Annual patterns within tree rings of the Arctic middle Eocene (ca. 45 Ma): Isotopic signatures of precipitation, relative humidity, and deciduousness

Geology ◽  
2008 ◽  
Vol 36 (2) ◽  
pp. 99 ◽  
Author(s):  
A. Hope Jahren ◽  
Leonel S.L. Sternberg
Keyword(s):  
Relative Humidity ◽  
Tree Rings ◽  
Middle Eocene ◽  
The Arctic ◽  
Isotopic Signatures ◽  
Annual Patterns

scholarly journals Temperature and Relative Humidity Profile Retrieval from Fengyun-3D/HIRAS in the Arctic Region

2021 ◽  
Vol 13 (10) ◽  
pp. 1884
Author(s):  
Jingjing Hu ◽  
Yansong Bao ◽  
Jian Liu ◽  
Hui Liu ◽  
George P. Petropoulos ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Real Time ◽  
Wide Spectrum ◽  
Warm Season ◽  
Arctic Region ◽  
Cold Season ◽  
The Arctic ◽  
Practical Applications ◽  
A New Technique ◽  
The Arctic Region

The acquisition of real-time temperature and relative humidity (RH) profiles in the Arctic is of great significance for the study of the Arctic’s climate and Arctic scientific research. However, the operational algorithm of Fengyun-3D only takes into account areas within 60°N, the innovation of this work is that a new technique based on Neural Network (NN) algorithm was proposed, which can retrieve these parameters in real time from the Fengyun-3D Hyperspectral Infrared Radiation Atmospheric Sounding (HIRAS) observations in the Arctic region. Considering the difficulty of obtaining a large amount of actual observation (such as radiosonde) in the Arctic region, collocated ERA5 data from European Centre for Medium-Range Weather Forecasts (ECMWF) and HIRAS observations were used to train the neural networks (NNs). Brightness temperature and training targets were classified using two variables: season (warm season and cold season) and surface type (ocean and land). NNs-based retrievals were compared with ERA5 data and radiosonde observations (RAOBs) independent of the NN training sets. Results showed that (1) the NNs retrievals accuracy is generally higher on warm season and ocean; (2) the root-mean-square error (RMSE) of retrieved profiles is generally slightly higher in the RAOB comparisons than in the ERA5 comparisons, but the variation trend of errors with height is consistent; (3) the retrieved profiles by the NN method are closer to ERA5, comparing with the AIRS products. All the results demonstrated the potential value in time and space of NN algorithm in retrieving temperature and relative humidity profiles of the Arctic region from HIRAS observations under clear-sky conditions. As such, the proposed NN algorithm provides a valuable pathway for retrieving reliably temperature and RH profiles from HIRAS observations in the Arctic region, providing information of practical value in a wide spectrum of practical applications and research investigations alike.All in all, our work has important implications in broadening Fengyun-3D’s operational implementation range from within 60°N to the Arctic region.

scholarly journals Early to middle Eocene history of the Arctic Ocean from Nd-Sr isotopes in fossil fish debris, Lomonosov Ridge

2009 ◽  
Vol 24 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. D. Gleason ◽  
D. J. Thomas ◽  
T. C. Moore ◽  
J. D. Blum ◽  
R. M. Owen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Middle Eocene ◽  
The Arctic ◽  
Lomonosov Ridge ◽  
Sr Isotopes ◽  
Fossil Fish ◽  
The Arctic Ocean ◽  
History Of

scholarly journals Long-Term Performance Assessment of Low-Cost Atmospheric Sensors in the Arctic Environment

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1919 ◽  
Author(s):  
Federico Carotenuto ◽  
Lorenzo Brilli ◽  
Beniamino Gioli ◽  
Giovanni Gualtieri ◽  
Carolina Vagnoli ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Relative Humidity ◽  
Air Temperature ◽  
Meteorological Parameters ◽  
Low Cost ◽  
Absolute Error ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Svalbard Archipelago ◽  
Arctic Environment

