you can experience a cloud just by walking around San Francisco
This fog is just a stratocumulus cloud where its base is at the surface
but we don't think of it that way
we think of of fog as this grey kind of haze
when it's actually just individual cloud droplets
that are obscuring our view
I think if people realize they're walking through a cloud
that's probably the most important cloud type on earth
they might think that's pretty cool
clouds are complicated because there's so many different types
some are liquid, some are ice, some are both
some grow all the way from the base of the atmosphere to the top
and there's seasonal timings to worry about
the biggest question that cloud physicists are investigating right now are
how cloud droplets and aerosol particles interact with each other
any particle in the atmosphere is considered an aerosol
you only make a cloud when you have a particle
for the water vapor to condense upon
in general, if you think of a cloud over the ocean
the majority of particles that serve as the center of a cloud drop are usually
this combination of sea salt and some biologically produced sulfur from algae
If we look over land dust is a huge component right because there's lots of
dust over the desert there's lots of dust over land
and then for industrial areas particles from say power plants or from industrial processes
wherever you are regionally the particle distribution changes
so places where there's lots of fires our clouds have smoke centers
the smoke is actually amazing and complicated
because it does two things
if it's on top of the cloud like in San Francisco bay
if you look down from space the sunlight's coming straight from above
the smoke, it would look much darker so it wouldn't reflect as much like back
it would actually heat the earth in that sense
now eventually the smoke can actually intermingle with the cloud and not only
does that change how the cloud behaves it gives us a lot of other things to worry about too
It changes whether or not it rains
which determines how long the cloud will stay there
if we start infusing the cloud with more particles
we can have new particle formation and have lots of smaller ones
and now our cloud looks brighter because now we've got more droplets to reflect light
the stratocumulus example is great where you'll have actually off the California coast it's
actually very easy to see with the ship's going to and from Hawaii
the ship track streak will be so much brighter and it looks thicker and fluffier
than the cloud near it
so when it's above it makes the cloud look darker,
when it's intermingled it makes it look brighter so it's a really complex system
because you could have both happening at the same time
so how much does one cancel out the other is really complicated
you can see that added smoke and added particles
from us doing something as a species is changing clouds
it's not just there's lightning and there's some fires
the amount of clouds that are on the earth determine how much light is bounced back
if we get rid of those huge cloud masses then there won't be as much energy going back to space
and the overall temperature of the earth would go up
we have to know why it is doing what it's doing right now so that we can be better informed
about how to calculate what's going to change in the future especially in
regions that are developing more people are doing farming
there's more particles being emitted and then that could exacerbate the problem
and maybe deplete the cloud and then it gets warmer on top of that
the future of our work is to really get an understanding of those interactions
across a range of aerosols and a range of cloud types
clouds are that important to what temperature the earth is
that we need to know what those changes are