Fwd: photo!

Also, a photo from Nick!
-B

Nick, Part 3

It's time again for our favorite guest-poster. Ladies and gentlemen,
Nick Huynh!



24 APRIL 2014

The sun has just broken free from the clutches of the horizon, lifting
the dark veil of night to reveal a quiet blue sky mottled with grey
clouds, some of which stand firm against the rising golden gleam while
the others simply shy away blushing pink. Having become accustomed to
mornings that merely fade into paler shades of grey, being able to
witness our sun paint the southern sky with subtle yet rich colors is
both numbing and invigorating.

We've finished sampling water from another station and I won't be
needed
at the bottle rosette again for several hours.

If not for the sudden onset of fatigue, which has likely precipitated
from my lack of rhythmic sleep, I would happily retreat to a
wind-sheltered nook somewhere on the ship, continue my slow progress
through Tolstoy's War and Peace, and watch the sun consume the hours as
it ventures west. For the sake of ship morale, though, I must try to
subdue my potentially contagious lassitude and find some rest. It has
been some time since I've attempted to fall asleep this early in the
lit
day. Fingers crossed I don't climb into my bunk only to be greeted by a
racing mind and a fidgeting body.
24 APRIL 2014

_Brrrreeeevvuuuummbreeevuuummbrreuummbreevummm ttzz ttzzz tzz tzzzz
tzzzz tzz tzz tzz CHIRP!_

Have I slept for long enough?

There's still light creeping through the edges of the cabin porthole.

What time is it?

Arrgh. Yikes, must remember to dim the telephone brightness before
going to sleep next time.

11:00.

Curses. Still early.

_Brrrreeeevvuuuummbreeevuuummbrreuummbreevummm ttzz ttzzz tzz tzzzz
tzzzz tzz tzz tzz CHIRP!_

I wonder if we're on station yet.

Where's that remote?

That's my phone again.

And that feels like War and Peace.

There you are. Ok. Not upside down. Power button top left.

_Brrrreeeevvuuuummbreeevuuummbrreuummbreevummm ttzz ttzzz tzz tzzzz
tzzzz tzz tzz tzz CHIRP!_

Oh, looks like the clouds rolled in.

_Flip._ Back deck. CTD bottle rosette is still on board.

_ Flip._ Baltic room. Doors are sealed.

_Flip._ Bow. We're still moving.

_Brrrreeeevvuuuummbreeevuuummbrreuummbreevummm ttzz ttzzz tzz tzzzz
tzzzz tzz tzz tzz CHIRP!_

_ Flip._ Current position. Station 63 ETA 0 hours.

0 hours? But we're haven't stopped…

_Brrrrrrrrrrrrrrrpphhhhwwwwwooooooooooosshhhhhhhhhhhh_

Aha, there goes our landing gear.

_BBBBRRRRRRRPPHHWWWOOOOOOOOOOSHHHHHHHH rittiinnnggtatiiinng
tatatatatatata tititititiitatata_

You can hear all the hidden loose bolts and screws in the walls and
cabinets rattle just slightly more as the bow thrusters fire up,
slowing
the ship to a halt. The ship underneath you initially rumbles with the
same sound as a landing jetliner and then, after you sway forward for a
moment, it calms to a vibrating hum similar to that of a moving
elevator.

_brevum brevum brevum brevum brevum brevum brevum brevum ttzz ttzzz tzz
tzzzz tzzzz tzz tzz tzz CHIRP!_

Listening to the ship shudder and strain as it decelerates brings to
mind the thought of something we left on land: the sound and feeling of
open and undisturbed silence. I had not noticed it's absence before,
but
now that I have, I look forward to meeting it again.

Boy, the things you remember to appreciate when at sea…

_brevum brevum brevum brevum brevum brevum brevum brevum ttzz ttzzz tzz
tzzzz tzzzz tzz tzz tzz CHIRP!_

Well, now that I'm awake, best I go downstairs and see if I can be
useful.

27 APRIL 2014

"116."

"DIC, 116 on sixteen!"

"CFCs clear on 20!"

"DOC, five on five!"

"Five on five; you have a duplicate on five, DOC!"

"Roger, thanks!"

"Nuts and salts, ones on one!"

"Ones on one, nuts and salts!"

"Alkalinity on 8!"

"Not yet, hold for pH, alkalinity!"

Dialogue around a freshly recovered CTD bottle rosette is similar to
what one might hear over radio communication. As water samplers move
back and forth from the rosette with their filled and unfilled bottles,
flasks, vials, or syringes, each calls out the number of the sampling
container they are about to use followed by the number of the rosette
bottle they are about to draw water from. A designated bottle cop
either
echoes the sampler's shout or instructs the individual to pause,
ensuring that water from each rosette bottle is drawn into the right
sample containers in the right order.

