WEBVTT FILE

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good evening everybody. So one of the
things we do at NASA and Earth science

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using the unique vantage point of space
is explore and that exploration leads to

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discoveries and those discoveries lead
to research to understand and protect

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our home planet for societal benefit,
okay, now we can explore the Earth

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spatially in this case the combined land
and ocean biosphere together and that's

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basically looking at Earth's primary
producers and what's really interesting

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is that in just a single global
composite we can actually see all of

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this dimension in the ocean biosphere in
the terrestrial biosphere, next slide

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actually using a series of images or
information allows us to not only

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explore in the spatial dimension but in
time and we can use this information to

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identify long-term trends now this is
kind of unprecedented so what you're

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looking at is the combined global land
and ocean biosphere and it's like

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watching the Earth breathe in Earth's
primary producers now missions like

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Terra and sensors like MODIS are
celebrating a 20-year anniversary or a

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20 year time series and what that does
is opens the door into looking at

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decadal changes in our earth system so
that's truly unique, now traditionally

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what we use is passive ocean color
radiometry which is what you're seeing

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here to actually look at the ocean
biosphere and this is only one piece of

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the puzzle what passive ocean color has
done is absolutely revolutionize our

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understanding of the ocean ecology and
Earth's carbon cycle in general, but if

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we really want to open new doors then we
have to push the boundaries

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scientifically and in engineering and
actually use some new scientific

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approaches and looking at things like
our ocean biosphere and so one of the

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limitations
I think of ocean color remote sensing is

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that our scientists actually think it's
incredibly valuable and critical for

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studying climate variability and change
however

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it has to be used during the daytime it
can't be used at low solar elevation

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angles and it has to be used in a cloud
free environment now what you can lump

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on top of that is actually it has some
depth integrated challenges it can only

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see you the first optical depth in the
ocean and in addition it's got some

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challenges when you have heavy aerosol
loading however there are technologies

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that we can use when coupled with
passive ocean color remote sensing

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absolutely revolutionize our view of the
ocean, next slide,

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LIDAR is one of them okay that stands
for Light Detection and Ranging and in

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2006 NASA and CNES together
launched the mission known as Calypso as

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a Cloud-Aerosol LIDAR and the main
sensor onboard it of it CALIOP has

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orthogonal polarization and so this has
been Calypso has a, sorry it's supposed

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to be the Calypso animation, sorry you
guys, just back up one so what you're

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actually, so Calypso has been reliably
providing global views of our earth for

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over 13 years now what's absolutely
revolutionary about it is that it can

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penetrate up to three optical depths in
the ocean okay so where is passive ocean

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color can only go the first optical
depth

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however LIDAR data such as that from
CALIOP can only see a limited spatial

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resolution has about a 16 day revisit
where as passive ocean color remote

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sensing can cover the earth in about two
days taken together however they provide

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unprecedented scientific benefit for
looking at things like dynamics in

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Earth's biosphere specifically in the
ocean, so we're going to talk about that

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in just a minute I just want to also
point out that studies of LIDAR have

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used have been used on both ships and on
aircraft and what they do is they use

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unique properties like the backscatter
coefficient the vertical attenuation

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coefficient to look at things like
phytoplankton properties, zooplankton and

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even fish stocks and this is important,
very important properties of the ocean

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when we're talking about commercial
viability in economics, so the other

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thing about LIDAR is that
is not limited by some of the things

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that limit ocean color remote sensing
you can use it day or night it can deal

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with considerably heavy aerosol loads as
well as thin clouds you don't have to

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worry about low solar elevation angles
which I'm going to show you in a minute

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and as I said it can penetrate up to
three optical depths, so this can be

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absolutely revolutionary and looking at
our ocean now remember I'm going to show

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you
CALIOP data in just a minute and

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remember that was not created to look at
the ocean it is an aerosol based sensor

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okay but it can give us unprecedented
views of our ocean system, next slide, so

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in 2013 what we did is we had the first
global view of plankton in the ocean not

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phytoplankton not primary producers but
actually secondary producers from a

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space-based LIDAR and we took this
unprecedented information and we

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estimated phytoplankton carbon and
particulate organic carbon at least to

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ocean carbon properties together were
derived directly from the calliope base

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back scattering by particles now
remember this was just a

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proof-of-concept study, right this system
was not created to produce anything in

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the ocean and yet here we are and so
what we, what we know from moving forward

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is that we can see into the ocean and
tell something about Earth's biosphere

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now that's not where it stops, next slide,
so I already mentioned that the sensor

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can function or we can get data in the
ocean at low solar elevation angles and

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basically what that means is that about
81 degrees north and south we can

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actually collect data where is on the
left hand side you see MODIS which is

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passive rate radiometry and what you're
seeing is that we don't have a lot of

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coverage
whereas CALIOP on the right hand side

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actually does so what this study was
able to do this was part of the the

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NAMES project the North Atlantic Aerosol
and Marine Ecosystem Study they actually

