Improving volcanic ash cloud detection by a robust satellite technique

Abstract Automated and reliable satellite-based techniques are strongly required for volcanic ash cloud detection and tracking. In fact, volcanic ash clouds pose a serious hazard for air traffic and the synoptic (and possibly frequent) coverage offered by satellites can provide exciting opportunities for monitoring activities as well as for risk mitigation purposes. A new, AVHRR-based technique for improved automatic detection of volcanic clouds by means of multi-temporal analysis of historical, long-term satellite records has been recently proposed. The technique basically rests on the Robust AVHRR Techniques (RAT) approach, which is an innovative strategy of satellite data analysis, devoted to a former characterisation of the measured signal, in terms of expected value and natural variability and a further recognition of signal anomalies by an automatic, unsupervised change detection step. In this work, an extension of this method to nighttime observations is presented, by using thermal infrared information coming from AVHRR bands centred approximately at 3.5, 11.0 and 12.0 μm. Results achieved for two recent eruptive events of Mount Etna (occurred in May 2000 and in July 2001) seem to be encouraging, showing clear improvements in terms of ash detection sensitivity as well as in terms of false alarms reduction. The technique performance is also evaluated by comparison with the traditional “split-window” brightness temperature difference method; this exercise revealed a general improvement obtained by the proposed approach, even though some common problems still remain unsolved. The main merits of such an approach are its intrinsic self-adaptability to different environmental/natural/observational conditions and its natural exportability also to different satellite sensors. The results here presented show the benefits of such a technique especially when different observational conditions (time of pass, seasonal period, atmospheric moisture, solar illumination, volcanic cloud composition, satellite angles of view, etc.) are considered. The future prospects, also in terms of possible operational scenarios, coming from the implementation of such an approach on the new generation of satellite sensors (like, for example, SEVIRI aboard Meteosat Second Generation platform) are also discussed.

[1]  T. Casadevall,et al.  Volcanic ash and aviation safety; proceedings of the First international symposium on Volcanic ash and aviation safety , 1994 .

[2]  Jay R. Herman,et al.  Detection of volcanic ash clouds from Nimbus 7/total ozone mapping spectrometer , 1997 .

[3]  J. Simpson,et al.  Airborne Asian Dust: Case Study of Long-Range Transport and Implications for the Detection of Volcanic Ash , 2003 .

[4]  J. Simpson,et al.  Response to “Comments on ‘Failures in detecting volcanic ash from a satellite-based technique’” , 2001 .

[5]  Rosa Lasaponara,et al.  Fire detection by AVHRR: toward a new approach for operational monitoring , 1998, Remote Sensing.

[6]  Donald W. Hillger,et al.  Principal Component Image Analysis of MODIS for Volcanic Ash. Part I: Most Important Bands and Implications for Future GOES Imagers , 2002 .

[7]  David A. Rothery,et al.  Remote Sensing of Active Volcanoes , 2000 .

[8]  Alfred J Prata,et al.  Infrared radiative transfer calculations for volcanic ash clouds , 1989 .

[9]  David J. Schneider,et al.  Tracking of 1992 eruption clouds from Crater Peak vent of Mount Spurr Volcano, Alaska, using AVHRR , 1995 .

[10]  Valerio Tramutoli,et al.  SANA: Sub-pixel automatic navigation of AVHRR imagery , 2000 .

[11]  Valerio Tramutoli,et al.  Two years of operational use of Subpixel Automatic Navigation of AVHRR scheme: accuracy assessment and validation , 2003 .

[12]  David C. Pieri,et al.  Analyses of in‐situ airborne volcanic ash from the February 2000 eruption of Hekla Volcano, Iceland , 2002 .

[13]  Teodosio Lacava,et al.  Robust satellite techniques for volcanicand seismic hazards monitoring , 2004 .

[14]  William I. Rose,et al.  Anatomy of 1986 Augustine volcano eruptions as recorded by multispectral image processing of digital AVHRR weather satellite data , 1991 .

[15]  Clive Oppenheimer,et al.  Review article: Volcanological applications of meteorological satellites , 1998 .

[16]  David J. Schneider,et al.  Observations of Volcanic Clouds in Their First Few Days of Atmospheric Residence: The 1992 Eruptions of Crater Peak, Mount Spurr Volcano, Alaska , 2001, The Journal of Geology.

[17]  William I. Rose,et al.  Atmospheric correction for satellite‐based volcanic ash mapping and retrievals using “split window” IR data from GOES and AVHRR , 2002 .

[18]  David C. Pieri,et al.  The February 2001 Eruption of Mount Cleveland, Alaska: Case Study of an Aviation Hazard , 2002 .

[19]  William I. Rose,et al.  Retrieval of sizes and total masses of particles in volcanic clouds using AVHRR bands 4 and 5 , 1994 .

[20]  Fred Prata,et al.  Comments on "Failures in detecting volcanic ash from a satellite-based technique" , 2001 .

[21]  T. Casadevall,et al.  World map of volcanoes and principal aeronautical features , 1995 .

[22]  Valerio Tramutoli,et al.  Robust AVHRR techniques (RAT) for environmental monitoring: theory and applications , 1998, Remote Sensing.

[23]  Donald W. Hillger,et al.  Principal Component Image Analysis of MODIS for Volcanic Ash. Part II: Simulation of Current GOES and GOES-M Imagers , 2002 .

[24]  Valerio Tramutoli,et al.  Satellite remote sensing of volcanic aerosols: a new AVHRR-based approach , 1998, Remote Sensing.

[25]  David J. Schneider,et al.  Satellite images offer aircraft protection from volcanic ash clouds , 1996 .

[26]  David C. Pieri,et al.  Operational implications of airborne volcanic ash , 2000 .

[27]  Alfred J Prata,et al.  Observations of volcanic ash clouds in the 10-12 μm window using AVHRR/2 data , 1989 .

[28]  David C. Pieri,et al.  Failures in detecting volcanic ash from a satellite-based technique , 2000 .

[29]  Valerio Tramutoli,et al.  Robust satellite techniques for remote sensing of seismically active areas , 2001 .

[30]  Arlin J. Krueger,et al.  Comparison of TOMS and AVHRR volcanic ash retrievals from the August 1992 eruption of Mt. Spurr , 1999 .

[31]  R. Lasaponara,et al.  Evaluation of a new satellite-based method for forest fire detection , 2001 .

[32]  William I. Rose,et al.  GOES imagery fills gaps in Montserrat volcanic cloud observations , 1998 .