Thermal regime of a valley glacier, Erikbreen, northern Spitsbergen

The thermal regime of the valley glacier, Erikbreen, northern Spitsbergen (79°40'N, 12°30'E) was studied using radio-echo sounding and temperature measurements from eight boreholes ranging from 13.5 to 24 m. Radar images indicate a glacier with a two-layered thermal structure. A surface layer of cold ice, 20 to 60 m thick along the centre flow line, extends from an altitude above equilibrium line to the glacier front. This layer represents 20 to 35% of the glacier thickness, except at the floating front, where the cold layer is about 50%. The ice beneath the cold surface layer is interpreted to be temperate. Cold-based areas exist near the glacier margin and in some locations in the accumulation area; the ice is interpreted to be entirely temperate in central parts of the accumulation area at high altitude. Freezing of temperate ice at the base of the cold surface layer is probably the main mechanism of cold ice formation in the frontal parts of Erikbreen. Calculated heat fluxes based on the borehole measurements show that a steady state cold layer 25 to 30 m thick is likely, assuming a surface melting of 1.7 m/y and a maximum water content of 3%. In the frontal parts the calculated mean annual upward heat flux at 10 to 15 m depth is roughly 0.6 W/m².     

Structure and heat content of the West Spitsbergen Current

The seasonal evolution of the hydrographic structure of the West Spitsbergen Current (WSC) above bottom depths from 300 m to 800 m is discussed based on a modern data set with high spatial resolution. The WSC appears to have a core with high temperature and salinity, linked to the topography in this depth interval, with a width on the order of 10 km. Strong cooling occurs in the autumn, reducing the heat content of the upper 200 m, but advected temperature and salinity maxima survive close to the surface in spring when air-sea exchange and vertical mixing is hampered by sea ice and meltwater.     

泥石流的阵性波状运动

首先描述了在云南东川蒋家沟观测到的在粘性泥石流运动过程中的铺床作用，阵次交替的波状运动，以及相关的波的分化、叠加等现象。然后具体分析了阵性波不同部分的速度分布特征，给出了泥石流龙身部分的速度剖面示意图，并提出龙头是以滚动方式在残留层上运动的。两者间存在物质循环流动。由实测数据推算的波速表明阵性波是一种急流。最后从波的空间形态和传播速度的角度将泥石流的波状运动分为缓波、滚动短波和滚动长波。     

The influence of subtropical cold fronts on the surface energy balance of a semi-arid site

The passage of subtropical cold fronts through central Australia produces the only significant mesoscale meteorological features in the region. The interaction of these cold fronts with the surface energy balance strongly affects the local weather and climate. The surface energy balance was measured at a semi-arid site in Alice Springs, central Australia, to determine how it was influenced by the passage of subtropical cold fronts. Both Bowen ratio and eddy correlation methods were used. The daytime energy balance of the site showed high net radiation that was partitioned into 75% sensible heat flux and 25% soil heat flux with little or no latent heat flux. At night there was a large net radiative loss that was balanced primarily by a loss of heat from the soil. The cold fronts predominately passed through Alice Springs at night and showed a strong surface signature. The fronts brought moister air resulting in higher water vapour pressures during their passage. The nocturnal boundary layer was often disturbed as the front passed, resulting in warm, moist air being mixed down toward the land surface. Mixing decreased the soil heat flux and increased latent heat fluxes toward the surface. Moisture that accumulated at the surface at these times was often evaporated after a return to drier conditions. During the daytime, surface signatures in soil and sensible heat fluxes were less distinct due to the strong convective mixing. Latent heat fluxes followed a similar trend to the nocturnal case.     

Glaciomarine sedimentation in a modern fjord environment, Spitsbergen

By means of high resolution acoustic profiling and correlation of echo character and sediment lithology, fjords in western and northern Spitsbergen are shown to be blanketed by a 5-20 m layer of acoustically transparent sediments consisting mainly of soft homogeneous mud with ice rafted clasts. Acoustically semi-transparent material is found on slopes and sills reflecting their coarser composition. The areal average depositional rate in the outer fjord is in the range of from 0.1 to 1.0 mm/year, increasing towards the glaciers. In Kongsfjorden, 50-100 mm/year of muddy sediments is deposited at a distance of 10 km from the calving Kongsvegen glacier. Close to the ice front (<0.5 km) coarser grained, interbedded (sand/mud) sediments are deposited. The main sediment sources are from settlement out of the turbid surface sediment plume, combined with various types of gravity flow (sediment creep, minor slides, and slumping). Material deposited from turbidity current is probably of minor importance. On shallow sills the sediments are remobilized by icebergs. The sediment adjacent to the ice front is reworked and compacted during surges, a common form of glacial advance for Spitsbergen glaciers. During the surge considerable amounts of coarse-grained sediment are deposited by meltwater in front of the ice margin.     

