Andrew Tupper

Comments on “Failures in detecting volcanic ash from a satellite-based technique”

Abstract The recent paper by Simpson et al. [Remote Sens. Environ. 72 (2000) 191.] on failures to detect volcanic ash using the ‘reverse absorption’ technique provides a timely reminder of the danger that volcanic ash presents to aviation and the urgent need for some form of effective remote detection. The paper unfortunately suffers from a fundamental flaw in its methodology and numerous errors of fact and interpretation. For the moment, the ‘reverse’ absorption technique provides the best means for discriminating volcanic ash clouds from meteorological clouds. The purpose of our comment is not to defend any particular algorithm; rather, we point out some problems with Simpson et al.s analysis and re-state the conditions under which the ‘reverse’ absorption algorithm is likely to succeed.

Facing the Challenges of the International Airways Volcano Watch: The 2004/05 Eruptions of Manam, Papua New Guinea

Abstract Devastating eruptions occurred at Manam, Papua New Guinea, from October 2004 to January 2005. An unprecedented set of pilot reports were obtained; ground-, air-, and satellite-observed eruption heights differed greatly. Satellite postanalysis 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 postanalysis). 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 Mount Pinatubo. The communications a...

Detection and analysis of the volcanic clouds associated with the 18 and 28 August 2000 eruptions of Miyakejima volcano, Japan

Two significant eruptions occurred at Miyakejima volcano on 18 and 28 August 2000 and were detected by multiple satellite sensors. For both eruptions, the cloud can be observed with high confidence for 2 days. Using Total Ozone Mapping Spectrometer (TOMS), MODerate resolution Infrared Spectroradiometer (MODIS), Advanced Very High Resolution Radiometer (AVHRR) and High Resolution Infra Red Radiation Sounder (HIRS) imagery, constraints are placed on the masses and distributions of ash and SO2 released by the eruptions. The 18 August eruption at 08:02 UTC (17:02 JST) emitted an ash cloud of at least 511 kt and a sulfur dioxide (SO2) cloud of 43 kt to a height of approximately 16 km asl, which then drifted south. The 28 August eruption (19:35 UTC, 04:35 JST) was smaller, with a cloud containing a minimum of 0.2 kt of ash and 21 kt of SO2 at a height of 5 km to the northeast of the volcano associated with a low‐temperature pyroclastic surge. The 18 August eruption probably represents a vent‐clearing phase, given the magmatic nature of the erupted products, the significant amounts of ash produced and the prodigious gas emission rates in the following passive degassing phase, while the 28 August eruption was mostly phreatic, with a cold‐surge component not easily detectable by any of the sensors used. Comparisons of detection ability of the sensors were also made. The results suggest that the ultraviolet sensor TOMS more regularly detected SO2, as it is less susceptible to interference of water vapour and other species, as is observed with the infrared sensor MODIS. TOMS was able to detect SO2 for a total of 5 days for both eruptions combined, whereas HIRS detected SO2 for 3 days of the first eruption and MODIS detected the gas cloud for 1 day of each eruption. AVHRR was the most consistent when detecting ash and was able to see ash clouds not detected by the other sensors because of its more serendipitous overpass timing.

Volcanic Ash Hazards and Aviation Risk

The risks to safe and efficient air travel from volcanic-ash hazards are well documented and widely recognized. Under the aegis of the International Civil Aviation Organization, globally coordinated mitigation procedures are in place to report explosive eruptions, detect airborne ash clouds and forecast their expected movement, and issue specialized messages to warn aircraft away from hazardous airspace. This mitigation framework is based on the integration of scientific and technical capabilities worldwide in volcanology, meteorology, and atmospheric physics and chemistry. The 2010 eruption of Eyjafjallajokull volcano in Iceland, which led to a nearly week-long shutdown of air travel into and out of Europe, has prompted the aviation industry, regulators, and scientists to work more closely together to improve how hazardous airspace is defined and communicated. Volcanic ash will continue to threaten aviation and scientific research will continue to influence the risk-mitigation framework.

