thermal monitoring of north pacific volcanoes from space long term thermal modeling of volcanoes using satellite imagery provides an effective tool for monitoring remote yet dangerous volcanoes in the north pacific this region includes volcanoes in alaska the aleutian islands and the kamchatkan peninsula thermal infrared data collected multiple times per day from weather satellites show distinct signatures for three different types of volcanic activity at different volcanic centers near real time automated techniques are being developed to monitor relative changes in radiant temperature at volcanoes in this region radiant temperature values as a function of time are extracted and compared to background values for a series of active volcanoes by establishing a long term thermal record for these volcanoes significant deviations indicative of an impending eruption can be detected this tool is used to search for precursors to explosive eruptions in order to increase warning times and hazard mitigation for these potentially catastrophic events a six year archive of satellite imagery has been compiled for this active region and is available for study

variations in magmatic processes along the east greenland volcanic margin summary seismic velocities and the associated thicknesses of rifted and igneous crust provide key constraints on the rifting history the differentiation between non volcanic and volcanic rifted margins the driving force of magmatism at volcanic margins that is active or passive upwelling and the temperature anomaly in the lithosphere this paper presents two new wide angle seismic transects of the east greenland margin and combines the velocity models with a compilation of 30 wide angle seismic velocity models from several publications along the entire east greenland margin compiled maps show the depth to basement depth to moho crustal thickness and thickness of high velocity lower crust hvlc with velocities above 7 0 km s 1 first we present two new wide angle seismic transects which contribute to the compilation at the northeast greenland margin and over the oceanic crust between shannon island and the greenland fracture zone velocity models produced by ray tracing result in total traveltime rms misfits of 100 120 milliseconds and 2 values of 3 7 and 2 3 for the northern and southern profiles with respect to the data quality and structural complexity 2 d gravity modelling is used to verify the structural and lithologic constraints the northernmost profile awi 20030200 reveals a magma starved break up and a rapidly thinning oceanic crust until magnetic anomaly c21 47 1 ma the southern seismic transect awi 20030300 exhibits a positive velocity anomaly associated with the shannon high and a basin of up to 15 km depth beneath flood basalts between shannon island and the continent ocean boundary break up is associated with minor crustal thickening and a rapidly decreasing thickness of oceanic crust out to anomaly c21 the continental region is proposed to be only sparsely penetrated by volcanism and not underplated by magmatic material at all compared to the vast amount of magmatism further south break up is proposed to have occurred at the seaward boundaries of the continent ocean transition zones at between 50 and 54 ma propagating from north to south based on a joint analysis incorporating transects from the kejser franz joseph fjord and godthab gulf secondly the variation of the hvlc along the east greenland margin from 60 to 77 n and from transects of its conjugate margin shows inverted emplacement of prominent landward and seaward hvlc thickness portions from north to south in a distribution chart the differences in the hvlc distribution are attributed to one or more of the following three models in the first model it is inferred that a transfer zone detachment acts as a barrier to northward magma flow in the second model underplating results in thicker and highly intruded lower crust with several small scale feeder dykes that locally increase the lower crustal velocities in the third model a second magmatic event associated with the separation of the jan mayen microcontinent is considered lithospheric scale inhomogeneities might be responsible for the heterogeneous melt generation the inversion of the hvlc distribution in continental and oceanic domains and differences in its velocities

spatially integrated geodetic glacier mass balance and its uncertainty based on geostatistical analysis application to the western svartisen ice cap norway estimates of glacier mass balance using geodetic methods can differ significantly from estimates using direct glaciological field based measurements to determine if such differences are real or methodological there is a need to improve uncertainty estimates in both methods in this paper we focus on the uncertainty of geodetic methods and describe a geostatistical technique that takes into account the spatial correlation of the elevation differences when calculating spatially averaged elevation changes we apply this method to the western svartisen ice cap norway using elevation differences from the surrounding bedrock derived from stereophotogrammetry we show that the uncertainty is not only dependent on the standard error of the individual elevation differences but is also dependent on the size of the averaging area and the scale of the spatial correlation to assess if the geostatistical analysis made over bedrock is applicable to glacier surfaces we use concurrent photogrammetrical and laser scanning data from bedrock and a range of glacier surfaces to evaluate the dependency of the geostatistical analysis on the surface type the estimated geodetic mass balance and its uncertainty is 2 6 0 9 m w e for the period 1968 85 and 2 0 2 2 m w e for 1985 2002

an evaluation of volcanic cloud detection techniques during recent significant eruptions in the western ring of fire we examined recent volcanic cloud events in the western pacific and indonesian area to validate the performance of remote sensing techniques used to support the international airways volcano watch iavw five events were considered during which eruptions from eight volcanoes injected ash into the upper troposphere or lower stratosphere for one of the eruptions at miyakejima japan at least five aircraft encountered volcanic ash clouds and the cost to three operators alone exceeded us 12 000 000 in aircraft repairs diversions and lost operating time we performed reverse absorption and pattern analysis using gms 5 vissr modis and avhrr data and we examined toms so2 and aerosol index data surface based observations pilot reports and dispersion model output our results verify that the introduction of reverse absorption using the geostationary gms 5 platform significantly enhanced our capacity to monitor volcanic ash clouds in the region in one case we tracked an eruption cloud for approximately 80 h the primary impediment to remote monitoring is the presence of overlying cloud or substantial amounts of ice within the volcanic clouds toms data showed success in identifying volcanic clouds during these conditions but was limited by the infrequency of observations more effective future operation of the iavw relies on developing complementary methods of volcanic cloud remote sensing and greatly increasing the amount and quality of available surface and air observations including observations of precursor activity an understanding of the likely future limitations of remote sensing techniques will aid in the refining of iavw procedures

measuring volcanic plume and ash properties from space the remote sensing of volcanic ash plumes from space can provide a warning of an aviation hazard and knowledge on eruption processes and radiative effects in this paper new algorithms are presented to provide volcanic plume properties from measurements by the michelson interferometer for passive atmospheric sounding mipas the advanced along track scanning radiometer aatsr and spinning enhanced visible and infrared imager seviri a challenge of remote sensing is to provide near real time methods to identify and so warn of the presence of volcanic ash to achieve this a singular vector decomposition method has been developed for the mipas instrument on board the environmental satellite envisat this method has been applied to observations of the ash clouds from the eruptions of nabro and the puyehue cordon caulle in 2011 and lead to a more sensitive volcanic signal flag which was capable of tracking changes in the volcanic signal spectra as the plume evolved a second challenge for remote sensing is to identify the ash plume height this is a critical parameter for the initialisation of algorithms that numerically model the evolution and transport of a volcanic plume as mipas is a limb sounder the identification of ash also provides an estimate of height provided the plume is above about 6 km this is complemented by a new algorithm stereo ash plume height retrieval algorithm saphra that identifies plume height using the parallax between images provided by along track scanning radiometer type instruments the algorithm was tested on an image taken at 14 01 gmt on 6 june 2011 of the puyehue cordon caulle eruption plume and gives a height of 11 9 1 4 km which agreed with the value derived from the location of the plume shadow 12 7 1 8 km this plume height was similar to the height observed by mipas 12 1 5 km at 02 56 gmt on 6 june the quantitative use of satellite imagery and the full exploitation of high resolution spectral measurements of ash depends upon knowing the optical properties of the observed ash laboratory measurements of ash from the 1993 eruption of mt aso japan have been used to determine the refractive indices from 1 to 20 m these preliminary measurements have spectral features similar to ash values that have been used to date albeit with slightly different positions and strengths of the absorption bands the refractive indices have been used to retrieve ash properties plume height optical depth and ash effective radius from aatsr and seviri instruments using two versions of oxford ral retrieval of aerosol and cloud orac algorithm for aatsr a new ash cloud type was used in orac for the analysis of the plume from the 2011 eyjafjallajokull eruption for the first 500 km of the plume orac gave values of plume height 2 5 6 5 km optical depth 1 2 5 and effective radius 3 7 m which are in agreement with other observations a weakness of the algorithm occurs when underlying cloud invalidates the

quantifying tropospheric volcanic emissions with airs the 2002 eruption of mt etna italy 1 the atmospheric infrared sounder airs is a hyperspectral ir spectrometer orbiting on the eos aqua spacecraft since may 2002 in late october 2002 airs detected lower tropospheric sulfur dioxide and ash emitted by an eruption of mt etna italy in plumes which could be tracked over 1000 km from the volcano into north africa we report retrievals of so2 and ash column amounts and ash particle size in the etna plumes airs total so2 compares favorably with contemporaneous ground based correlation spectrometry cospec measurements retrieval of ash cloud parameters in the eruption plumes permits quantitative studies of distal ash fallout the etna data demonstrate the potential of airs to improve measurements of volcanic so2 and ash loading in the troposphere and to refine our understanding of volcanic cloud composition structure and evolution

