scholarly journals Paleosols of the Interglacial Climates in Canada

2007 ◽  
Vol 44 (3) ◽  
pp. 363-374 ◽  
Author(s):  
Charles Tarnocai
Keyword(s):  
Forest Soils ◽  
The Arctic ◽  
Interglacial Period ◽  
Mean Annual Temperature ◽  
Tree Line ◽  
Climatic Parameters ◽  
The Holocene ◽  
Paleoclimatic Reconstruction ◽  
Soil Features ◽  
The Mean

ABSTRACTAlthough paleosols are useful indicators of paleoclimates. it is first necessary to establish the relationships between the northern limits of the various contemporary soils and the pertinent climatic parameters. It is then necessary to determine the age of the various paleosols and, if possible, their northern limits. Comparison of the distribution and northern limits of the contemporary soils with the distribution and northern limits of the analogous paleosols then permits the reconstruction of the paleoenvironments. For the purposes of comparison the mean annual temperature of the Old Crow area during the Pliocene epoch was also determined (about 4°C) even though this was not an interglacial period. It was found that during the pre-lllinoian interglacial periods the central Yukon had a mean annual temperature of about 7°C while during the Sangamonian interglacial period it had a mean annual temperature of about - 3°C. During the Holocene epoch, the current interglacial period, the climate has been similar to or only slightly cooler than that existing during the Sangamonian interglacial period. The fluctuating position of the arctic tree line (and associated forest soils) during the Holocene epoch, however, indicates that the climate has also been fluctuating during this time. The paleoclimatic reconstruction presented in this paper also relies heavily on both diagnostic soil features and the soil development during the various interglacial periods.

Correlation of Alaskan varve Thickness with Climatic Parameters, and use in Paleoclimatic Reconstruction

1983 ◽  
Vol 20 (3) ◽  
pp. 308-321 ◽  
Author(s):  
James A. Perkins ◽  
John D. Sims
Keyword(s):  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Climatic Parameters ◽  
Climatological Data ◽  
Dominant Source ◽  
Varve Thickness ◽  
Paleoclimatic Reconstruction ◽  
Regional Correlation ◽  
The Mean ◽  
Northern Alaska

The thickness of varves in the sediments of Skilak Lake, Alaska, are correlated with the mean annual temperature (r = 0.574), inversely correlated with the mean annual cumulative snowfall (r = −0.794), and not correlated with the mean annual precipitation (r = 0.202) of the southern Alaska climatological division for the years 1907–1934 A.D. Varve thickness in Skilak Lake is sensitive to annual temperature and snowfall because Skilak Glacier, the dominant source of sediment for Skilak Lake, is sensitive to these climatic parameters. Trends of varve thickness are well correlated with trends of mean annual cumulative snowfall ( = −0.902) of the southern Alaska climatological division and with trends of mean annual temperature of the southern ( = 0.831) and northern ( = 0.786) Alaska climatological divisions. Trends of varve thickness also correlate with trends of annual temperature in Seattle and North Head, Washington ( = 0.632 and 0.850, respectively). Comparisons of trends of varve thickness with trends of annual temperature in California, Oregon, and Washington suggest no widespread regional correlation. Trends of annual snowfall in the southern Alaska climatological division and trends of annual temperature in the southern and northern Alaska climatological divisions are reconstructed for the years 1700–1906 A.D. Climatic reconstructions on the basis of varve thickness in Skilak Lake utilize equations derived from the regression of series of smoothed climatological data on series of smoothed varve thickness. Reconstruction of trends of mean annual cunulative snowfall in the southern Alaska climatological division suggests that snowfall during the 1700s and 1800s was much greater than that during the early and mid-1900s. The periods 1770–1790 and 1890–1906 show marked decreases in the mean annual snowfall. Reconstructed trends of the annual temperature of the northern and southern Alaska climatological divisions suggest that annual temperatures during the 1700s and 1800s were lower than those of the early and mid-1900s. Two periods of relatively high annual temperatures coincide with the periods of low annual snowfall thus determined.

