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

satellite based constraints on explosive so2 release from soufriere hills volcano montserrat 1 numerous episodes of explosive degassing have punctuated the 1995 2009 eruption of soufriere hills volcano shv montserrat often following major lava dome collapses we use ultraviolet uv and infrared ir satellite measurements to quantify sulfur dioxide so2 released by explosive degassing which is not captured by routine ground based and airborne gas monitoring we find a total explosive so2 release of 0 5 tg which represents 6 of total so2 emissions from shv since july 1995 the majority of this so2 0 4 tg was vented following the most voluminous shv dome collapses in july 2003 and may 2006 based on our analysis we suggest that the so2 burden measured following explosive disruption of lava domes depends on several factors including the instantaneous lava effusion rate dome height above the conduit and the vertical component of directed explosions space based so2 measurements merit inclusion in routine gas monitoring at shv and other dome forming volcanoes

gas emissions from failed and actual eruptions from cook inlet volcanoes alaska 1989 2006 cook inlet volcanoes that experienced an eruption between 1989 and 2006 had mean gas emission rates that were roughly an order of magnitude higher than at volcanoes where unrest stalled for the six events studied mean emission rates for eruptions were 13 000 t d co2 and 5200 t d so2 but only 1200 t d co2 and 500 t d so2 for non eruptive events failed eruptions statistical analysis suggests degassing thresholds for eruption on the order of 1500 and 1000 t d for co2 and so2 respectively emission rates greater than 4000 and 2000 t d for co2 and so2 respectively almost exclusively resulted during eruptive events the only exception being two measurements at fourpeaked while this analysis could suggest that unerupted magmas have lower pre eruptive volatile contents we favor the explanations that either the amount of magma feeding actual eruptions is larger than that driving failed eruptions or that magmas from failed eruptions experience less decompression such that the majority of h2o remains dissolved and thus insufficient permeability is produced to release the trapped volatile phase or both in the majority of unrest and eruption sequences increases in co2 emission relative to so2 emission were observed early in the sequence with time all events converged to a common molar value of c s between 0 5 and 2 these geochemical trends argue for roughly similar decompression histories until shallow levels are reached beneath the edifice i e from 20 35 to 4 6 km and perhaps roughly similar initial volatile contents in all cases early elevated co2 levels that we find at these high latitude andesitic arc volcanoes have also been observed at mid latitude relatively snow free basaltic volcanoes such as stromboli and etna typically such patterns are attributed to injection and decompression of deep co2 rich magma into a shallower chamber and open system degassing prior to eruption here we argue that the c s trends probably represent tapping of vapor saturated regions with high c s and then gradual degassing of remaining dissolved volatiles as the magma progresses toward the surface at these volcanoes however c s is often accentuated due to early preferential scrubbing of sulfur gases the range of equilibrium degassing is consistent with the bulk degassing of a magma with initial co2 and s of 0 6 and 0 2 wt respectively similar to what has been suggested for primitive redoubt magmas

sulphur flows at lastarria volcano in the north chilean andes although several authors have suggested that sulphur plays an important role in the volcanism on the jovian moon io1 8 some deny the participation of elemental sulphur there at least in the form of cooled flows9 studies of volcanism on io have focused attention on the role of sulphur in terrestrial volcanism on earth fumarolic sulphur is very common in almost all active volcanoes but sulphur flows are rare having been reported only on siretoko iosan volcano in japan10 on sierra negra and azufre volcanoes in the galapagos islands11 12 and on mauna loa in hawaii13 14 of these the siretoko iosan example is the only natural molten sulphur flow to have been observed in the process of formation the others being rather poorly exposed i describe here a singularly well exposed example of sulphur lava flows on lastarria volcano in chile where the liquid sulphur appears to have been formed by melting of fumarolic sulphur deposits caused by a rise in the thermal gradient owing to the renewed activity of the magmatic source

monotonic laterally loaded pile testing in a stiff glacial clay till at cowden this paper describes the results obtained from a field testing campaign on laterally loaded monopiles conducted at cowden uk where the soil consists principally of a heavily overconsolidated glac