Coastal cliff temperatures related to the potential for cryogenic weathering processes, western Spitsbergen, Svalbard

The main purpose of this research was to measure the near surface ground temperatures and describe the main characteristics of the thermal regime of a sheltered arctic coastal cliff. Measurements were made near Ny-Alesund, western Spitsbergen, Svalbard (79°N, 12°E), in a transect across sediments on top of a coastal cliff, in a 8 m high coastal cliff and across the beach below the cliff. Temperatures were logged hourly from August 1987 to August 1988. A local snow cover of 1–4 m on the beach had a strong influence on surface heat exchange, and hence the dynamics of the ground thermal regime. Late winter temperatures in the cliff and backshore sediments were stable and ranged from -5°C to -9°C. At the first snow melt events in spring there was a large heat flux into the ground due to the release of latent heat from refreezing of meltwater. The interpretation of the temperature records leads to a discussion on some aspects of cryogenic weathering. The snow-melt period in spring and summer may be a period of rock fracturing, based on the model of segregation ice growth at subzero temperatures. Steep temperature gradients and available meltwater at the surface favor water migration in the heavily fractured dolomitic limestone even at the low hydraulic conductivities expected at below zero temperatures.     

Northward cooling and freshening of the warm core of the West Spitsbergen Current

The narrow slope-confined warm core of the West Spitsbergen Current (WSC) is a major pathway for warm and saline Atlantic Water to enter the Arctic Ocean. Long-term mean northward cooling and freshening rates in the warm core of the WSC are calculated with error ranges, and heat loss estimates are derived. The observed combination of cooling and freshening is not consistent with a hypothesis of pure isopycnal offshore mixing, but rather suggests influence from diapycnal mixing connected, for example, to exchange with shelf waters.     

长江源区五道梁的土壤热状况研究

活动层土壤热状况是寒区陆面物理过程研究的重要内容之一。利用五道梁能量收支观测站1993年9月～2000年12月份实测辐射及土壤热通量资料结合五道梁气象站1961-2010时段的气象资料分析了近50 a来该地区活动层土壤的热状况。结果表明：五道梁地区土壤热通量有显著的年际、年代际变化;20世纪60～80年代,土壤热通量小于0.0 W/m²,活动层土壤以放热为主,自90年代以来,土壤热通量大于0.0 W/m²,活动层土壤以吸热为主。过去50 a中该地土壤热通量呈现增大趋势,平均每10 a土壤热通量增大0.31 W/m²。土壤热通量随净辐射的增大而增大。土壤热平衡系数的变化特点与土壤热通量的变化特点一致。60～80年代,活动层土壤热平衡系数<1,该地区冻土相对比较稳定,而自90年代以来此间土壤热平衡系数<1,表明该地多年冻土呈现出退化迹象。活动层土壤热平衡系数可表示为气温、地表温度及水汽压的函数。     

