Found 2226 publications. Showing page 72 of 223:
2013
2013
Real-world application of new sensor technologies for air quality monitoring. ETC/ACM Technical Paper, 2013/16
2013
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.
2013
Measurement of volcanic ash in Norwegian air space. WP 1.4.2 Improved detection of ash clouds. NILU OR
Water and ice clouds and temperature conditions may often influence the detection of volcanic ash affected pixels in infrared satellite images. Several methods are available for the detection of ash clouds in SEVIRI images. Manual adjustments to the methods are often needed for a given ash situation. The report describes various methods for detection of ash affected pixels. A quantitative comparison of the methods is made based on synthetic SEVIRI images from the 2010 Eyafjallajokull eruption.
2013
Modellering av vulkanaske i norsk luftfrom. Pkt. 1.3 Enkle forbedringer av utslippsestimat. NILU OR
The report describes how a transport model is used to simulate the emission of ash from volcanic eruptions and how the ash emissions can be described in the model. A number of methods for calculating ash emissions are presented and the development of improved ash emissions by manual analysis of satellite data is presented.
2013