Chapter 8

Question 1

Rossby waves

Answer 1

also known as planetary waves, are a natural phenomenon in the atmosphere and oceans of planets that largely owe their properties to rotation of the planet.

Question 2

Rossby waves, also known as planetary waves, are a natural phenomenon in the atmosphere and oceans of planets that largely owe their properties to rotation of the planet. Rossby waves are a subset of

Answer 2

inertial waves.

Question 3

Atmospheric Rossby waves on Earth are

Answer 3

giant meanders in high-altitude winds that have a major influence on weather.

Question 4

Atmospheric Rossby waves on Earth are giant meanders in high-altitude winds that have a major influence on weather. These waves are associated with

Answer 4

pressure systems and the jet stream.

Question 5

Atmospheric Rossby waves result from

Answer 5

the conservation of potential vorticity and are influenced by the Coriolis force and pressure gradient.

Question 6

A fluid, on the Earth, that moves toward the pole will deviate toward the

Answer 6

east

Question 7

A fluid, on the Earth, that moves toward the pole will deviate toward the east; a fluid moving toward the equator will deviate

Answer 7

toward the west (true in either hemisphere).

Question 8

The deviations are caused by the

Answer 8

the Coriolis force and conservation of potential vorticity which leads to changes of relative vorticity.

Question 9

The deviations are caused by the Coriolis force and conservation of potential vorticity which leads to changes of relative vorticity. This is analogous to

Answer 9

conservation of angular momentum in mechanics.

Question 10

In planetary atmosphere, Rossby waves are due to the

Answer 10

variation in the Coriolis effect with latitude.

Question 11

One can identify a terrestrial Rossby wave as its

Answer 11

its phase velocity, marked by its wave crest, always has a westward component.

Question 12

One can identify a terrestrial Rossby wave as its phase velocity, marked by its wave crest, always has a westward component. However, the collected set of Rossby waves may appear to move

Answer 12

in either direction with what is known as its group velocity.

Question 13

However, the collected set of Rossby waves may appear to move in either direction with what is known as its group velocity. In general, shorter waves have an

Answer 13

eastward group velocity and long waves a westward group velocity.

Question 14

The terms “barotropic” and “baroclinic” are used to distinguish

Answer 14

the vertical structure of Rossby waves.

Question 15

Barotropic Rossby waves

Answer 15

do not vary in the vertical, and have the fastest propagation speeds.

Question 16

The baroclinic wave modes

Answer 16

on the other hand, do vary in the vertical. They are also slower, with speeds of only a few centimeters per second or less.

Question 17

Most investigations of Rossby waves have been done on those in

Answer 17

Earth’s atmosphere.

Question 18

Most investigations of Rossby waves have been done on those in Earth’s atmosphere. Rossby waves in the Earth’s atmosphere are

Answer 18

easy to observe as (usually 4-6) large-scale meanders of the jet stream

Question 19

Most investigations of Rossby waves have been done on those in Earth’s atmosphere. Rossby waves in the Earth’s atmosphere are easy to observe as (usually 4-6) large-scale meanders of the jet stream. When these deviations become very pronounced,

Answer 19

masses of cold or warm air detach, and become low-strength anticyclones and cyclones, respectively, and are responsible for day-to-day weather patterns at mid-latitudes.

Question 20

The action of Rossby waves partially explains why

Answer 20

eastern continental edges, such as the Northeast United States and Eastern Canada, are colder than Western Europe at the same latitudes.

Question 21

Poleward-propagating atmospheric waves

Answer 21

Deep convection (heat transfer) to the troposphere is enhanced over very warm sea surfaces in the tropics, such as during El Niño events.

Question 22

Deep convection (heat transfer) to the troposphere is enhanced over very warm sea surfaces in the tropics, such as during El Niño events. This tropical forcing generates

Answer 22

atmospheric Rossby waves that have a poleward and eastward migration

Question 23

Poleward-propagating Rossby waves explain

Answer 23

many of the observed statistical connections between low- and high-latitude climates

Question 24

Poleward-propagating Rossby waves explain many of the observed statistical connections between low- and high-latitude climates. One such phenomenon is

Answer 24

is sudden stratospheric warming

Question 25

Poleward-propagating Rossby waves are an important and unambiguous part of the

Answer 25

variability in the Northern Hemisphere, as expressed in the Pacific North America pattern.

Question 26

Some things to note regarding Rossby waves::

· The frequency is always

Answer 26

negative, and becomes larger in magnitude for the longer wavelengths (smaller wave numbers).

Question 27

Some things to note regarding Rossby waves::

· The frequency is always negative, and becomes larger in magnitude for the longer wavelengths (smaller wave numbers).

· The zonal phase speed is

Answer 27

always negative in the absence of mean flow

Question 28

Some things to note regarding Rossby waves::

· The frequency is always negative, and becomes larger in magnitude for the longer wavelengths (smaller wave numbers).

· The zonal phase speed is always negative in the absence of mean flow.

· The zonal group speed may be

Answer 28

either positive or negative, depending on the horizontal wave number.

Question 29

Some things to note regarding Rossby waves::

· The frequency is always negative, and becomes larger in magnitude for the longer wavelengths (smaller wave numbers).

· The zonal phase speed is always negative in the absence of mean flow.

· The zonal group speed may be either positive or negative, depending on the horizontal wave number.

o Long waves propagate

Answer 29

energy westward in the same direction as the phase speed.

Question 30

Some things to note regarding Rossby waves::

· The frequency is always negative, and becomes larger in magnitude for the longer wavelengths (smaller wave numbers).

· The zonal phase speed is always negative in the absence of mean flow.

· The zonal group speed may be either positive or negative, depending on the horizontal wave number.

o Long waves propagate energy westward in the same direction as the phase speed.

o Shortwaves propagate

Answer 30

energy eastward, opposite to the phase speed.

Question 31

Some things to note regarding Rossby waves::

· The frequency is always negative, and becomes larger in magnitude for the longer wavelengths (smaller wave numbers).

· The zonal phase speed is always negative in the absence of mean flow.

· The zonal group speed may be either positive or negative, depending on the horizontal wave number.

o Long waves propagate energy westward in the same direction as the phase speed.

o Shortwaves propagate energy eastward, opposite to the phase speed.

· The meridional phase speed is

Answer 31

negative, but the meridional group speed is positive.