Lidar observations of the Eyjafjallajokull volcanic ash plume at Leipzig, Germany

2010 ◽  
Author(s):  
Matthias Tesche ◽  
Albert Ansmann ◽  
Anja Hiebsch ◽  
Ina Mattis ◽  
Jörg Schmidt ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Ash Plume ◽  
Lidar Observations

scholarly journals Airborne lidar observations of the 2010 Eyjafjallajökull volcanic ash plume

2011 ◽  
Vol 116 ◽  
Author(s):  
Franco Marenco ◽  
Ben Johnson ◽  
Kate Turnbull ◽  
Stuart Newman ◽  
Jim Haywood ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Airborne Lidar ◽  
Ash Plume ◽  
Lidar Observations

scholarly journals Airborne observations of the Eyjafjalla volcano ash cloud over Europe during air space closure in April and May 2010

2011 ◽  
Vol 11 (5) ◽  
pp. 2245-2279 ◽  
Author(s):  
U. Schumann ◽  
B. Weinzierl ◽  
O. Reitebuch ◽  
H. Schlager ◽  
A. Minikin ◽  
...  
Keyword(s):  
Mass Concentration ◽  
Volcanic Ash ◽  
Particle Density ◽  
Airborne Lidar ◽  
Particle Sedimentation ◽  
Space Closure ◽  
Ash Plume ◽  
Ground Based Lidar ◽  
Ash Cloud ◽  
Mass Concentrations

Abstract. Airborne lidar and in-situ measurements of aerosols and trace gases were performed in volcanic ash plumes over Europe between Southern Germany and Iceland with the Falcon aircraft during the eruption period of the Eyjafjalla volcano between 19 April and 18 May 2010. Flight planning and measurement analyses were supported by a refined Meteosat ash product and trajectory model analysis. The volcanic ash plume was observed with lidar directly over the volcano and up to a distance of 2700 km downwind, and up to 120 h plume ages. Aged ash layers were between a few 100 m to 3 km deep, occurred between 1 and 7 km altitude, and were typically 100 to 300 km wide. Particles collected by impactors had diameters up to 20 μm diameter, with size and age dependent composition. Ash mass concentrations were derived from optical particle spectrometers for a particle density of 2.6 g cm−3 and various values of the refractive index (RI, real part: 1.59; 3 values for the imaginary part: 0, 0.004 and 0.008). The mass concentrations, effective diameters and related optical properties were compared with ground-based lidar observations. Theoretical considerations of particle sedimentation constrain the particle diameters to those obtained for the lower RI values. The ash mass concentration results have an uncertainty of a factor of two. The maximum ash mass concentration encountered during the 17 flights with 34 ash plume penetrations was below 1 mg m−3. The Falcon flew in ash clouds up to about 0.8 mg m−3 for a few minutes and in an ash cloud with approximately 0.2 mg m−3 mean-concentration for about one hour without engine damage. The ash plumes were rather dry and correlated with considerable CO and SO2 increases and O3 decreases. To first order, ash concentration and SO2 mixing ratio in the plumes decreased by a factor of two within less than a day. In fresh plumes, the SO2 and CO concentration increases were correlated with the ash mass concentration. The ash plumes were often visible slantwise as faint dark layers, even for concentrations below 0.1 mg m−3. The large abundance of volatile Aitken mode particles suggests previous nucleation of sulfuric acid droplets. The effective diameters range between 0.2 and 3 μm with considerable surface and volume contributions from the Aitken and coarse mode aerosol, respectively. The distal ash mass flux on 2 May was of the order of 500 (240–1600) kg s−1. The volcano induced about 10 (2.5–50) Tg of distal ash mass and about 3 (0.6–23) Tg of SO2 during the whole eruption period. The results of the Falcon flights were used to support the responsible agencies in their decisions concerning air traffic in the presence of volcanic ash.

