The Eyjafjöll explosive volcanic eruption from a microwave weather radar perspective

Abstract

Abstract. The sub-glacial Eyjafjöll explosive volcanic eruptions of April and May 2010 are analyzed and quantitatively interpreted by using ground-based weather radar data and the Volcanic Ash Radar Retrieval (VARR) technique. The Eyjafjöll eruptions have been continuously monitored by the Keflavík C-band weather radar, located at a distance of about 155 km from the volcano vent. Considering that the Eyjafjöll volcano is approximately 20 km from the Atlantic Ocean and that the northerly winds stretched the plume toward the mainland Europe, weather radars are the only means to provide an estimate of the total ejected tephra. The VARR methodology is summarized and applied to available radar time series to estimate the plume maximum height, ash particle category, ash volume, ash fallout and ash concentration every 5 min near the vent. Estimates of the discharge rate of eruption, based on the retrieved ash plume top height, are provided together with an evaluation of the total erupted mass and volume. Deposited ash at ground is also retrieved from radar data by empirically reconstructing the vertical profile of radar reflectivity and estimating the near-surface ash fallout. Radar-based retrieval results cannot be compared with ground measurements, due to the lack of the latter, but further demonstrate the unique contribution of these remote sensing products to the understating and modelling of explosive volcanic ash eruptions.

Interpretation of observed microwave signatures from ground dual polarization radar and space multi-frequency radiometer for the 2011 Grímsvötn volcanic eruption

“…When the observation is close to the volcano vent, remote sensing instruments can be used to estimate the near-source eruption parameters. The most important near-source parameters are the plume height and the tephra eruption rate and mass Marzano et al, 2011;Vulpiani et al, 2011;Maki et al, 2012). The retrieval of these parameters represents an important input for Lagrangian ash dispersion models, which are used to predict the geographical areas likely to be affected by significant levels of ash concentrations (Webley and Mastin, 2009).…”

Monitoring volcanic ash cloud top height through simultaneous retrieval of optical data from polar orbiting and geostationary satellites

“…On 16 April only one estimate is presented because of the unfavourable satellite's swath characteristics. The highest measured heights by a radar located at Keflavik airport (Marzano et al, 2011) are shown for the comparison. Please note that the radar height only reflects the eruption column height near the vent (e.g.…”

“…Figure 9 contains also the ACTH estimations from ground radar measurements at Keflavik airport (see Fig. 5 in Marzano et al, 2011). Both datasets show that ACTH tends to get lower over time as the eruption intensity decreases.…”

“…See Fig. 1 in Marzano et al (2011) to compare the radar range with our case study area shown in Fig. 7.…”

CARIBIC aircraft measurements of Eyjafjallajökull volcanic clouds in April/May 2010

“…Also the French Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE) ATR 42 and Falcon20 aircrafts, the British Facility for Airborne Atmospheric Measurements (FAAM) BAe146 and Natural Environment Research Council (NERC) Dornier Do228 aircrafts, the Netherlands National Aerospace Laboratory (NLR) Citation II aircraft, the Swiss METAIR Dimona motor glider, the Spanish CASA 212 aircraft and a number of smaller aeroplanes conducted measurement flights over Europe during the 2010 Eyjafjallajökull eruption. Microwave weather radars were used as well to study the eruption (Marzano et al, 2011).…”