Atmospheric Chemistry and Physics Assimilation of ground versus lidar observations for

Abstract. This article investigates the potential impact of fu-ture ground-based lidar networks on analysis and short-term forecasts of particulate matter with a diameter smaller than 10 µm (PM10). To do so, an Observing System Simulation Experiment (OSSE) is built for PM10 data assimilation (DA) using optimal interpolation (OI) over Europe for one month from 15 July to 15 August 2001. First, using a lidar network with 12 stations and representing the “true ” atmosphere by a simulation called “nature run”, we estimate the efficiency of assimilating the lidar network measurements in improving PM10 concentration for analysis and forecast. It is compared to the efficiency of assimilating concentration measurements from the AirBase ground network, which includes about 500 stations in western Europe. It is found that assimilating the lidar observations decreases by about 54 % the root mea