IAVWOPSG/3-IP/6
5/3/07
INTERNATIONAL AIRWAYS VOLCANO WATCH OPERATIONS GROUP
(IAVWOPSG)
THIRD MEETING
Bangkok, Thailand, 19 to 23 March 2007
Agenda Item 5: Operation of the IAVWOPSG
5.1: Implementation of the IAVW, including the IAVW Management Report
RECENT CASE PUBLICATIONS
(Presented by Australia)
SUMMARY
This paper introduces two recently published journal papers that give case studies relevant to the
Implementation of the IAVW, and are presented here for the information of the group.
1.
INTRODUCTION
1.1
Two papers have recently been published in peer-reviewed journals that deal with
strengths and deficiencies in the IAVW in relation to volcanic ash encounters and/or eruptions in the
Darwin VAAC region.
2.
DISCUSSION
2.1
The papers are given as attachments to this paper, with abstracts as follows:
Tupper, A., J. Davey, P. Stewart, B. Stunder, R. Servranckx, and F. Prata, 2006: Aircraft
encounters with volcanic clouds over Micronesia, Oceania, 2002/03. Australian Meteorological
Magazine, 55, 289-299.
Volcanic clouds pose a severe hazard to aviation; however, the extent of the threat, particularly for older
clouds, is still undefined. This study examines three aircraft encounters with apparently “old” volcanic
clouds over Micronesia, northeast of Papua New Guinea, in November 2002 and March 2003. Satellite
(2 pages)
106740031
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IAVWOPSG/3-IP/6
image analysis was performed using standard techniques, but no ash was detected in the area on the
occasions of the encounters. Backward and forward trajectories and dispersion forecasts were produced
using the emergency response models HYSPLIT and CANERM, to provisionally identify the source of
the volcanic clouds in each case. For the 8 March 2003 encounter, the volcanic cloud most likely
originated from Rabaul volcano, in New Britain, Papua New Guinea, and was lofted from low altitudes to
aircraft cruising levels during extensive convection in the area. For the two encounters on 23/24
November 2002, one of which caused significant but not life-threatening damage to the aircraft involved,
the volcanic materials almost certainly did not come from a local source, but were advected over a great
distance. The probable source was the explosive 3/5 November 2002 eruption of El Reventador, Ecuador,
South America, approximately 14000 km east of the encounters. Using AIRS satellite data, we were able
to track ash from this eruption along the forecast path towards the encounter locations for 7 days before it
became too difficult to track. This eruption cloud is probably the oldest and furthest travelled to have been
known to cause damage to an aircraft. These cases highlight the gap between our remote sensing and
modelling capabilities and the expectations of the aviation industry. Further work is required to better
define the nature of the ash threat and the standard of warning service that we aim to provide, and to
improve our capacity to provide the service.
Tupper, A., I. Itikarai, M. S. Richards, F. Prata, S. Carn, and D. Rosenfeld, 2007: Facing the
challenges of the International Airways Volcano Watch: the 2004/05 eruptions of Manam, Papua
New Guinea. Weather and Forecasting, 22, 175-191.
Devastating eruptions occurred at Manam, Papua New Guinea, from October 2004 to January 2005. An
unprecedented set of pilot reports was obtained; ground, air and satellite observed eruption heights
differed greatly. Satellite post-analysis and satellite CO2-slicing techniques give consistent heights. The
climactic eruption, on 27 January 2005, reached 21-24 km msl; four other eruptions reached 16.5-19 km.
Tracking of these ice-rich clouds was done by monitoring strong ‘ice’ signatures on 11-12 µm infrared
imagery (for two eruptions), by using reflectance-based techniques (during the daytime), and by using
SO2 detection (available only in post-analysis). A remote lightning detection network could not detect the
eruption clouds, despite detecting lightning from thunderstorms in the area. The eruptions appeared to
enhance the nocturnal cycle of (ash-contaminated) deep convection above the island, consistent with
previous work on diurnal volcanic-cumulonimbus at Mt Pinatubo. The communications and infrastructure
challenges of the region strongly affected the performance of the volcanic ash warning system, but can be
partially addressed with the development of appropriate strategies. A strategy of gradual advisory
cessation at the end of each event generally worked well but failed where numerical modelling and
satellite observation were insufficient. An aircraft apparently encountered SO2 from the cloud over Dili,
Timor-Leste; no engine damage was reported, but no close inspection was made at the time. It is
suggested that maintenance guidelines be developed to help clarify the risk of volcanic ash damage from
encounters with clouds where only SO2 odor is observed.
3.
1.2
ACTION BY THE IAVWOPSG
The IAVWOPSG is invited to note the information in this paper.
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