Still plenty of ash to be blown around, south of Vatnajökull for instance, when it is dry and windy as it was on the 17 and 18 of October.
MODIS image taken at 13:30 (Image courtesy of NASA/Rapifire).
MODIS image taken at 11:40 (Image courtesy of NASA/Rapifire).
Still dry weather, and wind, and lot of dust and ash blowing around. Source of particulate matter in Reykjavik from south of Langjökull; not only ash. Also, a clear source on Vatnajökull (see animation below).
This made for poor air quality, as well as poor visibility. An example from greater Reykjavik area below. View from underneath Helgafell towards Esja.
Satellite images show this well (images from NASA/Rapidfire).
Today, 10 September 2011, there is a lot of ash blowing off the surface of western Vatnajökull.
There is more ash blowing around, as can be seen from the satellite image from 12:30 today.
MODIS image from NASA/Rapidfire.
The source is also quite clearly seen on this image, taken at 12:15.
MODIS image from NASA/Rapidfire.
Sediments from pro-glacial lakes near Langjökull, and ash from the Eyjafjalljökull and Grímsvötn eruptions (most likely mixture of those) were blowing around today !
MODIS image taken 2011-09-09 at 11:30 (NASA/Rapidfire).
MODIS image taken 2011-09-09 at 13:25.
MODIS image 2011-09-09 at 15:05.
Made for very bad air quality, for instance at Raufarfell.
An article about dust storms and air quality in Reykjavík was just published in the journal Atmospheric Environment.
Here is a link to the corrected proof http://www.sciencedirect.com/science/article/pii/S1352231011005061.
Also welcome to drop me an e-mail for the final version.
The reference is:
Throstur Thorsteinsson, Guðrún Gísladóttir, Joanna Bullard and Grant McTainsh. 2011.
Dust storm contributions to airborne particulate matter in Reykjavík, Iceland.
Atmospheric Environment, 45: 5924 - 5933.
Part of Figure 5. MODIS image from NASA/Rapidfire.
NASA MODIS satellite image from 16 August 2011 over the Barents sea (see map below).
(Image NASA/Rapidfire)
Concentration of phytoplankton using chlorophyll colors the ocean – see description below the map.
Click for a larger image (Map by Google maps)
At the base of the ocean food web are single-celled algae and other plant-like organisms known as phytoplankton. Like plants on land, phytoplankton use chlorophyll and other light-harvesting pigments to carry out photosynthesis, absorbing atmospheric carbon dioxide to produce sugars for fuel. Chlorophyll in the water changes the way it reflects and absorbs sunlight, allowing scientists to map the amount and location of phytoplankton. In many coastal areas, the rising slope of the sea floor pushes cold water from the lowest layers of the ocean to the surface. The rising, or upwelling water carries iron and other nutrients from the ocean floor.
(Adapted from http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MY1DMM_CHLORA)
Throstur Thorsteinsson.
At Raufarfell the PM10 reached 590 micro-g/m3 just before 16:00.
The northerly wind direction blows sand from Landeyjasandur out to sea, over Vestmannaeyjar.
At Stórhöfði, Vestmannaeyjar, the wind was from the north at 21 m/s at 16:00. And between 15 and 18 m/s from the NNE between 12 and 13.
Satellite image taken at 12:35 by Terra (image NASA/Rapidfire and IMO).
Þröstur Þorsteinsson.
Environment and Natural Resources & Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland.
In the news yesterday, 4 June 2011, there were reports about an ash storm in the eastern fjords (see short text, in Icelandic, below):
| Öskumistur á Austfjörðum
Þétt öskumistur liggur nú yfir Fáskrúðsfirði Mynd: Óðinn Magnason | Vestlæg átt er nú ríkjandi á austfjörðum og leggur því öskumistur yfir. Að sögn Óðins Magnasonar á Fáskrúðsfirði er bærinn hulinn talsvert þykku mistri og snjórinn í fjöllunum orðinn gráleitur. Þá segir Óðinn augljóst af bragðinu á loftinu að ekki sé um að ræða venjulegt ryk eða moldrok, heldur ösku frá Grímsvatnagosinu, enda sé bíllinn hans hulinn svörtu öskuryki. |
No doubt that re-suspended ash probably was responsible, at least partly. But, from satellite images, it is clear that a well know dust storm source area is also involved. That area is north of Vatnajökull, north of Dyngjujökull, a large sandur area.
