Satellite techniques for timely detection and near real-time monitoring of volcanic ash clouds for aviation safety

Transcription

1 Satellite techniques for timely detection and near real-time monitoring of volcanic ash clouds for aviation safety N. Pergola A. Falconieri F. Marchese V. Tramutoli Consiglio Nazionale delle Ricerche Istituto di Metodologie per l Analisi Ambientale Università della Basilicata Scuola di Ingegneria

2 Volcanoes of the world - According to the Global Volcanism Program there are more than 1500 active volcanoes worldwide - Every year about volcanoes erupt in average somewhere on the Earth

3 From the local scale.. Volcanic activity.up to a global impact Aerosol optical depth increase (right) and average global air temperature decrease (left) after the Pinatubo (Philippines) June 1991 eruption

4 Volcanic ash and Aviation safety Emitted volcanic ash is a serious threat for aviation because: It is mostly invisible to onboard radars It may produces serious damages (i.e. flameout) to jet engines It can cause significant wear on propellers and scratch the cockpit windows It can damage the avionics

5 Volcanic ash and Aviation safety Some significant ash encounters (Casadevall & Murray) Mt. St. Helens United States A 727 and a DC-8 encountered separate ash clouds. Both airplanes experienced damage to their windshields and to several systems but both landed safely despite the windshield damage. Galunggung volcano Indonesia Several 747s encountered ash from this eruption. One airplane lost thrust from all four engines and descended from ft to ft before all four engines were restarted. This airplane subsequently had all four engines replaced before returning to service. Another 747 flew into the ash cloud and suffered significant engine damage. Mt. Redoubt United States On a flight from Amsterdam to Anchorage Alaska a new encountered ash. All four engines ingested ash and flamed out. Mt. Pinatubo Philippines More than 20 volcanic ash encounters occurred after the Mt. Pinatubo eruption which was the largest volcanic eruption of the past 50 years. Commercial flights and various military operations were affected; one U.S. operator grounded its airplanes in Manila for several days. Mt. Popocatepetl Mexico This volcano affected several flights in 1997 and One flight crew experienced significantly reduced visibility for landing and had to look through the flight deck side windows to taxi after landing.

6 VAACs (Volcanic Ash Advisory Centers) The worldwide network of Volcanic Ash Advisory Centers was set up in 1990s by the International Civil Aviation Organization (ICAO) an agency of the United Nations as part of the International Airways Volcano Watch (IAVW) after several aircraft incidents and ash encounters

7 Volcanic ash and Aviation safety Volcanic ash complete avoidance (i.e. any ash no fly ) is the most safe policy for airplanes but: -It needs to accurately know where the ash actually is Iceland eruption in April 2010 did cost about 2.5 billion to airline industry worldwide!! -It does cost money and has social impacts! Million passengers experienced troubles because of the air traffic shut-down

8 The role of Earth Observation (EO) EO Satellites thanks to their synoptic view (i.e. large spatial coverage in short times) are often the most suitable (sometimes the unique) observing system for monitoring volcanic ash emissions that may evolve very rapidly in the space-time domain

9 The role of Earth Observation (EO) Geographical coverage or horizontal distribution of ash (i.e. ash/no-ash maps) is the main product that satellites can provide. Iceland 14/05/ :00 GMT

10 The role of Earth Observation (EO) Besides geographical coverage (i.e. ash/no-ash maps) other products/information might be retrieved from EO data e.g.: - Ash concentration [g/m 3 ] - Mass loading [tons/km 2 ] - Plume height [km] However they are all computed over the ash-affected areas thus depending on the accuracy of the ash maps Detection accuracy is mandatory in order to have high quality information!

11 Satellite detection and tracking of volcanic ash: product requirements Being the main objective an operational monitoring the following requirements (at least) should be pursued: Real Time (RT) or Near Real-Time (NRT) product generation and availability Easy and Rapid processing schemes (i.e. automated/unsupervised techniques) Exportability on different satellite systems Independence on local conditions (e.g. atmospheric environmental) avoiding seasonal and regional tuning Continuous and frequent product updates and refreshing All time (i.e. night-time & daytime) product availability Low/no dependence on ancillary information (not always available)

12 Volcanic ash detection and tracking from space: the physical basis Traditional Brightness Temperature Difference (BTD) techniques (Prata 1989) Ash Ash cloud BTD = T 11m - T 12m < 0 For ash > 0 for Water/ice?

13 How often does BTD (11-12 μm) go negative? False alarms an economic issue! Traditional ash detection methods may trigger numerous false alarms Pavolonis et al. (2006) JTECH

14 T 11m - T 12m [K] How often does BTD (11-12 μm) go negative? Missed alarms NOAA-16 July GMT AVHRR Channel 4 Traditional ash detection methods may have significant sensitivity issues T 11m - T 12m < 0 A A A safety 15 issue! A A Prata s threshold 0 1x10 4 2x10 4 3x10 4 4x10 4 Distance [m] Pergola et al RSE

15 Based on the use of relative rather than absolute thresholds RST ASH algorithm (Pergola et al. 2004) x.. y t ) ( ) ( ) ( ) ( ) ( y x y x t y x T t y x T t y x T T T T TIR ) ( ) ( ) ( ) ( ) ( y x y x t y x T t y x T t y x T T T T TIR MIR

16 RST ASH versus traditional satellite techniques IMPROVING DETECTION SENSITIVITY BTD RST ASH ΔT<0 ΔT<-1 ΔT<-2 AVHRR Channel 4

17 RST ASH versus traditional satellite techniques BTD - 15/04/ :00 GMT

18 RST ASH versus traditional satellite techniques OPTIMIZED RST ASH - 15/04/ :00 GMT IMPROVING DETECTION RELIABILITY

19 Success stories: Etna (Italy) eruption 2002 Near Real-Time monitoring to support National Civil Protection Department in managing volcanic crisis and the operations of the Catania Fontanarossa International airport Polar satellites (AVHRR): 6 hours refreshing time

20 Success stories: Shinmoedake (Japan) eruption 2011 Shinmoedake (Japan) eruption of January 2011 Hourly Geostationary (MTSAT) data Marchese et al 2014 JVGR

21 Success stories: Shinmoedake (Japan) Plume height [m asl] eruption 2011 Other satellite-derived ash cloud parameters Marchese et al. 2014

22 Success stories: Eyjafjallajökull (Iceland) eruption 2010 Eruptive events : April 2010 and May 2010 Geostationary satellites (MSG- SEVIRI) data: 15 minutes refreshing time

23 Success stories: Eyjafjallajökull (Iceland) eruption 2010 Inter-comparisons with independent SEVIRI-based Ash maps(*) generated at London VAAC (Francis et al. 2012) RST ASH RGB_DUST LONDON VAAC (*) London VAAC ash maps provided by M. Cooke (Met Office)

24 Conclusions Volcanic ash represents a serious hazard for aviation safety with both economic and social impacts The rapid evolution and the large scale of the phenomenon require monitoring and observing systems with suitable spatial coverage and temporal resolution The Copernicus space segment Meteorological satellites represent the best (often the unique) (e.g. observing MTG) system will surely for detecting guarantee tracking and continuously improved monitoring observing volcanic ash capabilities plumes injected into the atmosphere Refined (and possibly integrated) satellite-based detection and tracking methods are mandatory to improve our monitoring accuracy and to provide useful information to decisors and to the relevant user community

25 Thank you for your attention 08/05/ :15 01:45GMT