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Meeting Minutes

Did the Iceland Volcano Impact our 2010 Weather?

by
Kyle Dittmer
- Marylhurst University
Chris Beltrone, science student, Lake Oswego High School.

On February 12, 2011, a record 33 folks attended this fun-filled family meeting, at the Old Spaghetti Factory, Clackamas.  OR-AMS President Bobby Corser welcomed folks and gave the opening remarks.  Kyle Dittmer, chair of the 2011 Election Committee, asked for nominations.

The eruption of the Icelandic volcano Eyjafyallajökull (AY-uh FYAT-luh YOE-kuutl-uh) on March 20, 2010, had a substantial impact on 2010 weather world-wide.  Kyle outlined the study goals: What were the temperature impacts and how long did it last?  How much was the west coast of North America impacted?  Can air-temperature data and statistics pin-point such impacts?  Chris explained the stations that were used, on our west coast and in Europe, plus the concept of temperature departures and the seasonal accumulated departures.

Kyle showed past examples of volcanic eruptions and their world-wide cooling effects, which can last up to three years.  Mt. St. Helens, Washington, El Chichon, Mexico, and Mt. Pinatubo, Philippines, were given as notable recent examples.

Some facts about “Eyja” include eruptions in 1920, 1821-23, and 1612.  During these eruptions, its larger neighbor, Katla, always erupted within months.  It was mentioned that Katla is now showing strengthening seismic activity, which may precede an eruption.  The “Eyja” event erupted in three phases, from March 20 to late June.  The “Eyja” eruption was troublesome this time, as the jet stream was remarkably “parked” above the volcano for weeks, combined with frequent recharge of glacial meltwater into the volcano (making the eruptions very explosive), thus allowing massive quantities of fine ash to be discharged for 60 days.  Plumes were 12,000 to 36,000 feet in height.  The ash covered most of Europe, half of Russia, and the north Atlantic.

At Kyle’s direction, Chris downloaded and organized into a spreadsheet the daily mean air temperature data and computed departures (from daily normals) from the NWS, Weather-Underground, and Environment Canada for 30 select stations, Jan. – Sept. 2010.  The data was grouped into regions.  Kyle examined the data for the dates of the maximum temperature cooling for each station.  Kyle then ran the Student t-test (α = 0.05) for significance on the temperature departures and accumulated seasonal departures for all the regions on the west coast and Europe.

The results show that the mean cooling in Europe lasted 91 days and 177 days on our west coast.  The seasonal accumulated departures were -119 degF-days in Europe and -14 to -211 degF-days on our west coast.  For the temperature departures, there is statistical significance for 10/17 stations (Europe) and 7/21 stations (west coast).  For the seasonal accumulated departures, there is statistical significance for 13/17 stations (Europe) and 20/21 stations (west coast).  Future work includes adding more coastal stations and examining continental interior stations.  Much Q&A followed.  We had a great time and good discussions!

Note-taker: Kyle Dittmer