Atmospheric Moisture Flashcards Preview

Intro to Physical Geography > Atmospheric Moisture > Flashcards

Flashcards in Atmospheric Moisture Deck (56)
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1
Q

What is the hydrologic cycle?

A

The transfer of water from earth to the atmosphere and back again

2
Q

What are the two types of moisture in the atmosphere?

A
  1. Absolute Humidity

2. Relative Humidity

3
Q

What is absolute humidity?

A

Mass of water vapor in a given volume of air; e.g. 20 gr H2O / 1 m3 air

4
Q

What is relative humidity?

A

RATIO (%)

Actual water content of air/ potential amt. water air could hold

5
Q

What controls the water capacity of an air parcel?

A

Temperature

6
Q

What has a greater capacity to hold water vapor, warmer or cooler air?

A

Warmer air has a greater capacity to hold water vapor

7
Q

What is dew?

A

When condensation occurs directly on a surface

8
Q

What is dew point?

A

DEW POINTis the temp at which saturation occurs (RH=100%) and condensation begins, DEW FORMS

9
Q

What happens if the dew point is less then the freezing point?

A

water vapor sublimates (gas to solid) as ice crystals = FROST

10
Q

When does Frost and Dew form and why?

A

FROSTFrost and Dew form at night (or early morning) due to radiationalcooling:earth radiates heat away and cools

11
Q

What is Dew Point a clear indicator of?

A

The water content of the air

12
Q

If there is a high dew point what does that mean?

A

Moist air

13
Q

If there is a low dew point temperature what does that mean?

A

Dry air

14
Q

What are clouds?

A

CLOUDS= Condensation forms that develop above the ground

15
Q

What are two important points to remember about clouds?

A
  1. Condensation does NOT= Precipitation (PPT)

2. Clouds consist of solid or liquidwater… NOT water vapor which is a gas

16
Q

How are clouds classified?

A

By height and shape

17
Q

What are the three main types of cloud I need to know?

A
  1. Cirrus
  2. Stratus
  3. Cumulus
18
Q

What happens when you add nimbus or nimbo to these clouds?

A

It means that the clouds produce rain.

Examples –nimbostratus, cumulonimbus

19
Q

What are Cirrus clouds?

A

Cirrus–highest, wispy, consist of ice crystals

20
Q

What do Cirrus clouds signal?

A

Approaching weather (a front)

21
Q

What are Stratus clouds?

A

Stratus –horizontal (layer) clouds that form a continuous sheet near the surface(altostratus would be mid-level)

22
Q

What are Cumulus clouds?

A

Cumulus–“fair weather cumulus”puffy clouds, show vertical development( indicating convection)–Known by flat bases, distinct outlines

23
Q

What do towering cumulus clouds indicate>

A

Towering cumulus clouds indicate intense convection! Much larger, more vertical development than fair weather cumulus

24
Q

What is fog?

A

FOG = “cloud on the ground”. Thick layer of moist air cooled to its dew point

25
Q

What are the 5 types of fog?

A
  1. Advection Fog
  2. Radiation Fog
  3. Valley Fog
  4. Orographic(upslope) Fog
  5. Steam Fog
26
Q

What is advection fog?

A

Involves horizontal movementof air warm air moves over cold surface, is chilled to dew point

27
Q

Where is advection fog found?

A

West coast, often involves coastal setting

28
Q

What is radiation fog?

A

Radiational cooling of ground surface, chills moist air and condensation occurs, usually pre-dawn hours under H-press. It is stationary rather than moving and always touching ground

29
Q

Where is radiation fog found?

A

In most of the world!

30
Q

Where is valley fog common?

A

common in Appalachians, any mountains except deserts. It is also common in early mornings with radiational cooling

30
Q

What is Orgographic fog?

A

upslope movement of moist air, Cools to dew point. (cloud spilling over mountains)

30
Q

Where is orgographic fog common?

A

common in all mountains, e.g., Appalachians and TROPICAL mountains.

30
Q

When is steam fog common?

A

Common in fall. also common where there are rivers and lakes and source of cool/ cold air

30
Q

Where are the foggiest places in the U.S.?

A

West coast, east coast, south , by great lakes (any where by water pretty much)

30
Q

What is valley fog?

A

Heavy cold air drains into valleys, reaches dew point and condensation occurs.

30
Q

What is convection?

A

Convection: Thermal heating of land, local heating

30
Q

What kind of precipitation happens when ITCZ or STH are dominant?

A

wet summer when ITCZ dominates

dry winter when STH dominates

30
Q

What is steam fog?

A

cold air moves over warmer water surface (rivers/lakes)

30
Q

What has to happen to get from condensation to precipitation?

A
  1. Small drops coalesce on condensation nuclei (e.g. dust, smoke)
  2. Drops get larger and larger, gravity brings them down
30
Q

To get precipitation to occur what must first happen?

A

We must chill air to the dew point. We do this by lifting the air to cool it.

30
Q

What are the three majoring complicating factors that disrupt the expect zonal pattern of precipitation?

A
  1. Mountains
  2. Continental Effects
  3. Cold Ocean Currents
30
Q

Where is convection common?

A

Common in tropics, subtropics year-round and mid-latitudes in summer

30
Q

When do thermal convection cells occur?

A

Often occurs in afternoon or evening when land is heated to the maxWhat

30
Q

What is convergence?

A

Area of low pressure pushes air upwards

31
Q

What are the four ways to lift air?

A
  1. Convection
  2. Convergence
  3. Orographic lifting
  4. Frontal
31
Q

What is orographic lifting?

A

Orographic lifting –air forced upslope, cools

-mountains create wet and dry locations

31
Q

Where is orographic lifting common?

A

Anywhere on mountains

31
Q

What is orographic lifting responsible for?

A

It is responsible for the rainiest places in the world, like Hawaii

31
Q

When is steam fog common?

A

Common in fall. also common where there are rivers and lakes and source of cool/ cold air

32
Q

What is frontal lifting?

A

It is when cold air is heavier so warm air rises and then cools

33
Q

Where is frontal lifting common?

A

It is common in mid-latitudes and along the polar front

34
Q

Where are the rainiest places in the U.S. and why?

A

North West coast (washington), East coast, especially in the south. This is due to these places having multiple lifting mechanism, onshore winds, access to moisture, and mountains

35
Q

Why are mountains a major complicating factor that disrupts the expect zonal pattern of precipitation?

A

Mountains life and cool air.

Orographic–high PPT in otherwise drier locations

Rainshadow–deserts in potentially moist places

36
Q

Why are cold oceans a major complicating factor that disrupts the expect zonal pattern of precipitation?

A

Cold currents stabilize ATM and reduce precip

37
Q

What else is a big factor in precipitation?

A

Seasonality. As sun’s direct rays move N&S, wind & pressure belts follow.

38
Q

What are seasonal changes in lifting mechanism?

A

Rainfall in eastern U.S. in SUMMER, mostly CONVECTIVE (T-storms). In Winter, eastern U.S. gets mostly FRONTAL precipitation.