scholarly journals Snow algae in a Himalayan ice core: new environmental markers for ice-core analyses and their correlation with summer mass balance

2006 ◽  
Vol 43 ◽  
pp. 148-153 ◽  
Author(s):  
Yoshitaka Yoshimura ◽  
Shiro Kohshima ◽  
Nozomu Takeuchi ◽  
Katsumoto Seko ◽  
Koji Fujita
Keyword(s):  
Mass Balance ◽  
Snow Cover ◽  
Air Temperature ◽  
Algal Biomass ◽  
Ice Core ◽  
Algal Growth ◽  
Environmental Indices ◽  
Snow Algae ◽  
Annual Layer ◽  
Cover Thickness

AbstractSnow algae in a shallow ice core (6.98 m long) from Yala glacier in the Langtang region of Nepal were examined for potential use as environmental markers in ice-core analysis. The ice core, taken at 5350m a.s.l. in 1994, was estimated to contain 11 annual layers from 1984 to 1994 from the profile of algal biomass. Algal biomass in each annual layer was noted to be correlated with air temperature, and the following two environmental indices which were calculated from air temperature and precipitation at Kyangjing (3920m a.s.l.), the village nearest to Yala glacier: estimated mean snow-cover thickness (MST) and estimated summer mass balance (SMB). Both parameters reflect snow-cover thickness on algal layers, which would be a major determinant of the light available for algal growth on the glacier. Snow algal biomass in the ice core appears to be a good environmental marker for indicating air temperature and accumulation during summer, which is important for understanding the mass balance of summer-accumulation-type glaciers in this region.

scholarly journals Himalayan ice-core dating with snow algae

2000 ◽  
Vol 46 (153) ◽  
pp. 335-340 ◽  
Author(s):  
Yoshitaka Yoshimura ◽  
Shiro Kohshima ◽  
Nozomu Takeuchi ◽  
Katsumoto Seko ◽  
Koji Fujita
Keyword(s):  
Vertical Profile ◽  
Algal Biomass ◽  
Ice Core ◽  
Algal Growth ◽  
Ice Cores ◽  
Late Summer ◽  
Layer Formation ◽  
Snow Algae ◽  
Potential Use ◽  
Ice Core Dating

AbstractSnow algae in shallow ice cores (7 m long) from Yala Glacier in the Langtang region of Nepal were examined for potential use in ice-core dating. Ice-core samples taken at 5350 m a.s.l. in 1994 contained more than seven species of snow algae. In a vertical profile of the algal biomass, 11 distinct algal layers were observed. Seasonal observation in 1996 at the coring site indicated most algal growth occurred from late spring to late summer. Pit observation in 1991, 1992 and 1994 indicated that algal layer formation takes place annually. δ18O, chemical ions (Na+, Cl−, SO42− and NO3−) and microparticles failed to show any clear seasonal variation, particularly at depths exceeding 2 m, possibly due to heavy meltwater percolation. Snow algae in ice cores would thus appear to be accurate boundary markers of annual layers and should prove useful for ice-core dating in Himalayan-type glaciers.

scholarly journals Geometry, motion and mass balance of Dyer Plateau, Antarctica

1996 ◽  
Vol 42 (142) ◽  
pp. 510-518 ◽  
Author(s):  
Charles Raymond ◽  
Bruce Weertman ◽  
Lonnie Thompson ◽  
Ellen Mosley-Thompson ◽  
David Peel ◽  
...  
Keyword(s):  
Mass Balance ◽  
Vertical Velocity ◽  
Accumulation Rate ◽  
Past History ◽  
Ice Core ◽  
Equivalent Thickness ◽  
Annual Layer ◽  
History Of ◽  
Current Mass ◽  
Mass Increase

