Water Transformation

There are a small number of regions in the ocean where water masses are formed through rapid mixing of former water masses. This mixing is generally driven by strong air-sea interactions in particular regions, due to favorable local conditions (atmospheric regimes, stratification, fronts, topography, coastal areas…) and/or in overflow regions. The water formation processes lead to large mixed patches (100s km) presenting quasi-homogeneous (physical, chemical and biological) properties, that can “buffer”
or “remember” signals for long periods of time, until these water masses are mixed again in the following years/decades/centuries and possibly far away (1000s of km) from their formation areas, driven by the general circulation, eddy shedding and general diffusion processes. While the average conditions of the oceanic circulation and processes have been studied and assessed in the past, direct observation of these water transformation zones has been very limited. It is challenging to observe the variability of the source (physical, chemical, biological) properties and volumes of these newly-formed water masses because the transformation often occurs on an “intermittent” basis, sometimes in localized areas (~100s km), during relatively short (days) episodes. These challenges require sustained in-situ observing efforts that are carried out throughout the year in relatively large areas, with high horizontal resolution because of the small scale circulation features involved. The observation of such phenomena remained a challenge until the use of autonomous underwater gliders in combination with more classical ocean observing techniques such as ships, floats and drifters. The OceanGliders Water Transformation observing network aims to develop sustained and integrated regional observing systems throughout the world, by sharing best practices, requirements, efforts and scientific knowledge, to address this critical issue.

Pierre Testor (CNRS/LOCEAN, France),

Brad de Young (MUN, Canada)

Charitha Pattiaratchi (UWA, Australia),

Alex Brearley (BAS, UK)

Laurent Coppola (LOV, France)

Ilker Fer (UiB, Norway)

Karen Heywood (UEA, UK)

Loic Houpert (SAMS, UK)

Burt Jones (KAUST, Saudi Arabia)

Johannes Karstensen (GEOMAR, Germany)

Gerd Krahmann (GEOMAR, Germany)

Elena Mauri (OGS, Italy),

Michael P. Meredith (BAS, UK)

Laurent Mortier (ENSTA/LOCEAN, France),

Moninya Roughan, (UNSW, Australia)

Grace Saba (Rutgers Univ., USA)

Amandine Schaeffer (UNSW, Australia)

Andrew Thompson (Caltech, USA)

Hugh Venables (BAS, UK)

theme: Climate Change & Variability

keywords: Discovery, Ecosystem Health & Biodiversity, Climate Change & Variability, Blue Economy