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>>Tropical regions are among the hottest
and most humid places on Earth.
But also the coldest and driest
Yeah... you heard right!
While temperatures on the surface can range
from 80 to 90 degrees Fahrenheit all year round,
they can dramatically drop as you go up in altitude.
In fact, as you get closer to the stratosphere,
they can be as low as -110 degrees Fahrenheit.
This extremely cold region between
the troposphere and the stratosphere
is called the Tropical Tropopause Layer (TTL).
>>In the tropics, it's very warm and moist down at the surface.
When you get up to the Tropopause Layer,
it's very cold and dry.
>>So it turns out that the Tropopause
is actually coldest in the Western Pacific.
>>Right above Guam is an ideal place because
it is the coldest and the driest part of the tropics.
>>Everything is ready for the second phase
of the field experiment.
We are 13 degrees North of the equator in the Pacific.
Our new home away from home, for the next several weeks.
We are in Guam.
>>So the tropics are the part of the planet that gets the warmest
from the heating from the sun
because it gets the most sunlight on average.
>>Because the surface is so warm and there is so much water,
you evaporate water, liquid water,
it becomes a vapor so you have this very hot, moist, air
down here at the surface.
So this is air that's got a lot of energy.
Just like a boiling pot of water it can rise very high.
>>And it tends to pull other gases
that come from the surface up with it.
So this is the part of the world
where most of the circulation getting up from the surface,
up into the upper part of the troposphere
and into stratosphere, this is where it occurs.
>>So here in the tropics we see these thunderstorms,
boiling up to very, very high altitudes.
And so we have a very high elevated tropopause
here in the tropics.
>>As you get convective processes going, the air rises.
As you know, if you take air and you expand it,
it cools really fast.
>>And it turns out that in fact,
the warmest places in the world they are in the tropics.
But about 55,000 feet above us, about 16 Kilometers,
is one of the coldest places on Earth.
>>So what that does is, as it cools really fast,
all that water vapor in the air going up gets squeezed out.
It's like wringing a towel,
and all of the water starts to squeeze out,
so you get cloud processes formed
that squeezes out the water.
The air that comes out of the top, tends to be dry.
>>But you still get some water making it up
to the tropical tropopause.
And there the atmospheric motions
transport air into the stratosphere.
So air is transported into the stratosphere
with a small amount of water that's left behind.
>>And this is the area that tends to be the controlling mechanism
for how much water gets into the upper troposphere
and then onto the stratosphere.
>>So if you want to understand the composition of the stratosphere
how much water there is...
how much ozone destroying substances
or trace gases there are,
you need to go to the tropics and study
the region around the troposphere in the tropics.
>>So this is the spot to be.
So this is the area where the ocean gets the warmest
The convection is the strongest
And then, the air that comes at the top, gets the coldest
>>We've known that for many decades...
For at least 20 years we've known we really need to go
to the Western Pacific
to study the extreme dehydration where the Tropopause is coldest
and where the most extreme dehydration
to low water vapor concentrations occurs.
>>Now, Guam is the coldest and driest part of the tropics.
>>It's actually a warm region at the surface
And a cold region at the tropopause.
And Guam is right in the center of action.
Plus it has the airfields and facilities we need
to operate our high-altitude aircraft.
>>It takes a lot of work to plan a remote deployment of this size
>>Preparing for a mission where we are deployed,
where we have to take the entire team and the aircraft
and all of our equipment, it's really quite an effort.
>>Making sure we had a hangar available to us...
making sure we had office space available...
making sure that we had an area where we could setup
our aircraft control trailer and our instrument control trailer
>>It's also difficult because you are away
from where you built your instrument,
where you operate your aircraft.
So, if you have a problem, you have to ship everything here.
>>Because when you are this far from home, so to speak...
you gotta have everything here.
Not just the airplane and the people,
but all your equipment including spares.
>>Actually, all of the work that's going into this ATTREX project
it's been one of the most difficult things I've ever done.
>>When we operate out of Edwards we do it from a fixed structure
called the "Global Hawk Operations Center"
That's the main command and control center
for the NASA Global Hawks.
>>Well, what is different from operating here in Guam,
versus operating back at Edwards
is we have these mobile ground stations so...
that's where we fly the airplane and operate our payloads from.
>>So the front room of the flight operations room is replicated
with a 40ft trailer with all the communications equipment,
all the computers, all the servers, everything.
And then another trailer replicates the 14 workstations
that the payload operations room has.
And that's in another trailer.
>>And we are basically providing the same functionality
from Andersen Air Force Base, in a forward location,
that we would have back at Edwards Air Force Base.
>>We can deploy anywhere in the world with these trailers
as long as we have the appropriate setup.
>>For the ATTREX campaign,
the NASA Global Hawk is basing out of Andersen Air Force Base.
And from Andersen Air Force Base we'll be flying north
all the way up to the Aleutians.
East towards the Philippines.
South down by Australia and New Zealand.
And out to the East, all the way to about Tahiti,
the other side of Hawaii basically.
It's roughly about a 4,000 mile radius of range
that the Global Hawk has from here, at Andersen AFB.
>>We really have daily meetings.
The forecasters, the modeling group and our pilots
meet almost everyday.
Whenever we are getting ready for a flight.
We are working everyday on the aircraft
work with the scientists.
They've gotta pre-flight their instruments,
after flight they've gotta post-flight their instruments...
Some want to come off, some don't want to come off...
So it's a constant ballet of activity around the airplane,
in between flights,
until the day when we are ready to go.
Everyone comes on.
We'll have engine start at 5 o'clock,
which means they've got to come in at 11 o'clock at night,
work until 2 AM, do their thing with the instruments...
Then our crew comes in, buttons up the jet...
It's rolling out at 4 o'clock.
Engine start at 5. Take off at 6...
It's an ensemble of people, all doing really great work together
to make this whole thing happen.
[Radio chatter]
[Radio: And traffic can I get a TAKE OFF Report?]
[Radio: Yes sir, runway is clear. You are go for TAKE OFF.]
[Radio: Roger that.]
[Radio: 3.... 2.... 1.... Launch!]
[People cheering]
>>So the Global Hawk has great capability,
with tremendous range and endurance.
>>So many lessons learned from this campaign,
that will make our Global Hawk operation
a much more globally deployable package.
>>And, as we've demonstrated, we can do a lot of science
from Dryden in California or we can deploy,
as we've illustrated here, to reach out.
And I think we've shown now
that we can really go almost anywhere in the world.
>>Because this is our first deployment away,
really away from the mainland...
This might be our first, but it won't be our last.
And we will be well suited to take our show on the road,
anywhere in the world from now on.
[Engine noise of airplane landing]
[People clapping]
>>We are collecting data over the tropical Western Pacific.
Data that will improve our understanding
of our atmosphere, weather and climate.
The ATTREX mission
will help us better comprehend the world we live in.
To learn more about this planet we call Home.