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Real-world application of new sensor technologies for air quality monitoring. ETC/ACM Technical Paper, 2013/16
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For retrieval of ash mass loading from infrared satellite measurements, estimates of the ash cloud temperature and the surface temperature are required. The ash cloud temperature and surface temperature may be taken from satellite measurements, weather model forecast, or deduced by satellite retrievals.
The report describes various methods to estimate the ash cloud temperatue and surface temperature. The impact of varying cloud temperature and surface temperature on the signal measured by an IR-sensor in space is investigated.
2013
Satellite-based measurements of volcanic ash give the total amount of volcanic ash per area, typically in units of grams of volcanic ash per square meter. To convert this to concentration the vertical thickness of the ash cloud is needed. The ash cloud thickness is not available from passive remote sensors, e.g. IR-sensors, but may be obtained from ground- and space-based lidars. Dispersion models will also provide information of the ash thickness.
This report gives an overview of volcanic ash cloud thickness as observed by space, aircraft and ground-based lidars. Also, ash cloud thickness as simulated by the Flexpart particle dispersion model is analysed. The impact of varying cloud thickness on the signal measured by IR-sensor in space is investigated. Focus is on the Eyjafjallajokull 2010 eruption for which a unique wealth of data are available.
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Measurement of volcanic ash in Norwegian air space. WP 1.4.2 Improved detection of ash clouds. NILU OR
Identifisering av aske i infrarøde satllittbilder forstyrres ofte av is- og vannskyer, samt de gitte temperaturforhold. Flere alternative metoder eksisterer for identifisering av askeskyer i SEVIRI-bilder. I en aktuell situasjon er ofte manuelle tilpasninger av deteksjonsmetodene nødvendig. Rapporten beskriver forskjellige metoder for identifisering av askeskyer. Metodene sammenlignes kvantitativt basert på syntetiske SEVIRI-bilder for Eyafjallajokull utbruddet i 2010.
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