a distributed temperature index ice and snowmelt model including potential direct solar radiation hourly melt and discharge of storglaciaren a small glacier in sweden were computed for two melt seasons applying temperature index methods to a 30 m resolution grid for the melt component the classical degree day method yielded a good simulation of the seasonal patient of discharge but the pronounced melt induced daily discharge cycles were not captured modelled degree day factors calculated for every hour and each gridcell from melt obtained from a distributed energy balance model varied substantially both diurnally and spatially a new distributed temperature index model is suggested attempting to capture both the pronounced diurnal melt cycles and the spatial variations in melt due to the effects of surrounding topography this is accomplished by including a radiation index in terms of potential clear sky direct solar radiation and thus without the need for other data besides air temperature this approach improved considerably the simulation of diurnal discharge fluctuations and yielded a more realistic spatial distribution of melt rates the incorporation of measured global radiation to account for the reduction in direct solar radiation due to cloudiness did not lead to additional improvement in model performance

glacier mass balance of norway 1961 2010 calculated by a temperature index model glacier mass balance in norway is only observed over a small portion 1 between 2000 and 2010 after four decades of zero to slightly positive annual mass balances

a mid cretaceous petroleum source rock in the north atlantic region implications of the nanok 1 fully cored borehole hold with hope northeast greenland abstract the cenomanian turonian transition includes the youngest of the two so called cretaceous oceanic anoxic events sometimes also referred to as the bonarelli event this is an interval of global deposition of organic rich oceanic deposits including some of the most prolific petroleum source rocks of the world however in the greater north atlantic realm little direct evidence of notable volumes of rich cenomanian turonian petroleum source rocks exists as part of a major study of the cretaceous succession in northeast greenland between 2009 and 2012 a fully cored borehole nanok 1 on eastern hold with hope was drilled to penetrate a poorly or non exposed stratigraphic succession including the cenomanian turonian transition the nanok 1 penetrated 160 5 m of cenomanian to campanian clastic deposits and terminated at a td of 168 35 m in an igneous intrusion although none of the deposits penetrated qualify as a petroleum source rock a downwards increasing trend in petroleum source potential starting at c 100m hint at the existence of such rocks at levels deeper than the td of the well the downwards increasing trend in petroleum generation potential is curtailed by maturation from c 140m but assuming the trend would have prevailed were it not for the intrusion the presence of at least a marginal source rock would be expected at the level of the sill and deeper the presumed existence of petroleum source rocks below the td of the borehole is supported by the presence of marked oil staining in sandstones i e migrated petroleum at shallower levels of the drilled succession the hopane and sterane distributions and stable carbon isotopic compositions and age specific nordiacholestane ratios of the oil stains are compatible with an origin from the cretaceous succession while the jurassic can be ruled out the oil stains recorded were probably generated from a marine shale source rock of cretaceous age containing a significant proportion of terrigenous organic matter the possible presence of at least one marginal petroleum source rock in the mid cretaceous succession at the nanok 1 location has implications for the exploration potential of the conjugate margin hence comparison of sediment accumulation histories of the more and voring basins and northeast greenland suggests that the presumed source rock was deposited before the accommodation space at the nanok 1 location was exhausted thus coeval sediment starvation and deposition of more condensed and richer petroleum source rocks may have prevailed in the offshore basins to the east during the mid late cenomanian this potential source rock will thus be slightly older than cenomanian turonian source rocks that are important worldwide

basin evolution in southern east greenland an outcrop analog for cretaceous paleogene basins on the north atlantic volcanic margins the cretaceous paleogene kangerlussuaq basin in southern east greenland represents a unique outcrop analog for the frontier petroleum provinces along the deep water volcanic margins of the northern north atlantic the 1 km thick sedimentary succession comprises six facies associations 1 alluvial plain and shallow marine late aptian 2 fluvio estuarine late aptian early albian 3 offshore marine late cretaceous early paleocene 4 submarine fan and channel levee early paleocene 5 fluvial mid paleocene and 6 volcanic late paleocene sedimentation was terminated in the late paleocene by extrusion of flood basalts related to continental breakup the basin fill is divided into two depositional megasequences related to regional tectonic events and sea level changes the oldest megasequence sq1 spans the late aptian to the earliest paleocene with sea level rise in the late aptian and maximum flooding in the late albian cenomanian followed by sea level highstand in the late cretaceous early paleocene sq1 is truncated by a basin wide unconformity related to regional uplift and basin reorganization in the mid paleocene the upper megasequence sq2 spans the mid to late paleocene and comprises sediments deposited during early sea level rise extensive volcanic deposits and continental flood basalts overlie it deep burial 6 km and middle eocene early oligocene uplift excludes the kangerlussuaq basin as a petroleum basin in itself however to evaluate the petroleum potential of similar volcanic influenced offshore basins such as the west shetland faeroe more and voring basins we discuss three conceptual play models based on the kangerlussuaq basin 1 early albian stratigraphic trap 2 early paleocene structural trap and 3 paleocene stratigraphic trap

major ion bulk deposition around an active volcano mt etna italy bulk atmospheric deposition of major cations na k ca mg and anions cl f so4 were measured at 15 sites around an active volcano mount etna from 2001 to 2003 their composition indicates several natural sources among which deposition of plume derived volcanogenic gas compounds is prevalent for f cl and s plume derived acidic compounds are also responsible for the prevailing acidic composition of the samples collected on the summit of the volcano ph in the 2 45 5 57 range cation species have complex origin including deposition of plume volcanogenic ash and aerosols and soil dust wind re suspension of either volcanic or carbonate sedimentary rocks

investigations on intra annual elevation changes using multi temporal airborne laser scanning data case study engabreen norway key issues of glacier monitoring are changes in glacier geometry and glacier mass as accurate direct measurements are costly and time consuming the use of various remote sensing data for glacier monitoring is explored one technology used and described here is airborne laser scanning the method enables the derivation of high quality digital elevation models dems with a vertical and horizontal accuracy in the sub metre range between september 2001 and august 2002 three laser scanner data acquisition flights were carried out covering the whole area of engabreen norway and corresponding well to the measurement dates for the mass balance year 2001 02 the data quality of the dems is assessed e g by comparing the values with a control area which has been surveyed independently or gps ground profiles measured during the flights for the whole glacier surface elevation change and consequently volume change is calculated quantified and compared with traditional mass balance data for the same time interval for the winter term emergence submergence velocity is determined from laser scanner data and snow depth data and is compared with velocity measurements at stakes the investigations reveal the high potential of airborne laser scanning for measuring the extent and the topography of glaciers as well as changes in geometry area volume

deep seismic and geochemical constraints on the nature of rift induced magmatism during breakup of the north atlantic abstract the deep crustal structure of the norwegian and east greenland conjugate passive margins has been investigated with two ship multichannel reflection and refraction techniques in the region from the iceland faeroe ridge to the greenland fracture zone the data demonstrate the presence of thick 15 20 km igneous crust that was emplaced along the conjugate margins during the initiation of seafloor spreading seaward dipping units comprise the uppermost 3 6 km of the thick crust the thickness of igneous crust diminishes seaward with oceanic layer 2 approaching normal thickness nearer to the margin than does oceanic layer 3 wide angle reflection techniques used in conjunction with expanded spread profiling reveal deep moho reflections beneath 20 km thick oceanic crust that continue seaward into the ocean basin margins that have experienced unusually prolific magmatic activity during breakup have been termed volcanic to distinguish them from non volcanic margins that have evolved into accreting plate boundaries without excessive volcanism the origin of volcanic margins cannot be determined from seismically derived crustal thicknesses alone however thermal and chemical properties of the mantle source may be revealed in the compositions of magmatic products emplaced within volcanic passive margins a combined investigation of crustal structure and associated basalt composition could better resolve processes that result in volcanic passive margins on the voring plateau of the norwegian margin seismic lines coincide with dsdp leg 38 drill sites whole rock major element abundances in the freshest basalts are compatible with moderate extents of partial melting of mantle much like that believed to underlie modern mid ocean ridge systems and would be expected to result in the emplacement of oceanic crust about 9 2 km thick this is about the thickness of oceanic crust located seaward of the dipping basaltic units off the hatton more and voring plateau margins and 10 km south of iceland on the reykjanes ridge these results together with regional heat flow depth gravity and geoid anomalies suggest that the mantle beneath this region has experienced a moderate long lived temperature increase compared to mantle beneath normal ocean basins the much greater thicknesses of igneous crust adjacent to the margins do not appear to reflect an unusually hot flux associated with their construction since this would lead to much greater extents of partial melting than are inferred from the basalt geochemistry evidently the difference between volcanic and non volcanic margins is not simply proximity to a hot spot instead we suggest that the magmatism is closely related to the continental rifting phase tectonism resulting in an abrupt transition from continental to oceanic lithosphere may induce small scale convection that results in the circulation of a greater amount of mantle material into the pressure temperature field where partial melting begins than would occur through passive upwelling alone initial crustal thicknesses are enhanced as a result of the convective partial melting crustal thickness is expected to diminish as this secondary convection slows but the degree of partial melting of the source should not change dramatically

