Aged Volcanic Clouds Are they an aviation hazard and why? Bill Rose, * Patricia Nadeau , Simon Carn Michigan Technological University David Schneider USGS Alaska Volcano Observatory A52A-04
Dec 20, 2015
Aged Volcanic CloudsAged Volcanic Clouds
Are they an aviation hazard and why?
Bill Rose, *Patricia Nadeau, Simon CarnMichigan Technological University
David SchneiderUSGS Alaska Volcano Observatory
A52A-04
Aircraft HazardsAircraft Hazards Volcanic clouds generally end up in the lower
stratosphere
Commercial aircraft fly at similar altitudes because of low turbulence, few clouds, jet stream winds
Volcanic ash advisory centers (VAACs) have the task of advising pilots where hazardous volcanic clouds may be
When are volcanic clouds no longer a threat to aircraft?
Young volcanic cloud hazardsYoung volcanic cloud hazards
Engine failure ‘Sandblasting’ of windshield, compressor fan
blades, etc. Blockage of fuel nozzles and cooling passages Etching of windshields
British Airways Flight 9 to Perth – Galunggung, 1982 KLM Flight 867 to Anchorage – Redoubt, 1989 16 damaging encounters – Pinatubo, 1991 ~100 encounters 1973-2000 (Guffanti, et al. 2004)
“Aged” volcanic clouds“Aged” volcanic clouds Coarse ash falls out of cloud within
~30 minutes
Most remaining ash has fallen out of cloud within 24-36 hours
Trackable up to 4 days with IR split window, mostly SO2 and sulfate after that
Aged = over 2 days old
Do they still pose a risk to aircraft?
Volcanic clouds over western Montana on 7/18/2008 (photo by Margaret Patton, Research Office, Montana Tech of The University of Montana)
Okmok July 12 plume seen from 28,000 ft over Billings, Montana from the cockpit of a commercial passenger flight on the evening of 7/19/2008. (Image courtesy of Bradley Johnson and Alaska Airlines)
Kasatochi and OkmokKasatochi and Okmok
Kasatochi - October 23, 2008Image courtesy of Jerry Morris
New cone at Okmok – September 15, 2008Image courtesy of AVO/USGS (Photo by Christina Neal)
August 7, 2008
July 12, 2008
Aircraft encountersAircraft encounters
Okmok ~28 pilot reports July 18-20 over Northern US and
parts of Canada Mentions of visible ash clouds, orange-tinted
clouds, smells and throat irritation Kasatochi
~38 pilot reports on/around August 10, Northern US and parts of Canada
Mentions of visible ash, brown haze, rapid sky color changes, sulfur smell
* These are likely minimums for total encounters
Aircraft encountersAircraft encounters Kasatochi
Major airline to Anchorage – brief (few minutes) encounter near
Whitehorse, Yukon Terr. No aircraft damage, but ash collected
on various parts of plane
Regional airline, B737 – problems with pressurization over
MacKenzie Valley of Northwest Terr. Following return to
Yellowknife, “grey-glittery” coating in wheelwells, ash-type
substance in out-flow valve
Same aircraft 4 days later, loss of cabin pressure en route to
Calgary. Re-routed to Fort McMurray, AB
4 encounters by CARIBIC (aboard Lufthansa flights)
instruments over Europe Aug. 15 – Sept. 12
GOES - visibleGOES - visible
Courtesy of Scott Bachmeier, U. Wisconsin, MadisonCourtesy of Scott Bachmeier, U. Wisconsin, Madison
OMI - UVOMI - UV
Hekla – March, 2000Hekla – March, 2000
Chemical Ionization Mass Spectrometer
Forward Scattering Spectrometer Probe
Hygrometers
DACOM IR Laser Spectrometer
SOLVE (ozone study) campaign flight with array of atmospheric sampling instruments, including:
Hekla – cloud chemistryHekla – cloud chemistry
CIMS measured SO2/H2SO4 (gas) ~30,000
However, although it wasn’t measured directly, there was probably abundant particulate H2SO4 in the cloud as well
Rose, W. I., et al. (2006), J. Geophys. Res., 111, D20206
Hekla – cloud chemistryHekla – cloud chemistry
Beyond SO2 and H2SO4, cloud chemistry included many volcanogenic species that could potentially
be hazardous to aircraft and passengers
Kasatochi cloud encounterKasatochi cloud encounter
A-Train views of the Kasatochi cloud on August 10
OMI SO2 - 21:35 UTCALIPSO Backscatter – 21:28 UT CALIPSO Backscatter – 21:28 UT
V-cloud? Ice?
Solid particles at 11 km alt.
CA
LIP
SO
Kasatochi cloud encounterKasatochi cloud encounter
Images courtesy of AVO/USGS. Images were taken on the Environmental Scanning Electron Microscope (ESEM) at the University of Alaska Fairbanks Advanced Instrumentation Laboratory
Scanning electron photomicrographs of material collected from the leading edge of the wing of a commercial aircraft that encountered the Kasatochi volcanic cloud at around 0100 UTC on August 11, 2008 over the Yukon region.45 μm
50 μm
30 μm30 μm
40 μm
Kasatochi cloud encounterKasatochi cloud encounter
1850 km
CA
RIB
IC flight (LH
759) - 4:00-6:00 UT
– 11.6 km alt.
CA
RIB
IC flight (LH
759) - 4:00-6:00 UT
– 11.6 km alt.
OMI SO2 - 11:55 UT
A-Train views of the Kasatochi cloud on August 15C
AL
IPS
O
CALIPSO 2:22 UT
Saharan dust
V-cloud
Hekla vs. KasatochiHekla vs. Kasatochi
Kasatochi cloud encounter in Europe (CARIBIC) found <2.6 - 17.8 ng/m3 of Si, equivalent to 15 - 100 ng/m3 of ash and 243 - 399 ng/m3 of S, equivalent to 500 - 800 ng/m3 of SO2
(Prof. Bengt G. Martinsson Div. Nuclear Physics, Lund UniversityProf. Bengt G. Martinsson Div. Nuclear Physics, Lund University)
These are equivalent to 0.005 to 0.1 μg/m3 ash and and 0.1 to 0.25 ppbv of SO2
The much younger Hekla cloud had significantly higher values: 1-10 μg /m3 ash and 1 ppmv SO2
The differences are partly explained by the much greater age of the Kasatochi cloud (8 days vs. 1.5 days for Hekla)
Future considerations…Future considerations…
Need ground tests with companies like Boeing, etc. to establish limits on what is a threat to aircraft
More work like CARIBIC
What we don’t know:What we don’t know:What we know:What we know:
What are damage/danger thresholds for volcanic cloud constituents? (e.g., SO2 and sulfate)
Effect of exposure time?
Health risks for passengers on board?
Locations of SO2 clouds (OMI)
Cloud heights (CALIPSO)
Minor amounts of ash persist for days
Hekla plume components
We would like to thank everyone who helped with and contributed to this presentation, including Bengt
Martinsson and the CARIBIC project, AVO/USGS, Kristi Wallace, Marianne Guffanti, the SOLVE
campaign, and Richard Honrath
We would like to thank everyone who helped with and contributed to this presentation, including Bengt
Martinsson and the CARIBIC project, AVO/USGS, Kristi Wallace, Marianne Guffanti, the SOLVE
campaign, and Richard Honrath
Thank you