final Flashcards
(493 cards)
1
Q
define weather
A
current state of the atmosphere
2
Q
define climate
A
collective state of the atmosphere over a long period of time (30 years)
3
Q
define meteorology
A
study of the Earth’s atmosphere
Ever changing; not a perfect science
4
Q
define atmosphere
A
the gases that surround earth and the other planets
**10-15 mile zone contains all weather
5
Q
what are the elements of weather?
A
- air temperature
- humidity
- clouds
- precipitation
- wind direction
- wind speed
- visibility
- air pressure
6
Q
define air temperature
A
how hot or cold the air is, molecular motion
7
Q
define humidity
A
Moisture in the air, invisible ; refers to any one of a number of different ways of specifying the amount of water vapor in the air
8
Q
define clouds
A
The visible part of the moisture; 10 types, only 2 of the 10 produce precipitation
9
Q
define wind speed
A
Speed of the molecules in the air
10
Q
define visibility
A
How far we can see; restricted by fog, pollution, etc.
11
Q
define air pressure
A
Pressure of the atmosphere; We (at this age) cannot see it or feel it; Pressure falls as the storm approaches; Older people feel it more…also you can feel it more if you are injured
12
Q
pressure __________ (rises/falls) as a storm approaches
A
falls
13
Q
what is a surface map
A
what the weather is like AT THE GROUND; fronts are only shown on these
14
Q
what are the 2 types of weather maps?
A
- surface map
2. upper air map
15
Q
on a surface station model…
the circle represents
A
clouds; the more filled in the circle is, the more cloud coverage there is
16
Q
on a surface station model…
the flag represents
A
wind speed
17
Q
on a surface station model…
the bar represents
A
wind direction
**same for upper air station model
18
Q
on a surface station model…
the full / half flags represent
A
full flag : 10 knots
half flag : 5 knots
- *pendant is 50 knots
- *same for upper air station model
19
Q
on a surface station model…
the upper number on the left side represents
A
air temperature (in degrees Fahrenheit)
20
Q
on a surface station model…
the lower number on the left side represents
A
dew point (in degrees Fahrenheit)
21
Q
on a surface station model…
the upper number on the right side represents
A
air pressure (millibars)
**add a decimal to the tenths place and add either a 9 or 10 in front (whichever brings the # closer to 1000)
22
Q
on a surface station model…
the lower number on the right side represents
A
change in air pressure (millibars)
**put a decimal point at the front
23
Q
on an upper air station model…
the upper number on the left side represents…
A
temperature (in degrees Celsius)
24
Q
on an upper air station model…
the lower number on the left side represents…
A
dew point depression (in degrees Celsius)
**how much the dew point temperature is away from the actual temperature
25
on an upper air station model...
the circle is...
shaded if the dew point depression is 5 or less
26
on an upper air station model...
the top right number represents...
the height of where the measurements are taken (in meters)
**add a zero to the number given
27
define isolines
lines of equal or constant values of a given property with respect to place and time
28
isobar
lines of equal atmospheric pressure
29
isotherm
lines of equal air temperature
30
isohyet
lines of equal rain fall amounts
31
isallobar
measures equal pressure change over time
32
isodrosotherm
lines of equal dew point temperature
33
isotach
lines of equal wind speed
34
Stanley Gedzelman's (CCNY) Seven Causes of Weather
1. Sun's heating varies over Earth and with Seasons
2. Difference in air temperatures over Earth causes winds
3. Rotation of Earth destroys wind patterns ... twisting the wind, produces spirals ... high / low pressure
4. Since less moisture can coexist in colder air, precipitation is generally caused by cooling the air
* ** Pressure in the atmosphere ALWAYS decreases with height ***
5. The process of decreasing air pressure ... temperatures drop
6. The process of increasing air pressure ... temperature rise
7. Clouds / precipitation are caused by rising air (lows) clear skies are caused by sinking air (highs)
35
hydrosphere
water part of the planet; affects the humidity
36
lithosphere
land part of the planet
37
biosphere
living part of the planet; brings moisture to the atmosphere
38
permanent gases and their percentages
Permanent Gases (98% volume)
Nitrogen (N) - 78.07%
Oxygen (O) - 20.95%
Argon (A) - .93%
Neon (Ne) - .001%
39
variable gases and their percentages
Variable Gases (2% volume) (greenhouse gases)
```
Water Vapor (H20)
Methane (CH4)
Carbon Dioxide (CO2)
Nitrous Oxide (N20)
Ozone (03)
CFC's
Aerosols / Particulates
```
40
outgassing
the atmospheric release of gas (including water vapor); contributed to the formation of the atmosphere
41
how did oxygen mostly form?
