Fluctuations in deep-ocean heat content and variations of steric sea level observed from Deep Argo floats
Event: 2022 Ocean Surface Topography Science Team Meeting
Session: Science I: Climate data records for understanding the causes of global and regional sea level variability and change
Presentation type: Type Poster
Contribution: PDF file
The Deep Argo array consists of 200 active autonomous floats deployed in deep (> 2000 m) ocean basins that measure temperature and salinity every 10 days between the surface and seafloor. This new dataset is available on the Global Telecommunication System and Argo Global Data Assembly Centers in near real time and after delayed mode quality control. Regional pilot arrays have demonstrated Deep Argo's ability to quantify changes in the amount of heat stored in the deep ocean, where and how it is distributed, and fluctuations in water mass characteristics with accuracies approaching repeat hydrographic data. Recent analyses using Deep Argo profiles reveal an acceleration of Antarctic Bottom Water warming in the Southwest Pacific Basin using historical data from the 1990s–2010s and deep Argo data from 2014–2018, steady warming of this water mass in the Brazil Basin from the 1980s–2000s through 2019–2020, and similar warming rates in the Argentine Basin between the 1970s–1990s and 2020–2021. There is no discernible warming trend within the Lower North Atlantic Deep Water in the Brazil Basin over the past few decades, but a cooling trend is observed in the Irminger Sea between 2016–2021 that interrupted the warming phase prevailing since the late 1990s. Preliminary results based on Deep Argo profiles collected between 2014-2022 in the North Atlantic Ocean will be reported describing the thermosteric and halosteric components of sea level variations, and showing comparisons of steric sea level estimates from satellite measurements (satellite altimetry minus space gravimetry) with Deep Argo data. Performances and development of float and sensor technology, and deployment plans and envisioned expansions of the Deep Argo mission will be outlined.