iceberg calving flux and mass balance of the austfonna ice cap on nordaustlandet svalbard 1 satellite radar interferometry 60 mhz airborne ice penetrating radar data and visible band satellite imagery were used to calculate the velocity structure ice thickness and the changing ice marginal extent of austfonna 8000 km2 and 2500 km3 the largest ice cap in the eurasian arctic ice cap motion is generally less than about 10 m a 1 except where faster flowing curvilinear features with velocities of several tens to over 200 m a 1 are present most drainage basins of austfonna have undergone ice marginal retreat over the past few decades at an average of a few tens of meters per year integrating margin change around the whole ice cap gives a total area loss of about 10 km2 a 1 iceberg flux from the marine margins of austfonna is about 2 5 0 5 km3 a 1 water equivalent about 45 of the total calving flux from the whole svalbard archipelago when mass loss by iceberg production is taken into account the total mass balance of austfonna is negative by between about 2 5 and 4 5 km3 a 1 this iceberg flux represents about 33 5 of total annual mass loss from austfonna with the remainder lost through surface ablation iceberg flux should be included in calculations of the total mass balance of the many large arctic ice caps including those located in the russian and canadian arctic that end in tidewater the neglect of this term has led to underestimates of mass loss from these ice caps and thus to underestimates of the contribution of arctic ice caps to global sea level rise

glaciological applications with landsat 7 imagery early assessments enhanced thematic mapper plus etm data from landsat 7 are providing glaciologists with an ever expanding data set that makes a comprehensive monitoring of the global cryosphere feasible for the first time in history examples of etm data illustrate its ability to satisfy major scientific needs in the glaciological subdisciplines of sea ice glacier ice cap and ice sheet research with high resolution optical satellite imagery examples shown include use as proxy ground truth positioning glacier termini and snowlines and determining snow facies boundaries the additional etm panchromatic band at a higher spatial resolution of 15 m improves the spatial accuracy of these applications the glaciological aspects of the landsat 7 long term acquisition plan are discussed to show how the timing and location of the image acquisitions will generate a cryospheric data set of unprecedented utility for future research

decorrelation in interferometric radar echoes a radar interferometric technique for topographic mapping of surfaces implemented utilizing a single synthetic aperture radar sar system in a nearly repeating orbit is discussed the authors characterize the various sources contributing to the echo correlation statistics and isolate the term which most closely describes surficial change they then examine the application of this approach to topographic mapping of vegetated surfaces which may be expected to possess varying backscatter over time it is found that there is decorrelation increasing with time but that digital terrain model generation remains feasible the authors present such a map of a forested area in oregon which also includes some nearly unvegetated lava flows such a technique could provide a global digital terrain map

the oleananes origin maturation and limits of occurence in southern nigeria sedimentary basins oleananes occur within well defined age and paleogeographic boundaries in the sedimentary province of southern nigeria thus signifying that the biomarkers may be analogous to index fossils in anambra syncline lower benue trough the biomarkers are found in rocks which are as old as late upper cretaceous in tertiary niger delta the concentration composition and distribution of the oleananes in rocks and oils are determined mainly by palaeodepositional environment and thermal history and are independent of age and geographical location of specific samples oleanane content varies with increasing burial depth with peak concentration coinciding within rm range 0 4 0 6 implying early generation of hydrocarbons from the basin s typically resin rich kerogens it is evident that the oleanane content parameter is superior to the hopane and sterane isomerisation indices for monitoring thermal maturation in the delta and for differentiating paralic from paralic marine source facies as well as early from late generated oils

observations of ice sheet motion in greenland using satellite radar interferometry we present interferometric observations of ice sheet motion in western greenland based on pairs of ers 1 synthetic aperture radar sar images these observations provide the first detailed regional view of ice motion associated with dynamically supported topography near the margin of an ice sheet the interferograms of this area are much more complicated than other interferograms of ice sheets presented to date we devote the largest part of this paper to explaining the source of the complexity in these interferograms a synthetic interferogram based on a simple model helps to illustrate the effects of different components of the ice velocity field in interferometric data and suggests a method for estimating the large scale ice velocity field from such data

satellite radar interferometry for monitoring ice sheet motion application to an antarctic ice stream satellite radar interferometry sri provides a sensitive means of monitoring the flow velocities and grounding line positions of ice streams which are indicators of response of the ice sheets to climatic change or internal instability the detection limit is about 1 5 millimeters for vertical motions and about 4 millimeters for horizontal motions in the radar beam direction the grounding line detected by tidal motions where the ice goes afloat can be mapped at a resolution of 0 5 kilometer the sri velocities and grounding line of the rutford ice stream antarctica agree fairly well with earlier ground based data the combined use of sri and other satellite methods is expected to provide data that will enhance the understanding of ice stream mechanics and help make possible the prediction of ice sheet behavior