Late-Quaternary summer temperature changes in the northern-European tree-line region

2008 ◽  
Vol 69 (03) ◽  
pp. 404-412 ◽  
Author(s):  
Heikki Seppä ◽  
Glen M. MacDonald ◽  
H. John B. Birks ◽  
Bruce R. Gervais ◽  
Jeffrey A. Snyder
Keyword(s):  
Kola Peninsula ◽  
Younger Dryas ◽  
Summer Temperature ◽  
The Arctic ◽  
Fossil Pollen ◽  
Tree Line ◽  
Temperature Changes ◽  
The Holocene ◽  
Northern European ◽  
Line Region

We present two new quantitative July mean temperature (Tjul) reconstructions from the Arctic tree-line region in the Kola Peninsula in north-western Russia. The reconstructions are based on fossil pollen records and cover the Younger Dryas stadial and the Holocene. The inferred temperatures are less reliable during the Younger Dryas because of the poorer fit between the fossil pollen samples and the modern samples in the calibration set than during the Holocene. The results suggest that the Younger Dryas Tjulin the region was 8.0–10.0°C, being 2.0–3.0°C lower than at present. The Holocene summer temperature maximum dates to 7500–6500 cal yr BP, with Tjulabout 1.5°C higher than at present. These new records contribute to our understanding of summer temperature changes along the northern-European tree-line region. The Holocene trends are consistent in most of the independent records from the Fennoscandian–Kola tree-line region, with the beginning of the Holocene thermal maximum no sooner than at about 8000 cal yr BP. In the few existing temperature-related records farther east in the Russian Arctic tree line, the period of highest summer temperature begins already at about 10,000 cal yr BP. This difference may reflect the strong influence of the Atlantic coastal current on the atmospheric circulation pattern and the thermal behaviour of the tree-line region on the Atlantic seaboard, and the more direct influence of the summer solar insolation on summer temperature in the region east of the Kola Peninsula.

scholarly journals High-frequency climate oscillations in the Holocene from a coastal-dome ice core in east central Greenland

2020 ◽  
Author(s):  
Abigail G. Hughes ◽  
Tyler R. Jones ◽  
Bo M. Vinther ◽  
Vasileios Gkinis ◽  
C. Max Stevens ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
The Arctic ◽  
Climate Information ◽  
East Central ◽  
The Holocene ◽  
Frequency Bands ◽  
Isotope Record ◽  
The Mean ◽  
Water Isotope

Abstract. An ice core drilled on the Renland Ice Cap in east-central Greenland contains a continuous climate record dating through the last glacial period. The Renland record is valuable because the coastal environment is more likely to reflect regional sea surface conditions, compared to inland Greenland ice cores that capture synoptic variability. Here we present the δ18O water isotope record for the Holocene, in which decadal-scale climate information is retained for the last 8 ka, and the annual water isotope signal is preserved throughout the last 2.6 ka. To investigate regional climate information preserved in the water isotope record, we apply spectral analysis techniques to a 300-year moving window to determine the mean strength of varying frequency bands through time. The strength of interannual frequency bands decays rapidly, but we find that the mean 15–20 year δ18O variability exhibits a millennial-scale cycle in line with the well-known Bond Cycle. Comparison to other North Atlantic proxy records suggests that the 15–20 year variability may reflect fluctuating sea ice conditions throughout the Holocene, driven by changes in the strength of the Atlantic Meridional Overturning Circulation. Additional analysis of the seasonal signal over the last 2.6 ka reveals that the winter δ18O signal has experienced a decreasing trend, while the summer signal has predominantly remained stable. The winter trend likely corresponds to an increase in Arctic sea ice cover, driven by a decrease in total annual insolation. In the context of anthropogenic climate change, the winter trend may have important implications for feedback processes as sea ice retreats in the Arctic.

Holocene tree line, permafrost, and climate dynamics in the Nenets Region, East European Arctic

2004 ◽  
Vol 41 (10) ◽  
pp. 1141-1158 ◽  
Author(s):  
Seija Kultti ◽  
Pirita Oksanen ◽  
Minna Väliranta
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
The Arctic ◽  
Tree Line ◽  
The Holocene ◽  
East European ◽  
Summer Temperatures ◽  
European Arctic ◽  
Peat Profile ◽  
Lake Core