The Arctic is an important natural laboratory that is extremely sensitive to climatic changes and its monitoring is, therefore, of great importance. Due to the environmental extremes it is often hard to deploy sensors and observations are limited to a few sparse observation points limiting the spatial and temporal coverage of the Arctic measurement. Given these constraints the possibility of deploying a rugged network of low-cost sensors remains an interesting and convenient option. The present work validates for the first time a low-cost sensor array (AIRQino) for monitoring basic meteorological parameters and atmospheric composition in the Arctic (air temperature, relative humidity, particulate matter, and CO2). AIRQino was deployed for one year in the Svalbard archipelago and its outputs compared with reference sensors. Results show good agreement with the reference meteorological parameters (air temperature (T) and relative humidity (RH)) with correlation coefficients above 0.8 and small absolute errors (≈1 °C for temperature and ≈6% for RH). Particulate matter (PM) low-cost sensors show a good linearity (r2 ≈ 0.8) and small absolute errors for both PM2.5 and PM10 (≈1 µg m−3 for PM2.5 and ≈3 µg m−3 for PM10), while overall accuracy is impacted both by the unknown composition of the local aerosol, and by high humidity conditions likely generating hygroscopic effects. CO2 exhibits a satisfying agreement with r2 around 0.70 and an absolute error of ≈23 mg m−3. Overall these results, coupled with an excellent data coverage and scarce need of maintenance make the AIRQino or similar devices integrations an interesting tool for future extended sensor networks also in the Arctic environment.

Late Paleocene-middle Eocene hydrocarbon source rock potential in the Arctic Beaufort-Mackenzie Basin

2017 ◽  
Vol 86 ◽  
pp. 1082-1091 ◽  
Author(s):  
L.A. Neville ◽  
D.H. McNeil ◽  
S.E. Grasby ◽  
O.H. Ardakani ◽  
H. Sanei
Keyword(s):  
Source Rock ◽  
Middle Eocene ◽  
The Arctic ◽  
Hydrocarbon Source Rock ◽  
Mackenzie Basin ◽  
Late Paleocene

Chemical pretreatment of Thuja occidentalis tree rings: implications for dendroisotopic studies

2009 ◽  
Vol 39 (9) ◽  
pp. 1777-1784 ◽  
Author(s):  
Robert Au ◽  
Jacques C. Tardif
Keyword(s):  
North America ◽  
Tree Ring ◽  
Tree Rings ◽  
Cross Sections ◽  
Close Agreement ◽  
Chemical Pretreatment ◽  
Broad Distribution ◽  
Thuja Occidentalis ◽  
Wood Component ◽  
Isotopic Signatures

Whether or not extractives, lignin, and (or) hemicelluloses, all of which have specific isotopic signatures, should be removed prior to dendroisotopic analysis is still debated. This study reports the range of modern tree-ring δ13C values of cellulose from Thuja occidentalis L., a species that has been under-utilized in dendroisotopic research despite its broad distribution and great longevity in North America. The main objective of the study was to recommend a wood component from T. occidentalis to isolate for future δ13C dendroisotopic analyses. Annually resolved tree-ring decadal segments common to eight T. occidentalis trees were excised from cross sections and homogenized. The tree-ring decadal segment from each tree was then chemically processed from untreated whole wood to extractive-free wood, to holocellulose, and to α-cellulose. Subsamples were analyzed for δ13C, percent carbon, and percent yield after each stage of chemical treatment. We recommend that holocellulose be extracted for T. occidentalis, as the α-cellulose yield may be too low when tree-ring samples are very small. The δ13C values for T. occidentalis tree rings were found to be enriched with respect to those for needle-leaved conifers but in close agreement with those reported in the literature for other scale-leaved evergreens.

scholarly journals Ten years trends in atmospheric mercury concentrations, meteorological effects and climate variables at Zeppelin, Ny-Ålesund

2013 ◽  
Vol 13 (1) ◽  
pp. 2273-2312
Author(s):  
T. Berg ◽  
K. A. Pfaffhuber ◽  
A. S. Cole ◽  
O. Engelsen ◽  
A. Steffen
Keyword(s):  
Relative Humidity ◽  
Wind Direction ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
The Arctic ◽  
Climate Indices ◽  
Atmospheric Conditions ◽  
Gaseous Elemental Mercury ◽  
Surface Emission ◽  
Wind Speeds