the duration of the active phase on surge type glaciers contrasts between svalbard and other regions many glaciers in svalbard and in other glacierized areas of the world are known to surge however the time series of observations required to assess the duration of fast motion is very restricted data on active phase duration in svalbard come from aerial photographs satellite imagery field surveys and airborne reconnaissance evidence on surge duration is available for eight svalbard ice masses varying from 3 to 1250 km 2 worldwide active phase duration is recorded for less than 50 glaciers few observations are available on high polar ice masses the duration of the active phase is significantly longer for svalbard glaciers than for surge type glaciers in other areas from which data are available in svalbard the active phase may last from 3 to 10 years by contrast a surge duration of 1 2 years is more typical of ice masses in northwest north america iceland and the pamirs ice velocities during the protracted active phase on svalbard glaciers are considerably lower than those for many surge type glaciers in these other regions mass is transferred down glacier more slowly but over a considerably longer period svalbard surge type glaciers do not exhibit the very abrupt termination of the active phase over periods of a few days observed for several alaskan glaciers the duration of the active phase in svalbard is not dependent on parameters related to glacier size the quiescent phase is also relatively long 50 500 years for svalbard ice masses detailed field monitoring of changing basal conditions through the surge cycle is required from surge type glaciers in svalbard in order to explain the significantly longer length of the active phase for glaciers in the archipelago which may also typify other high polar ice masses the finding that surge behaviour in the form of active phase duration shows systematic differences between different regions and their environments has important implications for understanding the processes responsible for glacier surges

the displacement field of the landers earthquake mapped by radar interferometry geodetic data obtained by ground or space based techniques can be used to infer the distribution of slip on a fault that has ruptured in an earthquake although most geodetic techniques require a surveyed network to be in place before the earthquake1 3 satellite images when collected at regular intervals can capture co seismic displacements without advance knowledge of the earthquake s location synthetic aperture radar sar interferometry first introduced4 in 1974 for topographic mapping5 8 can also be used to detect changes in the ground surface by removing the signal from the topography9 10 here we use sar interferometry to capture the movements produced by the 1992 earthquake in landers california11 we construct an interferogram by combining topographic information with sar images obtained by the ers 1 satellite before and after the earthquake the observed changes in range from the ground surface to the satellite agree well with the slip measured in the field with the displacements measured by surveying and with the results of an elastic dislocation model as a geodetic tool the sar interferogram provides a denser spatial sampling 100 m per pixel than surveying methods1 3 and a better precision 3 cm than previous space imaging techniques12 13

measuring snow and glacier ice properties from satellite satellite remote sensing is a convenient tool for studying snow and glacier ice allowing us to conduct research over large and otherwise inaccessible areas this paper reviews various methods for measuring snow and glacier ice properties with satellite remote sensing these methods have been improving with the use of new satellite sensors like the synthetic aperture radar sar during the last decade leading to the development of new and powerful methods such as sar interferometry for glacier velocity digital elevation model generation of ice sheets or snow cover mapping some methods still try to overcome the limitations of present sensors but future satellites will have much increased capability for example the ability to measure the whole optical spectrum or sar sensors with multiple polarization or frequencies among the methods presented are the satellite derived determination of surface albedo snow extent snow volume snow grain size surface temperature glacier facies glacier velocities glacier extent and ice sheet topography in this review emphasis is put on the principles and theory of each satellite remote sensing method an extensive list of references with an emphasis on studies from the 1990s allows the reader to delve into specific topics

ice sheet motion and topography from radar interferometry both topography and motion information are present in repeat pass ers 1 interferograms over ice sheets the authors demonstrate that the topography is separable from the surface displacement field when a sequence of radar images are available if the velocity field is constant over the time span of observation the topography can be derived from differential interferograms formed from sequential observations with this measurement a pure displacement field can then be obtained by removal of the topographic contribution to the interferometric phase at each pixel further they discuss how the vertical and horizontal components of displacement affect the interferometrically derived motion field they illustrate their approach with four successive 3 day repeat ers 1 images of a flow feature in northeastern greenland

