共查询到20条相似文献,搜索用时 15 毫秒
1.
Water balance investigations in Svalbard 总被引:1,自引:0,他引:1
This paper reviews and summarizes all known previous water balance studies in Svalbard. An updated water balance computation was then done for the three water catchments with the best data: Bayelva, De Geerdalen and Isdammen/Endalen for 10 hydrological years 1990-2001. The computations were based on the best available data and correction methods. Special emphasis was put on correction of precipitation data, both for catch errors and gradients in precipitation. Areal precipitation in the three catchments is more than two times the measured precipitation at the closest meteorological station: 548 mm/year in De Geerdalen, 486 mm/year in Endalen/Isdammen and 890 mm/year in Bayelva. Compared to this, average measured precipitation is only 199 mm/year at Svalbard Airport, close to Endalen/Isdammen and De Geerdalen, and 426 mm/year in Ny-Ålesund, close to Bayelva. Evaporation is not well understood in Svalbard; the best estimates indicate an average annual evaporation of ca. 80 mm/year from glacier-free areas, and no net evaporation from glaciers. Glacial mass balance has in general been negative in Svalbard during the last 40 years, leading to a significant contribution to the water balance, on the order of 450 mm/year on average. Annual runoff ranges from 545 mm in Endalen/Isdammen, 539 mm/year in De Geerdalen up to 1050 mm/year in Bayelva. Runoff computed from water balance compares well with observed runoff, and average error in water balance is less than ±30 mm/year in all three catchments. 相似文献
2.
从北极斯瓦尔巴群岛冰川流域的上、中、下游采集了5种代表性土壤和冰川融水样品(MT、AT、TN、BT、MS),采用常规LB和严格无氮培养基低温培养方法,对其中的可培养细菌和潜在固氮细菌进行了总菌计数以及菌株的富集、分离与纯化。经菌落菌体形态观察、16S r RNA基因初步测序排重、固氮基因nif H的PCR检测,分别选取48株可培养分离细菌和31株潜在固氮菌进行了基于16S r RNA基因全序列测定的系统发育分析。目的是初步了解该特殊生境中可培养细菌(包括潜在固氮菌)的多样性及其分布状况,为进一步研究它们在此生境中的生态功能奠定基础。实验结果表明,可培养细菌在5个采集样品中的总菌数为BTTNATMT=MS,严格无氮培养基分离菌总菌数为BTATMTTNMS。48株可培养代表菌分属于Proteobacteria、Actinobacteria、Bacteroidetes、Firmicutes 4个门的7纲、14属之中,它们在5个样品中的多样性程度为BT(6纲、6属)MT(4纲、6属)AT、MS(均为3纲、3属)TN(2纲、3属),优势菌群主要分布在γ-proteobacteria纲的Pseudomonas属(20.8%,集中在AT、BT、MS样品中)和β-proteobacteria纲的Janthinobacterium属(35.4%,集中在MS样品中),表现出一定程度的系统发育多样性。潜在固氮菌实验结果表明,能在严格无氮培养基上生长且可检测到nif H的31株代表菌具有极为单一的系统发育多样性。其中90.32%菌株集中在γ-proteobacteria纲的Pseudomonas属,仅在MT和MS样品中有3株菌分布在α-proteobacteria纲的Rhizobium属、β-proteobacteria纲的Janthinobacterium属和Actinobacteria纲的Arthrobacter属,它们与分离自其他极端环境的相关标准菌株具有高度16S r RNA基因同源性。另外,本实验还发现有8株菌的16S r RNA基因序列与相关标准菌株的相似度低于98.50%,推测它们具有成为该特殊生境下新种的潜质。 相似文献
3.
