Ice cores from low latitudes can provide a wealth of unique information about past climate in the tropics, but they are difficult to recover and few exist. Here, we report annually resolved ice core ...records from the Quelccaya ice cap (5670 meters above sea level) in Peru that extend back ~1800 years and provide a high-resolution record of climate variability there. Oxygen isotopic ratios (δ¹⁸O) are linked to sea surface temperatures in the tropical eastern Pacific, whereas concentrations of ammonium and nitrate document the dominant role played by the migration of the Intertropical Convergence Zone in the region of the tropical Andes. Quelccaya continues to retreat and thin. Radiocarbon dates on wetland plants exposed along its retreating margins indicate that it has not been smaller for at least six millennia.
Six ice cores from Kilimanjaro provide an ~11.7-thousand-year record of Holocene climate and environmental variability for eastern equatorial Africa, including three periods of abrupt climate change: ...~8.3, ~5.2, and ~4 thousand years ago (ka). The latter is coincident with the "First Dark Age," the period of the greatest historically recorded drought in tropical Africa. Variable deposition of F- and Na+ during the African Humid Period suggests rapidly fluctuating lake levels between ~11.7 and 4 ka. Over the 20th century, the areal extent of Kilimanjaro's ice fields has decreased ~80%, and if current climatological conditions persist, the remaining ice fields are likely to disappear between 2015 and 2020.
Results of studying isotopic characteristics of precipitation at the foot of the southern slope of Elbrus, in the Caucasus, are presented. The precipitation sampling was organized at Azau station (at ...an altitude of 2300 m) on an everyday basis. The main precipitation sources for the Elbrus region have been established using the method of HYSPLIT back trajectories. Values of δ
18
O of the precipitation reflect a pronounced relation to the temperature of the surface air layer: Δδ
18
O/Δ
T
= 0.85‰/°C.
Ice cores that were recovered from the summit of Sajama mountain in Bolivia provide carbon-14-dated tropical records and extend to the Late Glacial Stage (LGS). Oxygen isotopic ratios of the ice ...decreased 5.4 per mil between the early Holocene and the Last Glacial Maximum, which is consistent with values from other ice cores. The abrupt onset and termination of a Younger Dryas-type event suggest atmospheric processes as the probable drivers. Regional accumulation increased during the LGS, during deglaciation, and over the past 3000 years, which is concurrent with higher water levels in regional paleolakes. Unlike polar cores, Sajama glacial ice contains eight times less dust than the Holocene ice, which reflects wetter conditions and extensive snow cover.
The data of ground-based high-frequency radar survey on the Western Elbrus plateau (Central Caucasus) in the summer of 2017 showed that snow accumulation in the summit area is characterized by great ...variability and also has seasonal differences. Analysis of the accumulation fields showed that less snow accumulates in the middle part of the plateau than in the eastern and western parts, and that its distribution over the plateau area is similar. In the warm period of the year, snow accumulation is on average higher than in the cold period, occurs more uniformly over the plateau area, and its distribution is more stable from year to year.
Grigoriev ice cap, located in the Tien Shan mountains of Kyrgyzstan, has a rich history of firn and ice core drilling starting as early as 1962. Here we extend the exceptional record and describe an ...18 m firn core, drilled in February 2018 on the summit of Grigoriev ice cap, at 4600 m a.s.l. The core has been analyzed for firn stratigraphy, major ions, black carbon, water stable isotope ratios and total β activity. We find that the core covers 46±3 years and overlaps by 2 to 3 decades with legacy cores. A good agreement is found in major ion concentrations for the overlapping period. Concentrations of black carbon and major ions are reduced since the early 2000s, indicating the onset of meltwater runoff. Nevertheless, general concentration trends of these species are consistent with observations and Central Asian ice core records, since emissions were highest during periods when melt influence was negligible. The record of water stable isotopes does not reflect the strong increase of air temperatures during the last decades, implying that water stable isotope ratios ceased to be proxies of temperature variations at this site. Apart from runoff evidence, however, the firn's thermal regime appears remarkably unchanged. Firn temperatures in 2018 were the highest on record (∼-1.6 °C at ∼17 m depth). However, temperatures in 2023 are again similar to the early 2000s at ∼-2.5 °C. Furthermore, we find little change in net accumulation since the 1980s. We hypothesize (i) that firn temperatures are stabilized by the removal of latent heat through lateral meltwater runoff, and (ii) that mass loss by runoff is compensated by an increase in accumulation. Data from a nearby weather station support the latter hypothesis.
The surface temperature reconstruction for the Elbrus Plato is built. It takes into account new data on the annual layers in the glacier. The dendrochronological data are used as an additional ...information that allows us to improve accuracy of calculations and stability of the solutions.
Promising Trends in Ice Core Research Kutuzov, S. S.; Mikhalenko, V. N.; Legrand, M. ...
Herald of the Russian Academy of Sciences,
06/2022, Letnik:
92, Številka:
3
Journal Article
Odprti dostop
An overview of modern studies on ice cores from nonpolar regions of the Earth is presented. As an example of complex research on the territory of Russia, a description of the main results of the ...study of ice cores from Elbrus is given. The seasonally resolved data on the chemical and isotopic composition of the Elbrus core cover 1774–2009 reconstructed various aspects of atmospheric pollution in southeastern Europe from preindustrial times to the present day. The necessity of studying several ice cores from different regions to reconstruct the composition of the atmosphere, its pollution, and the reaction of vegetation to climate change and forest fires in Russia is shown.
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