Abstract. Results from ten years of gaseous elemental mercury (GEM) measurements at Zeppelin Station, Ny-Ålesund, Svalbard, show no overall annual trend between 2000 and 2009. Seasonal trend analysis showed significantly decreasing trends in January, February, March and June and significantly increasing trends in May and July through December. Results showed that atmospheric mercury depletion events (AMDEs) were equally distributed between April and May with only a few having been observed in March and June. A negative correlation between AMDEs and temperature is reported and supports earlier observations that AMDEs tend to occur at low temperatures. Lower concentrations of GEM were seen at lower temperatures below a threshold of 0°C. The occurrence of AMDEs and wind direction were well correlated with the lowest GEM measured when the wind direction was from the Arctic Ocean region. Wind speed was found to not correlate with AMDEs, but the lowest GEM concentrations were observed at low wind speeds between 4 and 11 m s−1. AMDEs and relative humidity did not correlate well, but the lowest GEM levels appeared when the relative humidity was between 80 and 90%. Diurnal variation was observed especially during the month March and is likley due to daytime snow surface emission induced by solar radiation. Relationships between GEM concentration and the Northern Hemisphere climate indices were investigated to assess if these climate parameters might reflect different atmospheric conditions that enhance or reduce spring AMDE activity. No consistent pattern was observed.

scholarly journals C / N ratio, stable isotope (δ<sup>13</sup>C, δ<sup>15</sup>N), and <i>n</i>-alkane patterns of bryophytes along hydrological gradients of low-centred polygon of the Siberian Arctic

2016 ◽  
Author(s):  
Romy Zibulski ◽  
Felix Wesener ◽  
Heinz Wilkes ◽  
Birgit Plessen ◽  
Luidmila A. Pestryakova ◽  
...  
Keyword(s):  
Water Level ◽  
Isotopic Signature ◽  
The Arctic ◽  
Specific Level ◽  
Δ13c And Δ15n ◽  
Lena River ◽  
Isotopic Signatures ◽  
Microbial Symbiosis ◽  
The Stability ◽  
The Individual

Abstract. Mosses are a major component of the arctic vegetation, particularly of wetlands. We present C / N ratio, δ13C and δ15N data of 400 moss samples belonging to 10 species that were collected along hydrological gradients within polygonal mires located on the southern Taymyr Peninsula and the Lena River delta in northern Siberia. Additionally, n alkane patterns of six of these taxa were investigated. The aim of the study is to see whether the inter- and intra-specific differences in biochemical and isotopic signatures are indicative of habitat with particular respect to water-level. Overall, we find high variability in all investigated parameters. The C / N ratios range between 15.4 and 70.4 (median: 42.9) and show large variations at intra-specific level. However, species preferring a dry habitat (xero-mesophilic mosses) show higher C / N ratios than those preferring a wet habitat (meso-hygrophilic mosses). We assume that this mainly originates from the association of mosses from wet habitats with microorganisms which supply them with nitrogen. Furthermore, because of the stability provided by water, they do not need to invest in a sturdy stem-structure and accordingly have lower C contents in their biomass. The δ13C values range between −37.0 and 22.5 ‰ (median = −27.8 ‰). The δ15N values range between −6.59 and +1.69 ‰ (median = 2.17 ‰).We find differences in δ13C and δ15N signatures between both habitat types and, for some species of the meso-hygrophilic group, a significant relation between the individual habitat water-level and isotopic signature was inferred as a function of microbial symbiosis. The n alkane distribution also shows differences primarily between xero-mesophilic and meso-hygrophilic mosses, i.e. having a dominance of n-alkanes with long (n-C29, n-C31) and intermediate chain lengths (n-C25), respectively. Overall, our results reveal that biochemical and isotopic signals of certain moss taxa from polygonal wetlands are characteristic of their habitat and can thus be used in (palaeo-)environmental studies.

