Title: Measurement of wind erosion on a landscape scale at Myrdalssandur
Abstract
Wind erosion is a major threat in Iceland which has > 20000 km2 of sandy deserts. The sandy areas have dark surfaces due to their basaltic origin. My goals were to gain knowledge of methods used in measuring the effect of wind erosion and to quantify wind erosion at the Myrdalssandur desert in South Iceland. The study area is a vast unstable sandy area formed by catastrophic flooding events. The area has frequent sandstorms, mostly blowing to the south with northerly winds. During 45 days, wind erosion was measured in an attempt to quantify the materials carried by wind, to analyse the relationship between grain size and aeolian transport, to analyse differences in sand transport on a landscape scale, to identify the main pathways, and to understand the relationship between wind speed, types of soil particles and transport. Only one storm was recorded during the experimental work with an average wind speed of 10 m s-1. The mass of aeolian transport ranged from 364.4 kg m-1 to less than 0.03 kg m-1. By looking at the research area and the differences in sand transport within the location, it seemed that the major differences in the erosibility of the surface area were caused by grain size distribution rather than meteorological factors. The presence of a grain size with a diameter more than 8 mm is a result of frequent flooding which brought these heavy materials that powerfully makes the sandy materials in Myrdalssandur poorly sorted. But still the Myrdalssandur desert is under severe erosion. A simple sediment catcher for measuring horizontal mass fluxes of wind-blown particles is described, and a method to calculate the total mass transport rate at the point of observation was explored.