Ben Harden


My research at WHOI centers around ocean circulation in the seas around Greenland and the role these currents have in regulating our planet’s climate. The Nordic seas to the east of Greenland are a unique confluence or waters that have travelled over vast distances. Warm salty tropic waters flow in to the ocean from the south, some of this continues on into the Arctic and the rest circulates in the Northern basins. Cold fresh meltwater streams out of the Arctic, spreading out into the nordic seas and progressing on down in to the North Atlantic. Dense water is also formed through intense cooling from Atlantic storms and exits at depth through channels in the ridge connecting Scotland with Greenland, cascading 100s of meters down in to the deep ocean to return towards the equator. In undertaking these movements, these waters transport huge amounts of heat from the Equator towards the pole and help regulate the climate of our planet.
My research is about looking at the particular branches of this global system and asking how they work locally. How do the waters entering the Nordic Seas interact with one another? where do they flow and why? and how might they be influencing and be influenced by a changing climate? I work mainly with observational data and I’m motivated by how much there is to find out in this historically data sparse region. In addition, I take an active interest in science communication - often practicing my skills on cruise blogs and in schools.
The projects I am working on currently are:
1. Denmark Strait Overflow
I work with data from the heart of a newly discovered current in the Nordic Seas. The North Icelandic Jet flows along the north coast of Iceland and pushes dense water towards the Denmark Strait Overflow - a major cascade of dense water out of the nordic seas through the channel between Greenland and Iceland. Studies have traditionally shown that the overflow water is transported down the Greenland coast from the north so the discovery of this current from the east a decade ago really shifted the communities thinking about where the dense water forms and how stable the return dense flow might be in a changing climate.
I am investigating the first year-long measurements of this current to really get at the heart of how important it is and how it works in moving dense water southward toward the equator. The data I use comes from a mooring deployment across the current that was in the water for one year talking extensive measurements of the currents speed and what waters it is transporting. I am looking at whether the current is a seasonal feature, how it varies and meanders, and what waters are drawn into the strait through this pathway. With this knowledge in hand, the community will be much better placed to assess future changes and incorporate accurate processes into climate modules.
As part of the project I as involved in the deployment and collection of this data aboard two WHOI expeditions in the summers of 2011 and 2012. I also documented both trips in video, one set of which was recently published in the book “To the Denmark Strait”.
2. East Greenland Coastal Current
The cold, fresh polar water that is ejected from the Arctic due to sea ice melt flows southward towards the Atlantic along the east coast of Greenland. We need to know how much water flows southward in order to understand how much of the warm water can flow northward and in order to appreciate how an increase in fresh water production could affect dense water formation. Doing so is difficult though; much of the greenland shelf is ice choked and we have no real indication of how representative snap-shot boat measurements are on longer than daily time scales.
I am trying to improve our understanding of the variability in this current by analyzing some of the first time series data from the inner Greenland shelf underneath the sea ice. The data shows how the current changes its character over the course of four years. I want to know how variable the flow of fresh water is and if we can understand why it might vary on weekly time scales. It looks like winds are an important driver of this variability as well as eddies and meanders in the current. If we can understand how this current moves we can better pin down its role in the climate stability of the Northern Oceans.
3. Outreach
I am committed to undertaking the highest quality science communication. I undertook a radio training course with this year to improve my story telling and journalistic skills. This not only helps me communicate my science more effectively to a lay audience, but has improved the quality of my science writing and presentations. Here are some links to outreach actives (video, radio and interviews) I have been involved in during my scholarship:
To Greenland’s Frozen Coast (cruise website)
To the Denmark Strait (book)
Warming Arcitc (cruise website)
Interview on WCAI about North Icelandic Jet