interactions between perched and saprolite aquifers on a small salt affected and deeply weathered hillslope a small hillslope was chosen to investigate the role of throughflow as a mechanism responsible for the movement of soil water and solutes towards a saline seep and as a source of recharge to a permanent regional aquifer at depth the hydraulic properties chemical characteristics and physical responses of both systems were studied on a deeply weathered salt affected hillslope additional data were also obtained from other sites in south western australia regional groundwater flow occurred in a variably textured deeply weathered material in which the hydraulic conductivity varied from 0 001 to 0 14m day 1 perched groundwater flow throughflow occurred in the higher permeability 1 5 m day 1 near surface soil materials throughflow occurred throughout winter contributing approximately 530 m3 of fresh 160 mg l 1 cl water to a saline seep by contrast the deep aquifer discharged approximately 1100 m3 of waters with salt concentrations of 2000 6000 mg l 1 cl recharge and discharge rates to and from the deep aquifer were estimated to be of the order of 5 20 mm a 1 and 50 300 mm a 1 respectively saturated conditions existed throughout winter within the seep and the immediately adjacent non saline area with up to 60 per cent of the hillslope soils becoming saturated after major rainfall events 20 mm day 1 in the mid slopes in particular along a central depression saturation of the shallow soils caused macropore channel recharge to take place through the clay textured subsoils water level responses suggest that approximately 25 30 per cent of annual recharge occurred from one storm studied in september 1984 recharge through macropore channels is a significant mechanism in the concave slope areas on the hillslope throughflow was found to be a major source of water but not salt contributing to the saline seep in general the contribution of throughflow was found to decrease further inland at other sites studied however at inland sites where perennial perched aquifers have developed in deep sands saline areas have been caused by throughflow and not by deep aquifer discharge

quantitative diamondoid analysis indicates oil cosourcing from a deep petroleum system onshore niger delta basin the niger delta basin is one of the most prolific hydrocarbon provinces in the world yet the origin of the vast amounts of oil and gas found in the numerous sub basins across the delta remains contested a total of 180 oil samples from more than 40 oil fields in the niger delta were analyzed by gas chromatography gc gc mass spectrometry gc ms and selected samples by gc tandem mass spectrometry gc msms the interpreted thermal maturity and source depositional environments of these hydrocarbons show significant variation depending on the components analyzed and allow no clear correlation to a single source rock but rather imply extensive mixed contributions diamondoid hydrocarbon parameters were used for the first time on these paleogene neogene reservoired oils to investigate source thermal maturity and mixing effects and to perform cross correlations of these oils the diamondoid abundances and distributions support the hypothesis of co sourcing of oil from a thermally cracked sub delta type ii marine source which was then mixed with oils of relatively lower maturities in the paleogene neogene reservoirs future geochemical interpretations should treat the niger delta oils as potential mixtures of oils of variable maturities from different sources often with the most important source biomarkers depleted because of the extent of thermal cracking

velocity structure flow instability and mass flux on a large arctic ice cap from satellite radar interferometry satellite radar interferometry allows calculation of the ice surface velocity distribution throughout the largest ice cap in the eurasian arctic austfonna in eastern svalbard data on ice cap velocity structure show strong spatial variations observed in unprecedented detail ice cap drainage basins have clearly defined fast flowing units with marked shear margins at the surface associated with troughs in the subglacial bedrock identified from 60 mhz ice penetrating radar interferometric measurements show that the velocity structure in most ice cap drainage basins remained stable over a 2 year period unexpectedly however in the basin where surface velocities were the highest on the ice cap at 140 m yr 1 in winter 1992 the flow rate had halved by winter 1994 a time series of visible band landsat imagery shows that this basin was relatively inactive between 1973 and 1991 but had a distinctly disturbed surface in 1993 this flow instability was initiated after summer 1991 and is likely to be a glacier surge or mini surge demonstrating the increasing diversity of motion events revealed by radar interferometry mass flux through this basin calculated using ice velocity and thickness data was 0 1 km 3 yr 1 in 1992 an increase of up to two orders of magnitude over that prior to flow instability calculated balance velocity is an order of magnitude less than the interferometrically derived velocity implying that the flow rates observed for the fast flowing unit cannot be sustained under the present climate c 1999 elsevier science b v all rights reserved

