Water chemistry and hydrometeorology in a glacierized catchment in the Polar Urals,Russia

This study aims to determine the relationships between local meteorological conditions,proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural mountain range, Russia. Fieldwork was conducted in the catchment of Obruchev Glacier(13 km2) during the summer peak flow period in 2008. River discharge was dominated by snowmelt and changed from 3300 l s-1 to less than 1000 l s-1. The mean daily air temperatures of stations situated in the mountain tundra and near Obruchev Glacier from July 11 th to August 1st 2008 were 14.4°C and 10.3°C, respectively. The glacial river had low total dissolved solids varying from 4.5 to 9 mg l-1 and coefficients of correlation between Na+ and Cl-, K+ and Cl-, as well as NH4+ and Cl- were 0.94, 0.90 and 0.84, respectively. Rainfall events affected the snowmelt initiation and provided an essential part of the discharge during the intense snowmelt period, which occurred from July 11 th to July 18 th 2008. Data showed that Na+ and K+ in the surface water derived from snowmelt rather than chemical weathering of silicates. Also, it was obtained that NO3- derived from the melting snowpack, whereas ammonification occurring under the snowpacks was the primary source for NH4+.     

Alpine ecotone in the Siberian Mountains:vegetation response to warming

Birch (Betula tortuosa) is one of the tree-line forming species within the Siberian Mountains.We analysed the area dynamics of birch stands and the upslope clim...     

Expansion of Juniperus sibirica Burgsd. as a response to climate change and associated effect on mountain tundra vegetation in the Northern Urals

Shrub expansion into arctic and alpine tundra is one of the prominent vegetation changes currently underway. We studied the expansion of shrub vegetation into high elevation tundra in the Kvarkush Range of the Northern Ural mountains, Russia. Age structure analysis of the dominant shrub Juniperus sibirica Burgsd. seems to support ongoing upslope advance of shrubs, a process particularly active in the second half of the 20 th century. We found a close connection between the expansion of shrub vegetation and the general change in climatic conditions of the cold season(months with mean airtemperature below 0°С from November to March). In general, the greatest influence on the distribution of J. sibirica is exerted by the climate conditions of the beginning(November-January) and the end(March) of the cold season. With increasing elevation, the correlation coefficients between the establishment of J. sibirica shrubs and the precipitation of the beginning of the cold season increased, and reached maximum values at the top elevation level of the study area. However, the upwards shift of J. sibirica into typical mountain tundra does not lead to changes in the ecological structure of vegetation at this stage, but simply a decrease in the area of mountain tundra.     

Larch growth across thermal and moisture gradients in the Siberian Mountains

Climate-driven changes in the thermal and moisture regimes may variously influence different tree species growth and ranges. We hypothesize that drought resistant Siberian larch(Larix sibirica Ledeb.) and precipitation-sensitive Siberian pine(Pinus sibirica Du Tour) responded differently to climate change along the elevational thermal and precipitation gradients. We studied the influence of air temperature, precipitation, soil moisture, and atmospheric drought(indicated by the drought index SPEI...     

Stability evaluation of radial growth of Picea schrenkiana in different age groups in response to climate change in the eastern Tianshan Mountains

Global warming causes an unstable response in tree radial growth at high latitudes in the Northern Hemisphere. Additionally, different climatic responses of different age groups of trees have been found due to their different physiological mechanisms.In this study, the response stability and growth trend of three age groups(young 100 a, middle 100-200 a, old ≥ 200 a) of Picea schrenkiana(Schrenk spruce) to climate change and the causes of the different responses in different age groups were analyzed in the relatively dry climate of the eastern Tianshan Mountains. The results showed that:(1) With the abrupt increase in temperature in 1989, the annual mean minimum temperature became the dominant radial growth-limiting factor of the three age groups of Schrenk spruce.(2) The radial growth of the middle and young groups was more sensitive than that of the old group based on growth-climate correlation analysis.(3) The radial growth of the different age groups had different responses to climate factors, and all age groups were unstable on time scales.(4) The trend of the linear regression simulation of the basal area increment(BAI) indicated that the Schrenk spruce had the same growth trends in different age groups with growth first increased and then decreased; however, the decreased growth rate was higher in the middle and young age groups than in the old age group after the abrupt increase in temperature. Therefore, we should pay active attention to the impact of drought on Schrenk spruce in the eastern Tianshan Mountains and should particularly strengthen the conservation and management of the middle and young age groups.     