AbstractGeodetic surveying and ground-based radar profiling were used to determine geometry and surface motion of the ice sheet on the Dyer Plateau, Antarctica, in the vicinity of an ice-core site on a local dome. Vertical strain measurements in the core hole constrain the depth profile of vertical velocity. These geophysical measurements are used to analyze the profiles of density and annual layer thickness measured on the ice core to estimate the current mass balance of the ice column and the past history of accumulation rate. Consideration of horizontal and vertical mass-flow divergence shows that the profiles of density and vertical velocity are not fully consistent with steady state. Mean density of the firn layer appears to be increasing, which leads to the deduction of a small rate of mass increase (≈ 0.02 m a− 1ice-equivalent thickness). Over the last 200a there has been a gradual increase in accumulation rate from about 0.46 m a− 1to 0.54 m a− 1ice-equivalent thickness in recent time.

scholarly journals Hydrothermal structure of a polythermal glacier in Spitsbergen by measurements and numerical modeling

2016 ◽  
Vol 56 (2) ◽  
pp. 149-160 ◽  
Author(s):  
A. V. Sosnovsky ◽  
Yu. Ya. Macheret ◽  
A. F. Glazovsky ◽  
I. I. Lavrentiev
Keyword(s):  
Numerical Modeling ◽  
Snow Cover ◽  
Air Temperature ◽  
Lower Layer ◽  
Glacier Surface ◽  
Ablation Area ◽  
Radio Echo Sounding ◽  
Polythermal Glacier ◽  
Cover Thickness ◽  
Echo Sounding

Thickness of the upper cold ice layer in the ablation area of the polythermal glacier Grønfjordbreen (Spitsbergen) was estimated by means of numerical modeling. The results were compared with data of radio-echo sounding of the same glacier obtained in 1979 and 2012. Numerical experiments with changing water content in the lower layer of temperate ice and surface snow cover thickness made possible to compare calculated and modeled cold ice thicknesses and to estimate their changes for 33‑year period caused by regional climate change. According to data of radio-echo sounding, thickness of the cold ice layer decreased, on average, by 34 m. Numerical modeling shown similar results: the cold ice layer became thinner by 31 m and 39 m at altitudes 100–300 a.s.l. under the snow cover thickness of 1 m and 2 m. We explain this by rising of annual mean air temperature by 0,6 °С as compared to data of the nearest meteorological station Barentsburg in the same period. We believe that changes in cold ice layer thickness in polythermal glaciers can be used for estimation of changes in such regional climatic parameter as mean air temperature at different altitudes of the glacier surface in the ablation area.

scholarly journals Annual-layer determinations and 167 year records of past climate of H72 ice core in east Dronning Maud Land, Antarctica

2002 ◽  
Vol 35 ◽  
pp. 471-479 ◽  
Author(s):  
Fumihiko Nishio ◽  
Teruo Furukawa ◽  
Gen Hashida ◽  
Makoto Igarashi ◽  
Takao Kameda ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Core ◽  
Ice Cores ◽  
Surface Mass Balance ◽  
Tritium Content ◽  
Surface Mass ◽  
Annual Layer ◽  
Dronning Maud Land ◽  
Annual Resolution ◽  
Continuous Accumulation

AbstractTo determine annual layers for reconstructing the past environment at annual resolution from ice cores, we employed snow-stake data back to 1972, tritium content, solid electrical conductivity measurements (ECM) and stratigraphic properties for the 73m ice core at the H72 site, east Dronning Maud Land, Antarctica. the average annual surface mass balance at H72 is 307 mma–1w.e. during the last 27 years from continuous accumulation data, 317 mma–1 w.e. according to the densification model and 311 mma–1 w.e. according to the average surface mass balance for 167 years based on annual-layer counting. the ECM age is closely coincident with tritium age, and corresponds with the snow-stake record back to AD 1972 from the surface to 15 m depth. the H72 ice core is dated as AD 1831by ECMat 73.16 mdepth.The time series of yearly surface mass balance at H72 shows an almost constant 311 mm a–1 w.e. for the last 167 years. the oxygen-isotope records indicate a significant trend to lower values, with negative gradient of 1.7% (100 years)–1.

scholarly journals The influence of surface characteristics, topography, and continentality on mountain permafrost in British Columbia