The images below are taken at 12:30, 14:05 and 14:20 and are all MODIS images, from NASA/Rapidfire.
12:30
14:05
14:20
The source areas can be others and more spread out, but clearly the sandur north of Vatnajökull is at least partly to blame. Of course it could well be covered with ash after the Grímsvötn eruption.
It seems that the eruption in Grímsvötn is quickly winding down.
Plenty of ash to deal with though !
Couple of satellite images, from NASA MODIS sensors, from 23 and 24 May 2011.
23 May 2011. A lot of ash, probably mostly windblown but hard to tell exactly.
24 May 2011. A little better, in terms of actually seeing down to the land surface, and less material being emitted and/or blown.
Measurements in the great Reykjavik area, at Hvaleyrarholti and Digranesheiði, show clearly that as from the eruption in Grímsvötn has reached Reykjavik. Around 20:30 on 22 May 2011.
Latest measurements indicate that this was about the top values, this time around, with concentration much lower now at 22:00, and high value of 194 micro-g/m3 at HEH.
Of course we can expect other peaks like this, even later tonight.
At 13:00 today, 22 May 2011 (NASA MODIS/Rapidfire).
Today at 11:26; 22 May 2011 (MODIS/NASA/RAPIDFIRE – EV).
Today at 13:04 (MODIS/NASA/Rapidfire).
Eruption has started in Grímsvötn, Vatnajökull, Iceland.
Big plume, and some ash fall. Can expect jökulhlaup, probably not very large, but depends on the size of the eruption site.
Image from 21 May 2011, at 22:00 (NASA/MODIS, from IMO).
Image from 22 May 2011, at 05:10 (NASA/MODIS, from IMO).
 |
| 2011 Glaciology Field Trip |
A few pictures, including:
This article deals with wave erosion and evolution of the banks of the man-made reservoir lake, Blöndulón.
The bank evolution has been monitored quite closely since formation of the lake.
Calculations of the wave power are compared to erosion rates. Complicated relationship, different types of banks, episodic events, and relatively short time series 1997 to 2010.
But, as seen in the figure below, it is possible to see some correlation.
“Ölduorka” – Wave power (kWh/m), and “Rof” – Erosion (m).
Reference:
Olga Kolbrún Vilmundardóttir, Þröstur Þorsteinsson, Borgþór Magnússon og Guðrún Gísladóttir. 2011.
Landbrot og mótun strandar við Blöndulón.
Náttúrufræðingurinn, 81(1): 17 - 30.
For a paper with more details about the theory, see:
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.
Rather high values of PM10 now in Reykjavik.
The reason, as seen in the image below, is partly due to dust storms from Landeyjasandur (just north of Vestmannaeyjar).
Measurement at Grensás, in Reykjavik, show that the PM10 concentration reached just over 400 micro-grams per cubic meter just after 16:00.
A poster presented at the EGU in Vienna and Spring conference of the Icelandic Geology Society in April 2011.
The abstract*:
High levels of particulate matter due to ash plume and ash re-suspension following the Eyjafjallajökull eruption.
Throstur Thorsteinsson1, Thorsteinn Johannsson2 and Gudrun Petursdottir3
1Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik (ThrosturTh@gmail.com), 2The Environment Agency of Iceland, Sudurlandsbraut 24, 108 Reykjavik, 3Institute for Sustainability Studies, University of Iceland, Gimli v/ Háskólatorg, 107 Reykjavík
The dangers to people living near a volcano due to lava and pyroclastic flow, and, on ice or snow covered volcanoes, jökulhlaup (floods) are well known. The level of risk due to ash fall is, however, not as well known.
