Professor Roy Grainger: Publications

A novel retrieval of daytime atmospheric dust and volcanic ash heights through a synergy of AIRS infrared radiances and MODIS L2 optical depths

Atmospheric Measurement Techniques Discussions European Geosciences Union (2015)

Authors:

S DeSouza-Machado, L Strow, E Maddy, O Torres, G Thomas, D Grainger, A Robinson

Abstract:

Abstract. We present a novel method to retrieve daytime atmospheric dust and ash plume heights using a synergy of infrared hyper-spectral radiances and retrieved visible optical depths. The method is developed using data from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS), both of which are on NASA's Aqua platform, and lends itself to also a χ2 height derivation based on the smallest bias between observations and calculations in the thermal infrared window. The retrieval methodology is validated against almost 30 months of dust centroid heights obtained from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIOP) data, and against ash plume heights obtained from the Advanced Along-Track Scanning Radiometer (AATSR) after the Puyehue Cordon Caulle volcanic eruption of June 2011. Comparisons are also made against Goddard Chemistry Aerosol Radiation and Transport (GOCART) climatological aerosol heights. In general there is good agreement between the heights from the CALIPSO data and the AIRS/MODIS retrieval, especially over the Atlantic and Mediterranean regions; over land one there are more noticeable differences. The AIRS/MODIS derived heights are within typically 25% of the CALIOP centroid heights.

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A neural network approach for monitoring of volcanic SO2 and cloud height using hyperspectral measurements

Proceedings of SPIE--the International Society for Optical Engineering SPIE, the international society for optics and photonics 9242 (2014) 924213-924213-6

Authors:

Alessandro Piscini, Elisa Carboni, Fabio Del Frate, Roy Gordon Grainger

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Identifying volcanic endmembers in hyperspectral images using spectral unmixing

Proceedings of SPIE--the International Society for Optical Engineering SPIE, the international society for optics and photonics 9242 (2014) 924215-924215-6

Authors:

Alessandro Piscini, Elisa Carboni, Fabio Del Frate, Roy Gordon Grainger

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Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties

Atmospheric Chemistry and Physics European Geosciences Union (2014)

Authors:

SK Ebmeier, AM Sayer, RG Grainger, TA Mather, E Carboni

Abstract:

Abstract. The impact of volcanic emissions is a significant source of uncertainty in estimations of aerosol indirect radiative forcing, especially with respect to emissions from passive degassing and minor explosions. Understanding the impact of volcanic emissions on indirect radiative forcing is important for assessing present day atmospheric properties and also to define the pre-industrial baseline to assess anthropogenic perturbations. We present observations of the time-averaged indirect aerosol effect within 200 km downwind of isolated island volcanoes in regions of low present-day aerosol burden using MODIS and AATSR data. Retrievals of aerosol and cloud properties at Kīlauea (Hawai'i), Yasur (Vanuatu) and Piton de la Fournaise (Réunion) are rotated about the volcanic vent according to wind direction, so that retrievals downwind of the volcano can be averaged to improve signal to noise ratio. The emissions from all three volcanoes, including those from passive degassing, strombolian activity and minor explosions lead to measurably increased aerosol optical depth downwind of the active vent. Average cloud droplet effective radius is lower downwind of the volcano in all cases, with the peak difference in effective radius of 4–8 μm at the different volcanoes. A comparison of these observations with cloud properties at isolated islands with no significant source of aerosol suggests that these patterns are not purely orographic in origin. This approach sets out a first step for the systematic measurement of the effects of present day low altitude volcanic emissions on cloud properties. Our observations of unpolluted, isolated marine settings may also capture processes similar to those in the pre-industrial marine atmosphere.

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Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties

Atmospheric Chemistry and Physics Copernicus Publications 14:19 (2014) 10601-10618

Authors:

SK Ebmeier, AM Sayer, RG Grainger, TA Mather, E Carboni

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Professor Roy Grainger

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A novel retrieval of daytime atmospheric dust and volcanic ash heights through a synergy of AIRS infrared radiances and MODIS L2 optical depths

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Abstract:

A neural network approach for monitoring of volcanic SO2 and cloud height using hyperspectral measurements

Authors:

Identifying volcanic endmembers in hyperspectral images using spectral unmixing

Authors:

Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties

Authors:

Abstract:

Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties

Authors:

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Professor Roy Grainger

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A novel retrieval of daytime atmospheric dust and volcanic ash heights through a synergy of AIRS infrared radiances and MODIS L2 optical depths

Authors:

Abstract:

A neural network approach for monitoring of volcanic SO2 and cloud height using hyperspectral measurements

Authors:

Identifying volcanic endmembers in hyperspectral images using spectral unmixing

Authors:

Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties

Authors:

Abstract:

Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties

Authors: