chapter 7: Jet and Jet streaks

Question 1

Weather processes strongly depend on

Answer 1

the structure and dynamics of jet streams

Question 2

There are ………………….major ……………………jet streams in the upper ………………………in each hemisphere

Answer 2

two

westerly

troposphere

Question 3

There are two major westerly jet streams in the upper troposphere in each hemisphere

Answer 3

– Polar jet stream
– Subtropical jet stream

Question 4

The structure of jet streams are related to

Answer 4

temperature distribution through the thermal wind relationship

Question 5

Warm air to the south results in

Answer 5

westerly geostrophic winds through the thermal wind relationship.

Question 6

Draw the jet stream (box)

Answer 6

Question 7

The thermal wind relationship also explains why

Answer 7

the jet stream tends to be collocated with the polar front.

Question 8

Large horizontal temperature gradients > > >

Answer 8

large horizontal temperature gradients

Large thickness gradients>

Large horizontal pressure gradient aloft>

strong winds

Question 9

The polar jet is the band of

(speed ) (found in)

Answer 9

meandering strong winds (~100 knots) found at the tropopause.

Question 10

The polar jet moves

Answer 10

meridionally (30°-60° latitude) and vertically (10-15 km) with the seasons.

Question 11

Large vertical extent: maximum usually near ……………….. but can be seen at ……………….

Answer 11

300 mb

200mb - 500mb

Question 12

At times, the polar jet will split into …………………………….and possibly merge with ………………………..

Answer 12

northern and southern branches

the subtropical jet

Question 13

Polar Jet and thermal wind balance:

it is associated with:

Answer 13

strong quasi-horizontal temperature gradients in the lower troposphere and strong vertical wind shear.

Question 14

It is associated with strong quasi-horizontal temperature gradients in the lower troposphere and strong vertical wind shear.

• These features are often associated with

Answer 14

the polar front.

Question 15

Meridional undulations of the jet stream are associated with

Answer 15

poleward and equatorward displacements of warm and cold air, respectively.

Question 16

The subtropical jet is associated with……………………………………. between……………………… usually found between…………………….

Answer 16

subtropical front between the tropical and mid-latitude air masses and is usually found between 25° and 30° N.

Question 17

It meanders less than…………………………., but in rare cases has been observed as far…………………………

Answer 17

the polar jet

north as 60°N

Question 18

Subtropical jet is ………………………

Answer 18

shallow

Question 19

subtropical jet stream is rather shallow – sometimes less than ……………………………..and may not show up on……………………………..

Answer 19

3 km in depth

either of the 200 mb or 300 mb standard levels

Question 20

Subtropical Jet Stream directly influences …………………………..

Answer 20

low-level flow only when it becomes coupled through deep cumulus convection and interactions with the polar jet

Question 21

what are the two cases that subtropical jet streams affect low:

Answer 21

1. when it becomes coupled through deep cumulus convection and
2. interactions with the polar jet

Question 22

Like the Polar-Front jet, the subtropical jet is associated with a

Answer 22

change in height of the tropopause.

Question 23

The meridional temperature gradient associated with the

Answer 23

vertical shear under the subtropical jet is concentrated in a shallow layer

Question 24

Sometimes the subtropical jet is associated with a

Answer 24

a portion of the Polar-Front jet that has migrated equatorward into the subtropics and has lost its low-level baroclinicity.

Question 25

define Barcoclinicity

Answer 25

surfaces of pressure intercect surfaces of temperature and density (occure at fronts)

FRONT HAS BAROCLINITY

Question 26

Subtropical Jet position is …………….. than polar jet

Answer 26

higher

Question 27

subtropical jets and polar jet separate ……..

Answer 27

cells

Question 28

The presence of the subtropical jet relates to the

Answer 28

conservation of absolute angular momentum in the context of the Hadley cell.