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Heather Tabisola >> Ok, and then Peggy, you
are up next.

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Peggy Sullivan is going to talk about sonar
ice data, telling us a story about the seasonal

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ice formation.

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All right, let's see.

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All right, Peggy, let's see.

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Sorry, I have to find you in two spots here.

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Ok.

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All right, Peggy, you should now be unmuted
and then I'm gonna move presenter to you.

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Shaun, I'm muting you now.

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Peggy, I can't hear you yet.

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There we go.

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Peggy Sullivan >> There, I unmuted myself.

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[Laughs]

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Heather Tabisola >> Perfect!

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Yeah, I never know how exactly if I'm truly
muting people.

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Perfect!

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Ok.

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I'm going to unmute and then you can take
it away.

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Peggy Sullivan >> All right.

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Thank you, Heather.

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Good morning, everyone, from all of our remote
locations.

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I have the benefit of having a sunny window
instead of an interior office.

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Woo hoo!

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I'm going to be talking about Chukchi Sea
ice and Chukchi Sea is a marginal ice zone.

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So in winter ice cover and open water, all
summer, with shoulder seasons are being transitioned

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seasons from waves to ice and then from ice
to waves.

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The Chukchi Sea has just been, has seen really
dramatic warming and sea ice changes in the

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recent years.

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So it's fortuitous for us that we have a long
set of data to look at some of these changing

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areas.

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Next slide.

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All right, I'm working on controls.

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There it is!

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[Laughs]
This is the area that we're working on, on

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the map.

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The seven stars are stations where we've had
ice profiler moorings set out and I'm actually

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going to be talking and have looked more at
the three that I've just circled: C1, C2

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and C3, which we call the Icy Cape Line.

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That line was located and because of proximity
to the Alaskan coastal current and proximity

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to Hanna Shoal, which is probably a little
further off than the label on the map but

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you can kinda get the sense of that.

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We do fall deployments and recoveries and
so have almost full years of data for each

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mooring that we pull back.

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We get ice draft as the main data product.

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Now, ice draft is very related to ice depth,
but what it really is defined as is as the

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surface of the water down into the depth of
the water it does not account for ice from

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the surface, and above.

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And it comprises about 90% of the depth, but
it actually is draft.

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We would have to do further instrumentation
with ADCPs to actually get depth.

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And we haven't done very much of that.

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In addition to the range data that turns into
ice draft, we also have temperature and pressure

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data.

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And at each of these stations we have not
only the ice profiler mooring, but also many

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other moorings that capture salinity, temperature,
and other parameters that we frequently get,

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like oxygen and PAR and chlorophyll and nutrients,
etc.

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C2 location has the longest running data record.

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We started putting these out consistently
in 2010 and C2 has been out every, well, almost

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every year since then.

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So, there are nine datasets for C2, four datasets
for C3, and seven for C1.

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And this table gives you a sense of what I
just said.

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C2 is the longest running and then the other
ones were earlier years and I haven't done

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as much with those.

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But in sum total we have nine years worth
of moorings.

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29 year-long datasets and have only lost data
from two years of instruments.

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So, about a 7% loss and it wasn't really loss
of instruments, it was problems with the instruments

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themselves.

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To the left of the screen, you can see some
information about the instrument.

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They are from ASL Environmental and they're
called IPS5 Upward-looking sonar instruments.

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I think we were kind of unique back in this
time in that ASL was mostly, if they weren't

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deploying their instruments, they were absolutely
taking the data, and processing for whomever

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was paying for it, and we pushed them to get
their software so we could process the data

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ourselves and it was kind of a big undertaking.

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It's a proprietary MATLAB tool.

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It's pretty large and it really takes months
to get through a dataset, so we're a bit of

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guinea pigs for them, but it's been pretty
cool working for the data...er, working with

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the data and with them.

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This illustration is one of the first cut
products that I make when I'm done.

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When I finally get from the range, data--raw
data--into the ice draft, and this is kind

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of an upside-down look, the zero line, there,
is the surface and you're seeing the spikes

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that go upward are what go into the depths
of the water.

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Each line of the six-line plot is one week
long.

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So it gives you a good sense of the variation
in how the ice looks underneath the surface,

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where you get all the chaos, spiky things,
and then you'll get some flat segments that

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are actually pancake ice or frazil ice, or
thin surface ice between the larger ice events.

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Yeah, the stretches of ice.

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This is a later product that I make and it
actually is a very long-term record.

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So you have to remember that these are one-second
data points.

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So that instruments sitting at the bottom
and looking up at the same spot in watching

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anything that goes by in every second, it's
taking a measurement.

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So if you look to the left of this plot with
the blue lines, you're starting in mid-November,

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to the right, you're ending at
late July.

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So you're seeing, to the left, some are waves,
damping down and then all the chaotic-looking

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lines through the middle are a formation of
ice and then ice cover through the winter.

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And then about three quarters of the way along
this plot, you can see a blob there where

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the blue is above and below the zero line.

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And that is a big wave segment that has come
in signifying the break-up of the ice over

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the winter.

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This has to do, of course, to increased solar
insulation, warming, and winds.

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And so eventually, it seems kinda like a duel
to me, where the winds come in and they fight

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with the ice until the winds win and it's
open water for the summer.

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If you look at the last, I don't know if you
can see my mouse here, the last segment of

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spiky stuff that goes below zero, that is
ice, so it comes after wind.

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And this is a really frequent thing we see,
and it signifies not ice formation, but ice

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coming through with break-up elsewhere in
the region.

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And then after June 4, you see that above
and below zero signal, that is all waves and

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open water.

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Ice keels are really important.