modvolc near real time thermal monitoring of global volcanism modvolc is a non interactive algorithm developed at the hawaii institute of geophysics and planetology higp that uses low spatial resolution 1 km pixel size infrared satellite data acquired by the moderate resolution imaging spectroradiometer modis to map the global distribution of volcanic thermal anomalies in near real time modvolc scans the level 1b modis data stream on a pixel by pixel basis for evidence of pixel and sub pixel sized high temperature radiators once a hot spot has been identified its details location emitted spectral radiance time satellite observation geometry are written to ascii text files and transferred via ftp to higp from where the results are disseminated via the internet http modis higp hawaii edu in this paper we review the underlying principles upon which the algorithm is based before presenting some of the results and data that have been obtained since its inception we show how modvolc reliably detects thermal anomalies at a large number of persistently and sporadically active volcanoes that encompass the full range of common eruptive styles including erebus antarctica colima mexico karymsky kamchatka popocatepetl mexico etna italy and nyiragongo democratic republic of congo amongst others we also present a few cautionary notes regarding the limitations of the algorithm and interpretation of the data it provides

geodetic mass balance of the western svartisen ice cap norway in the periods 1968 1985 and 1985 2002 the geodetic mass balance of the western svartisen ice cap in northern norway is determined in this work from photogrammetry on vertical aerial photographs taken in 1968 1985 and 2002 the existing 1968 digital terrain model dtm was generated using analogue photogrammetry and the 1985 and 2002 dtms are newly generated using digital photogrammetry the geodetic mass balance for 1968 85 is 2 6 0 8 m w e and for 1985 2002 it is 2 0 1 6 m w e the area of western svartisen decreased from 190 km 2 in 1968 to 187 km 2 in 1985 and to 184 km 2 in 2002 the outlet glacier flatisen in the southeast retreated 1700 m over the two periods the geodetic mass balance is also determined for engabreen drainage basin as 2 1 0 9 m w e for the first period and 0 3 2 4 m w e for the second the results for engabreen are compared to traditional mass balances and the large deviations cannot be explained from uncertainties determined for the geodetic method the assessed errors contributing to the uncertainty in the geodetic mass balance are elevation errors uncertainties from the applied melt correction and the use of sorge s law assuming constant snow thickness and density

simulated volcanic ash imagery a method to compare name ash concentration forecasts with seviri imagery for the eyjafjallajokull eruption in 2010 1 during volcanic eruptions that eject ash into the atmosphere volcanic ash advisory centers issue statements on the forecast dispersion of the ash so that the aviation industry can manage airspace to avoid aircraft encountering volcanic ash observations such as those from satellites are compared with the forecasts from an atmospheric dispersion model to assess the quality of the ash forecasts a method has been developed to enable like with like comparison between satellite imagery of volcanic ash and simulated imagery using the forecast ash concentration data from an atmospheric dispersion model the ash concentration and numerical weather prediction data are used as inputs to a radiative transfer model to simulate radiances simulated satellite images are created from these simulated radiances here spinning enhanced visible and infrared imager volcanic ash images based on infrared brightness temperatures for the eyjafjallajokull eruption in 2010 are simulated in addition to providing a useful tool for forecasters in a volcanic ash advisory center the simulated images can be used to aid the understanding of how the ash affects the satellite imagery and also the physical properties of the ash

early tertiary magmatism in ne greenland abstract between 73 and 74 n in ne greenland a lower series of quartz tholeiite lavas is overlain by an upper series which varies from quartz tholeiitic to basanitic the lower series basalts are attributed to large melt fractions produced east of the present outcrop where lithospheric thinning permitted the iceland plume to ascend to shallow levels relocation of eruption sites up to 150 km further west preceeded upper series activity in this small degree melts generated principally from garnet lherzolite facies sources were followed by products of more extensive shallower melting which gave rise successively to the upper series lavas a post upper series basaltic dyke swarm and its associated caldera complex palaeomagnetic observations and 40 ar 39 ar dating suggest that the lower series and part of the upper series erupted in c24r at 58 57 ma rejuvenescent activity at c 32 ma marking the termination of volcanism may relate to decompressive mantle melting associated with late regional uplift

operational prediction of ash concentrations in the distal volcanic cloud from the 2010 eyjafjallajokull eruption 1 during the 2010 eruption of eyjafjallajokull improvements were made to the modeling procedure at the met office uk enabling peak ash concentrations within the volcanic cloud to be estimated in this paper we describe the ash concentration forecasting method its rationale and how it evolved over time in response to new information and user requirements the change from solely forecasting regions of ash to also estimating peak ash concentrations required consideration of volcanic ash emission rates the fraction of ash surviving near source fall out and the relationship between predicted mean and local peak ash concentrations unresolved by the model to validate the modeling procedure predicted peak ash concentrations are compared against observations obtained by ground based and research aircraft instrumentation this comparison between modeled and observed peak concentrations highlights the many sources of error and the uncertainties involved despite the challenges of predicting ash concentrations the ash forecasting method employed here is found to give useful guidance on likely ash concentrations predicted peak ash concentrations lie within about one and a half orders of magnitude of the observed peak concentrations a significant improvement in the agreement between modeled and observed values is seen if a buffer zone accounting for positional errors in the predicted ash cloud is used sensitivity of the predicted ash concentrations to the source properties e g the plume height and the vertical distribution of ash at the source is assessed and in some cases seemingly minor uncertainties in the source specification have a large effect on predicted ash concentrations

investigating the use of the saharan dust index as a tool for the detection of volcanic ash in seviri imagery abstract despite the similar spectral signatures of ash and desert dust relatively little has been done to explore the application of dust detection techniques to the problem of volcanic ash detection the saharan dust index sdi is routinely implemented for dust monitoring at some centres and could be utilised for volcanic ash detection with little computational expense thereby providing a product that forecasters already have some familiarity with to complement the suite of existing ash detection tools we illustrate one way in which the index could be implemented for the purpose of ash detection by applying it to three scenes containing volcanic ash from the 2010 eyjafjallajokull eruption iceland and the 2011 eruption of puyehue chile it was also applied to an image acquired over etna in january 2011 where a volcanic plume is clearly visible but is unlikely to contain any ash these examples demonstrate the potential of the sdi as a tool for ash monitoring under different environmental and atmospheric conditions in addition to presenting a valuable qualitative product to aid monitoring this work includes a quantitative assessment of the detection skill using a manually constructed expert ash mask the optimum implementation of any technique is likely to be dependent on both atmospheric conditions and on the properties of the imaged ash which is often unknown in a real time situation here we take advantage of access to a truth rarely available in a real time situation and calculate an ash mask based on the optimum threshold for the specific scene which is then used to demonstrate the potential of the sdi the sdi mask is compared to masks calculated from a simplistic implementation of the more traditional split window method again exploiting our access to the truth to set the most appropriate threshold for each scene and to a probabilistic method that is implemented without reference to the truth and which provides useful insights into the likely cloud ash contamination of each pixel since the sensitivity of the sdi and split window methods to the tailored thresholds was not tested such tailoring is unlikely to be possible in a real situation this study presents the maximum anticipated skill for the sdi in the context of the maximum skill anticipated for the split window method although both are likely to be lower in a real time situation the results for the sdi are comparable to those of the other methods with a true skill score of 80 02 for the eyjafjallajokull night time scene compared to 88 81 and 46 63 for the split window and probabilistic method respectively and 90 06 for the eyjafjallajokull day time scene compared to 97 61 and 56 96 for the puyehue image the sdi resulted in a true skill score of 74 85 while the split window approach achieved 99 62 these results imply that the sdi which is already implemented operationally at some centres for dust detection could be a useful complement to existing ash monitoring techniques

evolution of the west greenland margin offshore thermostratigraphic data and modelling the origin and age of topography along the west greenland margin is a matter of continued debate evidence for tectonically driven neogene uplift has been argued from interpretations of offshore seismic surveys onshore fission track data and inferred episodes of cooling here analysis of seismic reflection profiles and 1d modelling of exploration wells along the greenland margin of davis strait demonstrate that the data are consistent with a model of ancient continental topography affected by late cretaceous early palaeocene rifting followed by thermal subsidence where offshore neogene tectonic uplift is not required this interpretation for the offshore evolution of the west greenland margin has implications for the adjacent onshore evolution and for other continental margins developed throughout the atlantic arctic rift system

a new geomagnetic polarity time scale for the late cretaceous and cenozoic we have constructed a magnetic polarity time scale for the late cretaceous and cenozoic based on an analysis of marine magnetic profiles from the world s ocean basins this is the first time since heirtzler et al 1968 published their time scale that the relative widths of the magnetic polarity intervals for the entire late cretaceous and cenozoic have been systematically determined from magnetic profiles a composite geomagnetic polarity sequence was derived based primarily on data from the south atlantic anomaly spacings in the south atlantic were constrained by a combination of finite rotation poles and averages of stacked profiles fine scale information was derived from magnetic profiles on faster spreading ridges in the pacific and indian oceans and inserted into the south ariantic sequence based on the assumption that spreading rates in the south atlantic were smoothly varying but not necessarily constant a time scale was generated by using a spline function to fit a set of nine age calibration points

