Several of the past blogposts center on the merchant marine vessel Oleander that provides weekly freight service between Bermuda and Port Elisabeth, NJ. We, Charlie Flagg and I, equipped her with an acoustic Doppler current profiler and started operation in fall 1992 and maintained uninterrupted service on her until the instrument failed mid-2018. The good news was that we had instrumented the new ship (with the same name) soon to arrive with two ADCPs (150 and 38 kHz units). Sadly, the challenges starting up the equipment and the restrictions imposed by COVID led to a multi-year hiatus until fall of 2023 when operation was restored – and we can all delight in how well it is going.
Magdalena Andres, senior scientist at WHOI, has done a fantastic job creating what must be viewed as a traveling ocean observatory, scanning waters from the Labrador Sea on the shelf and Slope Sea, tropical waters in the Gulf Stream, and the subtropical waters of the Sargasso Sea. In this post you will find links to various data sets that have been collected and archived as well as links to near-real-time data reports from the ship.
The Oleander has a home page or dashboard here:
https://sciencerocs-dev.whoi.edu/ol_index.html
You will find links to virtually all data there. For easier access to data from the ongoing operations go to this erddap server:
http://erddap.oleander.bios.edu:8080/erddap/info/index.html?page=1&itemsPerPage=1000
It is easy to browse the data. The historical 150 and 75 kHz ADCP plots of velocity (1992 - 2018) can be viewed here:
https://currents.soest.hawaii.edu/oleander/vel_ssh_old/index.html
This terrific link, prepared by Eric Firing, shows velocity vectors superimposed on concurrent altimetric maps of sea level. This provides the spatial context for understanding why the vectors align the way they do: notably due to the Gulf Stream, its meandering, and the passage of warm and cold core rings. Check it out!
The more recent 150 kHz plots of velocity (2023 to present), also superimposed on concurrent sea level maps, can be found here:
https://currents.soest.hawaii.edu/oleander/vel_ssh_quick/index.html
We all know that the Gulf Stream parts from the coast at Cape Hatteras, right? Not so, look at the October-November 2023 transects, and you’ll see the Gulf Stream hugging the continental slope from Cape Hatteras to the Oleander section where it several times turns SE and runs literally along the Oleander line. I was not aware of this until I saw these maps. What caused this to happen? If you see anything like this in the earlier (1992-2018) data please let me know! It might be instructive to animate SSH for this region spanning the entire Oleander period – which incidentally starts at the same time as modern altimetry!
All XBT sections can be viewed here:
http://erddap.oleander.bios.edu:8080/erddap/files/oleanderXbtPlots/
The National Marine Fisheries Service started taking XBTs across the shelf and Slope Sea in 1977. Starting in 2008 we improved coverage of the Gulf Stream including a few additional XBTs across the Sargasso Sea. That coverage improved over time such that by 2011 we were scanning the entire Oleander section monthly. We are grateful to Shenfu Dong at AOML/NOAA. Her contributions to the XBT program with Dr. Tim Noyes in charge of the field operation is adding tremendous value to the project. With the restart of the ADCP in fall 2023 the monthly XBT sections could be combined with velocity data to explore a number of questions, including to revisit the dynamical structure of the Gulf Stream in detail (Rossby and Zhang, 2001).
The thermosalinograph (TSG) data can be found here:
http://erddap.oleander.bios.edu:8080/erddap/files/oleanderTsgPlots/
These provide another perspective on the surface waters. Notice the ‘steppy’ character to temperature and salinity rather than a continuously or smoothly varying field. This suggests active stirring of waters with different properties with incomplete mixing to smaller and smaller scales.
The Oleander is now also equipped with a weather station reporting winds, temperature, and humidity:
https://sciencerocs-dev.whoi.edu/ol_index.html
These data are going to be valuable for future studies of air-sea interaction.
Here’s a novel feature: If you click on the IFCB dashboard button (Imaging FlowCytobot) on the Oleander dashboard or home page you will be taken here:
https://ifcb-data.whoi.edu/timeline?dataset=Oleander&bin=D20250605T181629_IFCB188
The IFCB is an incredible instrument, it’s like a microscope, camera, and computer all in one package. It takes pictures of particles in the 5 to 150 μmeter range in the surface waters. Every 20 minutes it draws in a small 5 ml volume of water and passes it through a microscopic cell such that the camera sees one particle at a time. A particle classification algorithm identifies and catalogues all the particles seen. mounted on the Oleander, the IFCB will be able to identify and classify particle patterns across the NW Atlantic from the continental shelf to Bermuda – and how these vary over season and eventually on longer time scales.
Rossby, T. and H.M. Zhang, 2001. The near-surface velocity and potential vorticity structure of the Gulf Stream. Journal of Marine Research, 59, 949-975.