At the start of the cruise, it often took us over three hours to finish
sampling the bottles around the rosette. After over five weeks at sea,
we have developed a systematic efficiency that has enabled us to drain
the rosette within two hours.

Performing the same motions for every station, for the past 70
stations,
has certainly been enough practice to maximize the speed at which we
maneuver and work around the rosette. Deviations to our established
work
routine are hardly apparent until there is a transformation in the
weather. Even then, those alterations are ever so slight and are mostly
centered on what to wear and where to place a queue of sample bottles.
Conditions might be calm enough that merely boots are needed to remain
dry while sampling outside; they may be rough enough that the only way
to avoid the discomfort of cold and damp clothing is to don a full set
of foul weather gear. The swell may be small enough that there is
little
worry over leaving a sample bottle at your feet; it may be large enough
that anything left unsecured on deck is likely to be swallowed and lost
to the sea.

Like the adjustments to our sample routine, the contrasts between our
days also seem to be dictated by the mood of the sea and the tone of
the
sky. Whether it is midday or midnight, the walk to an awaiting meat and
preserved produce breakfast is either fluid and effortless or awkward
and staggered. Sleep at day's end either comes quickly with a gentle
rock or comes as a slight struggle against rousing plunges. Time in
between breaking fast and falling asleep is filled by a variation of a
few activities: watching film, reading literature, procuring data,
running the treadmill, contemplating crosswords, checking e-mail,
nodding off, and for some, writing what appears to be ancient Arabic
code. The largely uniform pattern of the waking hours might seem
agonizingly monotonous, but actually, it can be quite enjoyable as it
fosters an even balance between solitude and social engagement. In the
same way that you can always find time for yourself, you can always
find
someone who is keen to exchange meaningful and trivial conversations.

You can find Brendan or Lynne contemplating copious lines of numbers on
a computer screen and distract them with questions about ocean theories
on circulation; make an espresso with Mike and talk about his
aspiration
to become an ocean engineer and pursue an endless summer of surf;
stumble on Veronica knitting a sweater for her mother and listen to her
remarks on the incongruences between Australian and American English;
bump into Isa just after her workout and hear her perspective on
balancing marriage with a career in science; or you can pay a visit to
the Captain while he scans the horizon from the bridge and learn about
his outlook on war history and life as a sailor.

With days seemingly distinguishable only by changes in weather, life
aboard the Palmer can become as mindless and routine as sampling around
the rosette. But with 55 others living and working with you on the
ship,
the final weeks of your adventure at sea can be as enriching and
stimulating as the first few.

.

Post 5: Timescales

I've used the word "timescales" plenty in this blog already. This is
because the Earth sciences require thinking over an incredible range of
time and space scales. I started my career worrying about how one atom
in a molecule bumps against another in seawater. Such chemical
reactions happen over time and space scales too short to properly
imagine... the best my brain can do is a grossly-blown up and slowed
down facsimile, akin to representing a blood pumping through our veins
as a glacier etching its way through a valley. Nowadays I'm working on
how a planet-spanning ocean is changing in response to patterns in human
behavior that emerged over hundreds of years of industrialization.
Earth's climate has been changing in response to greenhouse gases for as
long as I've been alive. This is still a difficult time scale for me to
imagine, but it is at least within reach. However, even if we stopped
emitting carbon and other greenhouse gases today, we'd expect Earth's
climate to continue to respond for many thousands of years to come. It
will likely be between hundreds of thousands to millions of years before
all of the gases we've emitted have been stripped out of the atmosphere
and sequestered back into various geological reservoirs by natural
cycles. My poor mind has no chance at imagining anything this long...

Timescales are on my mind partly because almost everything we do on the
boat is cyclical. Every 8-9 hours a rosette goes down to the ocean
depths. Then it comes back up; there's a flurry of communications
between technicians, scientists, and the crew piloting the boat; and the
samplers head out to collect their seawater. The samplers make their
measurements while we steam to the next station. The cycle begins anew.
Meals and shifts fly by. I pass out pieces of a chocolate bar once
each week, if only so we don't forget this vestigial unit of time
entirely while we are away from our lives on land. I keep a list of
stations to remind myself that the cycle is not endless. With each
iteration, another station is crossed off our list and we are 30-40
nautical miles closer to port... to planes that will take us home to
wives, husbands, children, friends, and pets.