海拔梯度及典型土地利用类型对北热带山地土壤有机质和综合肥力的影响

为深入了解北热带海拔梯度各山地土壤带及典型土地利用类型（次生林、香蕉园、橡胶林）土壤有机质（SOM）、综合肥力（SIF）分布特征,以云南省金平县蝴蝶谷地区为例,区分表层（0～20 cm）和亚表层（20～40 cm）,测定SOM、pH、全氮、全磷、全钾和速效氮磷钾,采用修正内梅罗指数法评价SIF,分析限制SIF的关键因素。结果表明,研究区海拔与SOM、SIF呈显著正相关,6个山地土壤带表层和亚表层SOM、SIF排序为棕壤带>黄棕壤带>黄壤带>红壤带>赤红壤带>砖红壤带（P<0.05）。无论表层还是亚表层,SOM和SIF均以次生林最大,香蕉园次之,橡胶林最小,次生林SOM显著大于香蕉园和橡胶林（P<0.05）,SIF则无显著差异。随着海拔升高,限制SIF的因素由速效氮、速效磷转变为速效磷和速效钾,且pH的限制逐渐加强,而维持和限制低海拔不同土地利用类型SIF的因素与同海拔段内自然土壤基本一致。未来山地开发利用过程中低海拔区域应该注重补充氮肥和磷肥,中高海拔区域注重补充磷肥和钾肥,同时调节适宜的pH更有助于土壤养分释放和植物吸收利用。综上,海拔梯度和...     

Heavy metals in water, ice and biological material from Spitsbergen, Svalbard

Concentrations of heavy metals Zn, Mn, Cu, Fe, Ni, Cr, Pb, Cd, Hg and Co were determined in surface waters, glacier ice and plant and animal materials from three regions in Spitsbergen, Svalbard. The concentrations of these metals in two samples of surface waters and in the vascular plants from Spitsbergen were found to be lower than what is commonly found in Cental Europe. Elevated concentrations were found in old ice from the surface of a glacier. The concentrations of heavy metals in algae were lower than in vascular plants. The concentrations of metals in the samples of feathers and animal hair from Spitsbergen were higher than what is common for Central Europe.     

荒漠下垫面陆面过程和大气边界层相互作用敏感性实验

建立了一个研究荒漠下垫面陆面物理过程与大气边界层相互作用的模式. 模拟了荒漠下垫面的土壤环境物理、地面热量通量、蒸发、蒸散及大气边界层结构特征.并对主要的环境物理参数进行了敏感性实验.结果表明,本模式能合理地模拟荒漠下垫面地表热量平衡、土壤体积含水量、地表植被蒸发散阻抗、地表水汽通量日变化和湍流交换系数、湍流动能、位温和比湿廓线等.该模式还可进一步应用于研究区域陆面物理过程与大气边界层相互作用机制,及与中尺度大气模式耦合用于区域环境生态和气候的研究.     

Volume, heat and salt transport by the West Spitsbergen Current

During the summer of 2000 (June-July) 14 CTD and ADCP transects perpendicular to the West Spitsbergen Current and along the western border of the Barents Sea were made. The measurements covered the area between 69° 43'and 80° N and 01° and 20° E. The main purpose was to follow changes in volume, heat and salt content of Atlantic Water (AW) on its way north. The strongest and most stable flow of AW was located along the continental slope where northward flowing currents exceeding 40 cm/sec were measured. A few weaker northward branches were also found to the west of the slope. South-directed currents were recorded between them and eddy-like mesoscale structures were commonly observed. Measured by vessel-mounted acoustic Doppler current profiler (VM-ADCP), the net northward transport of AW volume in the upper 136 m layer decreased from nearly 6 Sv at the southernmost transect to below 1 Sv at a latitude of 78° 50'N. Similarly, heat transport drops from about 173 TW to about 9 TW and relative salt transport (over 34.92 psu) from 980 × 10³ kg/sec to 14 × 10³ kg/sec. Transport in the southern direction prevails at the transect located between 79° 07'and 79° 30'N. The calculated baroclinic geostrophic transport of AW volume, heat and salt in the upper 1000 m layer behaves similarly. East-directed transport dominates at the Barents Sea boundary while westward flow prevails on the western side of the West Spitsbergen Current.     

Three-dimensional restoration of original sedimentary geometries in deformed basin fill, onshore Brunei Darussalam, NW Borneo

The western flank of the Jerudong Anticline, onshore Brunei Darussalam, provides a rare opportunity to analyse the base of a major Miocene mud‐rich delta in outcrop, including kilometre‐scale prograding clinoforms, delta‐front turbidites and large‐scale syndepositional faults. The lateral continuation of this system in the subsurface of the Belait Syncline is documented on two‐dimensional (2D) reflection seismic data and wireline logs. In order to link geological observations at surface with corresponding geophysical subsurface signatures, we constructed a combined, quantitative 3D surface–subsurface model of onshore Brunei Darussalam. This 3D model is used to analyse and discuss the relation between field geology and geophysical subsurface interpretation, and provides the base for a quantitative kinematic restoration of the Miocene Belait delta to its original shape before folding. Final decompaction of the balanced rock volume allows the reconstruction of the palaeo‐relief of a series of Miocene clinoforms, indicating a close relation between delta‐lobe activity, clinoform morphology and the generation of delta‐front turbidites.     

