevertheless, our analysis indicates that the GICC05 counting error is generally a robust uncertainty measurement but care has to be taken when treating it as a nearly Gaussian error distribution. The proposed IntCal13-GICC05 transfer function facilitates the comparison of ice core and radiocarbon dated paleoclimate records at high chronological precision.
description: Greenland ice core timescale (GICC05) and tree-ring based radiocarbon calibration timescale (IntCal13) timescale differences over the Holocene
DOI: 10.25921/jazv-m741
title: NOAA/WDS Paleoclimatology - Wise - Bear Creek Ridge - PIPO - ITRDB WA136

description: Moisture delivery to western North America is closely linked to variability in the westerly storm tracks of midlatitude cyclones, which are, in turn, modified by larger-scale features such as the El Niño-Southern Oscillation system. Instrumental and modeling data suggest that extratropical storm tracks may be intensifying and shifting poleward due to anthropogenic climate change, but it is difficult to separate recent trends from natural variability because of the large amount of decadal and longer variation in storm tracks and their limited instrumental record. We reconstruct cool-season, midlatitude Pacific storm-track position and intensity from 1693 to 1995 CE using existing tree-ring chronologies along with a network of newly developed chronologies from the U.S. Pacific Northwest, where small variations in storm-track position can have a major influence on hydroclimate patterns. Our results show high interannual-to-multidecadal variability in storm-track position and intensity over the past 303 years, with spectral signatures characteristic of tropical and northern Pacific influences. Comparison with reconstructions of precipitation and tropical sea surface temperature confirms the relationship between shifting drought patterns in the Pacific Northwest and storm-track variability through time and demonstrates the long-term influence of El Niño. These results allow us to place recent storm-track changes in the context of decadal and multidecadal fluctuations across the long-term record, showing that recent changes in storm-track intensity likely represent a warming-related increase amplified by natural decadal variability.
description: NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/jdmh-bm92
title: NOAA/WDS Paleoclimatology - Jageshwar, Northern India 388 Year Tree Ring Oxygen Isotope Data

description: We have constructed a regional tree-ring cellulose oxygen isotope (d18O) record for the northern Indian sub-continent based on two new records from northern India and central Nepal and three published records from northwestern India, western Nepal and Bhutan. The record spans the common interval from 1743 to 2008CE. Correlation analysis reveals that the record is significantly and negatively correlated with the three regional climatic indices: all India rainfall (AIR; r = -0.5, p < 0.001, n = 138), Indian monsoon index (IMI; r = -0.45, p < 0.001, n = 51) and the intensity of monsoonal circulation (r = -0.42, p < 0.001, n = 51). The close relationship between tree-ring cellulose d18O and the Indian summer monsoon (ISM) can be explained by oxygen isotope fractionation mechanisms. Our results indicate that the regional tree-ring cellulose d18O record is suitable for reconstructing high-resolution changes in the ISM. The record exhibits significant interannual and long-term variations. Interannual changes are closely related to the El Nino-Southern Oscillation (ENSO), which indicates that the ISM was affected by ENSO in the past. However, the ISM-ENSO relationship was not consistent over time, and it may be partly modulated by Indian Ocean sea surface temperature (SST). Long-term changes in the regional tree-ring d18O record indicate a possible trend of weakened ISM intensity since 1820. Decreasing ISM activity is also observed in various high-resolution ISM records from southwest China and Southeast Asia, and may be the result of reduced land-ocean thermal contrasts since 1820CE.
description: Cedrus deodara tree-ring oxygen isotope (d18O) data from Jageshwar, northern India, for the past 388 years. IITRDB28
DOI: 10.25921/j6s1-0y32
title: NOAA/WDS Paleoclimatology - Speer - Calimus Butte - PIPO - ITRDB OR059

description: Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives.  Most data sets include raw treering measurements (most are annual ring width, with some collections of earlywood or latewood width or wood density), plus chronologies (standardized growth indices for a site compiled from multiple treering samples). Reconstructions of climate variables are included with some of these data sets.  Each data type is stored in a separate data file; the data type is coded into the file name. For details please see: http://www.ncdc.noaa.gov/paleo/treeinfo.htmll
description: NOAA Template Chronology file added 2018-12-20. NOAA Template Raw Measurements file added 2019-02-08.
DOI: 10.25921/j7aj-s154
title: NOAA/WDS Paleoclimatology - Santa Barbara Basin Deglacial Foraminiferal Stable Isotope Data

