Regional Saharan dust modelling during the SAMUM 2006 campaign

Abstract

A B S T R A C TThe regional dust model system LM-MUSCAT-DES was developed in the framework of the SAMUM project. Using the unique comprehensive data set of near-source dust properties during the 2006 SAMUM field campaign, the performance of the model system is evaluated for two time periods in May and June 2006. Dust optical thicknesses, number size distributions and the position of the maximum dust extinction in the vertical profiles agree well with the observations. However, the spatio-temporal evolution of the dust plumes is not always reproduced due to inaccuracies in the dust source placement by the model. While simulated winds and dust distributions are well matched for dust events caused by dry synoptic-scale dynamics, they are often misrepresented when dust emissions are caused by moist convection or influenced by small-scale topography that is not resolved by the model. In contrast to long-range dust transport, in the vicinity of source regions the model performance strongly depends on the correct prediction of the exact location of sources. Insufficiently resolved vertical grid spacing causes the absence of inversions in the model vertical profiles and likely explains the absence of the observed sharply defined dust layers.

Atmospheric dust modeling from meso to global scales with the online NMMB/BSC-Dust model – Part 2: Experimental campaigns in Northern Africa

“…6a-f). The model is not able to capture the intensity of the event due to an inaccurate representation of the moist convection as discussed in previous modeling studies (Haustein et al, 2009;Heinold et al, 2009) and as evident in the simulated 10 m wind speed which is rather smoothly distributed and not exceeding moderate velocities (not shown). Nonetheless, the pattern of the modeled AOD at least resembles the shape of dust plume in the DB retrieval.…”

“…The data from both campaigns have already been used for extensive model evaluation (e.g. Tegen et al, 2006;Bouet et al, 2007;Todd et al, 2007Todd et al, , 2008aHaustein et al, 2009;Heinold et al, 2009;Müller et al, 2009;Otto et al, 2009Otto et al, , 2011. The first phase of SAMUM-1 took place in May/June 2006 at three sites in Morocco accompanied by overflights of two research aircraft as integral part of the campaign.…”

Seasonal variability of Saharan desert dust and ice nucleating particles over Europe

“…The simulations were re-initialised every 48 h to keep the modelled meteorology close to the analysis fields. The model results have been extensively evaluated with field measurements of ground-based and airborne measurements of dust concentrations as well as size distribution, aerosol optical thickness and lidar backscatter and extinction (Heinold et al, 2009(Heinold et al, , 2011Tegen et al, 2013). The evaluation of the dust model results shown in Tegen et al (2013) were performed with the same model setup as described in this work.…”

Optical properties of Saharan dust aerosol and contribution from the coarse mode as measured during the Fennec 2011 aircraft campaign

“…In contrast, the other events during Fennec were caused by more synoptic-scale flows. The low resolution of the meteorological information input to Hysplit (one degree) therefore make it less likely to be able to correctly resolve the convection and associated dust uplift (Heinold et al, 2009;. Dust sampled during Fennec 2011 has been categorised into event types based on the age of the dust sampled and the dominant meteorology.…”