I've also been thinking about timescales in the context of the science
we are doing. One of the great difficulties with using repeat
hydrographic measurements is making sense of changes which are happening
over a wide range of timescales. We measure our sections once every 10
years or so with the goal of examining climate oscillations happening
over ~10 years and climate change happening over longer timescales
still. However, tides, eddies, seasons, movements of fronts, and
internal waves (waves that move between seawater masses with different
densities much like a typical wave moves along the surface of the ocean)
are all capable of moving water around in the ocean--even the deeper
parts of the ocean--over timescales much shorter than 10 years. This
means we sometimes see big changes in the properties we are measuring
that are just due to our choice of which day or month of the year we
have chosen to make measurements!

So, how do we make sense of our measurements despite these fast
variations? One main way is through the use of the robotic floats that
we are so excited about. These floats will keep measuring the ocean
once every 10 days. This means they don't have to worry about these
short timescale processes nearly as much. Why? It isn't a problem if
they measure one profile in an eddy because they would also measure
another ~364 in the span of time it would take for repeat hydrography to
measure the ocean a second time, and the fast variations would average
out. (I should note that a single float would run out of batteries
before the full 10 years were up). My research involves a second way to
get around fast variability, which is to take advantage of the fact that
we are measuring such a large number of seawater properties all at once.
When a passing internal wave pushes the water we are measuring deeper
down in the ocean, all of the various things we are measuring tend to
tend to look as though we measured them just a little bit shallower.
With a bit (read: lot) of coding (read: hair pulling), we can figure out
how much an internal wave, eddy, or tide has changed the properties of
the water we are measuring by considering the measurements collectively.
We can then look at the changes in the measurements that cannot be
explained by these fast changes. This is another reason I'm so excited
about the prototype floats which are capable of measuring more
properties than the typical floats: the more distinct measurements we
can make, the more weapons we have in our arsenal to figure out exactly
what changed between our sets of measurements. Data assimilating
computer models are a final way to interpret repeat hydrographic
measurements in the context of long term changes. It would take a whole
post to explain these computer models though... perhaps next week. For
now I'll just say these models devour data in an effort to make a
climate model reflect what actually happened on Earth rather than just
what could plausibly have happened.

My Advisor has the dream of an "all of the above" approach to measuring
ocean climate changes (I do as well, but I credit him with convincing me
that the scientific community and the technology are ready). His vision
is of a network of profiling floats in the Southern Ocean outfitted with
the full array of the new sensors. The floats would be calibrated using
the high quality measurements made on the hydrographic cruises that
deploy them, and the data the floats collect would be passed into
data-assimilating computer models. The models would then do the brute
number-crunching on the huge volumes of data sent back to land by the
floats. Monitoring climate change in the ocean is daunting challenge
with monumentally high stakes. I'm not sure anything short of his
vision could get the job done. Many of us in the oceanographic
community have been working to refine the sensor technology and computer
modeling software we need to realize this vision. This P16S cruise is
case in point, as we have deployed a number of the floats with the new
sensors and software as part of a proof-of-concept for the larger study.
The Southern Ocean State Estimate computer model (see Veronica's figure
from the last post) is already assimilating similar float data from
older floats, and some of my research with colleagues at the Scripps
Institution of Oceanography will allow this model to assimilate the data
from the new sensors as well. The funding proposals to get the broader
network started are pending. Fingers crossed!

~2 weeks to go!

Nick, Part 2, haiku and photos

Nick has sent along haiku with accompanying photos. They are below.
By way of explanation, the winch outside is called the Waterfall winch
(for reasons I've yet to be able to divine). The second haiku is about
changes in station spacing we implemented to make sure we can finish the
entire cruise track in our allotted time.

-Brendan
From Nick:


Moving the CTD from the Baltic to the Waterfall winch

Switch the winch
retire Baltic wire
waterfall flows

Re-spacing science stations from 30 to 40 nm apart

Delays in time
Which can stretch life thin
Space distance
 

Nick Huynh

Hello folks,

Nick Huynh, our carbon isotope and dissolved organic carbon tech, has
been doing some writing of his own. He doesn't have a blog set up just
yet, but he was interested in posting his writing anyway. I love it, so
I offered to put it on this blog. Here it is!