2014 ◽  
Vol 8 (5) ◽  
pp. 4779-4822 ◽  
Author(s):  
A. Hasler ◽  
M. Geertsema ◽  
V. Foord ◽  
S. Gruber ◽  
J. Noetzli
Keyword(s):  
British Columbia ◽  
Snow Cover ◽  
Air Temperature ◽  
Climatic Factors ◽  
Small Variation ◽  
Surface Characteristics ◽  
Climatic Conditions ◽  
Distribution Models ◽  
The Mean ◽  
Cover Thickness

Abstract. Thermal offset and surface offset are terms that describe the deviation of the mean annual ground temperature from the mean annual air temperature. These offsets are controlled by surface characteristics and topo-climatic factors on a micro- and meso-scales. Macro-climatic conditions may, however, influence the effectiveness of the responsible processes. Existing knowledge on surface- and topography-specific offsets is not easily transferable and limits the applicability of empirical permafrost distribution models over large areas with macro-climatic gradients. In this paper we describe surface and thermal offsets derived from distributed measurements at seven field sites in British Columbia. Key findings are (i) a surprisingly small variation of the surface offsets between different surface types and small thermal offsets in general (excluding wetlands and peat), (ii) a clear influence of the micro-topography at wind exposed sites (snow cover erosion), (iii) a north–south difference of the surface offset of 4 °C in near-vertical bedrock and of 1.5–3 °C on open (no canopy) gentle slopes, (iv) only small macro-climatic differences caused by the reverse influence of snow cover thickness and annual air temperature amplitude. These findings suggest, that empirical permafrost models based on topo-climatic variables may be applicable across regions with significant macro-climatic differences.

scholarly journals Biological ice-core analysis of Sofiyskiy glacier in the Russian Altai

2006 ◽  
Vol 43 ◽  
pp. 70-78 ◽  
Author(s):  
J. Uetake ◽  
S. Kohshima ◽  
F. Nakazawa ◽  
K. Suzuki ◽  
M. Kohno ◽  
...  
Keyword(s):  
Algal Biomass ◽  
Major Ions ◽  
Ice Core ◽  
Ice Cores ◽  
Seasonal Cycles ◽  
Altai Mountains ◽  
Snow Algae ◽  
The Mean ◽  
Potential Use ◽  
Snow Samples

AbstractWe examined microorganisms and pollen in a pit (4.5m deep) and a shallow ice core (25.01m long) from Sofiyskiy glacier in the Altai mountains of Russia for potential use in dating ice cores from a mid-latitude glacier. The ice-core and pit samples contained various green algae, cyanobacteria, bacteria, fungi and pollen. In the vertical profiles of the pit, algal biomass peaks corresponded to high δ18O layers and Pinaceae pollen peaks, suggesting that these algae grew during the melt season. In contrast, the layer with the lowest δ18O contained almost no algal cells. Major peaks of the cyanobacteria, bacteria and a fungus roughly corresponded to those of the algae. However, seasonal changes in these microorganisms became indistinct deeper in the core, as did the seasonal variation in δ18O and major ions, most likely due to heavy meltwater percolation and/or post-depositional decomposition. In contrast, clear seasonal cycles were evident in the algal biomass and pollen in snow samples. Assuming that the peaks of the snow algae and Pinaceae pollen marked summer layers and that the layers with almost no snow algae represented the winter layers, we estimated that the ice core contained 16 annual layers (1985–2001). The mean annual mass balance for the period was estimated to be 1.01mw.e. The value agreed well with those estimated from stake measurements, indicating that snow algae and pollen could provide reliable boundary markers of annual layers in the ice cores of this region.

