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Professor Stephen Ackley ( is the principal investigator (PI) for the Sea Ice research conducted during the Oden cruise 2006/2007 to Antarctica by Dr. Hongjie Xie and Burcu Cicek from UTSA. He participated in outreach efforts of POLARTREC and helped to answer numerous questions related to Antarctic research in the public forums and live conference calls during the Oden cruise. ** *Ute Kaden...

Interview written by my physics students at Homer Hanna HS, Brownsville, TX

Prof. St. Ackley at UTSA, TX ,11/06

How did you become interested in sea ice?

A "life accident"

As generally with many workers in Polar Science (at least the older generation), my involvement with sea ice was a "life accident"!

In short, in the late 1960s, I was drafted into the US Army and, because of my degree in science, I was assigned to the US Army Cold Regions Research and Engineering Laboratory, rather than being sent to VietNam. There I was a junior scientist working with Dr. K. Itagaki, an ice physicist in the Snow and Ice Branch (SIB). After my two year service in the military, I took a civilian research scientist position in the same group. Dr. Willy Weeks, also in the SIB, one of the giants in sea ice research, invited me to join an Arctic expedition to study sea ice in my first year as a civilian scientist. Under Willy's mentorship, I then developed my own research interests in sea ice science and expanded CRREL's efforts to the Antarctic sea ice zone, which has been my primary area of study for the last thirty years.

Can you tell us about The International Polar Year and outreach with our physics teacher Mrs. Kaden?

Offer young people some "clear paths" to careers in polar science

Part of our effort in International Polar Year will be to see if we can take the Polar Sciences out of this somewhat "medieval" apprenticeship approach to polar education and offer young people some "clear paths" to careers in polar science through university courses and student research experiences. Having teachers like your teacher, Mrs. Ute Kaden, participate in our field research efforts to expose future scientists to the challenges and opportunities of polar education and research at early ages is an important contribution to that effort, so, keep up the good work!

What are the benefits and concerns surrounding sea ice?

The big issue

The big issue of concern of the day of course is global warming and its impact on the sea ice cover. The area of ocean covered by sea ice, while large, is still only 10% of the ocean surface.

Polar regions as "Air conditioner" and Global Warming However, the Polar Regions act as the earth's "air conditioner" and the ice covers with their high reflectivity (or albedo) of sunlight represent an important cooling element. Without the ice cover, we have what is called the "ice albedo-feedback effect", so that solar radiation, instead of being reflected to space is absorbed at the ocean surface. The feedback is a further increase in the warming, radically, so the predictions of global warming are most felt in the Polar Regions, but also worldwide in disproportion to the area covered presently by sea ice.

Polar Regions are important ecosystems of our Earth Of equal weight in my mind, is the generally less-known appreciation of sea ice as habitat for an important ecosystem. So a benefit is that we have a highly-evolved, adapted ecosystem that gives us the enjoyment as humans of the "charismatic megafauna" of the polar regions, the polar bears, seals, whales of the north polar region and the penguins, seals, whales of the south polar region. I think it is important to realize also, that these animals have a whole unique food chain supporting them.

Global Warming and animals While global warming may cause humans to have to adapt, that there is no place or food chain for these animals if the sea ice habitat is destroyed or even significantly modified by global warming. They will, unquestionably in my opinion, become extinct species, so perhaps future generations will call them the "dinosaurs" of the 21st century and study their fossils instead of the living animals.

What is the ice's effect on the climate around the area, or the circumpolar water current around the Antarctic continent?

The ice has the effect of radically increasing the area that is polar and subpolar in climate. You saw this in your travels, where the climate, ecosystems changed markedly as you crossed the Polar Front between South America and the Antarctic Peninsula. The sea ice at maximum extent occupies an area the size of South America, and together with the continent of Antarctica is as big as Africa, so it has the effect of radically changing, or extends the polar climate into areas that would otherwise be much warmer. (Compare, for example, the climates in Punta Arenas Chile, with the island of South Georgia. Both are at the same latitude, but PA is not influenced by the sea ice and has a mid-latitude marine climate and South Georgia is influenced by sea ice and has a subpolar climate.)

Antarctic Circumpolar Current The Antarctic Circumpolar Current has more indirect interactions with the ice cover, since the primary forcing dates back to the opening of the Drake Passage by plate tectonics, allowing a complete circumpolar ocean circuit to be established around Antarctica. So the basic circulation was established before the ice covered the Antarctic continent and it was surrounded by sea ice. The structure of the current is thus more dependent on the geography and the winds, while the compositions of the water masses have more relationship to the ice cover. The high latitude ocean circulation features such as the Gyres that circuit the Weddell Sea and Ross Sea are however, more directly connected to the existence of the sea ice covers both in their circulation and water mass properties.

What can sea ice tell us?

