Real-time prediction trace gases from the Fagradalsfjall volcanic eruption

During the Fagradalsfjall volcanic eruption in Iceland in 2021, the atmospheric flow was simulated at high-spatial and temporal resolutions with the numerical system WRF, including the WRF-Chem for the simulation of trace gases and aerosols.  The output of the real-time simulations of SO2 has been compared to observations, showing that on time-scales of 12-24 hours, the numerical system has considerable skill, but moving to temporal scales shorter than 6 hours leads to substantial drop in the model performance.  The data and the model output suggest that there may be strong long-lasting horizontal gradients in the trace gases and limited horizontal mixing at times, calling for a more dense network of monitoring of gases from the volcano.  Wind variability on the time scale of minutes up to few hours remains a challenge.