Influence of snow cover and air temperature on variations of ground freezing depth in Moscow and the Moscow region

2021 ◽  
Author(s):  
Denis Frolov
Keyword(s):  
Thermal Conductivity ◽  
Snow Cover ◽  
Air Temperature ◽  
Winter Season ◽  
Moscow Region ◽  
Frozen Ground ◽  
Ground Freezing ◽  
Meteorological Observatory ◽  
Freezing Depth ◽  
Cover Thickness

<p>According to consdidered influence of snow cover thickness and air temperature on variations of ground freezing depth at the site of meteorological observatory of Moscow State University and also according to the data of observatories in the Moscow region it is expected to make conclusions about the impact of the urban heat island to a ground freezing depth in Moscow region. For this purpose, the values of the maximum ground freezing depth were analyzed for MSU meteorological observatory and for the weather stations of the Moscow region: Kolomna, Mozhaisk and Sukhinichi. And since not always the data of actual observations are avaliable, for these weather stations the calculated values of the maximum ground freezing depth were obtained. The calculations were performed according to the previously developed calculation scheme, based on the problem of thermal conductivity of a three-layer medium (snow, frozen and thawed ground) with a phase transition at the boundary. The heat balance equation included the energy of the phase transition, the inflow of heat from the thawed ground and the outflow to the frozen ground and, in the presence of snow cover, through it to the atmosphere. The heat flow was calculated according to Fourier's law as the product of the thermal conductivity and the temperature gradient. It was assumed that the temperature in each medium varies linearly. For snow cover and frozen ground, the formula of thermal conductivity of a two-layer medium was used. The obtained calculated values were compared with the actual values of the ground freezing depth. The coefficients R<sup>2</sup> of the reliability of the linear trend line approximation when comparing the calculated and actual values for Moscow and the Moscow region were at the level of 0.6-0.7. The maximum ground freezing depth in Moscow and in the Moscow region in the same years may differ by an average of 10 cm. This confirms that the designed scheme well describes ground freezing depth based on data on air temperature and snow cover thickness and can be used to model the underground heat island of the Moscow region. In report it is also supposed to present the results of the recent years observations of snow cover and freezing depth variations in Moscow and the Moscow region. The past  2020 year is considered as the warmest in the entire history of observations according to the MSU Meteorological Observatory for Moscow, according to the Hydrometeorological Center of Russia for the whole of Russia and according to the Copernicus Climate Change Service (C3S) for the entire Globe. So the winter season of 2019/20 in Moscow region was also unusually warm, and therefore in the winter season of 2019/20 there was very little snow in the Moscow region. However, the warm summer of 2020 resulted in one of the lowest summer values of sea ice extent in the Arctic and, as a result, abnormally strong minimum temperatures and heavy snowfall in the winter of 2020/21 in Eurasia and Moscow. The work was done in a frame of state topic AAAA-A16-116032810093-2.</p>

scholarly journals Geometry, motion and mass balance of Dyer Plateau, Antarctica

1996 ◽  
Vol 42 (142) ◽  
pp. 510-518 ◽  
Author(s):  
Charles Raymond ◽  
Bruce Weertman ◽  
Lonnie Thompson ◽  
Ellen Mosley-Thompson ◽  
David Peel ◽  
...  
Keyword(s):  
Mass Balance ◽  
Vertical Velocity ◽  
Accumulation Rate ◽  
Past History ◽  
Ice Core ◽  
Equivalent Thickness ◽  
Annual Layer ◽  
History Of ◽  
Current Mass ◽  
Mass Increase

AbstractGeodetic surveying and ground-based radar profiling were used to determine geometry and surface motion of the ice sheet on the Dyer Plateau, Antarctica, in the vicinity of an ice-core site on a local dome. Vertical strain measurements in the core hole constrain the depth profile of vertical velocity. These geophysical measurements are used to analyze the profiles of density and annual layer thickness measured on the ice core to estimate the current mass balance of the ice column and the past history of accumulation rate. Consideration of horizontal and vertical mass-flow divergence shows that the profiles of density and vertical velocity are not fully consistent with steady state. Mean density of the firn layer appears to be increasing, which leads to the deduction of a small rate of mass increase (≈ 0.02 m a− 1 ice-equivalent thickness). Over the last 200a there has been a gradual increase in accumulation rate from about 0.46 m a− 1 to 0.54 m a− 1 ice-equivalent thickness in recent time.

Sign in / Sign up

Export Citation Format

Share Document