Clouds are one of the most important aspects of climate and we need to
understand how clouds work better. Y’know, we have instrumentation that
can measure physical properties of clouds, but actually being able to collect samples
of the cloud water we’re flying through to analyze the chemistry of those cloud
droplets is an important part of the puzzle that we haven't yet been able
to do in this mission.
People have collected cloud water. I mean, clearly when the aircraft flies through
clouds the airframe collects water. Unfortunately, that fine detail that
were trying to tease out from the cloud chemistry is lost when you contaminated
with everything that the aircraft has been picking up through it’s flight.
So the idea here is essentially it's a control. We have a way of controlling
what we take in as cloud water and we try to reject the stuff they don't want
to include.
The clouds we are measuring here are what is known as boundary layer clouds.
And that's really what's important for the NAAMES mission, is understanding
those low boundary layer clouds over the water.
So, these clouds have, essentially, a fairly well defined profile of liquid
water.
As you go higher, the cloud gets generally thicker so there is more cloud water
available.
Down at the bottom of the cloud the cloud droplets aren't as large and there's not
as much clout water available for collection.
We want to target both of those regions, both the cloud base and the cloud top,
because even though the cloud base is harder to get a large volume of cloud
water collected, it has interesting information about the aerosols that
were involved in activating those cloud water droplets.
The top of the cloud, it's juicier there's more liquid water content
availablefor us to collect, but essentially it's potentially more dilute.
The interesting thing is we know how the water mass changed vertically, but
if the concentrations show something different that's essentially information
about chemistry that's happening within the cloud, which is one of the areas of
study that I'm really interested in trying to understand better.
What were trying to understand is the small amount of impurities that are
in the cloud.
They may have come from locally produced, uh, in-situ production of these species
in the cloud water through this wet chemistry, if you like in the cloud.
Or it could have been dry chemistry below the cloud, so it didn’t need
the cloud to perform that chemical reaction.
We’re measuring below the cloud.
We know what the composition of aerosol and gases are below the cloud.
With this cloud water we add another piece of the puzzle.
We try to understand other things like sulfate chemistry which is an important
aspect of this study.
The ideas that within clouds you have gasses, you have aerosols, and you have
activated aerosol particles which are the cloud droplets.
The chemistry becomes that much more difficult when you have this phase change.
You have liquid water in abundance and it acts as this new medium where chemical
reactions can take place. When you’re out of the cloud you don’t have that.
That's an experiment we’ll do off-line.
So now that we've collected this cloud water—it’s going to be done with Luke
we’ll set up an experiment and the lab and, again, it's a new technique
and I don't believe that anybody has looked at biological particles in cloud
water in this way, certainly in connection with a mission such
as NAAMES, where there is a strong focus on ocean and aerosols interactions and
how that interacts with clouds, so this is a new thing.
We've had requests to use the cloud water we collect during this mission
to supplement other investigators work.
People who are outside of my knowledge in biology have taken an interest in the
cloud water to do their analysis, particularly the kind of analysis
that's done on seawater and use that as a comparison to see whether stuff comes
off the ocean and makes it into clouds and how it affects the clouds.
It's a tracer, essentially. The nice thing about using those biological
particles is that they are a tracer that doesn't necessarily change in the same
way that chemical tracers change.
Chemical tracers can evolve and react into other species,
but these biological tracers are somewhat inert in that sense to
chemical transformations.
That's another exciting technique that we may do to try and understand the
connection between the clouds locally and potentially regionally transported
particles that affect clouds.
This probe that hangs down here is called the AC3, the axial cyclone
cloud water collector.
This is the new prototype collector for collecting in situ cloud water.
In the inside of the probe, the stator which basically generates that swirl,
it is made out of stainless steel.
The rest of the probe is aluminum.
To make that part out of aluminum using conventional milling would have been very
very difficult, and taken a long time and been very costly.
We used an experimental technique. It's steel powder that we start off with.
It’s a process called laser sintering.
Essentially the laser melts the steel powder and builds the shape
in the same way that a printer would accept that it's three-dimensional.
it's 3-D printing but for steel.