Fćrsluflokkur: Vísindi og frćđi

Agnir í andrúmlofti "földu" hlýnun í BNA

 Vegna vandrćđa viđ ađ flytja fćrslur birtast ţćr hér:

http://throsturth.wordpress.com/2012/04/28/agnir-andrmlofti-fldu-hlnun-austurhluta-bna/

 

Sama fćrsla einnig hér - ađeins almennari greinar birtast hérna:

http://joklahopur.blogspot.com/2012/04/agnir-i-andrumlofti-foldu-hlynun-i.html


Ný grein um heilsu og eldgosiđ í Eyjafjallajökli

Ný grein í BMJ open um fyrstu niđurstöđur rannsókna á heilsufari íbúa í nágrenni Eyjafjallajökuls eftir gosiđ 2010.

Í stuttu máli virđist askan ekki hafa haft verulega alvarleg áhrif, engin bráđatilfelli, fyrir utan ertingu í öndunarfćrum og ađ ţeir sem höfđu astma fundu fyrir meiri áhrifum.

Tilvitnun:

Hanne Krage Carlsen, Thorarinn Gislason, Bryndis Benediktsdottir, Thorir Bjorn Kolbeinsson, Arna Hauksdottir, Throstur Thorsteinsson, Haraldur Briem. 2012. 
A survey of early health effects of the Eyjafjallajökull 2010 eruption in Iceland: a population-based study
BMJ Open 2012;2:e000343. doi:10.1136/bmjopen-2011-000343 (Paper on BMJ Open web site)


Ný grein í JGR um ösku og öskufok vegna eldgossins í Eyjafjallajökli 2010

High levels of particulate matter in Iceland due to direct ash emissions by the Eyjafjallajökull eruption and resuspension of deposited ash
Hár styrkur svifryks vegna öskufalls og öskufoks í kjölfar eldgossins í Eyjafjallajökli

Throstur Thorsteinsson
Environment and Natural Resources and Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland
Thorsteinn Jóhannsson
The Environment Agency of Iceland, Reykjavík, Iceland
Andreas Stohl and Nina I. Kristiansen
Norwegian Institute for Air Research, Kjeller, Norway

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117, B00C05, 9 PP., 2012

Citation: Thorsteinsson, T., T. Jóhannsson, A. Stohl, and N. I. Kristiansen (2012), High levels of particulate matter in Iceland due to direct ash emissions by the Eyjafjallajökull eruption and resuspension of deposited ash, J. Geophys. Res., 117, B00C05, doi:10.1029/2011JB008756.

Abstract / Ágrip (athugiđ ađ mjög gróf ţíđing á ágripi hér ađ neđan)

Ţćr hćttur sem steđja ađ ţeim sem búa nálćgt eldfjalli eru margar hverja vel ţekktar, eins og glóandi hraun og ef eldfjalliđ er undir jökli jökulhlaup. Hinsvegar er minna vitađ um ţá hćttu sem kann ađ stafa af miklu magni af fíngerđri ösku í lofti, hvort heldur um er ađ rćđa öskufall eđa öskustorm. Eldgosiđ í Eyjafjallajökli, sem stóđ frá 14. apríl til 20. maí 2010, framleiddi mikiđ af ösku. Eftir ađ gosi lauk var enn mikiđ af fíngerđri ösku í lofti (svifryk) vegna öskustorma. Sólarhringsmeđaltal svifryks (PM10) í Vík fór í 1230 μg m−3, sem er 25 sinnum meira en heilsuverndarmörkin segja til um, ţann 7. maí 2010. Ţann dag náđu 10-mín međaltöl yfir 13,000 μg m−3. Jafnvel eftir ađ gosi lauk mćldust gríđarlega há gildi, 8000 μg m−3 (10-mín) og 900 μg m−3 (sólarhringsmeđaltal), vegna öskustorma. Í Reykjavík, sem er 125 km í VNV frá Eyjafjallajökli, mćldist PM10 yfir 2000 μg m−3 (10-mín) í öskustormi ţann 4. júní, 2010, en sá styrkur er nćgjanlega mikill til ađ réttlćta lokun flugvalla. Ţessi rannsókn sýnir ađ öskufok er mjög mikilvćgt og ćtti ađ huga ađ alveg eins og beinu öskufalli. Öskufok hefur áhrif á loftgćđi, en einnig veruleg áhrif á líkanreikninga af dreifingu ösku, ţar sem flest líkön taka ekki öskufok međ í reikninginn.

The dangers to people living near a volcano due to lava and pyroclastic flows, and, on glacier- or snow-covered volcanoes, jökulhlaups, are well known. The level of risk to human health due to high concentrations of ash from direct emission and resuspension from the ground is, however, not as well known. The eruption at Eyjafjallajökull, 14 April to 20 May 2010, produced abundant particulate matter due to its explosive eruption style. Even after the volcanic activity ceased, high particulate matter (PM) concentrations were still measured on several occasions, due to resuspended ash. The 24 hour mean concentration of PM10 in the small town of Vík, 38 km SE of the volcano, reached 1230 μg m−3, which is about 25 times the health limit, on 7 May 2010, with 10 min average values over 13,000 μg m−3. Even after the eruption ceased, values as high as 8000 μg m−3 (10 min), and 900 μg m−3 (24 h), were measured because of resuspension of freshly deposited fine ash. In Reykjavík, 125 km WNW of the volcano, the PM10 concentration reached over 2000 μg m−3 (10 min) during an ash storm on 4 June 2010, which should have warranted airport closure. Summarizing, our study reveals the importance of ash resuspension compared to direct volcanic ash emissions. This likely has implications for air quality but could also have detrimental effects on the quality of ash dispersion model predictions, which so far generally do not include this secondary source of volcanic ash.