description: A new piston core from Santa Barbara Basin, California provides evidence of the timing, magnitude, and character of deglaciation, including evidence of warming prior to Termination IA. IMAGES Site MD02-2503 (570 m water depth) consists of intermittently laminated hemipelagic sediments extending to Interstadial (D/O) event 6 (~34 ka), that accumulated at ~135 cm/ka. During the deglacial episode (16.75-10 ka), d18O values decreased by 3.2 permil in the planktonic species Globigerina bulloides, indicating a total warming of 8-9C recorded by surface-dwelling foraminifera (inferred by removing the 1 permil influence of ice volume change). Similarly, benthic species (Bolivina argentea and Uvigerina peregrina) record a 1.65 permil d18O decrease across the deglacial, interpreted as a 2-3C warming at upper intermediate depths. d18O values of both planktonic and benthics indicate that surface and intermediate waters began to warm ~2 ka prior to Termination IA, beginning at ~16.5 ka. Intermediate water warming exhibits similar structure and synchronous timing with surface waters. These findings are consistent with a growing number of records from around the globe that exhibit pre-Bolling warming prior to Termination IA, and extends the record of such processes to the northern Pacific.
DOI: 10.25921/jkwx-pk38
title: NOAA/WDS Paleoclimatology - Schweingruber - Lac Peribonca - PCMA - ITRDB CANA054

description: Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives.  Most data sets include raw treering measurements (most are annual ring width, with some collections of earlywood or latewood width or wood density), plus chronologies (standardized growth indices for a site compiled from multiple treering samples). Reconstructions of climate variables are included with some of these data sets.  Each data type is stored in a separate data file; the data type is coded into the file name. For details please see: http://www.ncdc.noaa.gov/paleo/treeinfo.htmll
description: NOAA Template Raw Measurements file added 2019-02-04.
DOI: 10.25921/jrwn-ht54
title: NOAA/WDS Paleoclimatology - Kairaitis - Kurtuvenai - QURO - ITRDB LITH036

description: Pedunculate oak (Quercus robur L.) is one of the widely used and dendrochronologically investigated species in Europe. Still, it is a problematical dating object if its outermost section is missing partly or totally. Thus, we need sapwood estimation of living trees. As sapwood amount varies geographically, numbers of sapwood rings have been published for different regions in Europe but no such estimation has been done for the Baltic States yet. Therefore, this paper deals with the estimation of pedunculate oak sapwood growing in the eastern Baltic region, i.e. in Finland, Estonia, Latvia, and Lithuania.

In total, 668 oak core samples of living trees from 43 stands were investigated. Ring widths were measured and the number of sapwood rings was determined according to two criteria: difference of colour and absence of tyloses in earlywood vessels. The samples were divided into two sets, according to the tH-values between site chronologies and the major geobotanical sub-provinces. Thus, the nine Finnish and western Estonian sites were attributed to the western region and the 34 eastern Estonian, Latvian and Lithuanian sites to the eastern region.

As the result of a statistical analysis, we explain that the number of oak sapwood rings ranges from 4.09 to 20.85 and 6.45 to 18.02 within 95% confidence limits in the western and eastern regions, respectively. For the three Baltic countries and southern Finland in general, we recommend to consider a sapwood estimate of 6.18-18.71 rings. Regarding earlier studies, the general European trend of decreasing sapwood ring number towards the east was confirmed. A geographical pattern of eastward decrease of the median sapwood ring number was noticed in the Baltics as well. The chronology based upon 668 samples of living oak trees from all sites covered the period of 1631-2008.
description: NOAA Template Raw Measurements file added 2019-02-05.
DOI: 10.25921/jxfa-f732
title: NOAA/WDS Paleoclimatology - Mundo fire data from San Lorenzo, Patagonia - IMPD CHSLC001