John F. Shroder Michael P. Bishop Luke Copland & Valerie F. Sloan 《Geografiska Annaler: Series A, Physical Geography》2000,82(1):17-31
The origin and mobilization of the extensive debris cover associated with the glaciers of the Nanga Parbat Himalaya is complex. In this paper we propose a mechanism by which glaciers can form rock glaciers through inefficiency of sediment transfer from glacier ice to meltwater. Inefficient transfer is caused by various processes that promote plentiful sediment supply and decrease sediment transfer potential. Most debris‐covered glaciers on Nanga Parbat with higher velocities of movement and/ or efficient debris transfer mechanisms do not form rock glaciers, perhaps because debris is mobilized quickly and removed from such glacier systems. Those whose ice movement activity is lower and those where inefficient sediment transfer mechanisms allow plentiful debris to accumulate, can form classic rock glaciers. We document here with maps, satellite images, and field observations the probable evolution of part of a slow and inefficient ice glacier into a rock glacier at the margins of Sachen Glacier in c. 50 years, as well as several other examples that formed in a longer period of time. Sachen Glacier receives all of its nourishment from ice and snow avalanches from surrounding areas of high relief, but has low ice velocities and no efficient system of debris removal. Consequently it has a pronounced digitate terminus with four lobes that have moved outward from the lateral moraines as rock glaciers with prounced transverse ridges and furrows and steep fronts at the angle of repose. Raikot Glacier has a velocity five times higher than Sachen Glacier and a thick cover of rock debris at its terminus that is efficienctly removed. During the advance stage of the glacier since 1994, ice cliffs were exposed at the terminus, and an outbreak flood swept away much debris from its margins and terminus. Like the Sachen Glacier that it resembles, Shaigiri Glacier receives all its nourishment from ice and snow avalanches and has an extensive debris cover with steep margins close to the angle of repose. It has a high velocity similar to Raikot Glacier and catastrophic breakout floods have removed debris from its terminus twice in the recent past. In addition, the Shaigiri terminus blocked the Rupal River during the Little Ice Age and is presently being undercut and steepened by the river. With higher velocities and more efficient sediment transfer systems, neither the Raikot nor the Shaigiri form classic rock‐glacier morphologies. 相似文献
4.
5.
Glacier balance trends in the Kongsfjorden area, western Spitsbergen, Svalbard, in relation to the climate 总被引:2,自引:1,他引:2
Bernard Lefauconnier Jon Ove Hagen Jon Børre Ørbæk Kjetil Melvold Elisabeth Isaksson 《Polar research》1999,18(2):307-313
For the last thirty years, the mean net balance of two glaciers, Austre Brøggerbreen and Midre Lovénbreen, has been -0.43 and -0.34 m of water equivalent (w.e.). respectively. The mean net balance of Kongsvegen, a tidewater glacier that has been measured since 1987, is 0.11 m w.e. The negative balances of the two first glaciers are driven by the increase in atmospheric temperature which occurred at the end of the Little Ice Age at the beginning of the century. The positive balance of Kongsvegen is due to its higher elevation and larger accumulation area. There is no significant trend in the net balances and no increase of the melting has been detected during the last thirty years.
A correlation coefficient of R = 0.83 has been obtained between the net balance of Lovénbreen and the winter precipitation, together with the summer temperature recorded at the neighbouring station of Ny-Ålesund since 1969. With 14 years of data, the correlation coefficient between the net balance and climatic parameters does not increase consistently by introducing any radiation component, but the coefficient correlation between the summer balance of Austre Brøggerbreen and summer temperature increases from 0.68 to 0.77 when introducing global and long-wave radiation for July and August. Weather conditions and the frequency of their changes influence the balance between global and long-wave radiation and changes in albedo values. 相似文献
A correlation coefficient of R = 0.83 has been obtained between the net balance of Lovénbreen and the winter precipitation, together with the summer temperature recorded at the neighbouring station of Ny-Ålesund since 1969. With 14 years of data, the correlation coefficient between the net balance and climatic parameters does not increase consistently by introducing any radiation component, but the coefficient correlation between the summer balance of Austre Brøggerbreen and summer temperature increases from 0.68 to 0.77 when introducing global and long-wave radiation for July and August. Weather conditions and the frequency of their changes influence the balance between global and long-wave radiation and changes in albedo values. 相似文献
6.
I. Sobota 《Polar Science》2011,5(3):327-336
This study examines the mass balance, accumulation, melt, and near-surface ice thermal structure of Irenebreen, a 4.1 km2 glacier located in northwest Spitsbergen, Svalbard. Traditional glaciological mass balance measurements by stake readings and snow surveying have been conducted annually at the glacier since 2002, yielding a mean annual net mass balance of −65 cm w.e. for the period 2002–2009. In 2009, the annual mass balance of Irenebreen was −63 cm w.e. despite above-average snow accumulation in winter. The near-surface ice temperature in the accumulation area was investigated with automatic borehole thermistors. The mean annual surface ice temperatures (September–August) of the accumulation area were −3.7 °C at 1 m depth and −3.3 °C at 10 m depth. Irenebreen is potentially polythermal, with cold ice and a temperate surface layer during summer. This temperate surface layer is influenced by seasonal changes in temperature. In winter, the temperature of all the ice is below the melting point and temperate layers are probably present in basal sections of the glacier. This supposition is supported by the presence of icings in the forefield of Irenebreen. 相似文献
7.