el chichon the genesis of volcanic sulfur dioxide monitoring from space the 1982 eruption of el chichon inspired a new technique for monitoring volcanic clouds data from the total ozone mapping spectrometer toms instrument on the nimbus 7 satellite were used to measure sulfur dioxide in addition to ozone for the first time precise data on the sulfur dioxide mass in even the largest explosive eruption plumes could be determined the plumes could be tracked globally as they are carried by winds magmatic eruptions could be discriminated from phreatic eruptions the data from el chichon are reanalyzed in this paper using the latest version of the toms instrument calibration v8 they show the shearing of the eruption cloud into a globe circling band while still anchored over mexico in three weeks the measured sulfur dioxide mass in the initial march 28 eruption was 1 6 tg the april 3 eruption produced 0 3 tg more and the april 4 eruptions added 5 6 tg for a cumulative total of 7 5 tg in substantial agreement with estimates from prior data versions toms aerosol index absorbing aerosol data show rapid fallout of dense ash east and south of the volcano in agreement with advanced very high resolution radiometer avhrr ash cloud positions

the magmatic and hydrothermal dominated fumarolic system at the active crater of lascar volcano northern chile low to high temperature fumaroles discharging from the active crater of lascar volcano northern chile have been collected in november 2002 may 2005 and october 2006 for chemical and isotopic analysis to provide the first geochemical survey on the magmatic hydrothermal system of this active volcano chemical and isotopic gas composition shows direct addition of high temperature fluids from magmatic degassing mainly testified by the very high contents of so2 hcl and hf up to 87 800 29 500 and 2 900 mol mol and the high r ra values up to 7 29 contributions from a hydrothermal source mainly in gas discharges of the active crater rim has also been detected significant variations in fluid chemistry mainly consisting of a general decrease of magmatic related compounds i e so2 have affected the fumarolic system during the period of observation indicating an increase of the influence of the hydrothermal system surrounding the ascending deep fluids the chemical composition of active crater fumaroles has been used to build up a geochemical model describing the main processes that regulate the fluid circulation system of lascar volcano to be utilized in volcanic surveillance

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

so2 bro ratios studied in five volcanic plumes abstract the distribution of bromine monoxide bro and sulphur dioxide so2 was measured by ground based max doas scattered light multi axis differential optical absorption spectroscopy in the plume of five volcanoes soufriere hills volcano on montserrat in may 2002 masaya volcano in nicaragua in march 2003 etna volcano on sicily in september october 2003 and august october 2004 stromboli volcano in italy in september 2003 and villarica in chile in november 2004 maximum slant column densities scds of several 1014 molecules cm2 of bro were observed bromine monoxide sulphur dioxide ratios of 10 0 10 4 0 8 10 4 4 8 10 4 2 1 10 4 2 1 10 4 and 1 3 10 4 were found in the plumes of soufriere hills masaya etna 2003 etna 2004 stromboli and villarica respectively causes for the differences in the bro so2 ratios for the various volcanic sites are discussed

daily monitoring of ecuadorian volcanic degassing from space we present daily measurements of sulfur dioxide so2 emissions from active volcanoes in ecuador and southern colombia between september 2004 and september 2006 derived from the ozone monitoring instrument omi on nasa s eos aura satellite omi is an ultraviolet visible spectrometer with an unprecedented combination of spatial and spectral resolution and global coverage that permits daily measurements of passive volcanic degassing from space we use non interactive processing methods to automatically extract daily so2 burdens and information on so2 sources from the omi datastream maps of monthly average so2 vertical columns retrieved by omi over ecuador and s colombia are also used to illustrate variations in regional so2 loading and to pinpoint sources the dense concentration of active volcanoes in ecuador provides a stringent test of omi s ability to distinguish so2 from multiple emitting sources our analysis reveals that tungurahua reventador and galeras were responsible for the bulk of the so2 emissions in the region in the timeframe of our study with no significant so2 discharge detected from sangay at galeras and reventador we conclude that omi can detect variations in so2 release related to cycles of conduit sealing and degassing which are a critical factor in hazard assessment the omi so2 data for reventador are the most extensive sequence of degassing measurements available for this remote volcano which dominated regional so2 production in june august 2005 at tungurahua the omi measurements span the waning stage of one eruptive cycle and the beginning of another and we observe increasing so2 burdens in the months prior to explosive eruptions of the volcano in july and august 2006 cumulative so2 loadings measured by omi yield a total of 1 16 tg so2 emitted by volcanoes on mainland ecuador s colombia between september 2004 and september 2006 as much as 95 of this so2 may originate from non eruptive degassing approximate apportionment of the total so2 loading indicates that 40 originated from tungurahua with 30 supplied by both reventador and galeras these measurements of volcanic so2 degassing in ecuador confirm omi s potential as an effective economical and risk free tool for daily monitoring of so2 emissions from hazardous volcanoes

