Characterization of SLA and SST errors in a regional simulation with Symphonie
Characterization of SLA and SST errors in a regional ocean simulation of the Bay of Biscay with the Symphonie model
N. Ayoub, P. De Mey, P. Marsaleix (Laboratoire d’Aérologie), J. Lamouroux (Noveltis), C. de Nicola (CDD), C. Nguyen
This work is done using the SYMPHONIE model and the SEQUOIA libraries on a Bay of Biscay configuration with a 3km x 3 km grid and 43 vertical levels. An ensemble of 54 members is generated over the period Jan-Mar 2008 by perturbing the wind forcing.
The figure below shows the ensemble spreads on 25 March 2008, of sea surface height in cm (left) and of sea surface temperature in °C (right). This example emphasizes the existence of two very distinct regimes over the shelf and in the deep ocean. The spread was found to be larger over the shelf (>5cm and >0.5°C) and shows a much larger time variability. In the Bay of Biscay (south of 49°N) the maximum spread for SSH is right at the coast and likely also corresponds to wind-driven surges. The SST maximum is farther offshore between the 100 m and 200 m isobaths. Over the abyssal plain, the spread in SST is relatively weak (< 0.3°C), grows little with time and is characterized by small-scale filament-like patterns. In contrast, the spread in SSH in the deep part is almost zero until 15 February, growing continuously up to about 6 cm at the end of the simulation, with spatial scales of a few hundreds of km (from Kourafalou et al., 2014).
Kourafalou V., P. De Mey, J. Staneva, N. Ayoub, A. Barth, Y. Chao, M. Cirano, J. Fiechter, M. Herzfeld, A. Kurapov, AM Moore, P. Oddo, J. Pullen, A. Van Der Westhuysen, R. Weisberg, 2014: Coastal Ocean Forecasting: science foundation and user benefits, Journal of Operational Oceanography, in press.