Volcanic Ash and Aviation—The Challenges of Real-Time, Global Communication of a Natural Hazard

More than 30 years after the first major aircraft encounters with volcanic ash over Indonesia in 1982, it remains challenging to inform aircraft in flight of the exact location of potentially dangerous ash clouds on their flight path, particularly shortly after the eruption has occurred. The difficulties include reliably forecasting and detecting the onset of significant explosive eruptions on a global basis, observing the dispersal of eruption clouds in real time, capturing their complex structure and constituents in atmospheric transport models, describing these observations and modelling results in a manner suitable for aviation users, delivering timely warning messages to the cockpit, flight planners and air traffic management systems, and the need for scientific development in order to undertake operational enhancements. The framework under which these issues are managed is the International Airways Volcano Watch (IAVW), administered by the International Civil Aviation Organization (ICAO). ICAO outlines in its standards and recommended practices (International Civil Aviation Organization 2014a, b) the basic volcanic monitoring and communication that is necessary at volcano observatories in Member States (countries). However, not all volcanoes are monitored and not all countries with volcanoes have mandated volcano observatories or equivalents. To add to the efforts of volcano observatories, a system of Meteorological Watch Offices, Air Traffic Management Area Control Centres, and nine specialist Volcanic Ash Advisory Centres (VAACs) are responsible for observing, analysing, forecasting and communicating the aviation hazard (airborne ash), using agreed techniques and messages in defined formats. Continuous improvement of the IAVW framework is overseen by expert groups representing the operators of the system, the user community, and the science community. The IAVW represents a unique marriage of two scientific disciplines, volcanology and meteorology, with the aviation user community. There have been many multifaceted volcanic eruptions in complex meteorological conditions during the history of the IAVW. Each new eruption brings new insights into how the warning system can be improved, and each reinforces the lessons that have gone before. The management of these events has improved greatly since the major ash encounters in the 1980s, but discontinuities in the warning and communications system still occur. A good example is a 2014 ash encounter over Indonesia following the eruption of Kelut where the warnings did not reach the aircraft crew. Other events present enormous management challenges—for example the 2010 Eyjafjallajokull eruption in Iceland was, overall, less hazardous than many less publicised eruptions, but numerous small to moderate explosions over several weeks produced widespread disruption and a large economic impact. At the time of writing, while there has been hundreds of millions of US dollars in damage to aircraft from encounters with ash, there have been no fatalities resulting from aviation incidents in, or proximal to volcanic ash cloud. This reflects, at least in part, the hard work done in putting together a global warning system—although to some extent it also reflects a measure of good statistical fortune. In order to minimise the risk of aircraft encounters with volcanic ash clouds, the global effort continues. The future priorities for the IAVW are strongly focused on enhancing communication before, and at the very onset of a volcanic ash-producing event (typically the more dangerous stage), together with improved downstream information and warning systems to help reduce the economic impact of eruptions on aviation.

Chapter 4 – Volcanic Ash Hazards and Aviation Risk

The risks to safe and efficient air travel from volcanic-ash hazards are well documented and widely recognized. Under the aegis of the International Civil Aviation Organization, globally coordinated mitigation procedures are in place to report explosive eruptions, detect airborne ash clouds and forecast their expected movement, and issue specialized messages to warn aircraft away from hazardous airspace. This mitigation framework is based on the integration of scientific and technical capabilities worldwide in volcanology, meteorology, and atmospheric physics and chemistry. The 2010 eruption of Eyjafjallajokull volcano in Iceland, which led to a nearly week-long shutdown of air travel into and out of Europe, has prompted the aviation industry, regulators, and scientists to work more closely together to improve how hazardous airspace is defined and communicated. Volcanic ash will continue to threaten aviation and scientific research will continue to influence the risk-mitigation framework.

Volcanic ash hazards and aviation risk: Chapter 4

The risks to safe and efficient air travel from volcanic-ash hazards are well documented and widely recognized. Under the aegis of the International Civil Aviation Organization, globally coordinated mitigation procedures are in place to report explosive eruptions, detect airborne ash clouds and forecast their expected movement, and issue specialized messages to warn aircraft away from hazardous airspace. This mitigation framework is based on the integration of scientific and technical capabilities worldwide in volcanology, meteorology, and atmospheric physics and chemistry. The 2010 eruption of Eyjafjallajokull volcano in Iceland, which led to a nearly week-long shutdown of air travel into and out of Europe, has prompted the aviation industry, regulators, and scientists to work more closely together to improve how hazardous airspace is defined and communicated. Volcanic ash will continue to threaten aviation and scientific research will continue to influence the risk-mitigation framework.