depletion rates of sulfur dioxide in tropospheric volcanic plumes the tropospheric sulfur cycle has been closely studied from the standpoint of anthropogenic emissions but less so with respect to volcanic sources we document here evidence for wide variation in lifetimes of volcanic so2 in the troposphere at one extreme our observations of the plume associated with the lavadome eruption of soufriere hills volcano montserrat suggest loss of gaseous so2 at rates exceeding 10 3 s 1 while this efficent so2 depletion reflects unusual environmental factors published measurements for mount etna s plume approach these rapid rates in such cases source strengths of so2 must significantly exceed apparent fluxes measured several kilometres downwind this implies that meteorological and geographic factors as well as volcanic degassing rates should be considered in the interpretation of fluxes of so2 measured beyond source vents with ramifications for volcano monitoring and eruption prediction furthermore since most calculations of global volcanic fluxes of sulfur and other species to the troposphere are based on extrapolation of so2 flux data they may underestimate true source strengths finally we consider that fast sulfur chemistry may also prevail in convecting eruption columns resulting in partial tropospheric scrubbing of sulfur from stratosphere bound plumes

in situ measurements of tropospheric volcanic plumes in ecuador and colombia during tc4 a nasa dc 8 research aircraft penetrated tropospheric gas and aerosol plumes sourced from active volcanoes in ecuador and colombia during the tropical composition cloud and climate coupling tc 4 mission in july august 2007 the likely source volcanoes were tungurahua ecuador and nevado del huila colombia the tc 4 data provide rare insight into the chemistry of volcanic plumes in the tropical troposphere and permit a comparison of so 2 column amounts measured by the ozone monitoring instrument omi on the aura satellite with in situ so 2 measurements elevated concentrations of so 2 sulfate aerosol and particles were measured by dc 8 instrumentation in volcanic outflow at altitudes of 3 6 km estimated plume ages range from 2 h at huila to 22 48 h downwind of ecuador the plumes contained sulfate rich accumulation mode particles that were variably neutralized and often highly acidic a significant fraction of supermicron volcanic ash was evident in one plume in plume o 3 concentrations were 70 80 of ambient levels downwind of ecuador but data are insufficient to ascribe this to o 3 depletion via reactive halogen chemistry the tc 4 data record rapid cloud processing of the huila volcanic plume involving aqueous phase oxidation of so 2 by h 2o 2 but overall the data suggest average in plume so 2 to sulfate conversion rates of 1 2 h 1 so 2 column amounts measured in the tungurahua plume 0 1 0 2 dobson units are commensurate with average so 2 columns retrieved from omi measurements in the volcanic outflow region in july 2007 the tc 4 data set provides further evidence of the impact of volcanic emissions on tropospheric acidity and oxidizing capacity

satellite observations of the impact of weak volcanic activity on marine clouds 1 because emissions from weak volcanic eruptions tend to remain in the low troposphere they may have a significant radiative impact through the indirect effect on clouds however this type of volcanic activity is underreported and its global impact has been assessed only by model simulations constrained with very limited observations first observations of the impact of high latitude active volcanoes on marine boundary layer clouds are reported here these observations were made using a combination of standard derived products and visible images from the modis amsr e and goes detectors two distinctive effects are identified when there is an existing boundary layer cloud deck an increase in cloud brightness and a decrease in both cloud effective radius and liquid water content were observed immediately downwind of the volcanoes the visible appearance of these volcano tracks resembles the effect of man made ship tracks when synoptic conditions favor low cloudiness the volcano plume or volcano cloud increases significantly the cloud cover downwind the volcano cloud can extend for hundreds of kilometers until mixing with background clouds unlike violent eruptions the volcano clouds reported here the aleutian islands in the north pacific and the south sandwich islands in the south atlantic have retrieved microphysical properties similar to those observed in ship tracks however when comparing the volcano clouds from these two regions liquid water content can decrease increase or remain unchanged with respect to nearby unperturbed clouds these differences suggest that composition at the source type of eruption and meteorological conditions influence the evolution of the cloud

