Impact of Icelandic dust and volcanic ash on snow and ice

Located on the mid-Atlantic ridge, Iceland has the largest volcaniclastic desert on Earth, created by glacio-fluvial processes and frequent volcanic eruptions. Due to its location along the North Atlantic Storm track, Iceland frequently experiences high winds. With an abundance of loose dust (particulate matter) from sandur plains and high winds, Icelandic glaciers are exposed to dust storms and redistributed ash. Deposited material is influencing glacier albedo and therefore the surface energy balance. The effects of deposited volcanic ash on ice and snow melt were examined using laboratory and outdoor experiments to find an insulating threshold and showed that ash insulated the ice at a thickness of 9-15 mm whereas maximum melt occurred at a thickness of ≤1-2 mm. To estimate the frequency of dust events, the dispersion model FLEXDUST was used to simulate dust events on Brúarjökull, a north outlet of Vatnajökull for the year 2012. All simulated dust events showed a corresponding albedo drop at the weather stations. For the weather station B13, near the ELA on Brúarjökull, FLEXDUST produced 10 major dust deposition events and a total annual deposition of 20.5 g m-2. Surface snow samples from Vatnajökull were analysed for impurities to map the distribution over the ice cap in 2013 and 2015, as well as two 4.5 m deep firn cores on Brúarjökull were drilled in 2015. The cores reached down to the year 2006 and showed distinct dust layers for the years 2014, 2012, 2011 and 2008 and only very small amounts for the years 2007 and 2013.Á Íslandi er að finna stærstu sanda heims úr basísku gjóskugleri. Þeir hafa myndast úr eldfjallaösku frá fjölda eldgosa og við jökul- og vatnsveðrun gosbergs. Mjög vindasamt er á Íslandi vegna legu landsins í brautum lægða eftir Norður Atlantshafi . Gnægð lausra efna (svifryks) í söndum landsins og vindasöm veðrátta gerir jökla á landsins útsetta fyrir sandog öskufoki. Efnið sem sest á jöklana hefur áhrif á endurkast sólarljóss frá yfirborðinu. Yfirborðið verður dekkra og tekur upp meira af orku frá sólgeislun; það hefur áhrif á orkubúskap við jökulyfirborð, leysingu og þannig afkomu jöklanna. Áhrif eldfjallaösku sem sests á snjó og ís voru rannsökuð með tilraunum, bæði á tilraunastofu og í náttúrunni. Fundin voru mörkin þar sem öskuþykkt er svo mikil að hún einangrar alveg og hindrar bráðnun íss og reyndust þau vera 9 - 15 mm. Hámarks aukning í bráðnunar varð hinsvegar þegar öskulagið er um ≤1-2 mm þykkt. Reiknilíkanið FLEXDUST, sem reiknar dreifingu loftborinna efna, var notað til að herma sandfok á Brúarjökul í norður Vatnajökli árið 2012. Við öll tilvik sandfoks sem komu fram í líkanreikningum mældist samsvarandi lægra hlutfall endurkastaðs sólarljóss frá yfirborði við sjálfvirkar veðurstöðvar á jöklinum. Við veðurstöð nærri jafnvægislínu Brúarjökuls, voru 10 tilvik verulegs sandfoks og uppsafnað magn efnis var 20.5 g/m2 samkvæmt líkanreikningunum. Kort af dreifingu ryks á yfirborði Vatnajökuls voru gerð eftir mælingum á rykmagni í snjósýnum sem safnað var af yfirborði (við hausthvörf) Vatnajökuls haustin 2013 og 2015. Einnig var borað eftir tveimur 4.5 m löngum kjörnum úr efsta hluta hjarns á safnsvæði Brúarjökuls árið 2015. Kjarnarnir náðu aftur til ársins 2006 og greinileg ryklög í þeim rakin til hausthvarfa áranna 2014, 2012, 2011 og 2008, en aðeins fannst mjög lítið ryk árin 2007 og 2013

Junge Psychoanalyse am PSZ: Eine Generation von PsychoanalytikerInnen zwischen Identifikation und Frustration

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Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland

Deposition of small amounts of airborne dust on glaciers causes positive radiative forcing and enhanced melting due to the reduction of surface albedo. To study the effects of dust deposition on the mass balance of Brúarjökull, an outlet glacier of the largest ice cap in Iceland, Vatnajökull, a study of dust deposition events in the year 2012 was carried out. The dust-mobilisation module FLEXDUST was used to calculate spatio-temporally resolved dust emissions from Iceland and the dispersion model FLEXPART was used to simulate atmospheric dust dispersion and deposition. We used albedo measurements at two automatic weather stations on Brúarjökull to evaluate the dust impacts. Both stations are situated in the accumulation area of the glacier, but the lower station is close to the equilibrium line. For this site ( ∼  1210 m a.s.l.), the dispersion model produced 10 major dust deposition events and a total annual deposition of 20.5 g m−2. At the station located higher on the glacier ( ∼  1525 m a.s.l.), the model produced nine dust events, with one single event causing  ∼  5 g m−2 of dust deposition and a total deposition of  ∼  10 g m−2 yr−1. The main dust source was found to be the Dyngjusandur floodplain north of Vatnajökull; northerly winds prevailed 80 % of the time at the lower station when dust events occurred. In all of the simulated dust events, a corresponding albedo drop was observed at the weather stations. The influence of the dust on the albedo was estimated using the regional climate model HIRHAM5 to simulate the albedo of a clean glacier surface without dust. By comparing the measured albedo to the modelled albedo, we determine the influence of dust events on the snow albedo and the surface energy balance. We estimate that the dust deposition caused an additional 1.1 m w.e. (water equivalent) of snowmelt (or 42 % of the 2.8 m w.e. total melt) compared to a hypothetical clean glacier surface at the lower station, and 0.6 m w.e. more melt (or 38 % of the 1.6 m w.e. melt in total) at the station located further upglacier. Our findings show that dust has a strong influence on the mass balance of glaciers in Iceland.The study described in this manuscript was supported by NordForsk as part of the two Nordic Centres of Excellence Cryosphere-Atmosphere Interactions in a Changing Arctic climate (CRAICC), and eScience Tools for Investigating Climate Change (eSTICC). Part of this work was supported by the Centre of Excellence in Atmospheric Science funded by the Finnish Academy of Sciences Excellence (project no. 272041), by the Finnish Academy of Sciences project A4 (contract 254195). Data from in situ mass balance surveys and on glacier automatic weather stations are from joint projects of the National Power Company and the Glaciology group of the Institute of Earth Science, University of Iceland. C. Groot Zwaaftink was also funded by the Swiss National Science Foundation SNF (155294), and Louise Steffensen-Schmidt, Finnur Palsson and Sverrir Gudmunds-son by the Icelandic Research Fund (project SAMAR) and the National Power Company of Iceland. Olafur Arnalds was in part funded by Icelandic Research Fund (grant no. 152248-051)Peer Reviewe

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Der vorliegende Bericht beruht auf den Ergebnissen der von Statistik Austria quartalsweise durchgeführten Befragung "So geht's uns heute". Im Mittelpunkt der Analysen stehen finanzielle Schwierigkeiten in den Privathaushalten Österreichs, deren Entwciklungen im Zeitverlauf - insbesondere im Vergleich zum Vorjahr (Q1/2022) und zum Vorquartal (Q4/2022) - nachgezeichnet werden. Darüber hinaus wird in diesem Bericht ein Fokus auf das Thema Engergiearmut gelegt

The N-terminal coiled-coil of Ndel1 is a regulated scaffold that recruits LIS1 to dynein

Binding of the N terminus of Ndel1 to dynein facilitates microtubule self-organization in Ran-induced asters

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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