fast flowing outlet glaciers on svalbard ice caps four well defined outlet glaciers are present on the 2510 km2 ice cap of vestfonna in nordaustlandet svalbard airborne radio echo sounding and aerial photograph and satellite image analysis methods are used to analyze the morphology and dynamics of the ice cap and its component outlet glaciers the heavily crevassed outlets form linear depressions in the ice cap surface and flow an order of magnitude faster than the ridges of uncrevassed ice between them ice flow on the ridges is accounted for by internal deformation alone whereas rates of outlet glacier flow require basal motion one outlet has recently switched into and out of a faster mode of flow rapid terminal advance a change from longitudinal compression to tension and thinning in the upper basin indicate surge behavior observed outlet glacier discharge is significantly greater than current inputs of mass to the ice cap indicating that present rates of flow cannot be sustained under the contemporary climate

topography and dynamics of austfonna nordaustlandet svalbard from sar interferometry the ice caps of nordaustlandet svalbard represent one of the largest glaciated areas outside of antarctica and greenland they demonstrate a variety of different flow regimes within a comparatively compact area we report on the first interferometrically derived elevation models and velocity visualisations of austfonna this initial investigation had three purposes to determine whether the coherence and velocity characteristics of the region permitted interferometric survey to determine the accuracy of derived elevations and to assess the possibility of investigating time variant flow of the more dynamic ice bodies using differential interferometry a trio of coherent synthetic aperture radar images from ers 1 s first ice phase was identified the images were combined to separate the topographic and velocity components of the resultant interferograms the topographic phase difference was used to produce a digital elevation model of austfonna its accuracy relative to radio echo sounding derived tie points is 8 m and its resolution 40 m we also present synoptic views of the velocity held of three of austfonna s drainage basins and comment on the extraction of useful velocity information

influence of antecedent soil moisture on hydraulic conductivity in a series of texture contrast soils antecedent soil moisture significantly influenced the hydraulic conductivity of the a1 a2e and b21 horizons in a series of strong texture contrast soils tension infiltration at six supply potentials demonstrated that in the a1 horizon hydraulic conductivity was significantly lower in the wet treatment than in the dry treatment however in the a2e horizon micropore and mesopore hydraulic conductivity was lower in the dry treatment than the wet treatment which was attributed to the precipitation of soluble amorphous silica in the b21 horizon desiccation of vertic clays resulted in the formation of shrinkage cracks which significantly increased near saturated hydraulic conductivity and prevented the development of subsurface lateral flow in the dry treatment in the wet treatment the difference between the hydraulic conductivity of the a1 and b21 horizons was reduced however lateral flow still occurred in the a1 horizon due to difficulty displacing existing soil water further down the soil profile results demonstrate the need to account for temporal variation in soil porosity and hydraulic conductivity in soilwater model conceptualisation and parameterisation

accuracy of topographic maps derived from ers 1 interferometric radar an interferometric radar technique for topographic mapping of surfaces promises a high resolution approach to the generation of digital elevation models the authors present analyses of data collected by the synthetic aperture radar instrument on board the ers 1 satellite on successive orbits use of a single satellite in a nearly repeating orbit is attractive for reducing cost and spaceborne hardware complexity also it permits inference of changes in the surface from the correlation properties of the radar echoes the data have been reduced to correlation maps and digital elevation models the correlation maps show that temporal correlation decreases significantly with time but not necessarily at a constant well defined rate likely depending on environmental factors when correlation among passes remains high however it is possible to form digital elevation models analyses of noise expected in ers 1 interferometric data collected over alaska and the southwestern united states indicate that maps with relative errors less than 5 m rms are possible in some regions however orbit uncertainties imply that tie points are required in order to reduce absolute height errors to a similar magnitude the authors find that about 6 tie points per 40 spl times 40 km scene with 5 m rms or better height accuracy are needed to keep systematic map height errors below 5 m rms the performance of the ers 1 radar system for topographic applications though useful for a variety of regional and local discipline studies may be improved with respect to temporal decorrelation errors and absolute height acuity by modifying the orbit repeat period and incorporating precise orbit determination techniques the resulting implementation will meet many but not all objectives of a global mapping mission