A mesoscale model used in the Polar regions： modification and verification

1 IntroductionChina has been carrying out 23 field experiments over the Antarctic since 1984 andmany observations on the aspect of oceanography were conducted. The changes of tempera-ture and precipitation in the polar regions have effecton global climate…     

Latitudinal distribution of CO2 and CH4 on the route of the Chinese Arctic Research Expedition 2003

1 Introduction From July 10th to September 26, 2003,“Xuelong”scientific expedition icebreaker executed the 2nd Chinese Arctic Research Expedition (CHINARE2003). The voyage star- ted from Shanghai to Dalian via Yellow Sea and Bo Hai and the cruising rout…     

Latitudinal patterns of climatic variables and influence of local topography on climatic variables in the dry valleys of southwestern China

Climate is a key factor to determine the pattern of ecosystems; however, the latitudinal patterns of climatic variables in the arid and semiarid areas remain largely unclear when compared to humid areas. The topography of the dry valleys of southwestern China plays an important role in the formation of climate. However, its impact on the climate remains qualitative. In this study, eight climatic variables from 12 meteorological stations were analyzed to explore their latitudinal patterns in the ...     

Study of the climatic teleconnection between the Siberian high and maritime continent warm pool

This paper attempts to establish a method for analysing the relationship between the polar and equatorial climate of the Northern Hemisphere. The Arctic Oscillation （AO） is known to have no direct relationship with the monsoon over the Maritime Continent （MC）. Thus, an index called the Siberian High（SH~Maritime Continent（MC） Index （SHMCI） is developed to represent the mean sea level pressure difference between the SH and the warm pool over the MC. This index indicates a strong link with the monsoon circulation. A positive （strong） value of the SHMCI is associated with strong meridional winds and intense and frequent cold surge events over the South China Sea. The correlation between the AO index and the SHMCI is -0.39, which is medium but statistically significant; however, it is not sufficiently conclusive to infer direct correlation. Nevertheless, the SHMCI can be used as a tool to relate the AO with the monsoon over the MC because of the influence demonstrated by the AO towards the SH. Further analysis on the convergence and divergence anomalies over the MC reveals an impact discernible only from the SHMCI. This implies that the SHMCI manifests clearly the relationship between the Arctic and equatorial climate.     

Palynostratigraphy of Upper Cretaceous and boundary Paleogene deposits in West Siberian Plain

The article presents the results of many years of studies of the Upper Cretaceous and Paleogene sediments in the territory of West Siberian Plain. The heterogeneous structure of these sediments in different regions of the plain is shown. The lithological and palynological characteristics of a number of studied wells drilled in different years in Omsk and Kulunda Depressions, in Baraba Lowland and Bakchar Basin are given. The obtained palynological data allowed to substantiate the age of the deposits and to make suggestions concerning their depositional environment, and to clarify the subdivision of geological section into formations. The sections of the Upper Cretaceous and Paleogene deposits in different lithofacial regions of the Western Siberia differ from each other in completeness, genesis, and paleontological characteristics. The Upper Cretaceous sediments in Western Siberia are represented by formations of both marine(Pokur, Kuznetzovo, Ipatovo, Slavgorod and Gan'kino Formations) and continental genesis(Lenkovo and Sym formations). The Paleogene sediments, with the exception of Oligocene, mostly have a marine genesis-these are Talitsa-, Marsyat-, Lulinvor-, Tavda-and Yurki formations, but there are also continental sediments(Ostrovnoje Formation). A large stratigraphic break in the Upper Cretaceous and Paleogene boundary deposits, covering a significant part of the Maastrichtian, Paleocene, Ypresian, and Lutetian stages of the Eocene, was established in the sourheast of the West Siberian Plain(Bakchar Basin, Baraba Lowland and Kulunda Depression). The most complete sections are located in the Omsk Depression, where the Upper Cretaceous Gan'kino Formation is covered by Talitsa and Lulinvor Formations of Paleogene age. The most important events occurring at the boundary of the Cretaceous and Paleogene in Western Siberia can be traced currently in a few sections located in the Trans-Ural area, since there was no sedimentation in the rest of the territory at that time.     

Carbon stock of larch plantations and its comparison with an old-growth forest in northeast China

The overall goal of this study was to understand carbon(C) stock dynamics in four different-aged Japanese larch(Larix kaempferi) plantations in Northeast China that were established after clear-cutting old-growth Korean pine deciduous forests. Four Japanese larch plantations which were at 10, 15, 21, and 35 years old and an old-growth Korean pine deciduous forest which was 300 years old in Northeast China were selected and sampled. We compared the C pools of biomass(tree, shrub and herb), litterfall(LF), and soil organic carbon(SOC) among them. The biomass C stock of larch plantation at 10, 15, 21, and 35 years old was 26.8, 37.9, 63.6, and 83.2 Mg/ha, respectively, while the biomass C stock of the old-growth Korean pine deciduous forest was 175.1 Mg/ha. The SOC stock of these larch plantations was 172.1, 169.7, 140.3, and 136.2 Mg/ha respectively, and SOC stock of 170.4 Mg/ha in the control of old-growth forest. The biomass C stock increased with stand age of larch plantations, whereas SOC stock decreased with age, and C stock of LF did not change significantly(P 0.05). The increase of biomass C offset the decline of SOC stock with age, making total carbon stock(TCS) of larch plantations stable from stand ages of 10–35 years. The TCS in larch plantations was much smaller than that in the old-growth forest, suggesting that the conversion of old-growth forests to young larch plantations releases substantial C into the atmosphere.     

