Chapter 7 - Notes Flashcards
Is the growth of Cloud droplets consistant?
No. It’s rapid at first then it quickly diminishes because the available water vapor is consumed by the large number of competing droplets.
Name three basic Cloud Forms.
- **Cirrus **clouds are high, white, and thin. They are separated or detached and form delicate veil-like patches or extendend wispy fibers and often have a feathery appearance.
- **Cumulus **clouds consist of globular individual cloud masses. Normally they exhibit a flat base and appear as rising domes ot towers. Such clouds are frequently described as having cauliflower-like structure
- **Stratus **clouds are best described as sheets or layers (strata) that cover much or all of the sky. Although there may be minor breaks, there are no distinct individual cloud units.
Name the three **Cloud Height Levels. **
What are clouds called that extend through multiple height ranges?
- **High Clouds **normally have bases above 6000 meters (20,000 feet).
- **Middle Clouds **generally occupy heights from 2000 tp 6000 meters.
- **Low Clouds **form below 2000 meters (6500 feet).
These altitudes are not hard and fast. They vary somewhat by season of the year and by latitude. At poleward latitudes or during cold winter months, high clouds generally occur at lower altitudes.
Clouds of Verticle Development
What type of clouds are:
Cirrus, Cirrostratus, and Cirrocumulus.
Altocumulus and Altostratus.
Stratus, Stratocumulus, and Nimbostratus.
Cumulus and Cumulonimbus.
High Clouds.
**Middle Clouds. **
Low Clouds.
Clouds of Vertical Development.
(refer to pages 129 - 134 often)
Which one of the chief precipitation producers form in association with stable air?
Nimbostratus.
Name different Cloud Varieties.
**Uncinus, **meaning “hook-shaped”, is applied to streaks of cirrus cloudsa that are shaped like a comma resting on its side. Cirrus uncinus are often precursors of bad weather.
**Fractus, **is used when stratus or cumulus clouds appear to be broken into smaller pieces.
**Mammatus **clouds have rounded protuberances on their bottom surface, not unlike the udders of cows. This configuration is sometimes associated with stormy weather and cumulonimbus clouds.
Lens-shaped clouds are refferred to as **lenticular. **They are common in areas that have rugged or mountainous topography, where they are called *lenticular altocumulus. *Although lenticular clouds can form whenever the airflow undulates sharply in the vertical, they most frequently form on the lee side of mountains.
Define Radiation Fog.
Radiation Fog **results from radiation cooling of the ground and adjacent air. It is a nighttime phenomenon requiring clear skies and a fairly high relative humidity. For radiation fog to be extensive vertically, a light breeze of 3 to 5 mph wind creates enough turbulence to carry the fog upwards **10 to 30 meters without dispersing it.
Because the air containing the fog is relatively cold and dense, it drains downslope in hilly terrain. As a result radiation fog is thickest in valleys. Normally these fogs dissipate within one to three hours after sunrise. The sun warms the ground, which in turn heats the lowest layer of air first. Consequently, the fog evaporates from the bottom up, giving the impression of liftin.
Define Advection Fog.
When warm and moist air is blown over a cold surface, it becomes chilled by contact and, to a certain extent, by mixing with cold air created by the cold surface below. If cooling is sufficient, the result will be a blanket of fog called **Advection Fog. **
The fog around the Golden Gate Bridge is Advection Fog.
Define **Upslope Fog. **
**Upslope fog **is created when relatively humid air moves up a gradual sloping plain or, in some cases, up the steep slopes of a mountian. This is the only fog that form due to adiabatic cooling.
Define Steam Fog.
Define Frontal Fog.
When frontal wedging occurs, warm air is lifted over colder air. If the resulting clouds yield rain, and the cold air below is near the dew point, enough rain can evaporate to produce fog. A fog formed in this manner is called **Frontal or Precipitaion Fog. **The result is a more or less continuous zone of condensed water droplets reaching from the ground up though the clouds.
What is White frost?
**White Frost **forms when the dew point of air is below freezing. Thus, frost forms when water vapor changes directly from a gas into a solid (deposition)
What do **Jet Trails **tell us about the current state of the atmosphere?
It means that the Relative Humidity is high
