You mean Meteorology?
At least since Newton's days it is clear that weather is nothing but changing physical conditions in the atmosphere. The rise of meteorology as a separate scientific discipline is quite a recent affair (for instance, the meteorologic service in France was organized in 1855 by an astronomer, and probably most meteorological data were then still supplied by astronomical observatories). But still it's the laws of PHYSICS that reign in the atmosphere,
as they do in the entire universe
(we're in a Space Physics Institute, after all!).
The atmosphere is governed by nothing but the laws of physics,
and you need physical instrumentation to measure atmospheric conditions,
especially at altitudes above fractions of a picoparsec that
one cannot easily access from the ground.
And it's not just thermodynamics and hydrodynamics (well, aerodynamics), it also requires
classical and quantum mechanics,
atomic and molecular
physics,
electrodynamics and optics, etc.
And for building and operating instrumentation, you also need electronics
and computer science.
But couldn't you say the same things about the lowest parts of the atmosphere, the domain of meteorology?
Yes, in principle. But meteorology has much to do with weather prediction, and this has a lot to do with sunshine or rain. But, the phase transitions needed to convert water vapor into clouds and eventually into raindrops are very hard to describe in detail. Under equilibrium conditions, it is not hard to tell in which phase state most of the water must be. But how long it takes for that equilibrium to be reached, is surprisingly difficult to predict.
However, in the Upper Atmosphere (well above the highest cloud level), weather is always fair:
So, there's nothing to predict that would produce (and deserve) as much public attention as the weather forecast does.
You mean, nothing happens in the upper atmosphere?
Nobody needs Meteorology to be sure a lot happens
in the lower atmosphere,
but without Aeronomy, you would not have the faintest idea about the many
amazing things that happen in the upper atmosphere!
So, this is what the Aeronomy Group at IAFE does: find out what happens (each minute, each day; well: each night) in the upper atmosphere, and why.
In this context, "upper atmosphere" means something like stratosphere to thermosphere (with emphasis on mesosphere and thermosphere). Note that meteorologists also occasionally refer to tropospheric heights above ground-level (that is, beyond the reach of ground-based instrumentation, thermo-, hygro-, anemo-, and barometry) as "upper atmosphere".