Lagrangian Flexible Particle Dispersion Model Lab Report

To be able to determine mass and distribution of the volcanic emissions, a simulation with the Lagrangian Flexible Particle Dispersion Model, or FLEXPART, while using a beforehand assumed emission term for ash sources, as well as an inversion technique, was used to improve the results of ash distributions against findings in ash columns1. Since volcanic emissions contain large amounts of different substances, “ash” in this case is defined as a particle with radius smaller than 125 µm and is divided into 25 different size bins. During measurements, deposition fluxes and ash concentrations are provided daily at 1° x 1° horizontal resolution and 20 km vertical columns divided into 38 atmospheric layers1. For a full time series of SO2 emissions,
These characteristics consist of size distribution, shape and refractive index 1. The refractive index has an imaginary component which has strong influence on the magnitude and sign of shortwave forcing of ash 1. From figure x, where measurements of ash from Eyjafjallajökull along with measurements from old volcanic eruptions and measurements of natural minerals from volcanoes, it is shown that the refraction index has a high uncertainty. Therefore, a low, central and high scenario is conducted, to derive spectrally ash properties of each size bin 1.
The spectral curve of ash which was collected from Mount St. Helens eruption in 1980 is followed by the central scenario. The low scenario adapts the measurement from obsidian and measurements from a laboratory which showed that fine-ash from Eyjafjallajökull had a k value of ~0.001 between
Very small amounts of SO2 were injected into the stratosphere following the eruption. For most time, the injected SO2 reached a height of around 4.5-5 km up in the air, but mostly it varied around 2-6km 6. This can also be seen in figure x, where a maximum height of around 10 km is reached at around the 18th of May 6. During the eruption in the month of April, particles were also injected above 8 km 5 but did not contain a large concentration of SO2 1. From a diagnose by CAM, only 3% of ash burdens global mean for 2010 and 0.4% of the global mean of sulfate during 2010 was located above the tropopause 1. By looking at figure x, two eruptions are shown in the plot 1. One at which the volcanic activity starts and has a high concentration of ash particles where another starts at the end of April and has a high concentration of