High-resolution observations in the western Mediterranean Sea: the REP14-MED experiment

Abstract

Abstract. The observational part of the REP14-MED experiment was conducted in June 2014 in the Sardo-Balearic Basin west of Sardinia (western Mediterranean Sea). Two research vessels collected high-resolution oceanographic data by means of hydrographic casts, towed systems, and underway measurements. In addition, a vast amount of data was provided by a fleet of 11 ocean gliders, time series were available from moored instruments, and information on Lagrangian flow patterns was obtained from surface drifters and one profiling float. The spatial resolution of the observations encompasses a spectrum over 4 orders of magnitude from 𝒪(101 m) to 𝒪(105 m), and the time series from the moored instruments cover a spectral range of 5 orders from 𝒪(101 s) to 𝒪(106 s). The objective of this article is to provide an overview of the huge data set which has been utilised by various studies, focusing on (i) water masses and circulation, (ii) operational forecasting, (iii) data assimilation, (iv) variability of the ocean, and (v) new payloads for gliders.

Submesoscale dispersion of surface drifters in a coastal sea near offshore wind farms

“…Although Albatros MD03 drifters have been widely used during the last years (e.g. Lana et al, 2016;Callies et al, 2017;Sentchev et al, 2017;Onken et al, 2018), to our knowledge slippage of this drifter type has never been quantified. However, considering the drag ratio of 33.2, the pa-868 U. Callies et al: Surface drifters in the inner German Bight -A 3 21 May 17:20 34 B 1 -B 2 29 Jun 08:20 59 C 1 -C 2 14 Sep 21:20 145 A 2 -A 4 21 May 17:40 28 B 1 -B 3 29 Jun 08:20 56 C 3 -C 4 14 Sep 22:20 34 A 3 -A 4 21 May 17:40 36 B 2 -B 3 29 Jun 08:20 13 C 5 -C 6 14 Sep 23:40 64 B 4 -B 5 29 Jun 13:40 72 C 7 -C 8 15 Sep 00:20 103 C 9 -C 10 16 Sep 06:20 315…”

Response to referee #2

“…They also represent dynamically consistent covariances between different model variables and depths. Moreover, a domain localization strategy (Ott et al, 2004) is used to dampen the impact of remote observations. A 200 km localization radius is used, determined by both the size of mesoscale structures and the approximate distance between two Argo platforms in the western Mediterranean basin.…”

“…The potential of gliders to sample fine-scale processes and to identify different water masses has been demonstrated (Pascual et al, 2017;Heslop et al, 2012), as well as their capability to improve ocean model predictions via DA (e.g., Melet et al, 2012;Shulman et al, 2008;Pan et al, 2014;Mourre and Chiggiato, 2014). The question arises whether the sampling offered by a fleet of several gliders is as useful as a traditional ship-based CTD survey for regional ocean forecasting applications.…”

Sea gliders piloted by a centralised mission management system

“…A centralised global Mission Management System (MMS) is thus required to help the pilots, by leaving them only high-level tasks while algorithms perform the coordination activities. [5] have been achieved with a fleet of above gliders, which were either individually operated by pilots discussing together or virtually moored.…”