Wind and Weather Flashcards
What is the state of the atmosphere at a particular place and time?
Weather
List the quantitative variables used to describe the weather.
Temperature, humidity, cloudiness, precipitation, and wind speed and direction.
Meteorology is the study of _______.
The atmosphere, processes that cause weather, and the life cycle of weather systems.
Climate is defined quantitatively by the _____.
Arithmetic average of the values used to describe weather at some locality over a specified time interval.
By international convention, the arithmetic average of weather elements are
Computed for a 30-year period beginning with the first year of a decade.
Climatology is the study of _______.
The climate, its controls, and spatial and temporal variability.
What is Z time?
Z time is the time standard of meteorology and climatology, and is expressed according to a 24-hour clock
By international agreement, when are surface weather observations are taken?
At least four times per 24 hours, at 0000 Z, 0600 Z, 1200 Z, and 1800 Z.
By international agreement, how and when are upper-air measurements made ?
Via balloon-borne instruments at least two times per 24 hours, at 0000 Z and 1200 Z.
In the United States, when are surface weather observations are taken?
Hourly at the top of the hour.
In the United States, when are composite radar charts are issued?
Hourly at 35 minutes past the hour.
In the United States, when are fronts analyzed on weather maps?
Every 3 hours beginning at 0000 Z.
What are all the main types of pressure systems?
Highs/anticyclones and lows/cyclones
What are the four defining characteristics of air masses?
- uniform horizontal temperature distribution.
- uniform horizontal humidity distribution.
- associated with a large high pressure system.
- characteristics are determined by the surfaces over which they are formed.
What are all four basic types of air masses?
- Cold and dry
- Cold and humid
- Warm and dry
- Warm and humid
Cold air masses form at ________, warm air masses form at ________, humid air masses form over _________, and dry air masses form over ________.
Higher latitudes, lower latitudes, maritime surfaces, continental surfaces
What is the narrow transition zone between air masses that differ in temperature, humidity, or both called?
A front
What are the three most common fronts?
- Stationary
- Cold
- Warm
On both sides of this kind of front, winds blow roughly parallel to the front but in opposite directions.
Stationary front
Anticyclones feature _____ and are usually accompanied by _______.
Descending air, fair weather
Cyclones feature _____ and are usually accompanied by _______.
Ascending air, stormy weather
Highs are described as _____-weather systems.
Fair
Lows are described as _____-weather systems.
Stormy
Viewed from above in the Northern Hemisphere, surface winds in a high-pressure system blow in a ___________.
Clockwise and outward spiral
Viewed from above in the Northern Hemisphere, surface winds in a low-pressure system blow in a _______________.
Counterclockwise and inward spiral
Why are lows which form over arid or semiarid areas an exception to the general rule of lows being stormy-weather systems?
intense solar heating of the ground raises the air temperature and lowers the surface air pressure, producing a low that remains stationary over the hot ground
Define the weather parameter: “maximum temperature.”
The highest air temperature over a 24-hour period, usually between the midnight of one day and the midnight of the following day.
Define the weather parameter: “minimum temperature.”
The lowest air temperature over a 24-hour period, usually between the midnight of one day and the midnight of the following day.
Define the weather parameter: “dew point.”
The temperature to which air must be cooled to become saturated with water vapor
Define the weather parameter: “frost point.”
The temperature to which air must be cooled at constant pressure to become saturated with water vapor and for frost to begin forming on relatively cold surfaces.
Define the weather parameter: “relative humidity.”
A measure of the actual concentration of the water vapor component of air compared to the concentration the air would have if saturated with water vapor, expressed as a percentage.
Define the weather parameter: “precipitation amount.”
Depth of rainfall or melted snowfall over a 24-hour period
Define the weather parameter: “air pressure.”
The weight of a column of air over a unit area of Earth’s surface.
Define the weather parameter: “wind direction.”
direction the wind blows from
Define the weather parameter: “sky cover.”
Sky cover is described using different the fraction of the sky that is covered in clouds
Define the weather parameter: “weather watch.”
A notice issued by the National Weather Service when hazardous weather is considered possible
Define the weather parameter: “weather warning.”
A warning issued by the National Weather Service when hazardous weather is imminent or actually taking place
What is the average air pressure at sea level in atmospheres, millibars, millimeters of mercury, pascals, pounds per square inch, and torr?
1 atm, 1013.25 mbar, 760 mm of Hg, 101325 Pa, 14.6959 psi, 760 Torr
On average, 10 inches of freshly fallen snow melt down to about how many inches of water?
1 inch
If the sky cover is described as clear, then what is the fraction of cloud cover?
0
If the sky cover is described as a few clouds, then what is the fraction of cloud cover?
1/8 to 1/4
If the sky cover is described as scattered clouds, then what is the fraction of cloud cover?
3/8 to 1/2
If the sky cover is described as broken clouds, then what is the fraction of cloud cover?
5/8 to 7/8
If the sky is completely cloud covered, then in the vernacular of sky cover it is said to be _______.
Overcast
What is a GOES satellite?
A satellite revolving around Earth at the same rate and in the same direction as the planet so it is always over the same spot
What is the point on the planetary surface directly below a satellite?
The sub-satellite point
What does GOES in GOES satellite stand for?
Geostationary Operational Environmental Satellite
What is a POES satellite?
A satellite which orbits in a nearly north-south orbit passing close to the poles. on-board sensors sweep out successive overlapping north/south stripes.
How often do POES satellites pass over the same area on Earth?
Sun-synchronous - 2 times
Others - it sometimes takes several days
What type of satellite image uses sunlight reflected by Earth’s surface?
Visible satellite image
What type of satellite image uses infrared radiation?
Infrared satellite image
What type of satellite image uses specific wavelength bands of infrared radiation emitted by water vapor?
Water vapor satellite image
_____________ functions by emitting pulses of microwave energy which are then reflected by atmospheric targets such as raindrops, snowflakes, or hailstones.
Weather radar
What category of cloud forms in horizontal layers?
Stratiform clouds
What category of cloud appears puffy?
Cumuliform clouds
Stratiform clouds develop where
Air ascends gently over a broad region.
Cumuliform clouds develop where
Air ascends vigorously over a smaller region
What type of cloud often develops ahead of a warm front?
Stratiform clouds
What type of cloud often develops along or just ahead of a cold front?
Cumuliform clouds
What are small, white, fair-weather clouds resembling puffs of cotton floating in the sky, which usually vaporize rapidly near sunset?
Cumulus clouds
During certain atmospheric conditions, cumulus clouds build vertically and merge laterally, eventually forming a thunderstorm cloud, called a _________.
Cumulonimbus cloud
What direction Do monsoon winds blow in the winter?
West (toward Africa)
What do the trade winds fuel along the Peruvian Coast?
Upwelling
What are hurricanes called in the indo-pacific region?
Cyclones
What are hurricanes called in Japan?
Typhoons
How fast do winds have to blow to be considered a hurricane?
119 km/hr
3 factors considered on the saffir-Simpson scale?
Pressure
Wind
Storm surge size
What temperature are tropical waters?
20 degrees Celsius
What temperature are polar waters?
5 degrees Celsius
