The-Accountant-Jan-Feb-2018

ENVIRONMENT
By Angela Mutiso
UNDERSTANDING
THE CLOUDS
THAT FLOAT ABOVE US
Can You Imagine The Universe Without Clouds?
When we feel stuck, look at the sky. The clouds remind us that everything changes
Kelly Martin
Clouds are part of our water
cycle, and our water cycle is
the natural way of recycling
our water so we can drink
it again. Without the water
cycle (and clouds), we would have no
drinkable drinking water!
All over the world, each day, people
make decisions based on the weather.
Meteorologists’ give you the forecasts
which make it possible for you to make
the right decisions and to plan your day.
National Aeronautics and Space
Administration NASA (nasa.gov) points
out that one of the most interesting
features of Earth, as seen from space,
is the ever-changing distribution of
clouds; they are as natural as anything we
encounter in our daily lives. As they float
above us, we hardly give their presence a
second thought. And yet, clouds have an
enormous influence on Earth’s energy
balance, climate, and weather. Clouds are
the key regulator of the planet’s average
temperature. Some clouds contribute
to cooling because they reflect some of
the Sun’s energy—called solar energy
or shortwave radiation —back to space.
Other clouds contribute to warming
because they act like a blanket and trap
some of the energy Earth’s surface and
lower atmosphere emit—called thermal
energy or long wave radiation.
Cloud systems also help spread the
Sun’s energy evenly over Earth’s surface.
Storms move across the planet and
transport energy from warm areas near
the equator to cold areas near the poles.
(For more details on the topic of Energy
Balance, refer to NASA Facts 2005-9-
074-GSFC).NASA notes that even small
changes in the abundance or location of
clouds could change the climate more
than the anticipated changes caused
by greenhouse gases, human-produced
aerosols, or other factors associated with
global change. In order for scientists to
create increasingly realistic computer
simulations of Earth’s current and future
climate, they’ll have to include more
accurate representations of the behavior of
clouds.
Clouds can both cool the planet, by
acting as a shield against the sun, and
warm the planet, by trapping heat. But why
do clouds behave the way they do? And
how will a warming planet affect the cloud
cover? Julie Chao writing for Berkeley
Lab on the science of clouds - Why They
Matter, and Why There May be Fewer of
Them says; Lawrence Berkeley National
Laboratory scientist David Romps has
made it his mission to answer these
questions. “We don’t understand many
basic things about clouds,” Julie quotes
him as saying: “We don’t know why clouds
rise at the speeds they do. We don’t know
why they are the sizes they are. We lack a
fundamental theory for what is a very
peculiar case of fluid flow. There’s a lot of
theory that remains to be done.”
The Earth’s response to changes in
atmospheric CO2 is studied using what
are known as global climate models
(GCMs), which run on supercomputers.
Due to computational limitations,
however, these GCMs are unable to
explicitly model atmospheric phenomena
less than 100 kilometers in size. Since
convective clouds have sizes closer to 1
km, they cannot be resolved by a GCM.
“So the GCM has to ask a submodel: what
clouds do I have and what are they doing?”
Romps says (briefly); The submodel takes
the temperature and humidity profile of
a column of air and has to answer the
question, “what’s happening right now?”
Unfortunately, despite decades of research
and development on these submodels,
they remain far from perfect.
A cloud may look like just a billowing
mass of air, but cloud dynamics in fact
involve complicated physics. One of the
most important factors in cloud dynamics,
for example, is entrainment, which is when
52 JANUARY - FEBRUARY 2018