so2 and fine aerosol dispersion from the kilauea plume kau district hawaii usa proximal ground level assessment of sulfur dioxide gas and fine aerosol in the volcanic gas plume downwind from kilauea volcano indicates high levels of both species fine aerosol and so 2 data were collected in the kau district 37 74 km downwind from the eruption and at a nonexposed control site in hawi hawaii typical trade winds and effusive eruption occurred during sampling in august september 2003 ambient so 2 concentrations measured with diffusion tubes ranged from 6 to 34 ppbv and correlated negatively with altitude in contrast fine aerosol 0 3 m size concentrations measured with a cascade impactor ranged from 0 61 to 11 82 g m 3 and correlated positively with altitude we attribute decrease of so 2 with altitude to rapid oxidation as diurnal wind patterns blow the plume from oceanic terrain landward to more abundant oxidation sources aerosol increase with altitude likely reflects emission of h 2 so 4 from kilauea supplemented by oxidation of so 2 in atmospheric hydrosols kau residents are exposed to volcanogenic pollutants at concentrations that warrant concern for adverse health effects

evaluation of redoubt volcano s sulfur dioxide emissions by the ozone monitoring instrument abstract the 2009 eruption of redoubt volcano alaska provided a rare opportunity to compare satellite measurements of sulfur dioxide so2 by the ozone monitoring instrument omi with airborne so2 measurements by the alaska volcano observatory avo herein we 1 compare omi and airborne so2 column density values for redoubt s tropospheric plume 2 calculate daily so2 masses from mount redoubt for the first three months of the eruption 3 develop simple methods to convert daily measured so2 masses into emission rates to allow satellite data to be directly integrated with the airborne so2 emissions dataset 4 calculate cumulative so2 emissions from the eruption and 5 evaluate omi as a monitoring tool for high latitude degassing volcanoes a linear correlation r2 0 75 is observed between omi and airborne so2 column densities omi daily so2 masses for the sample period ranged from 60 1 kt on 24 march to below detection limit with an average daily so2 mass of 6 7 kt the highest so2 emissions were observed during the initial part of the explosive phase and the emissions exhibited an overall decreasing trend with time omi so2 emission rates were derived using three methods and compared to airborne measurements this comparison yields a linear correlation r2 0 82 with omi derived emission rates consistently lower than airborne measurements the comparison results suggest that omi s detection limit for high latitude springtime conditions varies from 2000 to 4000 t d cumulative so2 masses calculated from daily omi data for the sample period are estimated to range from 542 to 615 kt with approximately half of this so2 produced during the explosive phase of the eruption these cumulative masses are similar in magnitude to those estimated for the 1989 90 redoubt eruption strong correlations between daily omi so2 mass and both tephra mass and acoustic energy during the explosive phase of the eruption suggest that omi data may be used to infer relative eruption size and explosivity further when used in conjunction with complementary datasets omi daily so2 masses may be used to help distinguish explosive from effusive activity and identify changes in lava extrusion rates the results of this study suggest that omi is a useful volcano monitoring tool to complement airborne measurements capture explosive so2 emissions and provide high temporal resolution so2 emissions data that can be used with interdisciplinary datasets to illuminate volcanic processes

two scales of inflation at lastarria cordon del azufre volcanic complex central andes revealed from asar envisat interferometric data abstract asar envisat interferometric synthetic aperture radar insar data collected over the lastarria cordon del azufre complex chile argentina between march 2003 and may 2005 show the persistence of the large wavelength ground inflation revealed by pritchard and simons in 2002 from the analysis of ers insar data nature 418 2002 167 170 after reducing the tropospheric contribution in the interferograms using a combination of data network adjustment and analysis of modis images we produced an accurate interferometric time series showing a 2 yr long temporal evolution of the ground displacements patterns two distinct inflating signals are detected the main signal covers an elliptical area with a 45 km nne ssw major axis and a 37 km minor axis it is correlated with a regional topographic dome we estimated its maximum inflation rate to 2 5 cm yr 1 we inverted the insar data for a range of source geometries spherical prolate ellipsoids penny shaped cracks the inferred source parameters for 2003 2005 period are consistent with an over pressured reservoir at shallow to intermediate crustal depths 7 15 km with an average volumetric rate of inflation of about 14 106 m3 yr 1 in addition to this main signal a new feature highlighted by the asar data is short wavelength inflation 6 km wide at the location of lastarria volcano on the northern margin of the large wavelength signal we explain this short wavelength signal by a spherical over pressured source lying 1000 m below the summit of lastarria volcano we estimate the average volumetric rate of inflation during the observation period to be 35 103 m3 yr 1 it is remarkable that both volumetric variations for the large and small inflations exhibit the same evolution during the 2003 2005 period suggesting that both processes could be related on the basis of the inversion results and of arguments provided by field evidences and a morpho structural analysis of the digital elevation model of the area we propose that the deep source have a magmatic origin while the shallow source is most likely related to hydrothermal fluids in our interpretation the on going deformation processes observed at lastarria cordon del azufre volcanic complex could represent an evolving pre caldera silicic system further field geological and geophysical investigations will be required to confirm these hypotheses and refine the proposed model mostly based on satellite observations

