CH1 imp

Question 1

Govern the evolution of the atmosphere

Answer 1

Physical laws of motion and conservation of energy

Question 2

Core of NWP

Answer 2

Laws converted to mathematical equations

Question 3

Making a forecast

Answer 3

If you know the initial conditions you can solve the equations to find new values of the variables at a later time

Question 4

Parameterization

Answer 4

Physical terms expressed in terms of forecast variables

Question 5

Represent all scales of atmospheric motions

Answer 5

Hydrodynamical equations

Question 6

Obtaining model equations

Answer 6

Hydrodynamical equations are simplified by applying approximations and assumptions that are applicable to a particular scale of motion

Question 7

Thin layer approximation

Answer 7

Lead to system of nonhydrostatic equations that allows for the proper handling of mesoscale atmospheric motion. Those simplifications are made through scale analysis

Question 8

Hydrostatic balance equation

Answer 8

Synoptic scale where vertical velocity is on an order of magnitude smaller than horizontal velocity it is ignored. It will then become a diagnostic relation known as hydrostatic balance equation

Question 9

Adiabatic frictionless atmosphere

Answer 9

Primitive equations

Question 10

Basis of most NWP models

Answer 10

Primitive equations

Question 11

Anelastic approximation

Answer 11

Involves neglecting time derivative of density in the continuity equation

Question 12

QG approximation

Answer 12

Winds are approximated by their geostrophic values (prop. To Pressure gradient) acc in mom eqn Adv in temp eqn

Question 13

NWP models use …. Equations

Answer 13

Primitive

Question 14

Thin layer approximation properties

Answer 14

1. Model atmospheric flow over a wide spectrum of spatial scales (planetary to meso) 2. Simulate the propagation of Rossby, inertia-gravity and sound waves. 3. Cannot simulate geosphysical fluids with large vertical extension (gaseous planets)

Question 15

Hydrostatic assumptions properties

Answer 15

1. Terrestrial atmosphere if the phenomena has a horizontal scale exceeding 10 km or so

Question 16

Primitive equations properties

Answer 16

1. Simulating atmospheric motion whose horizontal space scale is greater than 10km 2. Take into account Rossby waves and inertia gravity waves but eliminate sound waves (hydrostatic relation filtering effect)

Question 17

Anelastic approximation properties

Answer 17

1. 3D divergence = 0 2. Horizontal divergence must be balanced by vertical divergence which act to maintain air density 3. Filter out horizontal propagation of sound waves since they require 3D divergence in order to propagate

Question 18

QG approximation properties

Answer 18

1. Vertical acceleration neglected (hydrostatic approximation) 2. Filter sound, gravity and inertial waves/oscillations 3. Cannot describe small scale motions such as mesoscale circulation in frontal zones

Question 19

example of source

Answer 19

precipitation

Question 20

example of sinks

Answer 20

evaporation

Question 21

sign of source and sinks

Answer 21

source +ve and sinks -ve`

Question 22

scales of atmospheric motion

Answer 22

micro <1

meso 1-100 “non hydrostatic

synoptic 100-5000 “hydrostatic

planetary 5000-40000

Question 23

compare hydrostatic and non hydrostatic

Answer 23