Pollen, stomata, and macrofossils in a lake core with a basal date of 9700 14C BP were used to reconstruct past changes in climate and vegetation in the arctic tree line area, northeast European Russia. A palsa peat profile was investigated to establish a chronology of mire initiation and permafrost development during the Holocene. Macrofossils show that tree birch was present in the study area at the beginning of the Holocene and stands of spruce became established shortly thereafter. However, pollen evidence suggests that almost 400 years passed before the area was occupied by a mixed spruce–birch forest, which lasted until ca. 5000 BP. Subsequently, the area reverted to forest–tundra. Paludification began ca. 9000 BP continuing at least until 5700 BP. The conditions were permafrost-free at least until 4500 BP. The latest permafrost aggradation phase is dated to the Little Ice Age. We interpret summer temperatures to have been ca. 3–4 °C higher between ca. 8900 and 5500 BP than at present, and the lowest temperature regime of the Holocene to have occurred between 2700 and 2100 BP.

scholarly journals Zum Problem der Stabilität der Klimabedingungen in Westsibirien während der Glaziale und Interglaziale

1960 ◽  
Vol 11 (1) ◽  
pp. 77-87
Author(s):  
W. Weischet
Keyword(s):  
Western Siberia ◽  
Meridional Circulation ◽  
Climatic Conditions ◽  
Summer Temperature ◽  
Deciduous Forests ◽  
The Arctic ◽  
Mean Annual Temperature ◽  
Last Glaciation ◽  
The Mean ◽  
Glacial Periods

Abstract. The depression values of the summer temperature and also of the mean annual temperature in Western Siberia during the last glaciation, have been deduced. This calculation has been based on the different position of the boreal boundaries of the tundra and the continental deciduous forests during the ice ages and at the present time. According to these calculations the following depressions of summer temperature have been obtained: 5-8° C near the arctic circle and 2-4° C in the latitude of 50° North, in comparison with the 10-12° C depression in Central Europe. Afterwards it has been discussed whether or not these relatively small depressions can be explained exclusively on the basis of the higher continentality of the central part of Eurasia in comparison with the western or eastern part of this continent. As this seems to be impossible, it is necessary to look for other facts that could be related to this problem. In the opinion of the author the relative stability of climatic conditions in Western Siberia during the whole Quaternary could be easily explained by the change between the meridional-circulation (low-index-type), prevailing during the glacial periods, and the reinforced zonal-circulation (high-index-type) during the interglacial and postglacial periods.

scholarly journals Towards Understanding Variability in Droughts in Response to Extreme Climate Conditions over the Different Agro-Ecological Zones of Pakistan

2021 ◽  
Vol 13 (12) ◽  
pp. 6910
Author(s):  
Adil Dilawar ◽  
Baozhang Chen ◽  
Arfan Arshad ◽  
Lifeng Guo ◽  
Muhammad Irfan Ehsan ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Principal Component ◽  
Mitigation Strategies ◽  
Precipitation Extremes ◽  
Climate Mitigation ◽  
Mean Annual Temperature ◽  
Climate Extreme ◽  
Ecological Zones ◽  
The Mean ◽  
Agro Ecological Zones

Here, we provided a comprehensive analysis of long-term drought and climate extreme patterns in the agro ecological zones (AEZs) of Pakistan during 1980–2019. Drought trends were investigated using the standardized precipitation evapotranspiration index (SPEI) at various timescales (SPEI-1, SPEI-3, SPEI-6, and SPEI-12). The results showed that droughts (seasonal and annual) were more persistent and severe in the southern, southwestern, southeastern, and central parts of the region. Drought exacerbated with slopes of −0.02, −0.07, −0.08, −0.01, and −0.02 per year. Drought prevailed in all AEZs in the spring season. The majority of AEZs in Pakistan’s southern, middle, and southwestern regions had experienced substantial warming. The mean annual temperature minimum (Tmin) increased faster than the mean annual temperature maximum (Tmax) in all zones. Precipitation decreased in the southern, northern, central, and southwestern parts of the region. Principal component analysis (PCA) revealed a robust increase in temperature extremes with a variance of 76% and a decrease in precipitation extremes with a variance of 91% in the region. Temperature and precipitation extremes indices had a strong Pearson correlation with drought events. Higher temperatures resulted in extreme drought (dry conditions), while higher precipitation levels resulted in wetting conditions (no drought) in different AEZs. In most AEZs, drought occurrences were more responsive to precipitation. The current findings are helpful for climate mitigation strategies and specific zonal efforts are needed to alleviate the environmental and societal impacts of drought.

scholarly journals Latitudinal distribution of microbial communities in anaerobic biological stabilization ponds: effect of the mean annual temperature