the 1989 1990 eruption of redoubt volcano alaska impacts on aircraft operations abstract the december 1989 june 1990 eruption of redoubt volcano affected commercial and military air operations in the vicinity of anchorage alaska these effects were due to the direct impact of volcanic ash on jet aircraft as well as to the rerouting and cancellations of flight operations owing to eruptive activity between december and february five commercial jetliners were damaged from ash encounters the most serious incident took place on december 15 1989 when a boeing 747 400 aircraft temporarily lost power of all four engines after encountering an ash cloud as the airplane descended for a landing in anchorage while there were no injuries to passengers the damage to engines avionics and aircraft structure from this encounter is estimated at 80 million four additional encounters between jet aircraft and redoubt ash clouds occurred in the anchorage area on december 15 and 16 1989 and february 21 1990 none resulted in engine failure two additional encounters took place on december 17 1989 when jet airliners encountered the redoubt cloud over west texas at the time of these encounters the cloud was up to 55 hours old and had traveled in excess of 2 900 nautical miles 5 300 km following the december 15 encounters anchorage international airport remained open however most airline companies canceled operations for up to several days as communications between federal agencies and airlines improved and as a better understanding of the nature and behavior of ash rich eruption clouds was achieved most airlines resumed normal service by early january 1990 the resulting loss of revenue at anchorage international airport during several months following the eruption is estimated to total 2 6 million the impact on general aviation and military operations consisted mostly of cancellation and rerouting of flights

widespread and accelerating glacier retreat on the lyngen peninsula northern norway since their little ice age maximum the recession of mountain glaciers worldwide is increasing global sea level and in many regions human activities will have to adapt to changes in surface hydrology thus it is important to provide up to date analyses of glacier change and the factors modulating their response to climate warming here we report changes in the extent of 120 glaciers on the lyngen peninsula northern norway where glacier runoff is utilised for hydropower and where glacial lake outburst floods have occurred glaciers covered at least 114 km2 in 1953 and we compare this inventory with those from 1988 2001 and a new one from 2014 and previously dated little ice age lia limits results show a steady reduction in area 0 3 a 1 between their lia maximum 1915 and 1988 consistent with increasing summer air temperatures but recession paused between 1988 and 2001 coinciding with increased winter precipitation air temperatures increased 0 5 c per decade from the 1990s and the rate of recession accelerated to 1 a 1 between 2001 and 2014 when glacier area totalled 95 7 km2 small glaciers 0 05 km2 with low maximum elevations 1400 m experienced the largest percentage losses and if warming continues several glaciers may disappear within the next two decades

improving volcanic ash cloud detection by a robust satellite technique abstract automated and reliable satellite based techniques are strongly required for volcanic ash cloud detection and tracking in fact volcanic ash clouds pose a serious hazard for air traffic and the synoptic and possibly frequent coverage offered by satellites can provide exciting opportunities for monitoring activities as well as for risk mitigation purposes a new avhrr based technique for improved automatic detection of volcanic clouds by means of multi temporal analysis of historical long term satellite records has been recently proposed the technique basically rests on the robust avhrr techniques rat approach which is an innovative strategy of satellite data analysis devoted to a former characterisation of the measured signal in terms of expected value and natural variability and a further recognition of signal anomalies by an automatic unsupervised change detection step in this work an extension of this method to nighttime observations is presented by using thermal infrared information coming from avhrr bands centred approximately at 3 5 11 0 and 12 0 m results achieved for two recent eruptive events of mount etna occurred in may 2000 and in july 2001 seem to be encouraging showing clear improvements in terms of ash detection sensitivity as well as in terms of false alarms reduction the technique performance is also evaluated by comparison with the traditional split window brightness temperature difference method this exercise revealed a general improvement obtained by the proposed approach even though some common problems still remain unsolved the main merits of such an approach are its intrinsic self adaptability to different environmental natural observational conditions and its natural exportability also to different satellite sensors the results here presented show the benefits of such a technique especially when different observational conditions time of pass seasonal period atmospheric moisture solar illumination volcanic cloud composition satellite angles of view etc are considered the future prospects also in terms of possible operational scenarios coming from the implementation of such an approach on the new generation of satellite sensors like for example seviri aboard meteosat second generation platform are also discussed

generation and polybaric differentiation of east greenland early tertiary flood basalts major element trace element isotope and petrographic studies of magma diverentiation mantle melting the basal volcanics in the kangerdlugssuaq fjord region of the east greenland margin provide constraints on the generation and subsequent diverentiation and contamination histories of magmas during the early stage of continental rifting creating the north atlantic ocean basin most primitive lavas of the succession are introduction shown to have accumulated olivine corrections for crystal ac the distinctive geochemical features of continental flood cumulation yield estimates for erupted primitive liquids with mgo basalts cfbs are strongly controlled by the composition contents between 9 and 13 wt the occurrence of suspended and structure of the continental lithosphere and underfo88 olivine phenocrysts further requires the existence of parental lying mantle significant controversy remains concerning magmas with mgo contents up to 17 wt and feo contents up the balance of contributions from the lithosphere and to 14 wt quantitative modeling of fractionation indicates the mantle and the mechanisms by which the various that kangerdlugssuaq magmas primarily diverentiated at moderate source components contribute to basalt petrogenesis pressures 8 kbar to form dunitic and wehrlitic cumulates at how are basalt compositions influenced by generation depths of 25 km evolved east greenland flood basalts from the in anomalous regions in the deep mantle plumes by scoresby sund region record a more complex fractionation history interaction between rising magmas and the continental involving olivine clinopyroxene fractionation in the lower crust lithospheric mantle and by contamination with conas found for the lower basalts followed by olivine plagioclase tinental crust how are the diverentiation con clinopyroxene fractionation at shallow crustal levels cor tamination magma mixing and storage histories of cfbs relations between sio2 incompatible elements and sr nd isotopic controlled by the structure of the continental lithosphere ratios for the lower basalts are consistent with bulk assimilation and how do the thermal and chemical features of the of up to 15 20 archean leucogneiss with unradiogenic sr and mantle and the extensional history of the continental nd isotopic ratios characteristic of lewisian type lower crust lithosphere avect mantle melting and compositions of comparisons between inferred magma types for lower basalts and primary liquids estimated primary liquids from elsewhere in the north atlantic these questions are best addressed in the context of show complex relationships among feo mgo tio2 contents a geologically and geochemically well constrained cfb and cao al2o3 ratios that relate to regional and temporal changes province such as the north atlantic tertiary province in mantle temperatures lithospheric thickness and involvement of separation of east greenland from northern europe in at least two end member mantle sources we postulate that the the early tertiary at 60 myr ago was accompanied by lower basalts of east greenland were derived from iron poor voluminous volcanic activity the blosseville coast of mantle depleted by prior melt extraction and distinct from morb east greenland extending from kangerdlugssuaq fjord source mantle that was enriched in tio2 and lrees by a to scoresby sund fig 1 contains spectacularly exposed metasomatic event shortly before early tertiary magmatism we sections of lavas these sections begin at the basal contact associate this depleted mantle source with the ancestral iceland of the lavas with underlying cretaceous tertiary sediments and archean basement and continue to the plume anomaly

langfjordjokelen a rapidly shrinking glacier in northern norway in this paper we document changes of langfjordjokelen a small ice cap in northern norway surface mass balance measurements have been carried out on an east facing part 3 2 km 2 o f the ice cap since 1989 measurements reveal a strong thinning the balance year 2008 09 was the 13th successive year with significant negative annual balance 0 30 m w e the average annual deficit was 0 9 m w e over 1989 2009 the recent thinning of langfjordjokelen is stronger than observed for any other glacier in mainland norway maps from 1966 1994 and 2008 show that the whole ice cap is shrinking the total volume loss over 1966 2008 was 0 264 km 3 the east facing part has been greatly reduced in volume 46 area 38 and length 20 for this part over 1994 2008 the cumulative direct mass balance 14 5 m w e is less negative than the geodetic mass balance 17 7 m w e a surface mass balance model using upper air meteorological data was used to reconstruct annual balances back to 1948 and to reconstruct unmeasured years 1994 and 1995 sensitivity of annual balance to 18c warming is 0 76 m w e and to 10 increase in precipitation is 0 20 m w e

