Isotope composition of snow from individual snowfall in the northeast of Europe, December 2003

Isotope composition of snow samples from individual snowfall was measured on the transect of approximately 1400 km through the northeast of Europe from Konosha station through Inta Town and Seida Town up to Polar Ural. Stable isotope contents of Oxygen-18 and Deuterium as well as Deuterium excess are not constant in uniform air mass, but strongly vary depending on condensation temperature. It is demonstrated that the values of Oxygen-18 and deuterium decrease by 1.4 and 10.8 ‰ per 1 degree of latitude. With decreasing Oxygen-18 content by 8.17 ‰ and Deuterium by 60.3 ‰, Deuterium excess increases by 8.1 ‰. Data was collected inthe northeast of Europe between December 23rd and 24th 2003

Footprints of climate in groundwater and precipitation

Abstract. In the last decades, the 18 O / 16 O signature of meteoric water became a key tracer intensively used both in hydrology and in paleoclimatology, based primarily on the correlation of the 18 O / 16 O ratio in precipitation with temperature. This correlation with temperature is generally well understood as a result of Rayleigh processes of atmospheric vapour during the formation of precipitation. The resulting isotopic signals in precipitation are also transferred into the groundwater body since the isotopic composition of groundwater is determined by the precipitation infiltrating into the ground. However, the whole variability of the 18 O / 16 O ratio especially in temporal data series of precipitation and groundwater can not be explained with temperature alone. Here we show that certain interactions between different climate induced changes in local parameters prevailing during precipitation events are able to explain a significant part of the observed deviation. These effects are superimposed by an overall isotopic pattern representing the large scale climate input primarily based on temperature. The intense variability of isotopes due to the particular topography of Austria recorded over a time period of 40 years provides an unique possibility to uncover this hidden information contributed by relative humidity and type of precipitation. Since there is a growing need to predict the variation of climate together with its associated potential hazards like floods and dry periods the results of this work are contributing to a better overall understanding of the complex interaction of climate with the corresponding water cycle.

Deuterium excess in precipitation of Alpine regions - moisture recycling.

The paper evaluates long-term seasonal variations of the deuterium excess (d-excess = delta(2)H - 8. delta(18)O) in precipitation of stations located north and south of the main ridge of the Austrian Alps. It demonstrates that sub-cloud evaporation during precipitation and continental moisture recycling are local, respectively, regional processes controlling these variations. In general, sub-cloud evaporation decreases and moisture recycling increases the d-excess. Therefore, evaluation of d-excess variations in terms of moisture recycling, the main aim of this paper, includes determination of the effect of sub-cloud evaporation. Since sub-cloud evaporation is governed by saturation deficit and distance between cloud base and the ground, its effect on the d-excess is expected to be lower at mountain than at lowland/valley stations. To determine quantitatively this difference, we examined long-term seasonal d-excess variations measured at three selected mountain and adjoining valley stations. The altitude differences between mountain and valley stations ranged from 470 to 1665 m. Adapting the 'falling water drop' model by Stewart [J. Geophys. Res., 80(9), 1133-1146 (1975).], we estimated that the long-term average of sub-cloud evaporation at the selected mountain stations (altitudes between about 1600 and 2250 m.a.s.l.) is less than 1 % of the precipitation and causes a decrease of the d-excess of less than 2 per thousand. For the selected valley stations, the corresponding evaporated fraction is at maximum 7 % and the difference in d-excess ranges up to 8 per thousand. The estimated d-excess differences have been used to correct the measured long-term d-excess values at the selected stations. Finally, the corresponding fraction of water vapour has been estimated that recycled by evaporation of surface water including soil water from the ground. For the two mountain stations Patscherkofel and Feuerkogel, which are located north of the main ridge of the Alps, the maximum seasonal change of the corrected d-excess (July/August) has been estimated to be between 5 and 6 per thousand, and the corresponding recycled fraction between 2.5-3 % of the local precipitation. It has been found that the estimated recycled fractions are in good agreement with values derived from other approaches

Grain stripper Performance and losses when harvesting cereals and linseed

Translated from German (Landtechnik v. 50(4) p. 196-97)SIGLEAvailable from British Library Document Supply Centre-DSC:9022.950(SRI-Trans--67)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

¹⁴C age, stable isotope composition and pollen analysis of massive ice, Bovanenkovo gas field, Central Yamal Peninsula

The origin of the massive ice is important for understanding the Quaternary history of the Yamal region and to predict the occurrence of massive ice, which is important for gas exploration and the development of infrastructure. Massive ice bodies occur in the Bovanenkovo gas field area within sediments such as layers, laccoliths, rods and lenses. Maximal thickness of the tabular ice is 28,5 m; mean thickness is about 8 m. Deposits of the third terrace underlying and overlapping the tabular ice had been formed from 25 ka BP to 20 ka BP, according to ¹⁴C dates. Oxygen-isotope values (δ¹⁸O) of massive ices are ranged from 12, 49‰ up to -22, 95‰. Deuterium (²H) values vary from -91, 7‰ up to -177, 1‰. Deuterium excess (dexc) changes from 3, 4 to 10, 6‰. Both homogenous and contrast distribution δ¹⁸O and (²H) vs. depths in massive ice bodies evidences the segregated and/or infiltrated-segregated manner of ice formation. Pollen, spores and algae spectra from ice are similar to pollen characteristics of modern lacustrine and coastal floodplain sediments in the area. The ingression of cold seawaters on a coastal flood plain caused freezing and ice segregation, with the formation of extensive ice layers under the large but shallow lakes. As a result, syngenetic and genetically heterogeneous ice, such as: segregated, infiltrated-segregated, lake bottom congelation ice etc. was formed