Model simulations of the annual cycle of the landfast ice thickness in the East Siberian Sea

The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year Augus...     

The research of Polar sea ice and its role in climate change

As an important part of global climate system, the Polar sea ice is effccting on global climate changes through ocean surface radiation balance, mass balance, energy balance as well as the circulating of sea water temperature and salinity. Sea ice research has a centuries - old history. The many correlative sea ice projects were established through the extensive international cooperation during the period from the primary research of intensity and the boaring capacity of sea ice to the development of sea/ice/air coupled model. Based on these reseamhes, the sea ice variety was combined with the global climate change. All research about sea ice includes： the physical properties and processes of sea ice and its snow cover, the ecosystem of sea ice regions, sea ice and upper snow albedo, mass balance of sea ice regions, sea ice and climate coupled model. The simulation suggests that the both of the area and volume of polar sea ice would be reduced in next century. With the developing of the sea ice research, more scientific issues are mentioned. Such as the interaction between sea ice and the other factors of global climate system, the seasonal and regional distribution of polar sea ice thickness, polar sea ice boundary and area variety trends, the growth and melt as well as their influencing factors, the role of the polynya and the sea/air interactions. We should give the best solutions to all of the issues in future sea ice studying.     

塔河油田奥陶系原油极性化合物浓度分布及运移趋势

根据原油中的3类极性化合物(烷基咔唑类化合物、烷基二苯并噻吩类化合物和烷基苯酚类化合物)在运移过程中与固
相的吸附机理及其吸附性特征,探讨了这3种极性化合物与固定相通过氢键或者范德华力等作用力而被吸附,并导致原油中极性
化合物浓度随着运移距离的增大逐渐降低的现象。通过对塔河油田22个奥陶系原油样品中3类极性化合物进行定量分析,结果
显示其浓度具有从南向北、从东向西逐渐降低的规律,指示出塔河油田奥陶系原油的运移具有从南部和东部指向主体区的趋势。      

Ectomycorrhiza of Larix sibirica Ledeb. along the gradients of main ecological factors and elevation at the Northern and Subpolar Urals

Siberian larch(Larix sibirica Ledeb.) forests cover the largest areas in the Eurasian boreal zone, but there are insufficient data on its root system including the structure and functional traits of ectomycorrhizas(EM). The aim of this research is to find out if the morphological parameters of Larix sibirica EMs responded to the changes in elevation and main ecological factors(soil humidity, soil richness, soil acidity and habitat illumination). Using light microscopy, we studied EM diameter, root diameter, mantle width, and mantle volume share, share of tannin cells layers, EM density and EM length of Larix sibirica in two main types of plant communities along the elevation gradient at the Northern and Subpolar Urals. Differences in the environment were traced using phytoindication approach and the Ellenberg ecological scales. All the studied traits depend on the elevation and studied ecological factors. The diversity of fungal mantles is low, and the proportion of unstructured and pseudoparenchymatous mantles is high in response to the deterioration of the humidity, soil nitrogen content and acidity at higher-altitude habitats. Results of EM quantitative parameters measurements confirmed this pattern. We found a decline in the EM linear dimensions accompanied by a compensatory growth of the EM density with the raised elevation and the deterioration of environmental conditions.     

Taxonomic and metabolic shifts in the Coorong bacterial metagenome driven by salinity and external inputs