determining the contribution of volcanic ash and boundary layer aerosol in backscatter lidar returns a three component atmosphere approach 1 a solution of the lidar equation is discussed that permits combining backscatter and depolarization measurements to quantitatively distinguish two different aerosol types with different depolarization properties the method has been successfully applied to simultaneous observations of volcanic ash and boundary layer aerosol obtained in exeter united kingdom on 16 and 18 april 2010 permitting the contribution of the two aerosols to be quantified separately first a subset of the atmospheric profiles is used where the two aerosol types belong to clearly distinguished layers for the purpose of characterizing the ash in terms of lidar ratio and depolarization these quantities are then used in a three component atmosphere solution scheme of the lidar equation applied to the full data set in order to compute the optical properties of both aerosol types separately on 16 april a thin ash layer 100 400 m deep is observed average and maximum estimated ash optical depth 0 11 and 0 2 it descends from 2800 to 1400 m altitude over a 6 hour period on 18 april a double ash layer 400 m deep is observed just above the morning boundary layer average and maximum estimated ash optical depth 0 19 and 0 27 in the afternoon the ash is entrained into the boundary layer and the latter reaches a depth of 1800 m average and maximum estimated ash optical depth 0 1 and 0 15 an additional ash layer with a very small optical depth was observed on 18 april at an altitude of 3500 4000 m by converting the lidar optical measurements using estimates of volcanic ash specific extinction derived from other works the observations seem to suggest approximate peak ash concentrations of 1500 and 1000 g m3 respectively on the two observations dates

lithostratigraphy of the cretaceous barremian santonian hold with hope group ne greenland the finest exposures of barremian to santonian sedimentary rocks in the northern north atlantic region are exposed in hold with hope ne greenland these rocks comprise the hold with hope group which together with its constituent formations and members are defined here as new lithostratigraphic units the strata are dated as cretaceous by use of molluscan macrofaunas and dinoflagellate cysts the marine mudstone dominated hold with hope group is over 1300 m thick and is divided into the steensby bjerg and home forland formations the sandstone dominated steensby bjerg formation barremian albian is 300 m thick it rests with angular unconformity on sandstones attributed to the vardekloft formation middle jurassic and is subdivided into the diener bjerg gulelv stribedal blaelv stensio plateau and rodelv members the mudstone dominated home forland formation albian santonian is over 1000 m thick it rests unconformably on the steensby bjerg vardekloft and wordie creek triassic formations it is subdivided into the fosdalen nanok ostersletten and knudshoved members the hold with hope group is overlain unconformably by tertiary basalts and sedimentary rocks the original proximity of hold with hope to the voring basin is significant for possible cretaceous hydrocarbon plays on the formerly adjacent nw european margin

foraminiferal and palynological biostratigraphy and biofacies from a santonian campanian submarine fan system in the voring basin offshore norway abstract foraminiferal assemblages from a santonian campanian submarine fan system in the northwestern voring basin offshore norway were investigated with the primary objectives to document the stratigraphic ranges of foraminiferal taxa calibrated with dinoflagellate cysts and to interpret foraminiferal biofacies of different fan sub environments previously proposed based on the analysis of ichnofossils the assemblages are composed of deep water agglutinated foraminifera dwaf without carbonate cemented taxa dwaf taxa of high biostratigraphic value are absent but the complete agglutinated nature of the assemblages and the presence of gerochammina stanislawi and rectogerochammina eugubina are similar to those of the lower campanian fenestrella bellii zone of the norwegian sea more reliable dating was provided by palynology and the age of the interval is estimated to be santonian to campanian the inner to middle fan assemblages contain small numbers of specimens and consequently the species diversity and relative abundance of morphogroups are inconsistent deep infaunal forms may be more common in this sub environment but because the abundance is low this observation should be treated carefully in contrast the abundance and diversity of the assemblages of the overbank fringe and basin plain sub environments are fairly high their morphogroup composition is also similar and comparable to each other when the assemblage size is large the assemblage from the interval with suggested hydrothermal activity is similar to those from outside the channel sub environment the presence of bottom water currents possibly in the form of a western boundary current in the basin is suggested based on the abundant occurrence of tubular forms in the overbank fringe and basin plain sub environments

a year of lava fountaining at etna volumes from seviri 1 we present a new method that uses cooling curves apparent in high temporal resolution thermal data acquired by geostationary sensors to estimate erupted volumes and mean output rates during short lava fountaining events the 15 minute temporal resolution of the data allows phases of waxing and peak activity to be identified during short 150 to 810 minute long events cooling curves which decay over 8 to 21 hour periods following the fountaining event can also be identified application to 19 fountaining events recorded at etna by msg s seviri sensor between 10 january 2011 and 9 january 2012 yields a total erupted dense rock lava volume of 28 106 m3 with a maximum intensity of 227 m3 s 1being obtained for the 12 august 2011 event the time averaged output over the year was 0 9 m3 s 1 this being the same as the rate that has characterized etna s effusive activity for the last 40 years

quantifying the effects of climate and surface change on glacier mass balance when a mass balance is computed using an outdated map that computation does not reveal the actual mass change but older maps often must be used for practical reasons we present a method by which with a few additional measurements each year a mass balance computed with an outdated map can be transformed into an actual mass change this is done by taking into account the influence of changes in areal extent and changes in the surface elevation of the glacier since the map was made this method is applied to south cascade glacier washington u s a as an example the computed cumulative mass balance from 1970 to 1997 would have been 16 too negative if the 1970 map had not been updated while the actual volume change of a glacier is relevant to hydrological studies the change that would have occurred on a constant or static surface is more relevant to certain glacier dynamics problems and most climate problems we term this the reference surface balance and propose that such a balance which deliberately omits the influence of changes in area and surface elevation is better correlated to climatic variations than the conventional one which incorporates those influences

space based estimate of the volcanic heat flux into the atmosphere during 2001 and 2002 satellite remote sensing offers a convenient way to monitor changes in the thermal budgets of earth s subaerially active volcanoes by using data acquired by the national aeronautics and space administration s moderate resolution imaging spectro radiometer we have calculated the amount of heat released into the atmosphere by 45 volcanoes active during 2001 and 2002 in order to quantify the contribution active volcanism makes to earth s energy budget we report that the amount of heat radiated into the troposphere by these volcanoes as detected from space was 5 34 3 10 16 and 5 30 3 10 16 j yr during 2001 and 2002 respectively this energy flux is three orders of magnitude less than the amount of energy consumed by the united states of america for residential manufacturing and transportation purposes during 1999

glacier change in norway since the 1960s an overview of mass balance area length and surface elevation changes in this paper we give an overview of changes in area length surface elevation and mass balance of glaciers in mainland norway since the 1960s frontal advances have been recorded in all regions except the northernmost glaciers in troms and finnmark storsteinsfjellbreen lyngen and langfjordjokelen more than half of the observed glaciers 27 of 49 had marked advances in the 1990s the glaciological mass balance values for the period 1962 2018 where 43 glaciers have been measured show great inter annual variability the results reveal accelerated deficit since 2000 the most negative decade being 2001 2010 some years with a positive mass balance or less negative after 2010s can be attributed to variations in large scale atmospheric circulation a surface elevation change and geodetic mass balance were calculated for a sample of 131 glaciers covering 817 km 2 in the 1960s and 734 km 2 in the 2010s giving an area reduction of 84 km 2 or 10 the sample covers many of the largest glaciers in norway and they had an overall change in surface elevation of 15 5 m for the 50 year period converted to a geodetic mass balance this gives a mean mass balance of 0 27 0 05 m w e a 1

near real time forecasting of lava flow hazards during the 12 13 january 2011 etna eruption we are grateful to eumetsat for seviri data to nasa for modis data and tonoaafor avhrr data the authors thank one anonymous reviewer and v acocella for their helpful and constructive comments this study was performed with the financial support from the v3 lava project ingv dpc 2007 2009 contract

photogrammetric reconstruction of glacier mass balance using a kinematic ice flow model a 20 year time series on grubengletscher swiss alps the kinematic boundary condition at the glacier surface can be used to provide glacier mass balance at individual points if changes in surface elevation horizontal and vertical surface velocities and surface slope are known vertical ice velocity can in turn be estimated from basal slope basal ice velocity and surface strain this relation is applied to reconstruct a 20 year mass balance curve of grubengletscher swiss alps largely using repeated aerial photogrammetry but only a minimum of field work for individual years the mass balance distribution on the glacier tongue was modelled with an accuracy of about 0 9 m a 1 ice mechanical assumptions and errors in glacier bed geometry markedly affect discrete mass balance patterns but are eliminated to a major extent when calculating year to year mass balance changes the resulting curve for the grubengletscher tongue 1973 1992 shows reasonable consistency with meteorological data and other glaciologically derived mass balance series large changes in measured ice speed on the glacier tongue 50 significantly governed the long term variability of ice thickness over the observational period

extracting a climate signal from 169 glacier records i constructed a temperature history for different parts of the world from 169 glacier length records using a first order theory of glacier dynamics i related changes in glacier length to changes in temperature the derived temperature histories are fully independent of proxy and instrumental data used in earlier reconstructions moderate global warming started in the middle of the 19th century the reconstructed warming in the first half of the 20th century is 0 5 kelvin this warming was notably coherent over the globe the warming signals from glaciers at low and high elevations appear to be very similar

