Description
Presentations on the Value of AMOC observing and Observational Priorities.
N.P. Holliday, I. Ansorge, K. Burmeister, E. Campo, M.P. Chidichimo, B. de Young, S. Heymans, J. Hounpké, L. C. Jackson, T. Lamont, S.-K. Lee, R. C. Perez, C. Sams, J. Snowden, A.-C. Zinkann
People living in coastal zones, islands and continents surrounding the Atlantic Ocean experience weather, climate and marine conditions that are directly impacted by the Atlantic Meridional Overturning...
The exchanges across the Greenland-Scotland Ridge compose the northernmost part of the Atlantic Meridional Overturning Circulation (AMOC), with the warm Atlantic inflow in the upper limb transporting heat towards the Arctic while the returning deep overflows provide density for the deep limb of the AMOC further south. Since the mid-1990s, the Faroe Marine Research Institute (FAMRI) has...
The Rockall Trough (RT) is a key pathway for warm and salty water flowing northward, a process which plays a key role in dictating the western European climate. The picture of the mean circulation and variability in the RT is still emerging, as the record of continuous transport observations has only recently been extended to eight years. Here, for the first time, we present the temporally...
A substantial portion of the dense water in the lower limb of the AMOC originates in the Nordic Seas, including the densest component. The volume of the water overflowing the Greenland-Scotland Ridge doubles through entrainment in the subpolar North Atlantic. As such, dense-water formation in the Nordic Seas is crucial for sustaining the AMOC. In this talk, I will highlight recent...
Most observational arrays that study the AMOC rely on the geostrophic method, by which a (small) number of measurements at endpoints of a section are used to infer the flow across the section. This is a necessity because measuring everywhere along the section is cost-prohibitive. Here, we will study a few different examples how the results from such applications have been validated using...
The South Atlantic Meridional Overturning Circulation (SAMOC) observing system has evolved tremendously since 2007, and has substantially improved our understanding of the dynamics and variability of the upper, deep, and abyssal South Atlantic circulation from daily to interannual time-scales. However, the SAMOC daily time series derived from moored arrays are still relatively short and are...
The Atlantic Meridional Overturning Circulation (AMOC) is an important player in Earth's climate system on a wide range of timescales and with a correspondingly long list of potential societal impacts. The drivers of its variability are still debated and climate models give diverging projections for AMOC change over the 21st century. Sustained AMOC observations are, therefore, needed to inform...
Since 2014 the OSNAP array has provided monthly estimates of the subpolar AMOC strength, structure and associated heat and fresh-water fluxes. A specific objective from the outset was to determine from the observations “the configuration of an optimally efficient long-term AMOC monitoring system in the North Atlantic subpolar gyre”. OSNAP is a huge international programme of 29 Principal...
The Atlantic Meridional Overturning Circulation (AMOC) is essential for the distribution of heat, salt, and carbon dioxide, so it is a fundamental part of understanding climate change and its ocean’s role as a mitigator of those changes. Focusing on the South Atlantic, this work aims to understand the AMOC upper and lower branch changes in the SSP3-7.0 scenario compared to the present climate....
Future projections indicate the Atlantic Meridional Overturning Circulation (AMOC) will weaken and shoal in response to global warming, but models disagree widely over the amount of weakening. We analyse the overturning pathways in 27 CMIP6 models to assess their impact on this weakening. The branch of the AMOC that returns through upwelling in the Indo-Pacific, but does not later upwell in...
The spatial scales of key AMOC processes are typically larger than the deformation radius and, thus, its variations are likely governed by lower order dynamics that acts on complex bathymetry. It is expected that a large portion of observed AMOC variations can be modeled and explained in simple models. In this study, we employ a 3-layer process model with realistic bathymetry and wind-stress...
The Atlantic Ocean is crucial for many regional climate phenomena through its linkage with the AMOC. For example, modeling studies suggest that the AMOC and associated Atlantic heat transport can affect multidecadal Arctic sea ice variability. Coherent multidecadal changes among the AMOC fingerprint and inverted vertical wind shear over the main development region of Atlantic hurricanes have...
The abyssal limb of the Atlantic Meridional Circulation (AMOC) redistributes heat and carbon northward as it carries Antarctic Bottom Water (AABW) from the Southern Ocean to the subtropical North Atlantic Ocean. Using primarily mooring observations from different AMOC observing arrays and hydrographic data from multiple sources, we show that northward flowing AABW is mainly constrained below...
From 2004 to 2014, the Line W moorings measured a 0.7 Sv/yr slowing of the Deep Western Boundary Current (DWBC) offshore of Cape Cod. Here, we combine these deep mooring observations with float and satellite altimeter data and find that this DWBC change corresponded to a slowing of the cross-basin Atlantic Meridional Overturning Circulation (AMOC) of about 0.3 Sv/yr. Our AMOC transport time...
Since the inception of the international South Atlantic Meridional Overturning Circulation initiative in the 21st century, substantial advances have been made in observing and understanding the Southern Hemisphere component of the Atlantic Meridional Overturning Circulation (AMOC). Here we synthesize insights gained into overturning flows, interocean exchanges, and water mass distributions and...
The South Atlantic Meridional Overturning Circulation (SAMOC) is a scientific program aiming to investigate and promote the progress of the knowledge regarding the AMOC through the Atlantic basin. The installation and maintenance of the SAMOC Basin-wide Array (SAMBA) along the latitude of 34.5ºS was an accomplishment that involved institutions and scientists from Argentina, Brazil, South...
The Labrador Sea is a key region for ocean ventilation, as it is one of the few places globally where deep water formation can transport atmospheric oxygen and anthropogenic carbon to the deep ocean. The newly formed Labrador Sea Water (LSW) is then exported out of the basin, spreading the biogeochemical signal set in the formation region to the rest of the ocean. While this general picture...
Canadian researchers have been making observations in the winter dynamics of the Labrador Sea with a focus on the links between convection, restratification and gas exchange with the atmosphere. These studies have been conducted with a mix of platforms including ships, gliders and fixed moorings, including one mooring system -Seacycler- with a profiling instrument package. This work has led...
