Atmospheric basics

Question 1

wind is a

Answer 1

vector quantity

Question 2

wind has

Answer 2

speed and direction

Question 3

the wind speed is measured in

Answer 3

m/s or knots

Question 4

1 knot =

Answer 4

0.51 m/s

Question 5

The wind direction is measured in ………………. from ……………………………

Answer 5

degree angle north (0 degrees / 360 degrees)

Question 6

Wind direction indicates the direction

Answer 6

from which the wind blows.

Question 7

wind velocity is a ……………. component

Answer 7

scalar

Question 8

The three scalar components of wind in Cartesian (x, y and z) coordinate system

are expressed as

Answer 8

Question 9

The horizontal wind vector can be expressed in terms of scalars as:

Answer 9

Question 10

The two scalar wind components (u and v) can be obtained from

Answer 10

wind speed and direction

Question 11

The two scalar wind components (u and v) can be obtained from the wind speed and direction as follows

Answer 11

Question 12

Synoptic scale motions have a size of approximately

Answer 12

1000 km

Question 13

for synoptic scale motions friction ……

Answer 13

can be neglected above the lowest few km

Question 14

scale analysis for the ………………………………. for ……………………………………. shows that ……………………………………………………….. are in exact balance

Answer 14

horizontal momentum equations

mid-latitude synoptic scale disturbance

the horizontal components of coriolis force and pressure gradient force

Question 15

geostrophic approximation for the x and y direction

Answer 15

Question 16

define Rossby number

Answer 16

nondimensional number which gives a measure of the magnitude of the acceleration compared to the Coriolis force

Question 17

how can you obtain the Rossby numbre?

Answer 17

by forming the ratio of the characteristic scales of acceleration and the coriolis force terms

Question 18

equation of Rossby number

Answer 18

Question 19

the smallness of the Rossby number is

Answer 19

a measure of the validity of the geostrophic approximation

Question 20

if R_o<1

Answer 20

the coriolis force is a dominant force, and the flow tends to become geostrophic

Question 21

if Ro>1

Answer 21

the flow tends to be non-geostophic

Question 22

you can neglect acceleration term in

Answer 22

mid latitude

Question 23

geostrophic wind always

Answer 23

blows parallel to the isobars with low pressure to the left

Question 24

as density is nearly constant at a given height, …………………………..

Answer 24

the geostrophic wind is linearly proportional to the pressure gradient

Question 25

as f—-> 0 near the ………………….., the geostrophic balance is not valid at …………………..

Answer 25

equator

low latitudes

Question 26

the vertical momentum equation indicated that

Answer 26

the vertical pressure gradient force is in exact balance with the gravity force

Question 27

define hydrostatic equilibrium

Answer 27

the pressure at any point is simply equal to the weight of a unit cross-section column of air above that point

Question 28

the hydrostatic approximation may be expressed as

Answer 28

Question 29

the higher the PGF the

Answer 29

stronger the wind

Question 30

vertical PGF =

Answer 30

gravity force