-Brendan



2 April 2014


Current coordinates are -65.2608, -149.9692. Air temperature is -0.2
with a wind chill of -17.6 centigrade, which is warm enough for a
venture outside to invigorate the blood with fresh air, but cold enough
to discourage staying out for longer than a single play through Led
Zeppelin's Stairway to Heaven. In the eight minutes that Robert Plant's
voice climbs mountains and Jimmy Page's guitar flows around river bends,
your face begins to tingle from the needle-like pricks of a persistent
wind, your hands numb from lack of motion, and your body shivers for
want of something to calm your quivering bones. That brief exposure to
the relatively mild conditions of the Southern Ocean is enough to leave
you astounded by the will and patience of those who braved the adventure
to Antarctica a century ago. How Earnest Shackleton and his crew
survived two winters after their wooden Endurance succumbed to the
pressure converging ice floes, bearing slightly more than their wools,
drifting with fragile hope, and fighting onslaughts of boredom, is a
feat that will always remain incomprehensible to me.


4 April 2014

March passed with 32 days, four time changes, a few iceberg sightings,
two Antarctic Circle crossings, and one really long steam to the
starting point, or station, of our science cruise. Our heading from that
point has been due north, towards the humidity, grass-skirts, and sky
blue waters of the French Polynesia. Our aim is to launch a new set of
autonomous instruments in the Southern Ocean and repeat a survey of the
physical and chemical properties that define the waters between 67ºS,
150ºW and 15ºS, 150ºW. The array of data that we collect will be
contributed to a internationally maintained dataset on global ocean
processes, including temperature, salt, and oxygen circulation, as well
as carbon and nutrient cycling. We hope that with this high quality,
repeated dataset, we can help bring understanding to how the ocean has
changed over time and how it may change in a future painted by the
accelerated rise of atmospheric CO2 and ocean acidification.

Marine Tech Meghan King and NASA scientist Scott Freeman deploying an
Inherent Optical Profiler (IOP), an instrument that measures the amount
and kind of light, uninfluenced by the sun, retained within the water
column.

There are 56 of us working towards this goal, all with a range of
responsibilities, narrow and wide, but all equally important. 18 make up
the crew of the 22-year old, 308 feet long, eight-deck deep Research
Vessel/Ice Breaker (RV/IB) Nathaniel B. Palmer. 9 consist supporting
staff members, who maintain electronics and communications as well as
operate, deploy, and retrieve machinery. These men and women are the
core of what keeps the ship moving and working at a safe efficiency
through the furious waters of the Southern Ocean. Without these
dedicated few, scientific objectives could not be realized. There 29 of
us in the science party, representing institutions from around the
world, including the Australian National University, Columbia University
LaMont-Doherty Earth Observatory, Florida State University, NASA, NOAA,
Princeton, Scripps Institute of Oceanography, Texas A&M University,
University Brest, UC Santa Barbara, University of Conception, University
of Hawaii, University of Washington, and Woods Hole Oceanographic
Institution. Aside from the Chiefs of Science, who oversee all science
operations, each member of the science party is responsible a specific
component of the expedition objective, whether that is to collect
seawater for a specific analysis, to measure water for a certain
parameter, to deploy a set of instruments, to manage activity around the
CTD (conductivity, temperature, and depth) water profiling bottle
rosette, or to manage and analyze all incoming and outgoing data. All of
the scientists aboard are ocean-going veterans with years of experience.
Each wields a knowledge of their field that has helped to stimulate and
exercise the underused regions of my mind. I have thoroughly enjoyed
listening to each share their interests and perspectives and I am so
pleased to be sailing, working, and living in their company.

5 April 2014

OPTIMUM TRACK SHIP ROUTING (OTSR) ADVISORY FOR RV NATHANIEL B. PALMER:
NO FEASIBLE ECONOMIC DIVERT EXISTS TO AVOID THESE BROAD AREAS OF HIGH
SEAS.

Because of gale force winds gusting at speeds greater than 30 knots and
swells reaching heights taller than the tallest giraffe, all science
deployments have been suspended, leaving many of us temporarily without
work. We've been walking through the hallways like sober drunkards for
the past 48 hours, trying to find conversations and distractions here
and there to keep ourselves occupied. There have been frequent trips to
the galley, where there is always a freshly baked dessert that tests
discipline, to the bridge, where the 360º view of the horizon recalls
the reality that we are alone, and to the 02 lounge, where you can
become endlessly lost in the world of film. The rowing-running-cycling
competition is still underway, with the Kill-ometers waiting for the
tides to help them gain the lead against P16Stacked. The cribbage
tournament has begun with Steve Howell, our expert on the Lowered
Acoustic Doppler Current Profiler, an instrument which uses sound to
measure current speeds, gaining the first win against one of our experts
on dissolved inorganic carbon, Dana Greeley. While the weather induced
holiday has been conducive for sleep and play, we are all itching to
deploy the next CTD and move our science forward. I don't believe anyone
is more eager than our Chief Scientist, Lynne Talley, who has been
scrupulously eyeing storm charts and working fervidly with the Captain
to plan our future course.