photosynthesis
42
troposphere
- first layer of the "thermal-structured" atmosphere
- surface to 10/15 miles up
- deeper near the equator shallower near the poles
- weather producing layer
- temperature generally decreases with height; because the sun's rays heat from the earth's surface up
43
stratosphere
- 15-30 miles up
- temperature generally increases with height in upper 2/3 levels of this layer because the ozone is absorbing UV radiation
44
mesosphere range of distance
30-55 miles up
45
thermosphere
about 55 miles and up
46
what layers make up the thermal structure of the atmosphere? (from bottom to the top)
troposphere, stratosphere, mesosphere, thermosphere
47
what are the atmospheric layers by composition?
homosphere and heterosphere
48
what is the atmospheric layer organized by electrical properties?
ionosphere
49
ionosphere
- 45/50 miles and higher
- not really a layer, but electrified region
- molecules (nitrogen) and atoms (oxygen) are readily ionized with high energy SW radiation
* D, E, F layers (lowest to highest)
* Daytime - all layers present
* Nighttime - D & E largely disappear...F remains...very reflective
- --(Aurora Borealis)
50
homosphere
- surface to 55/60 miles up
| - well mixed region
51
heterosphere
- small number of atoms/molecules causes layering with heavier on bottom (oxygen&nitrogen) and lighter above (hydrogen&helium)
52
the earth intercepts less than ___________ of all the sun's energy; however, solar energy represents ______% of the energy that heats the earth's surface
2 billionths; 99.9%
53
Vernal Equinox date (in northern hemisphere)
march 21
54
Summer Solstice date (in northern hemisphere)
june 21
55
Autumnal Equinox date (in northern hemisphere)
september 21
56
Winter Solstice (in northern hemisphere)
december 21
57
1 "atmosphere"
90 degrees overhead
58
2 "atmospheres"
30 degrees above horizon
59
11 "atmospheres"
5-10 degrees above horizon
60
Tropic of Cancer
23.5 degrees north of equator
61
Tropic of Capricorn
23.5 degrees south of equator
62
explain what a lag or march of temperature is?
when a high/low temperature occurs before predicted time (march); annually and daily
when a high/low temperature occurs after predicted time (lag); annually and daily
63
Circle of Illumination
- boundary separating light part of the planet from the dark part
* hits ATX (or anywhere) 1x/day
64
of 100% of incoming solar radiation...
how much is absorbed by the earth?
51%
65
of 100% of incoming solar radiation...
how much is absorbed by atmosphere and clouds?
19%
66
of 100% of incoming solar radiation...
how much is scattered and reflected by clouds?
20%
67
of 100% of incoming solar radiation...
how much is scattered from atmosphere?
6%
68
of 100% of incoming solar radiation...
how much is reflected from surface?