Ice cover can be considered like a rock or a mineral

In some ways, ice cover can be considered like a rock or a mineral. By analyzing its composition, both structural and chemical, information on its initial growth, its deformational history, and thermal history ("metamorphic changes") can be deduced. From these features, we can then determine if the ice cover could have achieved those changes at its present location or required some particular path from its origin to the present location. From ice structure for example, we can tell whether the ice formed at the ice edge when waves were around or in an area where the ice growth was quieter, like we see in a lake with no waves.

Has the ever-increasing ozone hole affected the amount of sea ice that has formed over time?

Some recent work has suggested that the regional changes in the sea ice cover, specifically the reduction in the ice cover in the region of the Antarctic Peninsula has been in response to a large-scale atmospheric shift called the Southern Hemisphere Annular Mode (SAM), which is an index number atmospheric scientists calculate that gives some idea of the strength of the westerly winds at the latitudes of the northern edge of the sea ice zone.

Ozone Hole and sea ice cover There has been some very interesting work recently that shows that the SAM has responded to the increased size of the ozone hole. So, surprisingly to me, there has been some suggestion that the ozone hole and the regional change in sea ice cover are related. I say, surprisingly to me, because the Ozone hole is in the high regions of the atmosphere, the stratosphere, while sea ice is responding to surface winds, so the connection was not obvious to me. But other people are smarter than I am, so I shouldn't be that surprisedJ.

What contributions to the scientific community have your studies on sea ice made?

Rather than specific findings (but I think I have a few), my contribution that I am proudest of is my involvement in building a community of polar scientists working on sea ice. When I started working on Antarctic sea ice, I took the first cores of sea ice in the Weddell Sea since Wordie on Shackleton's Endurance expedition in 1915-16.

This last year, in contrast, we held a workshop on Antarctic sea ice thickness and had sixty people attend it, just on the problem of the ice thickness. We've had many cruises to the sea ice zone specifically to look at the atmosphere-ice-ocean interaction and now two drift stations for scientific research on Antarctic sea ice. I remember talking to Charlie Bentley, a famous Antarctic continent geophysicist that the field has advanced, not only through his own plentiful work, but through his graduate students, who have expanded many fold his studies of Antarctica. In some smaller way, I've felt gratified to have a similar experience through students and colleagues and that it is continuing now through my new involvement at UTSA with Hongjie Xie and Burcu Cicek.

What has been the most dangerous situation you have encountered in Antarctica?

Dangerous crevasses…

I guess I've had my share of dangerous situations which, fortunately, have not had a "poor result". I generally am very risk averse but situations arise, not necessarily of your own doing. In an early trip on a Coast Guard vessel, I went out on a helicopter ride with one of the officers who was doing some "PR" photography of the region, the ship and the helicopters. We came across a large iceberg, several km long and the photographer said he wanted to get some pictures of the helicopter landing and taking off from the iceberg. I said over the radio that he should be careful as the iceberg might have crevasses on it which you can't see if they are covered over with snow. Well, as the helicopter landed, he jumped out and started running over the surface. So I got out and, carefully walking in his footsteps, caught up with him and told him, again, about the danger. He nodded, and took his pictures as the helicopter was flying over us. The helicopter landed a short distance from where they let us off, so we started walking toward it. Well, fwump, and I'm hanging by my elbows as the snow collapsed under me. I crawled out, looked down into the crevasse and couldn't see the bottom. Knowing what the surface now looked like over it, I could see that it ran as far as the eye could see. My erstwhile companion, somewhat whiter than before, was looking at me on the other side and I told him to jump over it which he did. Needless to say, it was a very quiet ride back to the ship and we didn't land on anymore icebergs.

And the funniest?

There are lots of funny incidents…

There are lots of funny incidents, most dealing with "you had to be there to see the humor" quality. One of these occurred when we were setting up the drifting ice station, Ice Station Weddell. We went down by ship and were constructing buildings to drift on the pack ice which we occupied for over five months. So we were dressed in full extreme weather gear, hats, boots, coats etc and were also carrying two-way radios. I had to "use the facilities" and we had outhouses for this purpose. I had the radio in my outside pocket and sure enough, it fell into the wrong spot. So I had to walk over to the camp manager's place seeking a flashlight and assistance to retrieve it and had to tell the tale. They thought it was very funny. I probably should have left it there and not told anybody, it never seemed to work right after that, or so they told me.

Thank you Professor STEPHEN ACKLEY for answering our questions. The seaice coverage from the Oden cruise was very interesting and some us are thinking of applying to UT San Antonio to study in the field of Earth science.

Your physics students from Mrs. Kaden's class

Homer Hanna HS, Brownsville, TX

Ute Kaden (l) and Prof. Ackley (r) at UTSA, TX in preparation for the Oden cruise

Ackley Point was named in Antarctica to honor Professor Ackley for his outstanding sea ice work in Antarctica by the U.S. Board on Geographic Names. Ackley Point is an ice covered spot located near McMurdo Sound where Prof. Dr. Ackley *worked and conducted research for more than 25 years.