2016 ◽  
Vol 9 (6) ◽  
pp. 834-845 ◽  
Author(s):  
Mengdong Yuan ◽  
Jing Zhu ◽  
Cheng Wang ◽  
Mengxiong Wu ◽  
Faqian Sun ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Mean Annual Temperature ◽  
Latitudinal Distribution ◽  
Stabilization Ponds ◽  
The Mean

scholarly journals Neoglacial history of Robson Glacier, British Columbia

2017 ◽  
Vol 54 (11) ◽  
pp. 1153-1164 ◽  
Author(s):  
B.H. Luckman ◽  
M.H. Masiokas ◽  
K. Nicolussi
Keyword(s):  
British Columbia ◽  
Little Ice Age ◽  
Ice Age ◽  
Tree Line ◽  
Canadian Rockies ◽  
The Holocene ◽  
Forest Sites ◽  
History Of ◽  
Subfossil Wood ◽  
Glacier Advance

As glaciers in the Canadian Rockies recede, glacier forefields continue to yield subfossil wood from sites overridden by these glaciers during the Holocene. Robson Glacier in British Columbia formerly extended below tree line, and recession over the last century has progressively revealed a number of buried forest sites that are providing one of the more complete records of glacier history in the Canadian Rockies during the latter half of the Holocene. The glacier was advancing ca. 5.5 km upvalley of the Little Ice Age terminus ca. 5.26 cal ka BP, at sites ca. 2 km upvalley ca. 4.02 cal ka BP and ca. 3.55 cal ka BP, and 0.5–1 km upvalley between 1140 and 1350 A.D. There is also limited evidence based on detrital wood of an additional period of glacier advance ca. 3.24 cal ka BP. This record is more similar to glacier histories further west in British Columbia than elsewhere in the Rockies and provides the first evidence for a post-Hypsithermal glacier advance at ca. 5.26 cal ka BP in the Rockies. The utilization of the wiggle-matching approach using multiple 14C dates from sample locations determined by dendrochronological analyses enabled the recognition of 14C outliers and an increase in the precision and accuracy of the dating of glacier advances.

scholarly journals Iron-bound organic carbon in forest soils: quantification and characterization

2016 ◽  
Vol 13 (16) ◽  
pp. 4777-4788 ◽  
Author(s):  
Qian Zhao ◽  
Simon R. Poulson ◽  
Daniel Obrist ◽  
Samira Sumaila ◽  
James J. Dynes ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Spatial Variability ◽  
Forest Soils ◽  
The United States ◽  
Biogeochemical Cycles ◽  
Mean Annual Temperature ◽  
Aliphatic Carbon ◽  
A Site ◽  
The Impact ◽  
X Ray Absorption

Abstract. Iron oxide minerals play an important role in stabilizing organic carbon (OC) and regulating the biogeochemical cycles of OC on the earth surface. To predict the fate of OC, it is essential to understand the amount, spatial variability, and characteristics of Fe-bound OC in natural soils. In this study, we investigated the concentrations and characteristics of Fe-bound OC in soils collected from 14 forests in the United States and determined the impact of ecogeographical variables and soil physicochemical properties on the association of OC and Fe minerals. On average, Fe-bound OC contributed 37.8 % of total OC (TOC) in forest soils. Atomic ratios of OC : Fe ranged from 0.56 to 17.7, with values of 1–10 for most samples, and the ratios indicate the importance of both sorptive and incorporative interactions. The fraction of Fe-bound OC in TOC (fFe-OC) was not related to the concentration of reactive Fe, which suggests that the importance of association with Fe in OC accumulation was not governed by the concentration of reactive Fe. Concentrations of Fe-bound OC and fFe-OC increased with latitude and reached peak values at a site with a mean annual temperature of 6.6 °C. Attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and near-edge X-ray absorption fine structure (NEXAFS) analyses revealed that Fe-bound OC was less aliphatic than non-Fe-bound OC. Fe-bound OC also was more enriched in 13C compared to the non-Fe-bound OC, but C ∕ N ratios did not differ substantially. In summary, 13C-enriched OC with less aliphatic carbon and more carboxylic carbon was associated with Fe minerals in the soils, with values of fFe-OC being controlled by both sorptive and incorporative associations between Fe and OC. Overall, this study demonstrates that Fe oxides play an important role in regulating the biogeochemical cycles of C in forest soils and uncovers the governing factors for the spatial variability and characteristics of Fe-bound OC.

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