On the mesoscale monitoring capability of Argo floats in the Mediterranean Sea

Antonio Sánchez-Román, Simón Ruiz, Ananda Pascual, Baptiste Mourre, Stéphanie Guinehut
2017 Ocean Science (OS)  
<p><strong>Abstract.</strong> In this work a simplified observing system simulation experiment (OSSE) approach is used to investigate which Argo design sampling in the Mediterranean Sea would be necessary to properly capture the mesoscale dynamics in this basin. The monitoring of the mesoscale features is not an initial objective of the Argo network. However, it is an interesting question from the perspective of future network extensions in order to improve the ocean state estimates. The true
more » ... eld used to conduct the OSSEs is provided by a specific altimetry-gridded merged product for the Mediterranean Sea. Synthetic observations were obtained by sub-sampling this <q>Nature Run</q> according to different configurations of the ARGO network. The observation errors required to perform the OSSEs were obtained through the comparison of sea level anomalies (SLAs) from altimetry and dynamic height anomalies (DHAs) computed from the real in situ Argo network. This analysis also contributes to validate satellite SLAs with an increased confidence. The simulation experiments show that a configuration similar to the current Argo array in the Mediterranean (with a spatial resolution of 2°<span class="thinspace"></span> × <span class="thinspace"></span>2°) is only able to recover the large-scale signals of the basin. Increasing the spatial resolution to nearly 75<span class="thinspace"></span>km<span class="thinspace"></span> × <span class="thinspace"></span>75<span class="thinspace"></span>km, allows the capture of most of the mesoscale signal in the basin and to retrieve the SLA field with a RMSE of 3<span class="thinspace"></span>cm for spatial scales larger than 150<span class="thinspace"></span>km, similar to those presently captured by the altimetry. This would represent a theoretical reduction of 40<span class="thinspace"></span>% of the actual RMSE. Such a high-resolution Argo array composed of around 450 floats, cycling every 10 days, is expected to increase the actual network cost by approximately a factor of 6.</p>
doi:10.5194/os-13-223-2017 fatcat:qke3h6lluzdqxn7fmrarq7z4zy