The eruption at Eyjafjallajökull, 14 April to 20 May 2010 (last day of visible plume), produced abundant particulate matter (PM). After the volcanic activity ceased high PM concentration has been measured on several occasions, due to re-suspended ash.
The particulate matter (PM10) concentration in the small town of Vík, 38 km south-east from the erupting Eyjafjallajökull volcano, reached levels that are 25 times the recommended health limit of 50 mg m-3 averaged over 24 hours, on 7 May 2010, with 10-min values reaching 13000 mg m-3. Even after the eruption, values as high as >8000 mg m-3 (10-min average), and >900 mg m-3 (24-h average), were measured.
In Reykjavik, 125 km WNW of the volcano, the PM10 concentration reached over 2000 mg m-3 (10-min average) during an ash storm event on 4 June 2010. The annual concentration in Reykjavik is about 25 mg m-3, and the only previous events of comparable magnitude are peaks during New Year's Eve celebration.
The eruption at Eyjafjallajökull posed a potential health risk to the inhabitants in the regions hit by severe ash fall. However, preliminary studies indicate that the ash has had minor short term health effects. Studies show that the crystalline silica content of the ash is negligible, so that the persistence of deposited ash in the soils and environment should not present a significant silicosis hazard. During periods of PM10 concentration over about 5000 mg m-3, most residents stayed indoors, or wore protective air filters and goggles when they had to go outside.
A study is ongoing to examine the potential long term health effects of the volcanic eruption, including the high concentration of PM10 during and after the eruption due to re-suspended ash in the area.
* Please contact Throstur (see e-mail on the poster) if you would like to cite or use information from the poster.
Many large earthquakes have rattle Japan this morning.
The list below is from USGS, showing earthquakes in the world having a magnitude greater than M 5.0. As can bee seen, Japan has experienced many, 16, such between 5:46 UTC and 7:42.
Associated is the risk, and realization of tsunami (up to 10 m high).
This project is about acquiring better data and information about basal sliding, focusing on Brúarjökul, Iceland.
Especially we will try to estimate the temporal and spatial change in basal sliding, by installing a number of GPS instruments on the glacier.
Landsvirkjun is our sponsor – and we thank them sincerely.
I say new because this is new to me, and also the students, and I haven’t seen this elsewhere. That does though not necessarily mean that I think no one has ever done this before.
This method is about letting the students post recent news about the topic of the course, for example glaciology and water science, on a web page.
Each student posts a news item about twice a semester. They write a short summary of the main points of the news item, and some related background.
They then introduce, explain, the news to the class.
This has proved to be lots of fun, the students are more interested in the topic and are pretty good in finding interesting news related to the class topics.
Examples from the water science class are here and from the glaciology class are here.
Finally our article in International Journal of Remote Sensing about the wildfires of 2006, Mýraeldana 2006, is out. This article emphasizes the use of satellite data to obtain estimates about the spread and intensity of wildfires.
Since final review, almost a year and a half has passed.
Thorsteinsson, Throstur , Magnusson, Borgthor and Gudjonsson, Gudmundur. 2011.
Large wildfire in Iceland in 2006: Size and intensity estimates from satellite data.
International Journal of Remote Sensing, 32(1): 17 — 29.
To link to this Article: DOI: 10.1080/01431160903439858
URL: http://dx.doi.org/10.1080/01431160903439858
An example about the type of information it is possible to obtain from satellite data on wildfires.
Strong winds cause high levels of PM10 this morning in Reykjavík.
Image taken from city of Reykjavik air quality monitoring station at GRE.
A little wind helped a lot to make the air quality good during New year’s eve 2010 (both at GRE and HEH - two measuring station in Reykjavik and Hafnafjordur, repsectively).
The highest value was “only” 350 micro-g/m3 – has previously reached well above 2000 micro-g/m3.
The wind kept the values low, wind speed even felt stronger than the measurement indicates, but it is also possible that there were a bit fewer fireworks this year (?).
Happy New YEAR !
