Chapter-4: Fronts and Jets Flashcards Preview

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Flashcards in Chapter-4: Fronts and Jets Deck (79)
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1

Define Synoptic

seen at the same time/together "simultaneous observations"

2

Midlatitude is also known as

Extra-tropics

3

Define midlatitude

between 23o27' N and 66o33'N and between 23o27' S and 66o33' S latitude, or, the earth's temperate zones between the tropics and the arctic and antarctic polar regions

4

important weather in the midlatitude

fronts and extratropical cyclones

5

front is defined as

a transition zone between two air masses of different temperatures/densities.

6

These atmospheric fronts are

hree-dimensional zones

7

These atmospheric fronts are three-dimensional zones that represent:

  • a rapid transition of the thermal field
  • marked shift in the wind direction
  • a significant transition in the moisture field
  • an increase in the magnitude of the wind

8

The thermal gradient is usually largest at ......................................and weakens as the ..................................

the Earth’s surface

zone slopes upward

9

The transition zone may extend over a distance of........................................., and a typical ............................................ratio is ...................

1000 km or more along the Earth’s surface

cross-front to along-front

1:10

10

a front is:
​........................ and ........................ (.........km)

long and wide (100 km)

11

frontal zones:

Polar front 

Arctic front

12

mP stands for:

Maritime polar

13

mT stands for:

Maritime tropical
warm, moist

14

cT stands for:

Continental tropical
hot, dry

15

cA stands for:

Continental arctic
very cold, dry

16

cP stands for:

Continental Polar
cold, dry

17

The polar front boundary:

eparates warm, humid air to the south from cold polar air to the north, extends upward to over 5 km.

18

arctic front:

separates cold air from extremely cold arctic air, is much more shallow than the polar front and only extends upward to an altitude of about one or two kilometers.

19

Fronts are observed at ......................in ..............................................and are associated with........................................................

all longitudes

the extratropical latitude belt

most of the significant weather events.

20

A jet is

an intense, narrow, quasihorizontal or horizontal current of wind that is associated with strong vertical shear.

21

Atmospheric jet streams dimention

thousands of kilometers long, a few hundred kilometers wide, and only a few kilometers thick.

22

Wind speeds in the central core of a jet stream often

exceed 100 knots and occasionally exceed 200 knots.

23

Jet streams are usually found at the .................................at elevations between ................................, although they may occur at ...........................................

tropopause

10 and 15 km

both higher and lower altitudes.

24

subtropical jet stream

the jet stream situated near 30° latitude at about 13 km above the subtropical high

25

polar front jet stream is also known as

polar jet stream

26

polar front jet stream

jet stream situated at about 10 km (33,000 ft) near the polar front

27

Both fronts and jets are usually marked by

a concentration of isotherms (strong temperature gradient) and strong vertical wind shear

28

Fronts and jets are .......................phenomenon because.................................................

hybrid

each is characterized by two different horizontal scales that differ by as much as an order of magnitude.

29

If the length of a front or jet is on the order of .........................., then the Rossby number is usually reasonably small for flow along the front or jet so that ...................................................

1000 km

geostrophic balance is approximately maintained across but not along the front or jet.

30

...........................................................................are associated with jets and jet streaks through the ............................................., and hence a dynamical explanation of fronts also explains jets.

Long, narrow zones of strong temperature gradient

thermal wind relation