Regionales Rechenzentrum der Universität Hamburg/ MCC/ Lecture2Go
Verlag/Körperschaft:
Universität Hamburg
Erscheinungsjahr:
2023
Medientyp:
Audiovisuell
Schlagworte:
AMOC
webinar
freshwater
North Atlantic Subpolar Gyre
volume transport time series
47N
Sonstiges
Beschreibung:
Title: Freshwater and AMOC in the North Atlantic Subpolar Gyre Speaker: Fiamma Straneo (Scripps Institution of Oceanography, USA) Abstract: Increasing freshwater discharge from the loss of Arctic sea-ice and from melting of the Greenland Ice Sheet has the potential to affect the AMOC by reducing dense water formation. In addition to these longer term trends, episodic release of freshwater from the Arctic (e.g. Great Salinity Anomalies) cyclically result in a modification of the stratification, dense water properties and, at times, a temporary slow down or shut down of convection. Here, I present some recent observation-based studies as part of the OSNAP (Overturning in the Subpolar North Atlantic Program) Program that provide insight into some of the processes and dynamics that are responsible for the spreading and mixing of freshwater. Specifically, I will present recent findings related to the circulation and spreading of Greenland meltwater, to the circulation and impact of the latest GSA in the Subpolar North Atlantic and, finally, a baseline estimate for the fraction of Arctic freshwater export that is entrained in the AMOC. Collectively, these studies point at the need to understand the processes that govern the freshwater transport and transformation before we can model their long-term impact on the AMOC. Title: The AMOC volume transport time series at 47N Speaker: Monika Rhein, (IUP-MARUM, University Bremen) Abstract: The AMOC in models and in observations disagree on many aspects. Here we calculate the AMOC volume transport at 47N (the NOAC array) from observations only, combining moorings at the western and eastern boundaries, PIES in the interior, altimetry and the ARMOR3D data set. The mean AMOC transport from 1993 – 2018 is 17.2 Sv, with no significant long-term trend. The low pass filtered AMOC is significantly correlated with the RAPID AMOC at 26N with r = 0. 53− 0. 71 (depending on the filtering method). The correlation increases to r = 0. 72–0. 84 when 47N leads by 10 months. This finding either points to an extended subtropical regime reaching farther north than anticipated before or challenges the notion that the subtropical and subpolar regimes are decoupled on inter-annual timescales. Please note that the talk "Simulation-based approaches for quantitative observing system design" by Patrick Heimbach (University of Texas at Austin, USA) was cancelled in this webinar.
