Retrieval of ash properties from IASI measurements

摘要: Abstract. A new optimal estimation algorithm for the retrieval of volcanic ash properties has been developed use with Infrared Atmospheric Sounding Interferometer (IASI). The method uses wave number range 680–1200 cm−1, which contains window channels, CO2 ν2 band (used height retrieval), and O3 ν3 band. Assuming a single infinitely (geometrically) thin plume combining this output from radiative transfer model RTTOV, produces most probable values optical depth (AOD), particle effective radius, top height, radiating temperature. comprehensive uncertainty budget is obtained each pixel. Improvements to through different measurement error covariance matrices are explored, comparing results sensitivity study process using trained on either clear-sky or cloudy scenes. result showed that, due smaller variance contained within it, matrix preferable. However, if fails pass quality control tests, implemented. applied scenes Eyjafjallajokull eruption in 2010, retrieved parameters compared ancillary data sources. gives root mean square error (RMSE) difference 0.46 when retrievals MODerate-resolution Imaging Spectroradiometer (MODIS) instrument all pixels an improved RMSE 0.2 low depths (AOD