Occurrence of perfluoroalkyl substances in the Bay of Marseille (NW Mediterranean Sea) and the Rhône River

International audienceFour perfluoroalkyl substances (PFAS) were analyzed in 62 duplicate surface water samples from the Rhône River and Marseille Bay (France; NW Mediterranean Sea). Perfluorooctane sulfonate (PFOS) was detected in all samples and exceeded the European Environmental Quality Standard (EQS) values in over 80% of the cases. The most contaminated samples were from the Rhône River (up to 200 ng L-1 ∑ 4 PFAS), as well as those collected near a wastewater treatment plant outlet in Marseille Bay (up to 9 ng L −1 ∑ 4 PFAS). While PFOS was the predominant PFAS in Marseille Bay, remarkably high concentrations of perfluorohexanoic acid (PFHxA) were measured in the Rhône River (8-193 ng L −1). The relative abundances of individual compounds differed thus significantly between the Rhône River and Marseille Bay, indicating different sources. A simulation made with the MARS3D model showed that PFOS inputs from the Rhône River can enter Marseille Bay at levels > EQS

Development of a fetch dependent sea-spray source function using aerosol concentration measurements in the North-Western Mediterranean

International audienc

WRF Sensitivity Analysis in Wind and Temperature Fields Simulation for the Northern Sahara and the Mediterranean Basin

Different configurations for the Weather Research and Forecasting (WRF) model were evaluated to improve wind and temperature fields predictions in the Northern Sahara and the Mediterranean basin. Eight setups, associated with different combinations of the surface layer physical parameters, the land surface model, and the grid nudging parameters, were considered. Numerical simulations covered the entire month of November 2017. Model results were compared with surface data from meteorological stations. The introduction of the grid nudging parameters leads to a general improvement of the modeled 10 m wind speed and 2 m temperature. In particular, nudging of wind speed parameter inside the planetary boundary layer (PBL) provides the most remarkable differences. In contrast, the nudging of temperature and relative humidity parameters inside the PBL may be switched off to reduce computational time and data storage. Furthermore, it was shown that the prediction of the 10 m wind speed and 2 m temperature is quite sensitive to the choice of the surface layer scheme and the land surface model. This paper provides useful suggestions to improve the setup of the WRF model in the Northern Sahara and the Mediterranean basin. These results are also relevant for topics related with the emission of mineral dust and sea spray within the Mediterranean region

Analysis of 5.5 years of atmospheric CO2, CH4, CO continuous observations (2014–2020) and their correlations, at the Observatoire de Haute Provence, a station of the ICOS-France national greenhouse gases observation network

International audienc

Atmospheric Sea Spray Modeling in the North-East Atlantic Ocean using Tunnel-Derived Generation Functions and the SUMOS Cruise Dataset

This study contributes to the communal effort to improve understanding of sea spray generation and transport. For the first time, laboratory-derived sea spray generation functions (SSGFs) are parameterized in the Meso-NH mesoscale atmospheric model and are field tested. Formulated from the MATE19 laboratory experiments (Bruch et al., 2021) two SSGFs are driven by the upwind component of the wave-slope variance S2x (herein B21A), or both S2x and the wind friction velocity cubed u3* (herein B21B). As part of our first attempt to incorporate the SSGFs in Meso-NH, the simulations are run without a wave model, and the wave-wind SSGFs are assumed wind-dependent. Model evaluation is achieved with sea spray and meteorological measurements acquired over the 0.1-22.75 µm radius range and 1-20 m s-1 U10 wind speeds, 15 meters above the sea surface onboard R/V Atalante during the 25 day SUMOS field campaign in the Bay of Biscay. The B21B SSGF offers particularly good sensitivity to a wide range of environmental conditions over the size range, with an average overestimation by a factor 1.5 compared with measurements, well below the deviations reported elsewhere. B21A also performs well for larger droplets at wind speeds above 15 m s-1. Associated with airflow separation and wave breaking, the wave-slope variance proves to be a key parameter for the scaling of sea spray generation. Using model outputs obtained with B21B, sea spray can be found far beyond the marine atmospheric boundary layer, with large plumes reaching 100 km inland and altitudes of 2.5 km. Plain Language Summary The effects of sea spray on weather and climate remain poorly understood as a result of sparse measurements and large uncertainties in the generation flux. With the aim of improving sea spray transport in atmospheric models, two sea spray generation functions derived from the MATE19 laboratory campaign are parameterized in the Meso-NH mesoscale atmospheric model. The simulations are run over the Bay of Biscay in February-March 2021, and are compared with sea spray concentrations measured during the SUMOS field campaign. Results show that the laboratory-derived generation functions allow accurate predictions of sea spray concentrations. Furthermore, simulations show that sea spray droplets can be transported far over land, and high into the atmosphere

Modélisation 3D des interactions atmosphère-océan-biogéochimie marine en zone côtière (application à la baie de Marseille): Influence des apports anthropiques de la métropole sur l'écosystème marin

Maste

Modélisation 3D des interactions atmosphère-océan-biogéochimie marine en zone côtière (application à la baie de Marseille): Influence des apports anthropiques de la métropole sur l'écosystème marin

Maste