陆面过程模型CoLM与BATS1e的模拟精度比较——以东北玉米农田为例

利用2008年锦州玉米农田生态系统野外观测站资料对CoLM与BATS1e模型模拟能力进行定量评价。比较发现： 两模型对净辐射和表层土壤温度的模拟精度都较高且差异不大,CoLM模型对感热、潜热、土壤热通量、次表层土壤温度模拟能力都不同程度高于BATS1e模型,模拟值对实测值解释能力分别偏高3%、22%、1%、10%,NS (Nash-sutcliffe效率系数)分别偏高1.042、0.266、0.023、0.138。从各月情况看,两模型在7月对感热、潜热模拟能力都较高,而在其它月份CoLM模型模拟精度明显高于BATS1e模型,土壤热通量和次表层土壤温度在5~8月前者模拟精度高于后者。由于CoLM模型对潜热更高精度的模拟可证明其对表层土壤湿度模拟精度高于BATS1e模型。     

古尔班通古特沙漠的辐射热量交换分析

位于新疆准噶尔盆地的古尔班通古特沙漠是我国第二大沙漠。根据古尔班通古特沙漠的自然条件,对不同下垫面区域的太阳短波辐射和大气长波辐射热量进行了测量。结果表明:在晴天状况下,流动沙丘和固定沙丘的热量交换差异主要是由地表状况、沙层性质和气温等因素决定的。流动沙丘区反射率与长波辐射大于固定沙丘区,并且日、季变化明显。长波最大辐射值出现在午后,近似于太阳总辐射,最小值出现在日出前;沙层热通量随着深度的增加而增大,而辐射热量传输则随其深度的增加而减小,无论是流动沙层还是固定沙层,其热通量的零界面深度却基本一致(9月份),均在30~35cm之间。根据上述结果,本文还讨论了沙漠区在热量交换过程中,辐射热量差异引起的沙漠小气候效应和沙漠对区域气候的反馈作用。     

Structural development of the Tertiary fold-and-thrust belt in east Oscar II Land, Spitsbergen

The Tertiary deformation in east Oscar II Land, Spitsbergen, is compressional and thin-skinned, and includes thrusts with ramp-flat geometry and associated fault-bend and fault-propagation folds. The thrust front in the Mediumfjellct-Lappdalen area consists of intensely deformed Paleozoic and Mesozoic rocks thrust on top of subhorizontal Mesozoic rocks to the east. The thrust front represents a complex frontal ramp duplex in which most of the eastward displacement is transferred from sole thrusts in the Permian and probably Carboniferous strata to roof thrusts in the Triassic sequence. The internal geometries in the thrust front suggest a complex kinematic development involving not only simple 'piggy-back', in-sequencc thrusting, but also overstep as well as out-of-sequence thrusting. The position of the thrust front and across-strike variation in structural character in east Oscar II Land is interpreted to be controlled by lithological (facies) variations and/or pre-existing structures, at depth, possibly cxtensional faults associated with the Carboniferous graben system.     

Soil thermal properties and heat transfer processes near Ny-Alesund, northwestern Spitsbergen, Svalbard

The annually thawing active layer of permafrost is central to considerations of climate change consequences in arctic areas and interpretations of deep permafrost temperatures that constitute and exceptional archive of past climate change. Moreover, a sound understanding of the thermal regime of the active layer is of great interest, because all chemical, biological and physical processes are concentrated there. The author studied this layer by examining the soil physical properties and heat transfer processes that dictate soil temperatures for an arctic desert site in northwestern Spitsbergen. A wide array of soil physical properties based on field observations and laboratory measurements were defined. These include mineralogy, grain size distribution, local regolith thickness, porosity, density, typical soil moisture profile, heat capacity and thermal conductivity. Heat transfer processes were studied through modeling of soil temperatures. The heat transfer model accounted for much of the observed soil thermal regime. It was found that thermal conduction, phase change of soil water at 0°C, and changes in unfrozen water content are the primary thermal processes that explain the observed soil temperatues in this field site. Melt-water infiltration, which is often overlooked in the energy budget, causes abrupt warming events and delivers considerable energy to the soil in late spring. An increase in frequency or magnitude of infiltration events could mimic simple spring time surface warming. Advection of ground water and soil internal evaporation were found to be generally unimportant at the site studied.     