near real time volcanic ash cloud detection experiences from the alaska volcano observatory volcanic eruptions produce ash clouds which are a major hazard to population centers and the aviation community within the north pacific nopac region there have been numerous volcanic ash clouds that have reached aviation routes others have closed airports and traveled for thousands of kilometers being able to detect these ash clouds and then provide an assessment of their potential movement is essential for hazard assessment and mitigation remote sensing satellite data through the reverse absorption or split window method is used to detect these volcanic ash clouds with a negative signal produced from spectrally semi transparent ash clouds single channel satellite is used to detect the early eruption spectrally opaque ash clouds volcanic ash transport and dispersion vatd models are used to provide a forecast of the ash clouds future location the alaska volcano observatory avo remote sensing ash detection system automatically analyzes satellite data of volcanic ash clouds detecting new ash clouds and also providing alerts both email and text to those with avo however there are also non volcanic related features across the nopac region that can produce a negative signal these can complicate alerts and warning of impending ash clouds discussions and examples are shown of these non volcanic features and some analysis is provided on how these features can be discriminated from volcanic ash clouds finally there is discussion on how information of the ash cloud such as location particle size and concentrations could be used as vatd model initialization these model forecasts could then provide an improved assessment of the clouds future movement

observations of mt etna volcanic ash plumes in 2006 an integrated approach from ground based and polar satellite noaa avhrr monitoring system abstract mt etna in sicily italy is one of the world s most frequent emitters of volcanic plumes during the last ten years etna has produced copious tephra emission and fallout that have damaged the inhabited and cultivated areas on its slopes and created serious hazards to air traffic recurrent closures of the catania international airport have often been necessary causing great losses to the local economy recently frequent episodes of ash emission lasting from a few hours to days occurred from july to december 2006 necessitating a look at additional monitoring techniques such as remote sensing the combination of a ground monitoring system with polar satellite data represents a novel approach to monitor etna s eruptive activity and makes etna one of the few volcanoes for which this surveillance combination is routinely available in this work ash emission information derived from an integrated approach based on comparing ground and noaa avhrr polar satellite observations is presented this approach permits us to define the utility of real time satellite monitoring systems for both sporadic and continuous ash emissions using field data visible observations collection of tephra samples and accounts by local inhabitants the duration and intensity of most of the tephra fallout events were evaluated in detail and in some cases the order of magnitude of the erupted volume was estimated the ground data vs satellite data comparison allowed us to define five different categories of etna volcanic plumes according to their dimensions and plume height taking into account wind intensity using frequent and good quality satellite data in real time this classification scheme could prove helpful for investigations into a possible correlation between eruptive intensity and the presence and concentration of ash in the volcanic plume the development and improvement of this approach may constitute a powerful warning system for civil protection thus preventing unnecessary airport closures

degree day glacier mass balance modelling with applications to glaciers in iceland norway and greenland a degree day glacier mass balance model is applied to three glaciers in iceland norway and greenland for which detailed mass balance measurements are available over a period of several years model results are in good agreement with measured variations in the mass balance with elevation over the time periods considered for each glacier in addition the model explains 60 80 of the year to year variance in the elevation averaged summer season mass balance measurements on the glaciers using a single parameter set for each glacier the increase in ablation on the glaciers due to a warming of 2 c is predicted to range from about 1 m w e year 1 at the highest elevations to about 2 5 m w e year 1 at the lowest elevations predicted changes in the winter balance measured between fixed date are relatively small except at the lowest elevations on the icelandic and norwegian glaciers where the winter balance is significantly reduced equilibrium line altitudes are raised by 200 300 m on the icelandic and norwegian glaciers except at the highest elevations the winter balance of the icelandic and norwegian glaciers is predicted to decrease even if the warming is accompanied by a 10 increase in the precipitation no firm evidence of a climate related variation in the degree day factors or in the temperature lapse rate on the same glacier could be found the model furthermore reproduces large variations in the mass balance with elevation and from year to year on each glacier using the same parameter set we assume therefore that these parameters will not change significantly for the climate scenarios considered here

mass balance of glaciers and ice caps consensus estimates for 1961 2004 1 working with comprehensive collections of directly measured data on the annual mass balance of glaciers other than the two ice sheets we combine independent analyses to show that there is broad agreement on the evolution of global mass balance since 1960 mass balance was slightly below zero around 1970 and has been growing more negative since then excluding peripheral ice bodies in greenland and antarctica global average specific balance for 1961 1990 was 219 112 kg m 2 a 1 representing 0 33 0 17 mm sle sea level equivalent a 1 for 2001 2004 the figures are 510 101 kg m 2 a 1 and 0 77 0 15 mm sle a 1 including the smaller greenland and antarctic glaciers global total balance becomes 0 38 0 19 mm sle a 1 for 1961 1990 and 0 98 0 19 mm sle a 1 for 2001 2004 for 1991 2004 the glacier contribution 0 77 0 26 mm sle a 1 is 20 30 of a recent estimate of 3 2 0 4 mm a 1 of total sea level rise for 1993 2005 while our error estimates are not rigorous we believe them to be liberal as far as they go but we also discuss several unquantified biases of which any may prove to be significant

lava discharge during etna s january 2011 fire fountain tracked using msg seviri etna s january 2011 eruption provided an excellent opportunity to test the ability of meteosat second generation satellite s spinning enhanced visible and infrared imager seviri sensor to track a short lived effusive event the presence of lava fountaining the rapid expansion of lava flows and the complexity of the resulting flow field make such events difficult to track from the ground during the etna s january 2011 eruption we were able to use thermal data collected by seviri every 15 min to generate a time series of the syn eruptive heat flux lava discharge waxed over a 1 h period to reach a peak that was first masked from the satellite view by a cold tephra plume and then was of sufficient intensity to saturate the 3 9 m channel both problems made it impossible to estimate time averaged lava discharge rates using the syn eruptive heat flux curve therefore through integration of data obtained by ground based doppler radar and thermal cameras as well as ancillary satellite data from moderate resolution imaging spectrometer and advanced very high resolution radiometer we developed a method that allowed us to identify the point at which effusion stagnated to allow definition of a lava cooling curve this allowed retrieval of a lava volume of 1 2 106 m3 which if emitted for 5 h was erupted at a mean output rate of 70 m3 s 1 the lava volume estimated using the cooling curve method is found to be similar to the values inferred from field measurements

experiments on gas ash separation processes in volcanic umbrella plumes abstract we present a series of analogue laboratory experiments which simulate the separation of ash and gas and the formation of secondary intrusions from finite volcanic umbrella plumes we examined the lateral spreading of mixtures of freshwater and particles released into a laboratory tank containing a uniformly stratified aqueous solution for times smaller than the sedimentation time of particles through the intrusion the current remains coherent and intrudes laterally as some of the particles settle into the underlying ambient fluid a layer of particle depleted fluid develops below the upper surface of the current and the density of the residual fluid is reduced over longer times the intrusion ceases to be coherent with small fingers of relatively buoyant particle depleted fluid rising from the upper part of the intrusion into the overlying fluid meanwhile the lateral motion of the injected solution induces a return flow in the ambient fluid which sweeps some of the particles sedimenting from the lower surface of the intrusion inwards as a result relatively dense particle laden fluid collects below the intrusion and then sinks into the underlying fluid eventually this fluid reaches a new neutral buoyancy height where it intrudes to form a second laterally spreading current below the original intrusion the process then repeats to form further weaker intrusions below these results of the separation of the ash and volcanic gas in an umbrella plume are consistent with field observations at sakurajima volcano where positively charged plumes thought to consist of volcanic gas have been observed above negatively charged plumes of ash this work also suggests that volcanic aerosols may form up to a kilometer above the original injection height of the ash in a strong wind shear this could result in very different trajectories of the ash and gas and so be important for evaluating the impact of ash plumes on both aviation safety and volcanic aerosol formation the separation of the ash from the umbrella plume after a time of order 10 3 10 4 s corroborates recent models of the may 18 1980 eruption at mount st helens that after a few hours the motion of the ash was simply controlled by wind dispersal and gravitational settling the complex motion of the sedimenting ash may also explain some of the observations of multiple intrusions in short lived umbrella plumes such as observed at redoubt alaska in april 1990

aviation response to a widely dispersed volcanic ash and gas cloud from the august 2008 eruption of kasatochi alaska usa 1 the extensive volcanic cloud from kasatochi s 2008 eruption caused widespread disruptions to aviation operations along pacific oceanic canadian and u s air routes based on aviation hazard warnings issued by the national oceanic and atmospheric administration u s geological survey the federal aviation administration and meteorological service of canada air carriers largely avoided the volcanic cloud over a 5 day period by route modifications and flight cancellations comparison of time coincident goes thermal infrared tir data for ash detection with ozone monitoring instrument omi ultraviolet data for so2 detection shows congruent areas of ash and gas in the volcanic cloud in the 2 days following onset of ash production after about 2 5 days the area of so2 detected by omi was more extensive than the area of ash indicated by tir data indicating significant ash depletion by fall out had occurred pilot reports of visible haze at cruise altitudes over canada and the northern united states suggested that so2 gas had converted to sulfate aerosols uncertain about the hazard potential of the aging cloud airlines coped by flying over under or around the observed haze layer samples from a nondamaging aircraft encounter with kasatochi s nearly 3 day old cloud contained volcanic silicate particles confirming that some fine ash is present in predominantly gas clouds the aircraft s exposure to ash was insufficient to cause engine damage however slightly damaging encounters with volcanic clouds from eruptions of reventador in 2002 and hekla in 2000 indicate the possibility of lingering hazards associated with old and or diffuse volcanic clouds