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And when I first started looking at these
data, that was one of the main things we were

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looking at was how deep can the ice keels
be?

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And we're trying to answer questions like,
is ice gonna come through and destroy the

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instrument that we have, as near the bottom
as we can?

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And at the time, Shell and some of the oil
companies were also up there.

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And there was some concern about things that
they were putting in, and would...

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would they be...would prevalence be created
by ice coming too deep and hitting things

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that were near bottom?

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And we're kind of happy to be able to quantify
this.

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And I have listed here that the deepest keels
that we have seen are what, 28.6 and 31.1

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meters.

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And this is down where instrument depths are
between 32 and 40 meters, so it comes fairly

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close.

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Now, this is not all the time, but it's often
enough and enough of a liability that it was

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a great thing to report to both researchers
who are putting instruments in, but also to

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oil companies that where liabilities might
exist for putting things in the water.

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Um, another thing that I've been looking at
with this is seasonal transitions.

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So, you have summer open water, winter ice
cover, and then you have the transition time,

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where you have a chaotic mix of waves and
ice coming through.

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Generally, in the fall, the transitions are
much more orderly.

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So you get a strong sense of when things stop
and start.

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Spring is much more chaotic, with lots of
starts to wind and then ice will come back

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pretty solidly for awhile and back and forth,
back and forth.

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I've made this illustration.

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If you look at the blue, that's open water
for the summer.

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The light blue is ice cover, and the red is
the transition zone.

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And, essentially, it shows this trend of...
the transition coming later and later.

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The duration of the transition is seasonal,
just variability from year to year.

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But the transition to or the evolution to
this event or this transition happening later

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00:11:00,060 --> 00:11:04,290
and later every year is pretty obvious.

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And very closely, it's correlated with the
ice caps, satellite ice concentration data.

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Now, I'm looking at my time.

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This is just another closeup of some of the
snapshot of the data, but it shows you spring

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transition.

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And even though I just said spring transition
is longer and more chaotic, this is a really

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fast one that occurred.

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And if you notice in the top plot, it's 2.6
day duration.

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And so to the left, you're seeing the ice
tendrils going down.

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00:11:40,800 --> 00:11:44,310
And to the right, you're seeing the wave signal.

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And zoomed out on the bottom, it goes from
the top is a 2.6 day view.

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00:11:50,760 --> 00:11:58,500
The bottom is a 2.7 hour view of this transition
from ice to waves, and I've taken the opportunity

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in this plot to show you what ice formation
and frazil ice, thin ice looks like.

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The tendrils are ice, of course.

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There's a wave shown in there in the center,
that helped break up the ice.

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00:12:11,779 --> 00:12:15,529
And then I'm showing you ice keel, which is
probably something that came through from

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elsewhere, because it's a transition from
winter to summer.

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00:12:19,500 --> 00:12:21,700
And then, to the right of this plot are all
waves.

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00:12:21,700 --> 00:12:25,720
And it is the start of the summer open season.

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00:12:25,720 --> 00:12:31,019
Then, kind of off on a tangent, but this is
something we're looking at right now, with

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00:12:31,019 --> 00:12:37,250
Catherine Berchok, over at AFSC in the Cetacean
and Assessment Ecology Group.

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00:12:37,250 --> 00:12:40,430
She noticed in some of her walrus data.

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00:12:40,430 --> 00:12:46,079
So, they've got hydrophones up there that,
just a couple of times that, there seem to

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00:12:46,079 --> 00:12:55,800
be a pattern of having daily, maximum ice
signal, followed fairly quickly by a heightened

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00:12:55,800 --> 00:12:58,470
signal of walrus in the area.

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00:12:58,470 --> 00:13:03,829
And so we've plotted the daily maximum ice
draft.

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00:13:03,829 --> 00:13:10,200
The walrus data and satellite ice concentration
here.

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00:13:10,200 --> 00:13:17,079
And to do a blow-up of what we're looking
at, in April of 2011, the black in, in the

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00:13:17,079 --> 00:13:21,490
add-on plot there, the black is ice signals,
the red is the walrus signal.

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00:13:21,490 --> 00:13:26,460
And so, there's some conversation and thoughts
about going forward about looking at correlation

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00:13:26,460 --> 00:13:33,290
between the presence of walrus, what the ice
looks like, whether there's open ice before

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00:13:33,290 --> 00:13:44,860
or after the peak in the ice segment and also
how the winds might impact all this.

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00:13:44,860 --> 00:13:48,410
I think I've just covered all that.

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00:13:48,410 --> 00:14:01,639
And
that's it!

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00:14:01,639 --> 00:14:05,930
So the data analysis and processing are ongoing.

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00:14:05,930 --> 00:14:13,130
We didn't have data in 2019-20, but we hope
to have one going out this summer.

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00:14:13,130 --> 00:14:14,130
Maybe.

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00:14:14,130 --> 00:14:16,120
We'll see.

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00:14:16,120 --> 00:14:21,940
We're working on a paper that will talk about
seasonal changes and the wind-ice-polynya

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00:14:21,940 --> 00:14:23,750
interplay.

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00:14:23,750 --> 00:14:28,699
Collaboration with Catherine Berchok at AFSC
regarding the walrus and...

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00:14:28,699 --> 00:14:35,562
I actually have a web area that is outside
of our Drupal but it's ice profiler and ice

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00:14:35,562 --> 00:14:39,440
draft plots and it's under EcoFOCI.

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00:14:39,440 --> 00:14:43,940
So, any questions are welcome and thanks very
much for listening.

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00:14:43,940 --> 00:14:48,230
Heather Tabisola >> Thank you so much, Peggy.