space and ground based measurements of sulphur dioxide emissions from turrialba volcano costa rica remotely sensed measurements of sulphur dioxide so2 emitted by turrialba volcano costa rica are reported for the period september 2009 january 2011 these measurements were obtained using images from advanced spaceborne thermal emission and reflexion radiometer ozone monitoring instrument and a ground based uv camera these three very different instruments provide flux measurements in good agreement with each other which demonstrate that they can be integrated for monitoring so2 fluxes fluxes from turrialba increased fourfold in january 2010 following a phreatic explosion that formed a degassing vent in the w crater of turrialba since then the so2 flux has remained high 30 50 kg s but seems to be showing a slowly decreasing trend we interpret this evolution as the start of open vent degassing from a recently intruded magma body the opening of the degassing vent decreased the confining pressure of the magma body and allowed the gases to bypass the hydrothermal system

so2 loss rates in the plume emitted by soufriere hills volcano montserrat to improve interpretation of volcanic so2 flux data it is necessary to quantify and understand reactions involving so2 in volcanic plumes so2 is lost in volcanic plumes through a number of mechanisms here we report so2 measurements made with miniature ultraviolet spectrometers at soufriere hills volcano montserrat a low altitude volcano 1000 m above sea level whose plume entrains humid marine air in the planetary boundary layer traverses very near 2 km downwind from soufriere hills volcano significantly underestimate at source so2 emission rates on the order of 70 146 when not accounting for the decay rate similar so2 loss is likely to occur in plumes from other tropical low altitude volcanoes under conditions of high relative humidity 20 of active volcanoes worldwide these results suggest that the global volcanic so2 emission rate may be underestimated as the estimates are based on measurements taken downwind of volcanoes by which time significant loss of so2 may have taken place the loss rates calculated here could be used in conjunction with downwind so2 fluxes to estimate at source so2 emission rates from volcanoes with similar environmental conditions to those at soufriere hills volcano

sulfur dioxide flux estimation from volcanoes using advanced spaceborne thermal emission and reflection radiometer a case study of miyakejima volcano japan abstract a method is described for estimating the two dimensional spatial distribution of volcanic so2 using thermal infrared image data acquired by the advanced spaceborne thermal emission and reflection radiometer aster the author proposes a new method to estimate wind velocity and plume height using an along track stereoscopic pair image volcanic so2 flux can be estimated from the spatial distribution of so2 and wind velocity since aster has both the thermal infrared radiometer tir and stereoscopic viewing function in the along track direction the volcanic so2 flux can be estimated from the aster data alone these methods are applied to the miyakejima volcano japan the so2 flux derived from aster is around 5 104 ton day 580 kg s 1 which is slightly larger than the value derived from cospec the plume height estimation error may cause this disagreement because the so2 estimation procedure is very sensitive to the plume height

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

remarkable geochemical changes and degassing at voui crater lake ambae volcano vanuatu abstract ambae also known as aoba is a 38 16 km 2 lozenge shaped island volcano with a coastal population of around 10 000 at the summit of the volcano is lake voui one of the largest active crater lakes worldwide with 40 10 6 m 3 of acidic water perched 1400 m a s l after more than 300 years of dormancy ambae volcano reawakened with phreatic eruptions through voui in 1995 and culminating in a series of surtseyan eruptions in 2005 followed by a rapid and spectacular colour change of the lake from light blue to red in 2006 integrating lake water chemistry with new measurements of so 2 emissions from the volcano during the 2005 2006 eruptive period helps to explain the unusual and spectacular volcanic activity of ambae initially a degassed magma approached the lake bed and triggered the surtseyan eruption depressurization of the conduit facilitated ascent of volatile rich magma from the deeper plumbing system the construction of a cone during eruption and the high degassing destabilised the equilibrium of lake stratification leading to a limnic event and subsequently the spectacular colour change