Relentless blows
Fighting wind angers sea
Poised like mantis

Watching the strong winds and powerful waves clash and bite at the
steel sides of our ship is enough to understand why the Southern Ocean
remains one of the most under-sampled regions of the world and why there
is a paucity of understanding on its processes. It is critical that we
continue trying to conduct science in the region despite its hostile
conditions to not only continue developing our fundamental knowledge of
the oceans, but also to become more conscious of how our Earth is being
changed by our human footprint.

Global ocean circulation is primarily driven by the formation of
deepwater masses that result from differences in water temperature and
salinity. The Southern Ocean is a major region where this deepwater
formation occurs; in certain areas of the Southern Ocean where intense
winds blow and sea ice melts, surface waters can become cooler or
saltier than the waters beneath it and as a result, can sink to depth,
becoming deepwater that circulates in the ocean basins for centuries
before coming into contact with the atmosphere again.

This deepwater formation is a major conduit for the long-term storage
of atmospheric carbon dioxide into the ocean interior and consequently,
makes the Southern Ocean influential in moderating the rate of
human-incurred climate change. It is therefore vital that we make
accurate observations of how deepwater formation and circulation
patterns in the Southern Ocean respond to the long term effects caused
by rising atmospheric CO2 emissions, including ocean warming, ocean
acidification, and regional wind intensification, in order to predict
how the whole Earth system will respond to climate change.

Hopefully this weather will relax sooner rather than later so that we
can get back to surveying the seas and achieving our aims. Until then,
well, for now I suppose I'll have another hot chocolate to keep me warm
while I loiter about and remain poised like a praying mantis.


5 April 2014

"Good news. Cock your bottles, we've got the O-K to deploy within the
hour." -Marine Projects Coordinator, Ken Vicknair

Far out.


14 April 2014

Like moths attracted to a porch light, fishing vessels are lured by the
commanding stature of the RV/IB Nathaniel B. Palmer. Capable of
penetrating through 3 feet of ice at a cruising speed of 3 knots, the
Palmer is attuned to performing its primary mission making remote and
inaccessible regions accessible to scientific measurements. While
serving this purpose, however, the Palmer also inadvertently opens up
Antarctic and Patagonian toothfish, also respectively known as Antarctic
cod and Chilean sea bass, fishing grounds to small fishing operations.

Antarctic fishers sail on ice-strengthened vessels, which are fortified
to withstand clashes with drifting ice floes but are not equipped with
enough steel and power to plow through the thick ice sheets that protect
the deep dwelling toothfish the fishers seek. Knowing that the Palmer
makes transits around Antarctica during the austral summer when the
continent's pack ice is still extensive but melting, these fishers have
recognized that they can minimize the duration of their transit,
maximize their fishing time and yields, reach their quotas before
season's end, and return to their families with their pockets full if
they simply follow the Palmer's cruise track.

This past austral summer, three fishing vessels somehow located the
Palmer as it was transiting through the pack ice with a scientific party
planning to conduct research in the Ross Sea. These vessels were able to
find the Palmer through the ship's AIS signal, which can be detected
within a 30 mile radius, and subsequently hailed the Palmer via VHF
radio to request that the icebreaker lead them through the ice. Though
no laws that exist that forbid these fishing vessels from following
ice-breaking research vessels, the Palmer is prohibited by the United
States Coast Guard from leading non-authorized vessels through Antarctic
pack ice. Adhering to this regulation, the Palmer declined the fisher's
requests but could do nothing to stop the vessels from following behind.
These fishing vessels eventually fell far away from the Palmer's course
and thus did not pose a problem for the icebreaker. However, this
incident unlikely to be the last and the Palmer may eventually be forced
to rescue vessels that followed it too far into the pack ice.

Fishing vessels that venture too far into the Antarctic pack ice not
only put risk on themselves, they also put unnecessary risk on the
forward progress of the Palmer's science program and possibly incite
sustainability concerns from the scientific team.

In the case that the trailing fishing vessels become trapped in ice,
the Palmer would need to delay the science program being hosted and
rescue the trapped fishers, which is only natural as the preservation of
human life is paramount to the work of science. Nevertheless, the time
lost to these rescues would still be upsetting not only because the
rescues were preventable, but also because acquiring ship access and
realizing scientific projects in the Southern Ocean requires incredible
effort and capital.

Additionally, after trapped fishing vessels are freed and brought to
safety, there will be the question of who is to claim responsibility for
subsidizing the cost of rescue.