thermal infrared remote sensing of volcanic emissions using the moderate resolution imaging spectroradiometer the volcanological community has a powerful new tool in the spaceborne moderate resolution imaging spectroradiometer modis which from its synoptic perspective provides satellite imagery of every volcano on earth every 2 days modis has the spectral characteristics to be able to utilise previously developed retrievals that quantify volcanic ash ice sulfates and sulfur dioxide using their thermal infrared 8 12 am transmission signature in this paper we present a detailed description of the methodologies based within the thermal infrared region that are being applied to modis data modis data for two eruptions hekla iceland and cleveland alaska are presented to show results from the ice ash and so2 retrieval schemes we look at current problems with the retrievals used to quantify volcanic emissions detail recent developments within the field that can be applied to modis data and suggest areas where improvements need to be made in the future published by elsevier b v

volcano monitoring applications of the ozone monitoring instrument the ozone monitoring instrument omi is a satellite based ultraviolet uv spectrometer with unprecedented sensitivity to atmospheric sulphur dioxide so2 concentrations since late 2004 omi has provided a high quality so2 dataset with near continuous daily global coverage in this review we discuss the principal applications of this dataset to volcano monitoring 1 the detection and tracking of large eruption clouds primarily for aviation hazard mitigation and 2 the use of omi data for long term monitoring of volcanic degassing this latter application is relatively novel and despite showing some promise requires further study into a number of key uncertainties we discuss these uncertainties and illustrate their potential impact on volcano monitoring with omi through four new case studies we also discuss potential future avenues of research using omi data with a particular emphasis on the need for greater integration between various monitoring strategies instruments and datasets

simultaneous retrieval of volcanic ash and so2 using msg seviri measurements 1 volcanic ash and sulphur dioxide masses from the november 2005 eruption of karthala volcano comoros islands are simultaneously retrieved using rapid scan multispectral infrared measurements from the spin enhanced visible and infrared imager on board the meteosat second generation geosynchronous satellite retrievals are made every 15 min which show that the ash and so2 separate in the vertically sheared atmosphere producing a fast moving upper level 12 km so2 cloud a slower moving middle level 8 km ash cloud and a boundary layer 3 km so2 plume the total mass of fine ash is 0 1 0 05 tg sio2 the upper level so2 mass is 0 19 0 01 tg s while the boundary layer so2 mass is 0 009 0 01 tg s these are the first simultaneous satellite measurements of ash and so2 from an erupting volcano and confirm previous ideas about vertical separation we suggest care must be exercised when using so2 as a tracer for volcanic ash in aviation hazard warning systems

centreline and cross glacier air temperature variability on an alpine glacier assessing temperature distribution methods and their influence on melt model calculations the spatio temporal distribution of air temperature over mountain glaciers can demonstrate complex patterns yet it is often represented simplistically using linear vertical temperature gradients vtgs extrapolated from off glacier locations we analyse a network of centreline and lateral air temperature observations at tsanteleina glacier italy during summer 2015 on average vtgs are steep 1 but they are shallow under warm ambient conditions when the correlation between air temperature and elevation becomes weaker published along flowline temperature distribution methods explain centreline observations well including warming on the lower glacier tongue but cannot estimate lateral temperature variability application of temperature distribution methods improves simulation of melt rates rmse in an energy balance model by up to 36 compared to the environmental lapse rate extrapolated from an off glacier station however results suggest that model parameters are not easily transferable to glaciers with a small fetch without recalibration such methods have potential to improve estimates of temperature across a glacier but their parameter transferability should be further linked to the glacier and atmospheric characteristics furthermore cold spots which can be 2 c cooler than expected for their elevation whose occurrence is not predicted by the temperature distribution models are identified at one quarter of the measurement sites

modelling 60 years of glacier mass balance and runoff for chhota shigri glacier western himalaya northern india glacier mass balance and runoff are simulated from 1955 to 2014 for the catchment 46 glacier cover containing chhota shigri glacier western himalaya using gridded data from three regional climate models 1 the rossby centre regional atmospheric climate model v 4 rca4 2 the regional atmosphere model remo and 3 the weather research and forecasting model wrf the input data are downscaled to the simulation grid 300 m and calibrated with point measurements of temperature and precipitation additional input is daily potential global radiation calculated using a dem at a resolution of 30 m the mass balance model calculates daily snow accumulation melt and runoff the model parameters are calibrated with available mass balance measurements and results are validated with geodetic measurements other mass balance model results and run off measurements simulated annual mass balances slightly decreased from 0 3 m w e a 1 1955 99 to 0 6 m w e a 1 for 2000 14 for the same periods mean runoff increased from 2 0 m 3 s 1 1955 99 to 2 4 m 3 s 1 2000 14 with glacier melt contributing about one third to the runoff monthly runoff increases are greatest in july due to both increased snow and glacier melt whereas slightly decreased snowmelt in august and september was more than compensated by increased glacier melt

along strike variations in rifted margin crustal architecture and lithosphere thinning between northern voring and lofoten margin segments off mid norway abstract an extensive geophysical and geological database is used to integrate observations and structural and stratigraphic modelling along the northern voring and lofoten margins off mid norway subsidence and fault analysis demonstrates depth dependent lithosphere stretching along both margin segments and the modelling concurs with an emergent or relatively shallow water emplacement environment for the breakup lavas along the northern voring margin however off lofoten subsidence modelling predicts 1500 m of bathymetric relief during breakup in contradiction to the view of subaerial volcanic emplacement environment off mid norway a distinct early eocene bathymetric gradient from voring to lofoten margin is suggested exhibiting depths in the order of 500 1000 m on the latter margin and thus an environment for submarine lava emplacement the water depth may even have reached 1250 m following breakup due to an initial rapid margin subsidence of the lofoten margin along a deep rooted low angle detachment fault the differences between northern voring and lofoten margin segments in pre and post breakup evolution are attributed to the bivrost lineament a transfer zone separating the two margin segments which appears as a major across margin boundary in terms of margin physiography and paleogeography differential sediment accommodation space crustal and lithosphere scale structure and breakup magmatism furthermore gravity inversion results appear to independently predict a significantly greater volcanic addition on the voring than on the lofoten margin

failures in detecting volcanic ash from a satellite based technique abstract immediate and accurate detection of airborne volcanic ash is an operational imperative of the aviation industry especially jet aircraft ash encounters place passengers aboard these aircraft at severe risk and significantly impact via forced rerouting both the safety and profit margins of freight carriers due to their limited fuel supply moreover the airlines can suffer high economic costs for repair and replacement of equipment operational detection and tracking of volcanic ash by most national weather services has relied heavily on a split window differencing technique of thermal longwave infrared channels on currently operational satellites unfortunately prior work on volcanic ash detection has not emphasized the dynamical interaction between the erupting volcano and the effects of overlying atmospheric water vapor phreatic and phreatomagmatic water sources six volcanic ash eruptions from around the globe were chosen for study because they have wide variation in ambient atmospheric water vapor available ground and surface water and different magma types results show that the present differencing technique is not uniformly effective in properly classifying volcanic ash pixels in the satellite scene and often falsely interprets meteorological clouds as volcanic ash clouds and conversely moreover it is not always a robust early detector an operational aviation requirement seasonal variability in global integrated atmospheric water vapor coupled with the geographical distribution of currently active volcanoes suggests the concerns discussed herein with regard to six specific eruptions have applicability to the global aviation industry operational implications are discussed and a strategic proposal is presented on necessary steps to improve detection

timing and duration of volcanism in the north atlantic igneous province implications for geodynamics and links to the iceland hotspot abstract we combine new and published 40 ar 39 ar age determinations from incremental heating experiments on whole rocks and mineral separates to assess the timing duration and distribution of volcanic activity during construction of the north atlantic igneous province we use these ages together with volume estimates of erupted magmas and their cumulates to calculate melt production rates for the early tertiary flood basalts of east greenland and the faeroes islands the lavas lie at opposite ends of the greenland iceland faeroes ridge the postulated iceland hotspot track and record volcanic activity leading up to during and following continental breakup between greenland and europe dominantly basaltic but also alkalic and picritic magmas were erupted from beneath thick continental lithosphere simultaneously at 61 ma from baffin island to the western and eastern margins of greenland to the faeroe islands and the western british isles a roughly circular area 2000 km in diameter volcanic activity was increasingly intermittent by 57 56 ma but at 56 1 0 5 ma the average melt production rate increased by more than an order of magnitude over previous levels from 3000 km 3 km of rift my coinciding with continental rifting and shallow decompressional melting of the mantle that fed subaerial volcanic activity along most of the eastern margin of greenland and its complement on the northwestern european margin offshore abnormally thick oceanic crust was produced along the line of plate separation the upper part of this crust comprises seismically imaged seaward dipping subaerially erupted lavas by 50 ma eruption rates had diminished drastically and volcanic activity had narrowed to a much restricted portion of the east greenland margin at the western end of the greenland iceland ridge that subsequently connected in an age progressive trend to present hotspot activity in southeastern iceland the startup mantle plume head and tail model with moderate excess temperature t 100 c and active upwelling best explains the time space and compositional aspects of volcanism in this province

