A 15‐year‐long, 16 km horizontal resolution, present‐day climate simulation has been conducted with the HIRHAM4 regional climate model. The model has been forced by the European Centre for ...Medium‐Range Weather Forecasts reanalyses at the lateral boundary and over sea by sea surface temperature and sea ice concentrations from the same source. The model domain is centered over the European part of Arctic Russia focusing on the Usa River basin near the Ural Mountains. It is demonstrated that with this fine mesh, the model simulates the annual course and interannual variability in temperature and precipitation quite realistically. Furthermore the model captures the timing of permanent snow cover very accurately with less than 1‐week discrepancy in both autumn and spring. An interpretation of modeled subsurface layer temperatures in terms of mean annual temperature and a “frost index” reveals that the model captures presentday regional permafrost patterns to a high degree of accuracy.
Major glacial advances in the Eastern Cordillera of Colombia preceded the global ice volume maximum at ca. 20 ka BP. Two glacial events are recognized for Isotope Stage 3, dated between probably 43 ...and 38 ka BP and between 36 and 31 ka BP. The events are recorded in glacial deposits and strongly subdued morainic ramparts. Three glacial advances during Isotope Stage 2 are dated between 23.5 and 19.5 ka BP, 18.0 and 15.5 ka BP and 13.5 and 12.5 ka BP. The glacial landforms associated with the period 18.0 to 15.5 ka BP are most distinct. The arcuate, multiple morainic ridge system of up to tens of meters of height can be traced throughout the region. The moraines that formed during the earlier Isotope Stage 2 advance are more subdued. The youngest Isotope Stage 2 morainic complex consists of low winding ridges. Isotope Stage 1 glaciations affected only the highest areas of the Eastern Cordillera, where morainic complexes associated with at least three glacial events occur but remain poorly dated. The glacial record of the Colombian Eastern Cordillera registers high climatic variability in the tropical Andes during the Late Quaternary period.
This study provides estimates of average soil organic carbon content for the Usa Basin in Northeast European Russia, using two independent databases and two separate upscaling tools. The results are ...very similar despite differences in sample size and spatial resolution. Based on the merged databases and landcover upscaling, the average carbon content in the Usa Basin is 10,7 Kg Cm
−2
for the upper 30 cm soil layer, 25,5 Kg Cm
−2
for a reference 1 m soil depth and 31,2 Kg Cm
−2
for total soil. The 'peatland' cover classes, with an average 76,3 Kg Cm
−2
and 30% surface coverage, account for 73% of total organic carbon storage in the Usa Basin. Upland forest and tundra classes have similar average total carbon contents-on the order of 11,2-11,4 Kg Cm
−2
. Detailed regional and national assessments of northern terrestrial carbon pools, upscaled using landcover or soil classification schemes like the one presented here for the Usa Basin, arrive at much higher average total soil carbon estimates than generally cited in the literature from global data sets for tundra and taiga life zones or biomes.
The assignment of Colombian pollen data to biomes allows the data to be synthesised at 10 ‘time windows’ from the present-day to 6000 radiocarbon years before present (BP). The modern reconstructed ...biomes are compared to a map of modern potential vegetation to check the applicability of the method and the a priori assignment of pollen taxa to plant functional types and ultimately biomes. The reconstructed modern biomes are successful in describing the composition and distribution of modern vegetation. In particular, altitudinal variations in vegetation within the northern Andean Cordilleras are well described. At 6000 BP the biomes are mainly characteristic of warmer environmental conditions relative to those of the present-day. This trend continues until between 4000 and 3000 BP when there is a shift to more mesic vegetation that is thought to equate to an increase in precipitation levels. The period between 2500 and 1000 BP represents little or no change in biome assignment and is interpreted as a period of environmental stability. The influence attributed to human-induced impact on the vegetation is recorded from 5000 BP, but is particularly important from 2000 BP. The extent of this impact increases over the Late-Holocene period, and is recorded at increasingly high altitudes. Despite these changes, a number of sites do not change their biome assignment throughout the analysis. This asynchronous vegetation response is discussed within the context of site location, non-linear response of vegetation to Late-Holocene environmental change, regionally differential signals, localised human impact and methodological artefacts.
The relationship between permafrost conditions and the distribution of infrastructure in the Usa Basin, Northeast European Russia, is analyzed. About 75% of the Basin is underlain by permafrost ...terrain with various degrees of continuity (isolated patches to continuous permafrost). The region has a high level of urban and industrial development (e.g., towns, coal mines, hydrocarbon extraction sites, railway, pipelines). GIS-analyses indicate that about 60% of all infrastructure is located in the 'high risk' permafrost area, here defined as the zones of isolated to discontinuous permafrost (3-90% coverage) with 'warm' ground temperatures (0 to -2 degree C). Ground monitoring, aerial photo interpretation, and permafrost modeling suggest a differential response to future global warming. Most of the permafrost-affected terrain will likely start to thaw within a few decades to a century. This forecast poses serious challenges to permafrost engineering and calls for long-term investments in adequate infrastructure that will pay back over time.
Using interdisciplinary field research in the Usa Basin, northeast European Russia, we compared local inhabitants' perception of environmental problems with chemical and remote-sensing signatures of ...environmental pollution and their local impacts. Extensive coal mining since the 1930s around Inta and Vorkuta has left a legacy of pollution, detected by measuring snowpack, topsoil, and lichen chemistry, together with remote-sensing techniques and analysis of lake water and sediments. Vorkuta and its environs suffered the worst impacts, with significant metal loading and alkalization in lakes and topsoils, elevated metals and cations in terricolous (reindeer) lichens, and changes in vegetation communities. Although the coal industry has declined recently, the area boasts a booming oil and gas industry, based around Usinsk. Local perceptions and concerns of environmental pollution and protection were higher in Usinsk, as a result of increased awareness after a major oil spill in 1994, compared with Vorkuta's inhabitants, who perceived air pollution as the primary environmental threat. Our studies indicate that the principal sources of atmospheric emissions and local deposition within 25 to 40 km of Vorkuta were coal combustion from power and heating plants, coal mines, and a cement factory. Local people evaluated air pollution from direct observations and personal experiences, such as discoloration of snow and respiratory problems, whereas scientific knowledge played a minor role in shaping these perceptions.
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