The main lab is empty, downright bereft of instruments (mine is the only computer in sight) and people. They’re all out on the fantail loading gear and craning it onto the hardcore industrial wharf, which we lay-to about dawn, somewhere in the vast Durban Harbor complex. By 1400, I hear, we’ll leave the ship. And that will end the second of three Agulhas Current Time-Series cruises.
Now, 26 November 2010, we’ve retrieved the moorings we deployed on the first cruise in April 2010, downloaded their current-meter and ADCP data, installed fresh batteries, and re-deployed the moorings. There were tense moments this time: the tardy container full of essential gear, the pre-cruise saga of the breakaway moorings, not to mention the inherent tension waiting to hear if the acoustic releases would actually release. Also, this was Lisa’s first look at the acquired data, the point of this whole endeavor, another tense moment. (Have the instruments flooded? Have the moorings been blown down to depths exceeding the ADCP’s range? Have any number of things gone awry to ruin the data?) No, the data were very good indeed. No one is ever sanguine about leaving their instruments in the ocean for over a year; there is always anxiety about the safety of their data. But now, after this second voyage, Lisa and her team can breathe a little easier about what they’ll find on the third and final voyage in April 2013.
Thus far, the human and technological components have all done their jobs superbly. It was fun to again watch a group of partial strangers (both to one another and to day-to-day work at sea) coalesce around a common purpose; fun, too, to be part of the fast-growing friendships that inevitably form during a month at sea. But now our parting draws neigh (Robert just told me they’re “ninety-percent” finished with the off loading), and I’m thinking about endings—this immediate one for us and, as for the science, the next step, essentially a new beginning, that will be built on ACT research.
When complete, ACT will produce unprecedented knowledge about the long-term changes in Agulhas velocity and transport; however, “long term” is relative. Because ocean currents are consistently variable and the climate they affect is by definition a long-term matter, only a sustained, decades-long mooring array can deliver the kind of data capable of understanding the Agulhas in its climatic context. At this writing, the Global Ocean Observing System, founded on the concept that sustained observation of the ocean are critical to understanding climate variability and change, has accepted a proposal from Lisa and her team to add an array across the Agulhas Current to the Global System. The groundwork has already been laid for the collaboration and capacity building necessary to construct and sustain an observing system off east Africa, although the mode of implementation remains to be decided at an international conference next year. These data will establish the role of the still-under-studied Indian Ocean in world-ocean circulation—and thereby to global climate.
“Okay, here’s the story,” said Robert leading a group of sweaty off-loaders into the lab. “We’ve got to go into Durban with passports and flight information to do some kind of immigration thing.”
“I thought we could do that at the airport.”
“Don’t think, just get your stuff. Leave your luggage; we’ll be coming back aboard. The bus is waiting.”
Okay, so this isn’t the end, not exactly, anyway.