The Storfjorden polynya: ERS-2 SAR observations and overview

Persistent polynyas have been observed over several winters in Storfjorden, situated between Spitsbergen and Barentsøya/Edgeøya in the south of the Svalbard archipelago. Polynyas are in general active regions with respect to ocean-atmosphere heat exchange, presenting strong convection phenomena and as such being involved in important water mass formation and having an impact on the marine ecosystem. Hydrographic observations have revealed very dense (cold and saline) brine-enriched bottom waters leaving the continental shelf as gravity driven plumes into the deep sea west of Spitsbergen. Satellite observations, using ERS-2 SAR imagery, reveal the evolution of the Storfjorden polynya during winter 1997/98. After forming a complete ice cover until mid-January, Storfjorden responds dynamically to northerly winds by opening a large latent heat polynya. It occupies at its largest extent a region of up to 6000 km² of open water, thin ice and brash ice. Comparable in size to other large Arctic polynyas, the Storfjorden polynya might have the same or even greater importance in the thermohaline circulation and bottom water mass formation. Ice production is estimated at 30 km³ in Storfjorden, rejecting around 700 Mt (Megatons) of salt that can raise the salinity in Storfjorden by 0.9-1.0 PSU. First studies and the winter 1997/98 evolution of this polynya are presented in this paper.     

Analysis about the influence on the thermal regime in permafrost regions with different underlying surfaces

In the last several decades, the underlying surface conditions on the Qinghai-Tibet Plateau have changed dramatically, causing permafrost degradation due to climate change and human activities. This change severely influenced the cold regions environment and engineering infrastructure built above permafrost. Permafrost is a product of the interaction between the atmosphere and the ground. The formation and change of permafrost are determined by the energy exchange between earth and atmosphere system. Fieldwork was performed in order to learn how land surface change influenced the thermal regime in permafrost regions. In this article, the field data observed in the Fenghuo Mountain regions was used to analyze the thermal conditions under different underlying surfaces on the Qinghai-Tibet Plateau. Results show that underlying surface change may alter the primary energy balance and the thermal conditions of permafrost. The thermal flux in the permafrost regions is also changed, resulting in rising upper soil temperature and thickening active layer. Vegetation could prevent solar radiation from entering the ground, cooling the ground in the warm season. Also, vegetation has heat insulation and heat preservation functions related to the ground surface and may keep the permafrost stable. Plots covered with black plastic film have higher temperatures compared with plots covered by natural vegetation. The reason is that black plastic film has a low albedo, which could increase the absorbed solar radiation, and also decrease evapotranspiration. The ＂greenhouse effect＂ of transparent plastic film might effectively reduce the emission of long-wave radiation from the surface, decreasing heat loss from the earth＇s surface, and prominently increasing ground surface temperature.     

黄河下游冲积平原潮土土壤孔隙微形态特征

土壤颗粒排列是影响孔隙特征的最基本因素。土壤薄片能够直接观察且定量的分析土壤孔隙特征。为了解不同质地土壤的孔隙差异,于山东省东昌府区采集不同质地土壤（壤土、黏壤土、砂质壤土）,通过常规方法和土壤微形态技术对比分析土壤孔隙特征。结果表明：三类样地土壤孔隙度均为表层向下逐渐减少。表层、底层差异在砂质壤土中主要体现于总孔隙度与毛管孔隙度,黏壤土、壤土则主要体现为总孔隙度与非毛管孔隙度。砂质壤土中各土层均以简单堆集孔隙为主;而0~10 cm黏壤土、壤土以复合堆积孔隙为主,其下复合堆积孔隙减少、其他形状孔隙增多。薄片图像测定孔隙数量可反映常规分析总孔隙度的50%左右,对于非毛管孔隙度则可反映80%左右。因此,土壤薄片更适合分析土壤非毛管孔隙。