interdecadal variability of degree day factors on vestari hagafellsjokull langjokull iceland and the importance of threshold air temperatures the skill of degree day glacier melt models is highly dependent on the choice of degree day factor ddf which is often assumed to remain constant in time here we explore the validity of this assumption in a changing climate for two locations on vestari hagafellsjokull 1979 2012 using a surface energy balance seb approach that isolates the effect of changes in the prevailing weather on the ddf at lower elevation we observe stable ddf during the period of study however at higher elevation ddf is noted to be more variable and a statistically significant downward trend is observed this is found to result from an inappropriate threshold air temperature t crit from which to initiate the positive degree day sum and is removed by setting t crit to 1 83 c rather than the usual value of 0 c used in degree day melt models the stationarity of ddf once t crit is adjusted contradicts previous research and lends support to the use of constant ddf for projecting future glacier melt optimizing t crit also improves the skill of melt simulations at our study sites this research thus highlights the importance of t crit for both melt model performance and the evaluation of ddf stationarity in a changing climate

a distributed surface energy balance model for complex topography and its application to storglaciaren sweden a grid based surface energy balance mass balance model has been developed to simulate snow and ice melt in mountainous regions with an hourly resolution the model is applied to storglaciaren a valley glacier in sweden using a 30 m resolution digital elevation model emphasis is directed towards computing the radiation components these are modelled individually considering the effects of slope angle aspect and effective horizon a new parameterization for snow albedo is suggested modifying the albedo of the preceding hour as a function of time after snowfall air temperature and cloudiness the model is used to provide the meltwater input for discharge modelling and to assess the influence of the individual components on melt results are validated by means of observed melt rates patterns of snow line retreat and proglacial discharge in general simulations are in good agreement with observations in particular the diurnal and seasonal fluctuations of discharge are simulated remarkably well

conventional versus reference surface mass balance glacier surface mass balance evaluated over the actual glacier geometry depends not only on climatic variations but also on the dynamic adjustment of glacier geometry therefore it has been proposed that reference surface balances calculated over a constant glacier hypsometry are better suited for climatic interpretation here we present a comparison of 82 year modelled time series 1926 2008 of conventional and reference surface balance for 36 swiss glaciers over this time period the investigated glaciers have lost 22 of their area and ice surface elevation close to the current glacier terminus has decreased by 78 m on average conventional balance in the last decade at 0 91 m w e a 1 is 0 14 m w e a 1 less negative than the reference surface balance about half of the negative stabilizing feedback on mass balance due to glacier terminus retreat is compensated by more negative mass balances due to surface lowering short term climatic variability is clearly reflected in the conventional mass balance series however the magnitude of the long term negative trend is underestimated compared to that found in the reference surface balance series both conventional and reference surface specific balances show large spatial variability among the 36 glaciers

transport of saharan dust over the caribbean islands study of an event 1 a dust plume transported across the atlantic ocean from west africa to guadeloupe in june 1994 is studied using several complementary and cross checking techniques during this event the dust optical depth measured in guadeloupe was high from 19 to 22 june peaking at 1 meteosat 5 ir imagery is used to locate in sw sahara the source of emitted dust consistent with the simulated backward trajectories of the dusty air masses arriving over guadeloupe meteosat 3 visible light spectrometer vis imagery over the north tropical atlantic shows the dust plume leaving the african coast on 15 june and its subsequent spreading over ocean on the following days the back trajectories indicate a strong uplift from the african source to an altitude of 5000 m on 14 and 15 june followed by a subsiding motion of the dust plume from the african coast to guadeloupe in agreement with the meteorological soundings performed at east and west sides of the atlantic ocean such uplifts observed during summer are shown to be a condition for the long range transport of dust through the atlantic it is also observed that while dust transport is associated with the dynamics of the saharan air layer the latter can be dust free the transported mass of dust was in the range 2 5 5 mt for this event electronic microscopy applied to the mineral particles collected in rainwater just after the dust event shows the predominance of particles larger than 1 m in the long range transport from africa

sensitivities of glacier mass balance and runoff to climate perturbations in norway this study evaluates sensitivities of glacier mass balance and runoff to both annual and monthly perturbations in air temperature and precipitation at four highly glacierized catchments engabreen in northern norway and alfotbreen nigardsbreen and storbreen which are aligned along a west east profile in southern norway the glacier mass balance sensitivities to changes in annual air temperature range from 1 74mw e k 1 for alfotbreen to 0 55mw e k 1 for storbreen the most maritime and the most continental glaciers in this study respectively the runoff sensitivities of all catchments are 20 25 per degree temperature change and 6 18 for a 30 precipitation change a seasonality of the sensitivities becomes apparent with increasing continentality the sensitivity of mass balance and runoff to temperature perturbations during summer increases and the sensitivity of annual runoff to both temperature and precipitation perturbations is constricted towards changes during the ablation period comparing sensitivities in northern and southern norway as well as the variability across southern norway reveals that continentality influences sensitivities more than latitude does

petrogenesis of late stage magmatism at hold with hope east greenland the myggbukta caldera complex and a swarm of basic dykes constitute the latest tertiary magmatism in the hold with hope region east greenland the sr and nd isotope ratios of these rocks show coherent variations which extend to high 87sr 86sr and low 143nd 144nd values and require a contribution from continental lithosphere broad correlations with major element differentiation indices suggest that the continental component was incorporated during magmatic differentiation thereby favouring a crustal contamination process trace element concentrations are strongly correlated with isotopic compositions but display ranges for many incompatible elements which extend beyond likely crustal contaminant compositions this is readily modelled by afc processes in which the dominant cause of trace element enrichment is the concentration effect of fractional crystallisation rather than the composition of the contaminant the simplest such models still require unrealistically high degrees of fractional crystallisation to explain the ten fold enrichment of some trace elements this can be overcome if the primary magmas entering the crust already had highly variable trace element compositions such variability is readily achieved if melts from different parts of the melting column escape without thorough homogenization an afc model which incorporates variability in parental magma composition is then able to simulate the range of compositions observed at hold with hope this carries the implication that the variations observed are more readily attributed to changes in uncontaminated parental magma than to variations in the composition or amount of contaminant

reconstruction of mass balance of glaciers in southern norway back to 1948 a model using upper air meteorological variables in the us national centers for environmental prediction and us national center for atmospheric research ncep ncar re analysis database is used to extend net balance bn back to 1948 for seven glaciers in southern norway the observational record of another glacier storbreen began in 1948 over the observational record of each of the seven glaciers correlation with storbreen estimates bn more accurately than the upper air model does for four of them and less accurately for three in all seven cases however an average of the model and the storbreen correlation is more accurate than either alone so the average is used to reconstruct bn for years when it was not observed for the seven glaciers other than storbreen a combined series is formed from observations during their period of record and from reconstructed values prior to then back to 1948 there are three distinct sections in all eight bn series prior to 1989 1989 1995 when the north atlantic oscillation index was strongly positive and after 1995 the 1989 95 mean bn was anomalously positive because of both decreased ablation and especially increased accumulation the mean bn since 1995 has been anomalously negative because of increased ablation whilst accumulation has been nearly the same as over 1948 88 the first principal component of the eight 1949 2005 bn series explains 78 of the total variance and the second explains 12 over 1949 88 there were no substantial shifts in bn or in either winter balance bw or summer balance bs at any of the seven glaciers where observations began after 1948 nor were there in the storbreen record there is a distinction between the three glaciers that gained mass over 1948 2005 and the five that lost mass each of the three that gained had accumulation area ratio aar 0 64 and 0 7 of its areas in the lowest tenth of its altitude range while the five that lost had aar 0 46 and 1 9 s 4 4 because of these hypsometries the five glaciers that lost mass now have an especially large ablation area

analyses of in situ airborne volcanic ash from the february 2000 eruption of hekla volcano iceland 1 a mcdonnell douglas dc 8 nasa research aircraft inadvertently flew into an airborne volcanic ash plume from the 26 february 2000 eruption of hekla volcano filter samples from the aircraft were compared with normal use and pristine clean filters using sem energy dispersive x ray spectrometer and nicolet ftir spectrophotometer analyses these analyses confirm that the dc 8 encountered airborne volcanic ash from hekla volcano this result is supported by independent onboard heated aerosol observations at the time of the encounter the analyses further demonstrate the ambiguous nature of the dual band thermal ir split window method for detecting volcanic ash from the point of view of aviation safety they also highlight the utility of in situ aircraft filter based observations of volcanic aerosols for scientific purposes