Operations within the Washington VAAC: using multiple sensors to detect and analyze volcanic ash

Operations Within the Washington VAAC: using multiple sensors to detect and analyze volcanic ash.

Alonzo Brown NOAA/NESDIS

ABSTRACT

The Washington Volcanic Ash Advisory Center(VAAC) is part of a global network of centers formed by the International Civil Aviation Organization(ICAO) to provide nearly worldwide coverage of volcanic ash events. The VAAC monitors volcanic activity and airborne ash and disseminates text and graphical messages to the aviation community. NOAA geostationary satellites(GOES) and polar orbiting satellites (POES) are often the primary source of information used in creating volcanic ash advisories(VAA). Visible satellite imagery is used for daytime observations but when the imagery is compromised by meteorological clouds and darkness the analysts are forced to rely on infrared imagery( longwave and shortwave) and multi-spectral imagery techniques. This presentation will focus on the operational multi-sensor techniques used at the Washington VAAC such as short wave infrared imagery used to locate “hot spots” indicating possible activity, the “split window” channel differencing technique, the 3.9 micron reflectivity product developed by Colorado State University’s Cooperative Institute for Research in the Atmosphere(CIRA), a multi-spectral imagery routine developed by Gary Ellrod of NOAA in collaboration with CIRA , Principal Component Image Analysis(PCI), automated “hot spot” detection algorithms developed by NASA and the University of Wisconsin in collaboration with the Cooperative Institute for Meteorological Satellite Studies(CIMSS) and a CO2 slicing technique.