modelling subsurface flow conditions in a salinized catchment in south western australia with a view to improving management practices finite element modelling of the saturated unsaturated surface subsurface flow mechanisms operative in a small salinized catchment in south western australia was used to help define the flow system and explain the causes of waterlogging and salinization there data available at the site from a previous study were used to obtain a first approximation to the flow system altering the properties of some of the strata gave a closer calibration it was found that the modelled saturated hydraulic conductivity of the b horizon in the duplex soil zone needed to be at least an order of magnitude lower than that measured in order to reproduce the perching conditions observed in the field also the model indicated the influence of a doleritic dyke whose presence was confirmed by field measurement our analysis showed that there were two main flow systems operating in the hillslope the first and most dominant was the recharge occurring through the upslope gradational soil zone and percolating down to both the deeply weathered regolith and the basal aquifer the second flow system is an unsaturated flow system operating in the high permeability a horizon in the downslope duplex soil zone the first system is primarily responsible for the saline seepage zone in the valley bottom the second contributes to the waterlogging and perching occurring upslope of the seepage zone vertical flow through the higher permeability b horizon in the gradational soil zone in the upper slopes is a major contributor of recharge recharge by flow through macropores occurs where but only where perched aquifers develop and allow the macropores to be activated areas with perched aquifers occurred in downslope locations and near a doleritic dyke located upslope thus the area where macropore recharge occurred was not large the recharge rate required to maintain the piezometric levels at present values is only about 30 mm yr about 5 of the annual rainfall the piezometric levels under the upper part of the catchment varied greatly with only small changes in recharge rate a 50 reduction in recharge rate had the effect of reducing the length of the seepage zone at the end of winter by 40 changes in recharge rate had little effect on the extent of the perched aquifer at the end of winter deep rooted perennial forages shrubs or trees on the gradational soil zone in the upper part of the catchment and on the zones upslope of geological barriers to flow would be required to reduce the recharge and to allow for rehabilitation of the saline valley floor waterlogging associated with the perched water table in the bottom part of the catchment would be best addressed by tree plantations located just upslope of the salinized zone in the valley floor

mechanisms responsible for streamflow generation on a small salt affected and deeply weathered hillslope this paper considers the contributions of overland flow throughflow and deep seepage to the generation of streamflow in a salt affected deeply weathered landscape runoff mechanisms on a small hillslope in south western australia were dependent on the extent and development of variable source areas in winter streamflow generation was controlled by returnflow saturation overland flow and throughflow in summer post ponding infiltration excess and saturation overland flow dominated the extent of the variable source area and the magnitude of streamflow were due to antecedent soil moisture rainfall and slope morphology concave hillslope sections accumulated soil moisture due to both saturated and unsaturated lateral flow processes throughflow provided the mechanism and vehicle for solute movement from the groundwater discharge area to the stream however discharge from the deep aquifer was the primary mechanism responsible for soil salinity and maintaining the core of the variable source area estimates of throughflow which only take account of soil water movement and disregard returnflow will underestimate the magnitude of throughflow

subaerial salt extrusions in iran as analogues of ice sheets streams and glaciers abstract ice h20 and salt halite nacl share many physical properties and resemble each other in hand specimens and subaerial gravity driven flows however while most significant bodies of ice accumulate in cold highlands and gravity spread where and soon after they form most significant bodies of salt accumulate in tropical marine basins and have to be buried by 1 km of other rocks before they flow buried salt is driven by differential loading into various categories of piercing structures known as diapirs many diapirs extrude onto the surface as sheets of allochthonous out of place salt thousands of sheets of allochthonous salt have been interpreted in over 35 basins worldwide in the last 25 years mainly in the toes of passive continental margins and in orogenic belts where some are 103 km2 in area most former salt sheets are now submarine or subsurface but several active examples are beautifully exposed in iran these were compared to ice glaciers soon after they were introduced to western science a comparison that has been neglected since here we update this analogy and use modern understanding of flowing ice and salt to examine the similarities and differences that might be mutually beneficial to both fields of study as well as to extraterrestrial scientists the profiles internal structures and fabrics in flowing bodies of ice and salt are sensitive gauges of the histories of their budgets of supply and loss however whereas snow merely compacts where it accumulates salt sheets are fed from below by already deformed salt when salt diapirs first emerge on land they extrude domes that mature to the profiles of viscous fountains that often feed glacier like flows known as namakiers after locally exhausting their deep source layers salt fountains spread to the profiles of viscous droplets normal for ice caps ice typically deforms at 80 usually 90 of its absolute melting temperature while most salt deforms at

topographic mapping from interferometric synthetic aperture radar observations interferometric synthetic aperture radar observations provide a means for obtaining high resolution topographic terrain maps from data acquired simultaneously at two slightly displaced antennas calculation of the three dimensional coordinates of all the points in a radar image can be made from the combination of along track slant range and interferometer fringe measurements thus the result compensates for the layover exhibited by conventional radar maps and removes the false targets generated by multiple signal paths to a given object in the scene we have derived a topographic map of a portion of the san francisco bay area utilizing data that were recorded by a radar system mounted on a nasa cv990 aircraft and processed by a general purpose digital computer this map displays the height above sea level of a region approximately 11 km by 10 km in size sampled on an 11 m pixel grid uncertainties in the estimated height result from imprecise knowledge of the observational geometry radar bandwidth limitations and finite signal to noise ratios for our system each factor contributed approximately 3 4 m to a relative rms error of about 6 m additional global errors of the order of 10 m can result from inaccurate monitoring of aircraft attitude the statistical variation of the height measurements from the ocean portion of the map which we can presume to be quite flat is 2 10 m rms which is consistent with the theoretical estimate comparison of our results with u s geological survey contour maps indicates a high degree of correlation between the two sets of altitude data