The Coorong estuary lies at the terminus of Australia's largest river system, the Murray-Darling; both are strongly influenced by human activities; including farming and extensive flow modification. Metagenomic approaches were used to determine the planktonic bacterial community composition and potential metabolic function at two extremes in the Coorong, the river mouth which exhibits marine-like salinity, and the hypersaline upper-reaches of the estuary. Significant shifts in taxa and metabolic function were seen between the two sites. The river mouth exhibited an increase in abundance of R hodobacteriaceae and Alteromonadaceae; families readily able to adapt to change in nutrient conditions; and the potentially pathogenic families B rucellaceae, Enterobacteriaceae and Vibrionaceae. Metabolisms over-represented include motility and chemotaxis, RNA metabolism and membrane transport, all of which are involved in actively searching for and obtaining nutrients. Also over-represented were metabolisms involved in population succession and stress response. An over-representation of taxa and metabolisms indicative of environmental change is reflective of anthropogenically af fected riverine input. In the hypersaline upper reaches of the estuary, the halophilic family Ectothiorhodospiraceae was over-represented, as were the families Flavobacteriaceae, Cytophagaceae and Nocardioidaceae, members of which are able to survive over a wide salinity range. Metabolisms over-represented here were reflective of increased bacterial growth, characteristic of hypersaline environments, and included DNA metabolism, nucleotide and nucleoside synthesis and cell cycle. Coorong metagenomes clustered taxonomically and metabolically with other planktonic metagenomes, but remained an outlier of this group with only 71% and 84% similarity, respectively. This indicates that the Coorong exhibits a unique planktonic bacterial community that is influenced by riverine input at the river mouth and salinity in the upper-reaches.     

Spatial and temporal variability of turbulent mixing in the near-field of the Changjiang River

Based on field hydrological,micro structural,and shipboard Acoustic Doppler Current Profiler data,we quantified the spatial and temporal variability of turbulent mixing in the near-field Changjiang(Yangtze) River plume.The surface dissipation rate(s) changed by three orders of magnitude from near-field(10~(-4) W/kg) to far-field(10~(-7) W/kg) plumes,indicating a decrease with distance from the river mouth.Below the river plume,ε changed with depth to 10~(-8) W/kg,and increased to 10~(-6) W/kg at the layer where the Taiwan Warm Current(TWC) intruded.Thus,ε in the near-field plume showed three layers:surface layer in the river plume,middle layer,and lower TWC layer.In the river plume,the strongest ε and turbulent diffusivity(Kz)were greater than 10~(-4) W/kg and 10~(-2) m~2/s,respectively,during strong ebb tides.A three-orders-of-magnitude change in ε and Kz was observed in the tidal cycle.The depth of the halocline changed with,tidal cycles,and stratification(N~2) varied by one order of magnitude.Stratification in the TWC layer followed the distribution of the halocline,which is opposite to the dissipation structure.Tidal currents led to intrusion and turbulent mixing in the TWC layer.During ebb tides,ε and Kz were as strong as those measured in the river plume,but did not last as long.The structure of the velocity shear was similar to the dissipation rate in both the river plume and TWC layer,whereas the velocity shear in the TWC layer did not match the stratification structure.In the high dissipation rate area,the gradient Richardson number was smaller than the critical value(Ri_g1/4).The Rig structure was consistent with shear and dissipation distributions,indicating that turbulent mixing in the near-field plume was controlled by a combination of shear induced by the discharged river flow and tidal current.     

以“3S”集成技术为基础的“LBS”极地应用研究

分析了极地环境特点,并根据极地的基本情况确定极地位置服务(LBS)的系统架构,详细介绍了在极地位置服务中所用到的技术内容及技术特点,主要包括车辆和人员的监控技术、基于PDA的定位技术及极地的通讯技术等.     

Alternative stable states in mountain forest ecosystems: the case of European larch(Larix decidua) forests in the western Alps

European larch(Larix decidua) forests of the western Alps form extensivecultural landscapes whose resilience to global changes is currently unknown. Resilience describes the capacity of ecological systems to maintain the same state, i.e., the same function, processes, structure, and composition despite disturbances, environmental changes and internal fluctuations. Our aim is to explore the resilience of larch forests to changes in climate and land use in the western Italian Alps.To do so, we examined whether larch forests can be described as an alternative stable state in mountain forest ecosystems. We used tree basal area data obtained from field forest inventories in combination with topography, forest structure, land use, and climate information. We applied three different probabilistic methods: frequency distributions, logistic regressions, and potential analyses to infer the resilience of larch forests relative to that of other forest types.We found patters indicative of alternative stable states: bimodality in the frequency distribution of the percent of larch basal area, and the presence of an unstable state, i.e., mixed larch forests, in the potential analyses. We also found:(1) high frequency ofpurelarchforestsathighelevation,(2)the probability of pure larch forests increased mostly with elevation, and(3) pure larch forests were a stable state in the upper montane and subalpine belts.Our study shows that the resilience of larch forests may increase with elevation, most likely due to the altitudinal effect on climate. Under the same climate conditions, land use seems to be the main factor governing the dominance of larch forests. In fact, subalpine larch forests may be more resilient, and natural succession after land abandonment, e.g., towards Pinuscembra forests, seems slower than in montane larch forests. In contrast, in the upper montane belt only intense land use regimes characterized by open canopies and forest grazing may maintain larch forests.We conclude that similar approaches could be applied in other forest ecosystems to infer the resilience of tree species.