滇池不同流域类型降雨径流对河流氮磷入湖总量的影响 总被引:20,自引:5,他引:20
通过对滇池三种不同流域类型的雨季初始期三场降雨径流的汇水河道的入湖口水质和流量监测 ,重点分析了典型城市纳污河流、城乡结合型河道和农业重污染区河道的营养盐携带状况与特征。研究结果表明 :不同流域类型河流的氮磷营养盐入湖总量受降雨过程及特征、流域类型特征、降雨径流流量、径流水营养盐浓度综合控制。城乡结合型河道 (大清河 )有最高的TP、KN (凯氏N)、NH3 N、NO3 N和NO2 N入湖总量 ,三场降雨累积量分别为11374 3、 12 7971 7、 85 36 5 4、 92 3 4和 84 1 2kg ;城市纳污河流 (乌龙河 )有最高的单位面积入湖总量负荷 ,TP、KN、NH3 N和NO2 N分别为 5 35 7、 5 86 0 5、 382 1 9和 2 4 6kg/km2 。 相似文献
8.
JON OVE HAGEN 《Polar research》1988,6(2):205-209
Storbreen in southern Norway has been measured continuously since 1949. The mean specific net balance -0.29 m water equivalents. In 1987, however, the net balance was 0.32 m, which is the highest surplus in twenty years. The results of the whole period are given in Table 1
In Svalbard the summer of 1987 was unusually cold, which resulted in the first year with positive net balance on Brøggerbreen and Lovénbreen since the measurements started in 1968, The net balance was 0.22 m and 0.24 m, respectively, while the average is -0.43 m and -0.34 m.
Measurements at Kongsvegen in the inner part of Kongsfjorden started in 1987. The work was concentrated along the central flow line. The result was a positive net balance of 0.50 m. 相似文献
In Svalbard the summer of 1987 was unusually cold, which resulted in the first year with positive net balance on Brøggerbreen and Lovénbreen since the measurements started in 1968, The net balance was 0.22 m and 0.24 m, respectively, while the average is -0.43 m and -0.34 m.
Measurements at Kongsvegen in the inner part of Kongsfjorden started in 1987. The work was concentrated along the central flow line. The result was a positive net balance of 0.50 m. 相似文献
9.
《极地研究》2002,13(1):67-74
This paper describes the Auroral Station in Adventdalen near Longyearbyen, Svalbard (78°N, 15°E). The main instruments at the site are for optical observation of aurora and airglow, but magnetic and radar observations are also carried out. Emission spectra show the difference between the dayside and nightside optical aurora. A newly compiled mesospheric temperature series from the station is also presented, derived through 20 years of spectral measurements of the hydroxyl airglow layer. 相似文献
10.
As in previous years Norsk Polarinstitutt has carried out mass balance investigations on Storbreen and Hardangerjøkulen in mainland Norway and on Broggerbreen and Lovenbreen in Svalbard. More than 20 years of measurements show that the glaciers both in mainland Norway and in Svalbard are retreating.
Both in 1985 and in 1986 the glaciers in Norway had a negative net balance. At Storbreen the mean annual net balance value 1949-86 is -0.30 m in water equivalents, while on Hardangerjflkulen the mean value 1963-86 is -0.02 m.
The two glaciers measured in Svalbard also had negative net balance in 1985 and in 1986. Both measured glaciers have had negative balance nearly all years since the measurements started in 1966. The mean value is close to -40g/cm2 or -0.4 m on both. 相似文献
Both in 1985 and in 1986 the glaciers in Norway had a negative net balance. At Storbreen the mean annual net balance value 1949-86 is -0.30 m in water equivalents, while on Hardangerjflkulen the mean value 1963-86 is -0.02 m.