interpretation of the anomalous growth of austfonna svalbard a large arctic ice cap as previously reported repeat pass airborne laser altimetry measurements made in may 1996 and may 2002 show a large positive ice surface elevation change rate over parts of the accumulation area of austfonna eastern svalbard the maximum growth rate is estimated to be equivalent to a 35 40 increase in snowfall over the area of thickening thinning is observed at lower elevations here we discuss in detail the possible causes of these elevation changes including ice cap dynamics and or firn density changes and conclude that sea ice loss producing a localized increase in precipitation over austfonna remains the most convincing explanation this study highlights the problems of interpreting relatively short term altimetry measurements where auxiliary data are limited in both spatial and temporal extent

hydrological and salinity impacts of a bio drainage strategy application in the yizre el valley israel the bio drainage commercial forestry strategy was applied in five plots in the yizre el valley northern israel to evaluate the hydrological and salinity impacts of eucalypt plantations each plot contained a mix of 11 selected eucalyptus species ecotypes two plots nahalal and genigar representing the two extreme waterlogging salinity conditions in the valley were selected for in depth monitoring over a 10 year period to assess the likely environmental improvement through bio drainage despite impressive growth rates of genetically improved eucalyptus camaldulensis in the year round waterlogged slightly saline nahalal site 650 mm annual rainfall the water uptake by the trees was insufficient to control the rising water table caused by excessive water inputs both natural and human in the more saline alkaline and drier genigar plot 450 mm annual rainfall where rainfall is the only water input the ground water dropped to below 3 m from soil surface in the fourth year after planting i e deeper than the adjacent ground water levels both sites showed appreciable rise in wells that penetrated the 3 to 4 m confining layer the 10 year salinity ec trend of the top layer in nahalal varied because the drainage was limited by the positive water balance and the above average spells of dry winters in and below the 4 m deep layer the ec remained below 1 5 ds m 1 throughout the entire 10 year study the last ec measurement taken in 2003 showed values not higher than 4 ds m 1 throughout the 6 m soil profile in genigar there was significant leaching of salts from the top layer 1 m during the 9 year monitoring period but recently a salts bulge was gradually developed in the 1 5 m strata indicating that the expected downward movement of leached salts was impeded by the 3 4 m deep low permeability clayey layer that lies over a coarser far more conductive and notably confined layer which leads to a perched water body the last ec measurement at the end of 2003 showed a maximum value of 5 5 ds m 1 at 3 m depth no signs of tree stress were observed in either site at any soil depth during the 10 years of monitoring theoretical considerations do not support the hypothesis that there would be a fatal long term accumulation of salts in the root zone the israeli experience has shown that the bio drainage technique can effectively lower a shallow water table and reverse salinity trends provided that the overall water balance is negative i e that the water inputs match the water use by the tree plantation and local drainage characteristics however the rate of improvement of the hydraulic salinity sodicity and soil physical properties is site specific excess fresh water inputs into the plantation although they create waterlogging conditions supply unlimited water to the trees which in turn show exceptional growth rates with usable commercial value copyright 2007 john wiley sons ltd

ice flow dynamics of the greenland ice sheet from sar interferometry synthetic aperture radar sar interferograms produced from esa s ers 1 satellite provide the first synoptic view of ice flow dynamics of the western sector of the greenland ice sheet glacial motion is detected in the radar ranging direction at millimetric scales across a complete sequence of snow accumulation and melting regimes despite significant variations in their radar scattering properties ice flow evolves from a slow regular motion at the higher elevations at lower elevations motion is strongly convoluted by meter scale undulations in surface topography which have a unique interferometric signature that enables a novel approach for retrieving flow direction inferred flow directions combined with surface displacements in the radar ranging direction yield ice velocity estimates that are within 6 of in situ measurements gathered along a 40 km survey line application of repeat pass sar interferometry to the entire greenland ice sheet should enable precise mapping of its ice flow dynamics at an unprecedented level of spatial detail