OS047-0005
Sea spray transport modeling in the North-West Mediterranean with a coupled wave-atmosphere numerical model combining the MESO-NH atmospheric model and the ECMWF HRES-WAM wave model, using a new sea spray production source function determined from both tunnel and field observations.
Sea spray transport modeling in the North-West Mediterranean with a coupled wave-atmosphere numerical model combining the MESO-NH atmospheric model and the ECMWF HRES-WAM wave model, using a new sea spray production source function determined from both tunnel and field observations.
Wednesday, 16 December 2020
Poster
Abstract:
Research conducted over the past four decades has shown that sea spray
production and transport plays an important role in heat and humidity
transfers in the marine atmospheric boundary layer (MABL), thus
affecting the global climate. Implementing a sea spray source function
(S3F) in current numerical weather prediction is therefore of great
interest for the reduction of numerical weather prediction errors,
especially in extreme wind speed conditions in which sea spray is
thought to dominate the flux problem. To this end, a S3F model
determined from a combination of tunnel and field measurements (Bruch et
al., 2020) is introduced in a coupled Wave-Atmosphere numerical model
using the MESO-NH atmospheric model, and the ECMWF HRES-WAM wave model.
The new S3F is valid over the 3-35 µm radius and for U10 wind speeds
ranging from 12 to 20 m s-1. The S3F is dependent on the sea surface characterisitics such as wave slope
variance; a non-dimensional surface parameter allowing the integration
of wave-wind boundary processes such as wave breaking and surface
tearing that are essential for film and spume droplet production,
respectively. Using this S3F, the modeled sea spray production and
transport is compared with sea-spray number concentrations measured on
board the Atalante research vessel during the MIRAMER campaign which
took place in the Northern Mediterranean in 2008 (see Laussac et al.,
2018). The surface wave slope variance representative of the field
conditions is calculated using formulae existing in the literature, such
as the celebrated wind-dependent semi-empirical function proposed by Cox
and Munk (1956).
production and transport plays an important role in heat and humidity
transfers in the marine atmospheric boundary layer (MABL), thus
affecting the global climate. Implementing a sea spray source function
(S3F) in current numerical weather prediction is therefore of great
interest for the reduction of numerical weather prediction errors,
especially in extreme wind speed conditions in which sea spray is
thought to dominate the flux problem. To this end, a S3F model
determined from a combination of tunnel and field measurements (Bruch et
al., 2020) is introduced in a coupled Wave-Atmosphere numerical model
using the MESO-NH atmospheric model, and the ECMWF HRES-WAM wave model.
The new S3F is valid over the 3-35 µm radius and for U10 wind speeds
ranging from 12 to 20 m s-1. The S3F is dependent on the sea surface characterisitics such as wave slope
variance; a non-dimensional surface parameter allowing the integration
of wave-wind boundary processes such as wave breaking and surface
tearing that are essential for film and spume droplet production,
respectively. Using this S3F, the modeled sea spray production and
transport is compared with sea-spray number concentrations measured on
board the Atalante research vessel during the MIRAMER campaign which
took place in the Northern Mediterranean in 2008 (see Laussac et al.,
2018). The surface wave slope variance representative of the field
conditions is calculated using formulae existing in the literature, such
as the celebrated wind-dependent semi-empirical function proposed by Cox
and Munk (1956).
References:
- Bruch W, Piazzola J, Branger H, Lunean C, Bourras D, van Eijk A,
Tedeschi G, (2020) Sea Spray Production Dependence on Wind and Wave
Combinations : A Tunnel Study. Submitted in Boundary Layer Meteorology.
- Cox C, Munk W (1956) Slopes of the sea surface deduced from
photographs of sun glitter. Bulletin of the Scripps Institution of
Oceanography, Volume 6, Issue 9, pages 401-488.
- Laussac S, Piazzola J, Tedeschi G, Yohia C, Canepa E, Rizza U, van
Eijk A (2018) Development of a fetch dependent sea-spray source function
using aerosol concentration measurements in the north-western
Mediterranean. Atmospheric Environment 193:177-189.