Lidar observations of volcanic aerosol over the UK since June 2019

2020 ◽  
Author(s):  
Geraint Vaughan ◽  
David Wareing ◽  
Hugo Ricketts
Keyword(s):  
Volcanic Ash ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Lidar System ◽  
Elastic Channel ◽  
Enhanced Sensitivity ◽  
Volcanic Cloud ◽  
The Uk ◽  
Lidar Observations

<p>On 22 June 2019, the Raikoke volcano in the Kuril Islands erupted, sending a plume of ask and sulphur dioxide into the stratosphere. A Raman lidar system at Capel Dewi, UK (52.4°N, 4.1°W) has been used to measure the extent and optical depth of the stratospheric aerosol layer following the eruption. The lidar was modified to give it much enhanced sensitivity in the elastic channel, allowing measurements up to 25 km, but the Raman channel is only sensitive to the troposphere. Therefore, backscatter ratio profiles were derived by comparison with aerosol-free profiles derived from nearby radiosondes, corrected for aerosol extinction. Small amounts of stratospheric aerosol were measured prior to the arrival of the volcanic cloud, probably from pyroconvection over Canada. Volcanic ash began to arrive as a thin layer at 14 km late on 3 July, extending over the following month to fill the stratosphere below around 19 km. Aerosol optical depths reached around 0.03 by mid-August and continued at this level for the remainder of the year. The location of peak backscatter varied considerably but was generally around 15 km. However, on one notable occasion on August 25, a layer around 300 m thick with peak lidar backscatter ratio around 1.5 was observed as high as 21 km.</p>

scholarly journals Ash plume top height estimate using AATSR

2014 ◽  
Vol 7 (4) ◽  
pp. 3863-3913
Author(s):  
T. H. Virtanen ◽  
P. Kolmonen ◽  
E. Rodríguez ◽  
L. Sogacheva ◽  
A.-M. Sundström ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Quality Parameters ◽  
Height Estimate ◽  
Brightness Temperatures ◽  
In Situ Data ◽  
Estimate Method ◽  
Ash Plume ◽  
Along Track

Abstract. An algorithm is presented for estimation of volcanic ash plume top height using the stereo view of the Advanced Along Track Scanning Radiometer (AATSR) aboard ENVISAT. The algorithm is based on matching the top of atmosphere (TOA) reflectances and brightness temperatures of the nadir and 55° forward views, and using the resulting parallax to obtain the height estimate. Various retrieval parameters are discussed in detail, several quality parameters are introduced, and post-processing methods for screening out unreliable data have been developed. The method is compared against other satellite observations and in-situ data. The proposed algorithm is designed to be fully automatic, and can be implemented into operational retrieval algorithms. Combined with automated ash detection using the brightness temperature difference between the 11 μm and 12 μm channels, the algorithm allows simultaneous retrieval of horizontal and vertical dispersion of volcanic ash efficiently. A case study on the eruption of the Icelandic volcano Eyjafjallajökull in 2010 is presented. The height estimate method results are validated against available satellite and ground based data.

scholarly journals Ash plume top height estimation using AATSR

2014 ◽  
Vol 7 (8) ◽  
pp. 2437-2456 ◽  
Author(s):  
T. H. Virtanen ◽  
P. Kolmonen ◽  
E. Rodríguez ◽  
L. Sogacheva ◽  
A.-M. Sundström ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Quality Parameters ◽  
Brightness Temperatures ◽  
In Situ Data ◽  
Vertical Dispersion ◽  
Fully Automatic ◽  
Ash Plume ◽  
Along Track

Abstract. An algorithm is presented for the estimation of volcanic ash plume top height using the stereo view of the Advanced Along Track Scanning Radiometer (AATSR) aboard Envisat. The algorithm is based on matching top of the atmosphere (TOA) reflectances and brightness temperatures of the nadir and 55° forward views, and using the resulting parallax to obtain the height estimate. Various retrieval parameters are discussed in detail, several quality parameters are introduced, and post-processing methods for screening out unreliable data have been developed. The method is compared to other satellite observations and in situ data. The proposed algorithm is designed to be fully automatic and can be implemented in operational retrieval algorithms. Combined with automated ash detection using the brightness temperature difference between the 11 and 12 μm channels, the algorithm allows efficient simultaneous retrieval of the horizontal and vertical dispersion of volcanic ash. A case study on the eruption of the Icelandic volcano Eyjafjallajökull in 2010 is presented.