Áhugasamir geta fengiđ eintak af greininni međ ţví ađ senda mér tölvupóst.


Ađ megninu til "gamaldags" sandstormur ?

Á gervitunglamyndum má sjá ađ sandstrókur liggur frá Landeyjasandi í áttina til höfuđborgarsvćđisins. Sjá hér ...

http://throsturth.wordpress.com/2011/07/23/dust-storm-from-landeyjasandur/


mbl.is Léleg loftgćđi í Reykjavík
Tilkynna um óviđeigandi tengingu viđ frétt

Svifryk í lofti fyrir austan ţann 4. júní 2011

Sjá ThrosturTh.wordpress.com

Fćrslu fćrđar á ThrosturTh.wordpress.com í bili

Vegna vandamála viđ ađ senda inn fćrslur á ţetta blogg, ţá bendi ég á ađ ég set inn myndir á ThrosturTh.wordpress.com á íslensku.

Á ensku:
EnvNatRes.wordpress.com


Eldgos í Grímsvötnum, Vatnajökli

Gos er hafiđ í Grímsvötnum.Stór og mikill gosstrókur og nokkuđ mikiđ öskufall austur af Vík. Búast má viđ jökulhlaupi, en sennilega ekki mjög stóru ţar sem lítiđ (nánast ekkert) vatn í Grímsvötnum. Ţađ veltur ţó mikiđ á stćrđ og legu gossprungunnar.

Gervitunglamynd frá 21. maí 2011, kl. 22:00 (NASA/MODIS, from IMO).

20110521_2200_modis_A20111412200 

Gervitunglamynd frá 22. maí 2011, kl. 05:10 (NASA/MODIS, from IMO).

20110522_0510_modis_P20111420510 


Feltferđ í jöklafrćđi 2011

2011 Glaciology Field Trip

Nokkrar myndir frá međal annars:

  • Gígjökli – stórbrotnar breytingar eftir gosiđ
  • Sólheimajökli – alltaf miklar breytingar
  • Reynisfjöru – flott stuđlaberg

Grein í Atmospheric Chemistry and Physics um útstreymi ösku í Eyjafjallajökuls-gosinu 2010

Determination of time- and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: the 2010 Eyjafjallajökull eruption

A. Stohl1, A. J. Prata1, S. Eckhardt1, L. Clarisse2, A. Durant1,3,4, S. Henne5, N. I. Kristiansen1, A. Minikin6, U. Schumann6, P. Seibert7, K. Stebel1, H. E. Thomas4, T. Thorsteinsson8, K. Třrseth1, and B. Weinzierl6

1
Norwegian Institute for Air Research (NILU), Kjeller, Norway, 2Spectroscopie de l'Atmosphére, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles, Brussels, Belgium, 3Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK, 4Department of Geological Engineering and Sciences, Michigan Technological University, Houghton, MI, USA, 5Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland, 6Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany, 7Institute of Meteorology, University of Natural Resources and Life Sciences, Vienna, Austria, 8Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland


Abstract. The April–May, 2010 volcanic eruptions of Eyjafjallajökull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that large improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 ± 4.2 Tg for particles in the size range of 2.8–28 μm diameter. We evaluate the results of our model results with a posteriori ash emissions using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "Normal" flying zone in up to 14 % (6–16 %), 2 % (1–3 %) and 7 % (4–11 %), respectively, of the European area. For a limit of 2 mg m−3 only two episodes with fractions of 1.5 % (0.2–2.8 %) and 0.9 % (0.1–1.6 %) occurred, while the current "No-Fly" zone criterion of 4 mg m−3 was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system.


Paper (PDF, 2220 KB)

Citation: Stohl, A., Prata, A. J., Eckhardt, S., Clarisse, L., Durant, A., Henne, S., Kristiansen, N. I., Minikin, A., Schumann, U., Seibert, P., Stebel, K., Thomas, H. E., Thorsteinsson, T., Třrseth, K., and Weinzierl, B.: Determination of time- and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: the 2010 Eyjafjallajökull eruption, Atmos. Chem. Phys., 11, 4333-4351, doi:10.5194/acp-11-4333-2011, 2011.   

 

Hlekkur á greinina: http://www.atmos-chem-phys.net/11/4333/2011/acp-11-4333-2011.html


Grein í Náttúrufrćđingnum um landbrot og mótun strandar viđ Blöndulón

Greinin fjallar um landbrot og mótun strandar viđ Blöndulón. Vel hefur veriđ fylgst međ rofi síđan 2004, og á einu sniđi síđan 1997.

Reikningar á ölduálagi eru bornir saman viđ mćlingar á rofi.

Ţróun strandar er rćdd út frá mćlingum og athugunum.

 

 

Heimildin:

Olga Kolbrún Vilmundardóttir, Ţröstur Ţorsteinsson, Borgţór Magnússon og Guđrún Gísladóttir. 2011.
Landbrot og mótun strandar viđ Blöndulón.
Náttúrufrćđingurinn, 81(1): 17 - 30.

Grein sem fjallar nánar um frćđin og slíkt:

O. K. Vilmundardóttir, B. Magnússon, G. Gísladóttir, Th. Thorsteinsson.  2010.
Shoreline erosion and aeolian deposition along a recently formed hydro-electric reservoir, Blöndulón, Iceland.
Geomorphology, 114(4): 542 - 555.


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