The two glaciers measured in Svalbard also had negative net balance in 1985 and in 1986. Both measured glaciers have had negative balance nearly all years since the measurements started in 1966. The mean value is close to -40g/cm
11.
Late Holocene palaeoceanography in Van Mijenfjorden, Svalbard 总被引:2,自引:0,他引:2
Based on detailed stratigraphical analysis of sediment cores spanning the last ca. 4000 calendar years, we reconstruct the palaeoceanograhic changes in the fiord Van Mijenfjorden, western Svalbard. Benthic foraminiferal δ18 O indicate a gradual reduction in bottom water salinities between 2200 BC and 500 BC. This reduction was probably mainly a function of reduced inflow of oceanic water to the fiord, due to isostatic shallowing of the outer fiord sill. Stable salinity conditions prevailed between 500 BC and. 1300 AD. After the onset of a major glacial surge of the tidewater Paulabreen (Paula Glacier) system (PGS) around 1300 AD, there was a foraminiferal faunal change towards glacier proximal conditions, associated with a slight bottom water salinity depletion. During a series of glacial surges occuring from 1300 AD up the present salinity in the fiord has further decreased, corresponding to a δ18 O depletion of 0.5 %o. This salinity decrease corresponds to the period when the PGS lost an equivalent of 30 – 40 % of its present ice volume, mainly through calving in the fiord. 相似文献
12.
Erosion and sediment transport in High Arctic rivers, Svalbard 总被引:2,自引:0,他引:2
This paper discusses sediment yield, sediment delivery and processes of erosion in rivers subject to High Arctic conditions in Svalbard. Long-term measurements reveal large variations between rivers and from year to year in each individual river. In the unglacierized catchment of Londonelva, annual sediment transport varied between 28 and 93 t/yr, with a mean sediment yield of 82.5 t/km2 /yr. In the glacier-fed rivers Bayelva and Endalselva, the suspended sediment transport varied in the range of 5126 t/yr to 22797 t/yr during a 12-year period. A mean of 11 104 t/yr gave rise to a mean sediment yield of 359 t/km2 /yr for the whole Bayelva catchment area. The sediment yield of the glacier and the moraine area was estimated at 586 t/km2 /yr. A conceptual model used to interpret the long- and short-term patterns of sediment concentration in the meltwater from the glacier and erosion of the neoglacial moraines is proposed. Evidence is found that a proportion of the sediments are delivered by a network of englacial and subglacial channels that exist even in cold ice. Regression analyses of water discharge versus suspended sediment concentration gave significant correlations found to be associated with the stability of ice tunnels in cold ice. Large floods have been found to flush the waterways and exhaust the sediment sources. A long-term change in the exponent of regression lines is attributed to changes in sediment availability caused by flushing and expansion of tunnels and waterways by large floods and a subsequent slow deformation of them caused by the ice overburden and the glacier movement. A comparison of sediment yields from a number of polythermal and temperate glaciers in various areas showed large differences that were attributed primarily to bedrock susceptibility to erosion and, secondarily, to glaciological parameters. 相似文献
13.
14.
A survey of the regional snow accumulation variability on Spitsbergen, Svalbard, was carried out during three field campaigns in May 1997. The survey was carried out along three transects from west-to-east approcimately at the following latitudes: 77°30', 78° and 78°50'degrees north. The altitudes span from sea level to 1000 metres elevation. Snow depth was measured with two different ground-penetrating radar systems, PulsEKKO (450 MHz) and GSSI SIR System-2 (500 MHz), pulled behind snow machines. Snow characteristics such as snow temperature, snow density and stratigraphy were measured in snow pits in nine areas, three along each transect. Our data suggest the following: (1)the accumulation-elevation gradients vary from 3 mm/100 m in the northeast to 237 mm/100 min the central-south with an average value of 104 mm/100m for all measurements: (2)snow accumulation was 38 to 49% higher at the eastern coast than at the western coast; (3) a clear minimum in accumulation (or continental climate) is seen for the central (inland) locations in the middle and northern transects while no such minimum exists along the southern transect; (4) a south-to-north gradient produces 55% and 40% less snow accumulation at the northern locations compared to the southern locations at the western and eastern coasts, respectively. These drops in winter snow accumulation occur over a distance of less than 200 km. 相似文献
15.
Holocene lithified sediments of glacial and glaciofluvial origin have been found in environments where carbonate cementation is a present-day process. The rocks occur as well cemented tillites, conglomerates, coarse sandstones and breccias, indicating a complex depositional pattern within a limited area. Both clasts and carbonate cement are mainly derived from underlying Carboniferous and Permian sequences which form the bedrock of this area. 相似文献
16.
The note informs about a new warm spring west of Jotunkjeldene with larger water discharge and much less sinter deposits than the other springs in Bockfjorden. 相似文献
17.
Recent karst forms in gypsiferous beds are reported from Mathiesondalen in Central Spitsbergen, where several sinkholes (dolines) and swallow holes have been formed after the deposition of Holocene raised beach sediments. The bedrock of the area is mostly interbedded gypsum/anhydrite and dolomites of the Carboniferous Ebbadalen Formation. 相似文献
18.
This year is a kind of anniversary for the Norwegian Polar Institute: its establishment can be traced back to Svalbard expeditions sponsored by Prince Albert I of Monaco in 1906 and 1907. In this unreviewed biographical article, biologist Eva Fuglei, who has spent many seasons on Spitsbergen (where her research has focused on Arctic foxes), and the editor describe part of the uncommon life of botanist Hanna Marie Resvoll-Holmsen, who participated in the 1907 expedition. 相似文献
19.
P.G. Appleby E.Y. Haworth H. Michel D.B. Short G. Laptev G.T. Piliposian 《Journal of Paleolimnology》2003,29(4):459-473
Although lake sediment archives are widely used for reconstructing historical records of atmospherically delivered pollutants, the quantitative relationship between fallout levels and their record in the sediments is complex and not well known. The original input signal from the atmosphere can be significantly distorted by mediating transport processes in the catchment, through the water column and within the sediments themselves. Since these processes also affect the fallout radionuclide 210Pb commonly used to date sediments, a better understanding of their impact is also important to improving the accuracy and reliability of sediment dating. Blelham Tarn has been the subject of a number of palaeolimnological investigations using radiometric dating techniques since the early 1970s. More recently it was the site of a major study carried out within the EU Transuranics project concerning the long-term fate of fallout radionuclides in catchment/lake systems. This paper reviews the radiometric data from this study and uses the results to determine mass balances for fallout 210Pb, 137Cs and 239+240Pu in Blelham Tarn, and their spatial distribution over the bed of the lake. Atmospheric fluxes were determined by measuring concentrations in rainwater and cumulative inventories in soil cores from non-eroding sites. Sediment records in a grid of 16 cores were used to determine the spatial distribution over the bed of the lake, and net inputs from the catchment. Mass balance calculations indicate that c. 47% of 210Pb in the sediments derives from erosive inputs from the catchment. For 239+240Pu the figure rises to 61%. Reduced amounts of 137Cs in the sediments are attributed to greater losses of this radionuclide from the water column via the outflow due to its greater solubility. Inputs of radionuclides from the catchment are concentrated near one of the major input streams. Away from this part of the lake the sediment record is dominated by direct atmospheric fallout, though the detailed pattern is influenced by sediment focussing. A one parameter catchment/lake transport model is developed that incorporates the assumption that transport rates will decline with time as fallout on the catchment diffuses into the soil and becomes less available for removal. Values of the transport parameter were calculated for 210Pb and 239+240Pu and found to be comparable. The results suggest that it will take c. 11000 years to remove 50% of 239+240Pu from the catchment to the lake. 相似文献
20.
Permafrost in Svalbard: a review of research history, climatic background and engineering challenges 总被引:3,自引:0,他引:3
This paper reviews permafrost in High Arctic Svalbard, including past and current research, climatic background, how permafrost is affected by climatic change, typical permafrost landforms and how changes in Svalbard permafrost may impact natural and human systems. Information on active layer dynamics, permafrost and ground ice characteristics and selected periglacial features is summarized from the recent literature and from unpublished data by the authors. Permafrost thickness ranges from less than 100 m near the coasts to more than 500 m in the highlands. Ground ice is present as rock glaciers, as ice-cored moraines, buried glacial ice, and in pingos and ice wedges in major valleys. Engineering problems of thaw-settlement and frost-heave are described, and the implications for road design and construction in Svalbard permafrost areas are discussed. 相似文献