scholarly journals Dual-Wavelength Polarimetric Lidar Observations of the Volcanic Ash Cloud Produced During the 2016 Etna Eruption

2021 ◽  
Vol 13 (9) ◽  
pp. 1728
Author(s):  
Luigi Mereu ◽  
Simona Scollo ◽  
Antonella Boselli ◽  
Giuseppe Leto ◽  
Ricardo Zanmar Sanchez ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Dual Wavelength ◽  
Backscattering Coefficient ◽  
Validation Data ◽  
Range Resolution ◽  
Lidar Measurements ◽  
Physically Based ◽  
Volcanic Cloud ◽  
Visible Wavelengths ◽  
Lidar Observations

Lidar observations are very useful to analyse dispersed volcanic clouds in the troposphere mainly because of their high range resolution, providing morphological as well as microphysical (size and mass) properties. In this work, we analyse the volcanic cloud of 18 May 2016 at Mt. Etna, in Italy, retrieved by polarimetric dual-wavelength Lidar measurements. We use the AMPLE (Aerosol Multi-Wavelength Polarization Lidar Experiment) system, located in Catania, about 25 km from the Etna summit craters, pointing at a thin volcanic cloud layer, clearly visible and dispersed from the summit craters at the altitude between 2 and 4 km and 6 and 7 km above the sea level. Both the backscattering and linear depolarization profiles at 355 nm (UV, ultraviolet) and 532 nm (VIS, visible) wavelengths, respectively, were obtained using different angles at 20°, 30°, 40° and 90°. The proposed approach inverts the Lidar measurements with a physically based inversion methodology named Volcanic Ash Lidar Retrieval (VALR), based on Maximum-Likelihood (ML). VALRML can provide estimates of volcanic ash mean size and mass concentration at a resolution of few tens of meters. We also compared those results with two methods: Single-variate Regression (SR) and Multi-variate Regression (MR). SR uses the backscattering coefficient or backscattering and depolarization coefficients of one wavelength (UV or VIS in our cases). The MR method uses the backscattering coefficient of both wavelengths (UV and VIS). In absence of in situ airborne validation data, the discrepancy among the different retrieval techniques is estimated with respect to the VALR ML algorithm. The VALR ML analysis provides ash concentrations between about 0.1 ?g/m3 and 1 mg/m3 and particle mean sizes of 0.1 ?m and 6 ?m, respectively. Results show that, for the SR method differences are less than <10%, using the backscattering coefficient only and backscattering and depolarization coefficients. Moreover, we find differences of 20%--30% respect to VALR ML, considering well-known parametric retrieval methods. VALR algorithms show how a physics-based inversion approaches can effectively exploit the spectral-polarimetric Lidar AMPLE capability.

scholarly journals Design and Preliminary Testing of the Volcanic Ash Plume Receiver Network

2019 ◽  
Vol 36 (3) ◽  
pp. 353-367
Author(s):  
Nicholas Rainville ◽  
Scott Palo ◽  
Kristine M. Larson ◽  
Mario Mattia
Keyword(s):  
Volcanic Ash ◽  
Detection Method ◽  
Low Cost ◽  
Signal Strength ◽  
Distributed Sensor ◽  
Additional Processing ◽  
Signal Path ◽  
Ash Plume ◽  
Processing Steps

AbstractThe presence of volcanic ash in the signal path between a GPS satellite and a ground-based receiver strongly correlates with a decrease in GPS signal strength. This effect has been seen in data collected from GPS sites located near active volcanoes; however, the sparse placement of existing GPS sites limits the applicability of this technique as an ash plume detection method to relatively few well-instrumented volcanoes. This deficiency has motivated the development of a low-cost distributed sensor system based on navigation-grade GPS receivers, which can take advantage of attenuated GPS signals to increase the quality and availability of real-time ash plume observations during an eruption. This GPS-based system has been designed specifically to meet remote sensing needs while operating autonomously in difficult conditions and minimizing on-site infrastructure requirements. Prototypes of this system have undergone long-term testing and the data collected from this testing have been used to develop the additional processing steps necessary to account for the different behavior of navigation grade GPS equipment compared to the geodetic equipment used at existing GPS sites.

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