AgHTH AS
B2o044¬e
National Institute of Technology
Department of Physics
PH7322 Physics of Climate
Mid semester Test, October 6, 2023
Duration: 2 hours Max. Marks: 30
Physical constants:
h=6.63 X10-34 J-s, k= 1.38 X 10:23 J/K, c = 3 x 108 ms-, g= 5.67 x 10-8 Wm² K*,
Avogadro's number NA = 6.022 x 1023 molecules mol1, R = 8.314 J Kl mol',
Cp = 1004 J K-1 kgl
1. For a global mean albedo of 0.3, show that the equilibrium temperature of the
Earth (assuming no greenhouse effect) is about 25S K. Take solar constant as
1370 Wm2 (2 Marks)
2. Explain the climate feedback mechanism using a single feedback loop. Use the
possible changes in temperature lapse rate to explain the positive and negative
feedback mechanisms (reinforcing/mitigating effects) of aprocess responsible for
(5 Marks) P
global warming, say, doubling of atmospheric CO2.
3. Derive a relationship for the height of a given pressure surface (p) in terms of the
pressure po and temperature To at sea level assuming that the temperature
decreases uniformly with height at a rate Kkm', (2Marks)
(Hint: you may use hydrostatic equation and ideal gas equation here) disturbance
synoptic scale
4. What is geostrophic balance? For a typical mid-latitude geostrophic
assess the magnitude of the Rossby number and state if the geostrophic
approximation is valid in this situation. What are the limitations of
(3 MarkS)
approximation? being an
common origin, the first
5, Consider two Cartesian coordinate systems with one with angular
inertial system and the second rotating with respect to the first
derivatives of a vector A in
velocity 2. Obtain the relation between the time (3 Marks)
the two frames. (6 Marks)
6. Answer the following: Which
What are the two types of nucleation that can form a cloud droplet?
(a)
type most commonly occurs? Why?
(b) What are haze particles? parcel, what factors
What is an activated droplet? In a rising supersaturated
(c) activated?
determine which droplets become vectors along the x (eastward) andy
variations of horizontal wind northward)
7. Consider the condition (u0 eastward and vo
(northward) direction over a steady possible sums of partial derivatives of u
the
about a geographic location. From pure divergence and pure vorticity. (4 Marks)
and v explain the flow fields of (3Marks)
8. Explain the following: parcels cool more rapidly than moist
when it is lifted. Dry
(a) A parcel of air cools
Parcels
which the hypsometric equation predict an exponential
(b) Condition(s) under
decrease of pressure with height.increases approximately exponentially with depth
(c) Pressure in the atmosphere increases approximately linearly with depth.
whereas the pressure in the ocean
alpa s
National Institute of Technology Calicut
Department of Physics
PH7262 Physics of Climate
Final Exam. Dec 6, 2023
Duration: 3 hours Max. Marks: S0
Physical constants:
h=6.63 x 10 -34 J-s, k= 1.38 x 1023 J/K, =3 x 108 ms, o= 5.67 x 108 W m' K.
Avogadro's number NA = 6.022 x 1023 molecules mol, R 8.314 J KI mol !
Cp = 1004 JK1 kgl
. Use hydrostatic equation and ideal gas law to showthat the atmospheric pressure p*
(3 Marks)
varies exponentially with height.
? Compute the total concentration of air molecules (number/cm') at sea level. You
temperatåre of 300 K.
N/m (at sea level) and
may assume pressure of1.0 x 10 (2 Marks)
numerical
3. Describe the following, with appropriate equation(s)/expression(s)/ (6 Marks)
value(s)/example(s) where necessary:
(a) Potential temperature ( o cC
0m
(b) Adiabatic lapse rate
ef B-effect
(d) Brunt-Väisäläfrequency
(e) Climate feedback parameter
() Feedback response time
a fluid
Brief Eulerian and Lagrangiat descriptions ofexplain
Bmarks)
the field of pure streiching
Wh¡t is stretching deformation? Sketch and GMarks)
deformation in horizontal flow of the atmosphere El nino. (3 Marks)
impacts of
6. What is ENSO? Mention three observed nucleation? With the heip of schematic
. . What is Köhler curve in heterogeneous cloud droplet as it grows along
curve explain the dominating effects on a typical
large droplet by condensation. What is an
this curve fromn very small to a (5 Marks)
actívated droplet in thiscontext? stream by the Himalayan Mountains have
perturbations caused in a jet
8, The waves) with wavelengths comparable to
wavelike character (Rossby or planetary
velocity of Rossby waves is given by
the Earth's radius. The group
velocity and radius, 0 is the SL
252cos bwhere O and R are Earth's angular
Rk? fact that these Rossby waves
negative sign describes the dispersion wt
latitude, and the opposite to the jet strean flow. Derive the
propagate in the direction Rossby waves
waves. Do longer or shorter
relation = ok) for these Rossby (4 Marks)
propagate faster?
quantity fux densily (Irradiance). Radiation is emitted
. Define the radiometric uniform intensity in all directions. What is the tlux
from a plane surface with a (3Marks)
radiation? ot
density of theemitted
continua of the solar spectrum? Explain its depth and
What is absorption atmospheric structure
penetration for an overhead sun, and its role in (3 Marks)
composition.
s.