The time and funding for research cruises reallocated to rescue
missions may be simply lost in a similar manner to a recent incident
this past December; tourists sailing on a Russian vessel became trapped
in Antarctic pack ice and were rescued by the joint collaboration
between an Australian and a Chinese icebreaker. No one has yet claimed
liability for the rescue nor have the Australian and Chinese rescuers
been compensated for their efforts.

In addition to the aforementioned concerns, it's likely that the
scientists and their sponsors may feel a little hesitant to indirectly
support the practices of the Antarctic fishers as the Antarctic and
Patagonian toothfish, which are readily sold throughout the world, are
both threatened by overfishing and unsustainable practices.

There's bound to be a solution that appeases both parties, but I'm not
sure what would distinguish a feasible idea from and impractical one.
Perhaps the countries and organizations issuing fishing licenses and
transit permits for Antarctic waters can also provide a state-funded
ice-breaker that can assist as well as regulate the Antarctic and
Patagonian toothfish fisheries. Presumably easier said than done though.

Our group is sailing in the midst of the austral summer when sea ice is
less of an issue for the fishers who bear enough salt to brave the
southern seas; I realize that this short piece brings to attention an
issue that does not relate to our daily lives or experiences on the
Palmer, but it is an issue that piqued my interest and I believe worth
addressing, considering the intensifying scientific work and increasing
ship traffic in the Southern Ocean.

Fourth Post, the Southern Ocean.

So, why do we care about the Southern Ocean?

I'll start with a definition again, though defining the Southern Ocean
is tricky. This seems to be one of those "ask any two oceanographers
and you'll get three answers" situations. Some people argue that it is
the ocean south of 30, 40, or 45 S. Captain DeSouza says it is the
ocean south of 60 S, and he has the weight of the British Admiralty
behind him so his answer is probably the best. However, defining the
Southern Ocean using lines of latitude is a bit like trying to figure
out exactly which year "the 80s" started... where there's a correct
answer, but most people will just know it when they see it. Well,
you'll definitely know the Southern Ocean when you see it. It is windy,
rough, cold, rainy, and fast moving. Perpetual trains of large waves
march from horizon to horizon. The wind and water moves from east to
west generally, though the Southern Ocean has an extraordinarily intense
eddy field which can turn the currents about any which way on shorter
timescales. In the southernmost reaches you'll find calmer and even
colder waters riddled with Antarctic icebergs and sea ice.

So why is the Southern Ocean this way? There are three unusual things
about the Southern Ocean that make it the way it is, the most important
of which is probably that it is the only place in the world where you
can draw a line around the Earth without ever touching land, aside from
the smaller Arctic Ocean. This allows waves, winds, and currents to
build up momentum without ever being redirected by landmasses. Second,
there is a strong westerly (coming from the West) wind belt that blows
over the Southern Ocean associated with the atmospheric Antarctic Polar
Vortex. Finally, the Southern Ocean is far enough south that parts of
it don't see sunlight at all for portions of the year, and, even during
summer, the sun is never directly overhead. This makes it cold.

Winds do something peculiar to the ocean which is central to the
importance of the Southern Ocean for global climate: the winds make the
seawater flow to the right of the direction that they blow in the
Northern Hemisphere, and to the left in the Southern. A student named
Vagn Ekman--who was trying to figure for why icebergs drifted to the
right of the direction of winds--first explained that this is due to the
interplay between the Coriolis force and friction between layers of
water. The Coriolis force is the tendency of objects to drift away from
the direction they are heading while moving across the spinning
spherical Earth. It is strongest near the poles, so it has an
especially large influence on water flow in the high latitude Southern
Ocean. Ekman realized that if the winds blow on the surface waters, and
the surface waters drag the waters below them, and the water below those
waters drags on the water deeper still, and each of these layers flows
in a direction that is a little off from the layer above due to
Coriolis, then the direction water flows will spiral down away from the
wind direction with depth. The speed of the flow decreases with depth,
and the result is that the net flow is to the right of the winds (in the
Northern Hemisphere). There are strong winds blowing from East to West
over the Southern Ocean, and, due to Coriolis, these winds will move the
water to the left of the direction of flow, or to the North. As you
might expect, the winds move water North fastest where the winds are
fastest. This means that in the center of the wind belt you have water
moving northward faster than you do on the slower flanks of the wind
belt. As a result, you have water piling up in the northern parts of
the wind belt and spreading out in the southern parts. Gravity will
only tolerate so much build-up of fluid water, so water tends to sink
where it is piles up in the North, and deeper water upwells from below
to replace surface water where it spreads out. The low temperatures of
the Southern Ocean also help to keep the surface water dense, which
helps the sinking water sink.