description: Fire is a major disturbance affecting forests worldwide with significant economic, social and ecological impacts. The southernmost forests on Earth extend continuously along the Andes from mid- to subantarctic latitudes in South America. In this region, warming and drying trends since the mid-20th century have been linked to a positive trend in the Southern Annual Mode (SAM), the leading mode of extratropical climate variability in the Southern Hemisphere. Due to the scarcity of documentary fire records and the lack of tree-ring fire histories, little is known about how wildfire activity responds to shifts in the westerly circulation pattern and associated climatic variability in the Andean region south of c. 44°S. For the first time, we applied dendrochronological techniques to reconstruct fire history from the angiosperm Nothofagus pumilio at 16 sites distributed from c. 44 to 50oS to determine relationships between fire occurrence and the two primary drivers of wildfire activity: climate variability and human activities. Partial cross-sections with fire-scars were collected from 363 trees in Argentina and Chile. Chronologies of annually resolved fire-scar dates start in 1791 and show a pattern of higher fire frequency during the 20th century, concurrent with the human occupation and colonization processes in southern Patagonia. Years of widespread fire occurring synchronously in two or more disjunct sites are associated with broad-scale climatic anomalies. Intense droughts inferred from extreme departures in temperature, precipitation and the Standardized Precipitation-Evapotranspiration Index (SPEI) during the growing seasons of 1944 and 1962 are consistent with the two most severe fires at northern sites. Extended droughts, reflected by the association of fire occurrence with 6-month cumulative precipitation and SPEI, create conditions for widespread fires at the southern sites (south of c. 46°S). Regional fires were concurrent with significant positive departures of SAM during the austral spring-summer. This tree-ring fire record reveals the influences of both climate variability and human activities on fire in the N. pumilio forests across the Andes, and also establishes the feasibility of using this tree species as a natural archive of fire history.
DOI: 10.25921/jjnk-hc53
title: NOAA/WDS Paleoclimatology - Porter - Timber Creek TM2 - PCGL - ITRDB CANA552

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/jhst-nn03
title: NOAA/WDS Paleoclimatology - Duckhole Lake, Tasmania 950 Year Sediment Reflectance and Temperature Reconstruction

description: A lack of quantitative high resolution paleoclimate data from the Southern Hemisphere limits the ability to examine current trends within the context of long-term natural climate variability. This study presents a temperature reconstruction for southern Tasmania based on analyses of a sediment core from Duckhole Lake (43.365S, 146.875E). The relationship between non-destructive whole core scanning reflectance spectroscopy measurements in the visible spectrum (380-730 nm) and the instrumental temperature record (ad 1911-2000) was used to develop a calibration-in-time reflectance spectroscopy-based temperature model. Results showed that a trough in reflectance from 650 to 700 nm, which represents chlorophyll and its derivatives, was significantly correlated to annual mean temperature. A calibration model was developed (R = -0.56, p auto < 0.05, root mean squared error of prediction (RMSEP) = 0.21C, five-year filtered data, calibration period 1911-2000) and applied down-core to reconstruct annual mean temperatures in southern Tasmania over the last c. 950 years. This indicated that temperatures were initially cool c. ad 1050, but steadily increased until the late ad 1100s. After a brief cool period in the ad 1200s, temperatures again increased. Temperatures steadily decreased during the ad 1600s and remained relatively stable until the start of the 20th century when they rapidly decreased, before increasing from ad 1960s onwards. Comparisons with high resolution temperature records from western Tasmania, New Zealand and South America revealed some similarities, but also highlighted differences in temperature variability across the mid-latitudes of the Southern Hemisphere. These are likely due to a combination of factors including the spatial variability in climate between and within regions, and differences between records that document seasonal (i.e. warm season/late summer) versus annual temperature variability. This highlights the need for further records from the mid-latitudes of the Southern Hemisphere in order to constrain past natural spatial and seasonal/annual temperature variability in the region, and to accurately identify and attribute changes to natural variability and/or anthropogenic activities.
description: Sediment reflectance data (650-700 nm trough, a proxy for Total chlorin) and temperature reconstruction for the past 950 years from Duckhole Lake, southern Tasmania, Australia.