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looked at CALIOP data at high latitude
and used a combination of the vertical

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attenuation coefficient and the back
scattering by particles to detail what

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was going on
ecologically in the

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shit what they were able to determine
looking specifically at predator-prey

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interactions was that in the Northern
Hemisphere basically at the northern

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polar, subpolar waters the ecosystem
dynamics were driving what was happening

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in the phytoplankton and in the plankton
in the ocean whereas in the Southern

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Hemisphere it was actually the ocean ice
dynamics that were driving what was

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happening in the predator-prey
interactions and this was unprecedented

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and impossible without using the LIDAR
in the ocean, so let's take things just a

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little bit further, next slide, now the
other thing that the NAMES team did

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going out specifically looking at a
number of objectives, one of them was

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what's driving phytoplankton blooms in
the ocean and you might be saying why

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should I care, well as primary producers
they're consumed by secondary producers

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and fish and if you know anything about
fisheries just taking that one economic

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aspect of the ocean it's more than a
trillion dollar economy worldwide okay

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so they did a transect in ships and with
an aircraft flying overhead with a LIDAR

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going from about 35 degrees north and
straight northward although this is I

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think they had some Wiggles in there but
what I want you to notice is that they

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were able to detail oligotrophic waters
which means they're almost devoid of

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nutrients are very low nutrients which
are makes it very difficult to support

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phytoplankton and plankton in general
they went straight through a

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phytoplankton bloom which you're
actually seeing in the vertical

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attenuation coefficient so this is the
LIDAR showing this and then they went

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into Mesa trophic conditions where they
have low productivity but some going on

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now let's zoom in on this a little bit,
next slide, and take a look at the eddy

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that they went through so if you look at
the top panel first you're looking at

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the back scattering by particles derived
from the CALIOP sensor okay and what

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you're seeing as you travel across is
the evidence of the eddy right here of

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the physics driving the biology now how
do we know the physics are driving the

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biology most physical oceanographers
will tell you everybody knows that but

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we're going to actually detail this with
a LIDAR remember you're looking

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at the back scattering by particle data
from a LIDAR not actually any ocean

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physics measurements if you look now on
the bottom panel and what the team knew

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actually first on the top is that some
dynamics were going on in that Eddy and

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they knew this because on the ship they
had a flow-through system that told them

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they had a high concentration of
phytoplankton in that area so what they

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did is they decide to look at the
depolarization ratio relative to the

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back scattering by particles and what
that does is it tells you something

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about cell size and what's actually in
the in the water and this was confirmed

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with instruments on the ship but when
they pass through the Eddy what you can

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see is a very strong signal here and
this depolarization to backscattering

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ratio actually enabled them to detail,
confirmed by the ship based measurements

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that they had different groups of
phytoplankton there that becomes very

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important when you talk about
biodiversity in the ocean and let this

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sink in a minute people because this is
kind of mind-blowing we're using a LIDAR

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that was not created to look in the
ocean to actually detail community

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structure which is not even something we
can do for passive ocean color yet okay

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so let's go further,
next slide, okay so this is sort of the

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like ultimate punch line what you're
seeing here is the largest animal

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migration on the face of the planet and
it happens every day, okay, so we are

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looking at what's called dial migration
zooplankton are secondary producers

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people have heard of phytoplankton these
are actually zooplankton and what they

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do is they might greet every single day
approximately 200 meters to the surface

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to feed on phytoplankton, phytoplankton
are primary producers they go up to the

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surface they need sunlight to actually
go through photosynthesis they take up

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carbon dioxide zooplankton consume
them and they excrete whatever they

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excrete and that carbon goes to the deep
ocean a lot of it permanently so what

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you're seeing is a conveyor belt of
carbon, now what this actually is is the

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global climate illogical signal of
vertically migrating animals in a

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normalized differential ratio, now
does that mean basically there are

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day/night differences in back scattering
by particles and this tells us something

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about vertically migrating animals in
the ocean, okay so you're seeing that

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conveyor belt of carbon and where the
zooplankton tend to go is in clear

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waters, okay,
that's because there are less visual

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predators there this is a little bit
counter to intuitive because you could

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think they would be found in highly
productive waters where there are a lot

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of phytoplankton that they can eat so
ecologically what you're seeing actually

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makes sense, okay, and if you look between
the two yellow lines that's basically

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the permanently stratified ocean, so
where we're seeing the high signal for

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the phyto, for the zooplankton and and
the lower signal actually corresponds

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significantly to what we would expect
ecologically so last slide that's kind

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of mind-blowing people, that we can't do
that with ships but we can do it with a

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LIDAR
so the future of LIDAR where is it going

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we have never built a LIDAR for the
ocean no one has and clearly what this

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tells us is this with the minor
modification to future LIDAR that are

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being planned for the atmosphere or not
we could actually detail the profiles of

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ocean particles in the ocean and what
these figures have actually shown is

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that we've got the first ever view of
vertically migrating zooplankton on a

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global scale which is unprecedented
thank you