Okay, so water upwells and sinks there. Who cares? Well,
oceanographers get very excited about exchanging water between the
surface ocean and deeper depths because this is how the real power of
the ocean is brought to bear on Earth's climate. The ocean is massive.
It holds a tremendous amount of heat, gases, and nutrients. However,
most of the mass (and gases and nutrients) are trapped by strong density
gradients at depths deeper than the Washington Monument is tall. This
means only a small fraction of the miles-deep ocean is exchanging with
the atmosphere on short timescales. It also means that the places where
you can bring water into or out of the deep ocean are really special...
and there aren't too many of them. The North Atlantic, the
Mediterranean, and the Sea of Okhotsk are a few of the places outside of
the Southern Ocean where intermediate and deeper waters are formed.
Upwelling also happens along coasts and at the equator, but nowhere are
deep waters brought to the surface as broadly or dramatically as in the
Southern Ocean. The Southern Ocean also forms the coldest, densest, and
deepest waters on Earth down around the coast of Antarctica.

To put some numbers on the importance of the Southern Ocean for
climate, a modeling study done by my advisor, Jorge Sarmiento, found
that if you prevented nutrients from upwelling in the Southern Ocean,
then the biological productivity of the rest of the world (i.e. the
ocean outside of the Southern Ocean) would decrease by 75%. I've
attached a figure to this effect. Also, about 60% of the ocean heat
uptake (of which the ocean accounts of 93% of the planetary total) and
about half of the uptake of the carbon emitted by mankind (of which the
ocean absorbs about 25%) happens in the Southern Ocean.

The other reason to pay attention to the Southern Ocean is that there
are a number of climate changes occurring there. The westerly winds
that drive the circulation patterns have gotten stronger, and modeling
studies have linked this to climate warming and ozone depletion over
Antarctica as well as to one of the decade-long climate oscillations
mentioned in a past blog post. There is a lot of fascinating research
going on into exactly how the circulation patterns in the Southern Ocean
might change in response to the wind increases, much of the research
having to do with figuring out how much the extra energy from the winds
will ramp up the currents we've discussed here and how much will just go
into making more eddies. We already noted that the Southern Ocean is
taking up large amounts of heat and carbon, and it follows that the
water here is getting warmer and more acidic. There are also
interesting questions regarding how the freshwater distribution will
change down there. Glacial ice and sea ice have the potential to change
with warming, and we have already witnessed the abrupt collapse of the
Larsen B ice sheet off of the Antarctic Peninsula, which is one of the
fastest warming places in the world. We noted earlier that the wet
areas of the world will likely get wetter, and I can personally attest
to just how rainy the Southern Ocean is already.

We are currently at 42 S, so we are well on our way to the placid and
warmer waters of the Southern Pacific Subtropical Gyre. For those of us
who left the Northern Hemisphere's winter, our "Spring thaw" will take
place over two weeks with Easter appropriately punctuating the midpoint
of our journey North.  We've had relatively smooth sailing and calm
weather for the last week. This has given us a much needed respite to
get station work done and deal with the wire problems Lynne noted in the
official cruise report. Switching to the outdoor winch created a large
number of additional and unexpected challenges for the technical and
engineering teams. We had several long days and nights of working
around the issues before we got things fully sorted out, but the
expertise and dedication of our crew prevailed yet again. I'm convinced
that our people could land the RV Palmer on the Moon given enough time.
I'm humbled to be working with them.

Third Post - Repeat Hydrography

So, why do we do repeat hydrography?

In case you aren't familiar with the term, "hydrography" is a term
meaning "measuring the properties of the ocean." "Repeat hydrography"
is going back to where you've been before and measuring the properties
again. The program that brought us out here is tasked with going back
and re-measuring some of the longest sections cutting across the oceans
once each decade.

There are several good reasons why we do this:

First, it is important to measure the ocean repeatedly because the
ocean is changing on just about every timescale we look on. For
example:

-There are several very long term changes occurring in Earth's climate
that we can monitor with repeat hydrography. Greenhouse gases emitted
by human activities are working like a planetary blanket, preventing the
Earth from shedding as much of the energy it gets from sunlight back
into space. About ~93% of the extra heat trapped on Earth by mankind's
greenhouse gases has gone into the oceans. The atmosphere is also
warming, and a warmer atmosphere can hold more water vapor, so the
evaporation of seawater is increasing globally. This means the dry
areas of the Earth will get drier and, since what goes up must come
down, the wet areas will get wetter too. Also, about a third of all
carbon dioxide released by mankind has been absorbed by the ocean.
Carbon dioxide reacts with water molecules in seawater to form carbonic
acid. The pH of the ocean is decreasing over time globally as a result
of this simple chemical reaction. This is called "ocean acidification"
by the scientific community. There are some free and surprisingly high
production quality videos discussing and presenting perspectives ocean
acidification on the web, so if you want to know more, look for "A Sea
Change" and "Acid Test."