first estimate of volcanic so2 budget for vanuatu island arc abstract the spatial and temporal coverage of measurements of volcanic gas emissions remains patchy however over the last decade emissions inventories have improved thanks to new measurements of some of the lesser known volcanic areas we report on one such region the vanuatu island arc in the southwest pacific for which we now have sufficient systematic observations to offer a systematic emissions inventory our new estimate is based on so 2 flux measurements made in the period 2004 2009 with ultraviolet spectroscopy techniques for the following volcanoes yasur lopevi ambrym ambae gaua and vanua lava from south to north these are the first ever measurements for lopevi gaua and vanua lava the results reveal the vanuatu arc as one of earth s prominent sources of volcanic degassing with a characteristic annual emission to the atmosphere of 3 tg of so 2 representing about 20 of hitherto published global estimates our new dataset highlights the sustained prodigious degassing of ambrym volcano whose 5 gg day 1 mean flux of so 2 represents nearly two thirds of the total budget for the vanuatu arc this confirms ambrym as one of the largest volcanic sources worldwide comparable to etna often considered as the most vigorous source of volcanic emission on earth we also report a high degassing for ambae of 2 gg day 1 so 2 representing more than 28 of the vanuatu arc budget thus 90 of the so 2 output from vanuatu is focused in the central part of the arc from ambrym and ambae where magmas originate from enriched indian type mantle and where peculiar tectonic conditions could favor high magma production rates

surge in sulphur and halogen degassing from ambrym volcano vanuatu volcanoes provide important contributions to atmospheric budgets of so2 and reactive halogens which play significant roles in atmospheric oxidative capacity and radiation however the global source strengths of volcanic emissions remain poorly constrained these uncertainties are highlighted here by the first measurements of gas emission rates from ambrym volcano vanuatu our initial airborne ultraviolet spectroscopic measurements made in january 2005 indicate fluxes of 18 270 kg s 1 of so2 and 62 110 g s 1 of bro into the atmosphere placing ambrym amongst the largest known contemporary point sources of both these species on earth we also estimate high cl and f fluxes of 8 14 and 27 50 kg s 1 respectively for this period further observations using both airborne and spaceborne remote sensing reveal a fluctuating so2 output between 2004 and 2008 with a surge in the first half of 2005 and underline the substantial contribution that a single passively degassing volcano can make to the atmospheric budget of sulfur and halogens

temporal variability of accumulation at neumayer station antarctica from stake array measurements and a regional atmospheric model in this study we investigate the ability of the regional atmospheric model racmo to represent temporal variations of antarctic accumulation using weekly stake array measurements from neumayer station the model uses ecmwf reanalyses data to force the atmospheric variables at the lateral boundaries of the model domain accumulation is defined as precipitation minus sublimation generally the model represents the synoptic situations that lead to precipitation reasonably well the amounts of accumulation are however usually lower in the model than in the measurements it cannot be distinguished whether the model underestimates precipitation or whether this effect is due to the redistribution of snow by the wind which is not taken into account in the model but affects the accumulation at the measuring site significant differences between model and measurements also occur in cases of net ablation due to wind erosion or when accumulation was due to snowdrift from southwest without precipitation observed

first synoptic analysis of volcanic degassing in papua new guinea we report the first satellite based survey of volcanic sulphur dioxide so2 degassing in papua new guinea using ozone monitoring instrument omi data omi is sensitive to low level passive degassing these observations are useful for volcano monitoring hazard assessment particularly aviation hazard and assessment of arc geochemical budgets and are of immense value in remote regions with little ground based instrumentation such as papua new guinea we identify bagana manam rabaul ulawun and langila as the active sources of volcanic so2 in papua new guinea with bagana being the largest source we present an omi so2 time series for 2005 2008 and a total detected regional output of 1 8 109 kg so2 about 40 of emissions were released by major eruption events at manam january 2005 bagana june 2006 and rabaul october 2006 over the past century however we estimate that major explosive eruptions contribute 5 of the arc scale so2 emission budget ground based doas measurements of so2 degassing at five of papua new guinea s volcanoes are compared with our omi observations the total omi so2 output is only 20 of the total extrapolated from doas a discrepancy which we demonstrate is consistent with other volcanic arcs therefore the true total regional so2 output may be considerably higher than that detected by omi uncertainties in the omi so2 data include the effects of in plume chemical processing and dilution of so2 prior to the satellite overpass omi s reduced sensitivity to low levels of so2 in the planetary boundary layer and interference by meteorological clouds