scholarly journals Regional Radiocarbon Effect Due to Thawing of Frozen Earth

Radiocarbon ◽  
1996 ◽  
Vol 38 (3) ◽  
pp. 597-602 ◽  
Author(s):  
P. E. Damon ◽  
George Burr ◽  
A. N. Peristykh ◽  
G. C. Jacoby ◽  
R. D. D'Arrigo
Keyword(s):  
Mass Spectrometry ◽  
Pacific Northwest ◽  
Tree Rings ◽  
Growing Season ◽  
Enso Event ◽  
The Arctic ◽  
Correlation Index ◽  
The Pacific ◽  
Strong Enso ◽  
Short Growing Season

Accelerator mass spectrometry (AMS) measurement of 25 single-year tree rings from AD 1861–1885 at ca. ±3.5‰ precision shows no evidence of an anomalous 11-yr cycle of 14C near the Arctic Circle in the Mackenzie River area. However, the Δ14C measurements are lower on average by 2.7 ± 0.9 (ō)‰ relative to 14C measurements on tree rings from the Pacific Northwest (Stuiver and Braziunas 1993). We attribute this depression of Δ14C to thawing of the ice and snow cover followed by melting of frozen earth that releases trapped 14C-depleted CO2 to the atmosphere during the short growing season from May through August. Correlation of Δ14C with May–August estimated temperatures yields a correlation index of r = 0.60. The reduction in Δ14C is dominated by seven years of anomalous depletion. These years are 1861, 1867–1869, 1879–1880 and 1883. The years 1867–1869 are coincident with a very strong ENSO event.

scholarly journals Methane at Svalbard and over the European Arctic Ocean

2018 ◽  
Author(s):  
Stephen M. Platt ◽  
Sabine Eckhardt ◽  
Benedicte Ferré ◽  
Rebecca E. Fisher ◽  
Ove Hermansen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Hot Spot ◽  
The Arctic ◽  
Mixing Ratio ◽  
Isotopic Signatures ◽  
Mixing Ratios ◽  
Area Of Interest ◽  
Short Course ◽  
European Arctic ◽  
A New Technique

Abstract. Methane (CH4) is a powerful greenhouse gas and atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH4 sources is essential for effective climate change mitigation. Here we report observations of the CH4 mixing ratios measured at Zeppelin Observatory (Svalbard) in the Arctic and aboard the Research Vessel (RV) Helmer Hanssen over the Arctic Ocean from June 2014 to December 2016, as well as the long-term CH4 trend measured at the Zeppelin Observatory (Svalbard) from 2001–2017. We investigated areas over the European Arctic Ocean to identify possible hot spot regions emitting CH4 from the ocean to the atmosphere, and used state-of-the-art modelling (FLEXPART) combined with updated emissions inventories to identify CH4 sources. Furthermore, we collected air samples in the region as well as samples of gas hydrates, obtained from the sea floor using a new technique developed as part of this work. Using this new methodology, we evaluated the suitability of ethane and isotopic signatures (δ13C in CH4) as tracers for ocean-to-atmosphere CH4 emission. We show that the mean atmospheric CH4 mixing ratio in the Arctic increased by 5.9 ± 0.38 parts per billion by volume (ppb) per year (yr−1) from 2001–2017. Meanwhile most large excursions from the baseline CH4 mixing ratio over the European Arctic Ocean are due to long-range transport from land-based sources, lending confidence to the present inventories for high latitude CH4 emissions. However, we also identify a potential hot spot region with ocean-atmosphere CH4 flux North of Svalbard (80.4° N, 12.8° E) of up to 26 nmol m−2 s−1 from a large mixing ratio increase at the location of 30 ppb. Since this flux is highly consistent with previous constraints (both spatially and temporally), there is no evidence that the area of interest North of Svalbard is unique in the context of the wider Arctic. Rather, that the meteorology at the time of the observation was unique in the context of the measurement time series, i.e. we obtained, over the short course of the episode, measurements highly sensitive to emissions over an active seep site, without sensitivity to land based emissions.

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