-There are several multi-year long cycles in Earth's climate that
repeat hydrography can potentially shed light on. For example, many
people have heard of ENSO (a.k.a. El Nino), which is a cycle of heat
build-up and release in the equatorial Pacific that takes about 2-7
years. There are similar climate-scale oscillations being studied in
the North Atlantic, over Antarctica, and broadly over the Pacific
Ocean... As an aside, several of my coworkers at Princeton are using
computer models to investigate a potential ~50 year cycle in deep water
formation around Antarctica, though I am not holding my breath that
repeat hydrography will generate enough decades of data to say anything
about that while I'm still doing science!

-Of course, the ocean is very dynamic on short daily and seasonal
timescales, but other programs look at these changes since measuring
once a decade can't tell us much about such short fluctuations.

Repeat hydrography is one our main tools for examining long timescale
changes in the ocean. Satellites can see the ocean surface, and our
floating robotic floats do a good job of plumbing the top 1000-2000
meters of the ocean. However, the deep ocean holds about 16% out of the
93% of excess heat in the ocean, and it is picking up a portion of the
extra precipitation and glacial meltwater as well. Repeat hydrography
is the only way we can currently monitor the ocean depths. Repeat
hydrography is an even more critical tool for looking at uptake of
carbon by the ocean and ocean acidification because there are no
satellites that can measure sea surface carbon concentrations and the
technology for measuring carbon from floats is still in the prototype
stage.

Another reason to do repeat hydrography is because it is a necessary
piece of the two other open ocean measurement strategies we have
mentioned: floats and satellites. As we've discussed in past blog
entries, deploying floats is one of the central tasks for this cruise,
and the floats we are deploying can measure several seawater properties
(including pH) that are not typically measured by floats. Our early
results are suggesting that these sensors are doing a great job of
capturing the variability in the ocean, but that the sensors have large
offsets in their readings. Since we deployed the floats on a repeat
hydrographic cruise, we have the best available measurements to
calibrate the float sensor readings against, so now we can apply the
corrections that will allow us to believe the ~300 profiles the floats
will provide over their several-year lifespan. Our NASA group is doing
something similar for satellite data. Satellites provide data with
unmatched coverage. They can measure the ocean globally every couple of
days, but with the limitation that the measurements only tell us about
the very surface of the ocean. Our NASA team is working to improve the
amount of information we can learn from a satellite that measures ocean
color. Scientists use the color measurement to estimate how much
chlorophyll there is in seawater. However, the critters that use
chlorophyll to make sugars from sunlight aren't always at the very
surface of the ocean, so the satellite doesn't always see them, or see
all of them. In addition, there are a number of colored chemical
compounds in seawater other than chlorophyll that can complicate the
satellite readings. Our team of NASA researchers have hitched a ride on
this repeat hydrography cruise to go out and directly measure the color
of seawater with depth, and determine exactly what gives the seawater
its color. They will then compare how the satellite measurements agree
or disagree with what they measured in this region, and use this to
improve the algorithms that estimate chlorophyll from seawater color.

Repeat hydrographic research cruises are also excellent platforms for
new measurements, prototyping measurement techniques, and collecting
samples for other research programs. Two thirds of my PhD research
relied on data collected on hydrographic cruises, and the remaining
third detailed a measurement system I developed and tested while on a
repeat hydrographic cruise. Also, right now I am working with a lab in
Princeton and in Zurich to collect seawater for nitrate and silicate
isotope measurements that these other labs will ultimately run.

Okay, I'll stop extolling the virtues of repeat hydrography now. Next
week I'll try to get to that update I promised about why I'm so excited
to be in the Southern Ocean... which will be odd because around then we
will no longer be in the Southern Ocean! As far as an update on the
progress of the cruise, we've managed to continue to get work done
intermittently despite being pummeled by an endless series of low
pressure systems. We were able to sneak in station work around the
worst of the winds and waves in large part due to Chief Scientist Lynne
Talley's careful planning and hours of staring at weather projections
with Captain DeSouza. The drama continues even now with 45 knot winds
raging outside, but we are almost out of the be-stormed latitudes.