4%
69
transfer of heat from molecule to molecule within a substance
EX:
grabbing a metal pot handle and it being hot
conduction
70
vertical transfer of heat in our atmosphere
the transfer of heat by the mass movement of a fluid, such as water and air
EX:
billowing of clouds
convection
71
the emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles that cause ionization
EX:
shortwave (solar)
longwave (terrestrial)
radiation
72
horizontal transfer of energy
EX:
wind, cold/warm fronts
advection
73
Rayleigh scattering
shortwave (blue part of spectrum); gases cause the blue sky
74
Mie scattering
lower levels of the atmosphere; pollen, dust, smoke, clouds, fog
75
Albedo varies...
place to place / time to time
due to cloud cover / particulate matter
due to the angle of the sun
due to the nature of Earth's atmosphere
76
define albedo
total fraction of total radiation that is reflected by a given surface
***higher albedo=higher reflectivity
77
higher albedo = ______ (lower/higher) reflectivity
higher
78
Average Planetary Albedo... (in percent)
30%
79
The Atmospheric "Greenhouse" Effect
the relatively easy transmission of shortwave (incoming /solar) radiation by the atmosphere coupled with the selective absorption of longwave (outgoing / terrestrial) radiation
80
If an object radiates more energy than it absorbs, the objects turns.....
cooler
81
If an object absorbs more energy than it radiates, the object turns....
warmer
82
what is a black body
a perfect absorber (all the radiation it receives is absorbed) or a perfect emitter (emits the maximum radiation possible at a given temperature)
Ex: Earth
Earth's atmosphere is NOT a black body
83
define energy
the property of a system that enables it to do work (kinetic, chemical, electrical, etc.)
84
define heat
form of energy transferred between objects by virtue of temperature differences
Mass MATTERS
85
define heat capacity
ratio of heat absorbed (or released) by a system compared to the corresponding temperature rise / fall
Water has a GREATER heat capacity than land
86
water has a _______ (higher/lower) heat capacity than land
higher
87
define latent heat
the type of heat that is required for a change of state
88
Latent Heat is absorbed during....
* *Cooling Process
- evaporation
- melting
- sublimation
>LAMES
89
Latent Heat is released during...
* *Warming Process
- freezing
- condensation
- deposition
>LRCDF
90
Maximum Thermometers use what substance?
Mercury
91
Minimum Thermometers use what substance?
Alcohol
92
albedo of...
fresh snow
85%
93
albedo of...
thick clouds
70 - 80%
94
albedo of...
water (low sun angle)
50 - 80%
95
albedo of...
old snow
50 - 60%
96
albedo of...
thin clouds
25 - 50%
97
albedo of...
sand surface
20 - 30%
98
albedo of...
green grass
20 - 25%
99
albedo of...
dry earth
15 - 25%
100
albedo of...
wet earth
10%
101
albedo of...
forested areas
5 - 10%
102
albedo of...
water (sun overhead)
3 - 5%
103
Earth's RET temperature vs. actual observed surface temperature
Earth's RET = 0 degree F / -18 degree C
AOST = 59 degrees F / 15 degrees C
**Without gases (CO2 & H2O) the atmosphere would be like the Earth's RET; BUT...Earth's atmosphere
is NOT a black body and selectively absorbs & emits radiation
104
RET stands for...
radiated equilibrium temperature
105
latent heat of evaporation
Heat is "hidden away" in resulting water vapor when water evaporates
Evaporation is a COOLING process
106
latent heat of condensation
Sensible heat is released with the rising air parcels
Condensation is a WARMING process
107
what is significant about 30 - 50 latitude?
- Location at which most heat transfer occurs
| - Areas of Stormy weatherf
108
at 36 degrees latitude or below, _______ (more/less) shortwave radiation is received than lost
more
109
above 36 degrees latitude, _______ (more/less) shortwave radiation is lost than received
more
110
what are the three main temperature scales
fahrenheit, celsius, kelvin
111
who developed the Fahrenheit scale and in what year
Gabriel Daniel Fahrenheit ; 1714
112
based on mercury-in-glass thermometer based upon a "zero point" ; only in US
Fahrenheit Scale
113
what are the three significant temperatures on the Fahrenheit scale
98.6 - human body temperature
212 - water's boiling/steam point
32 - freezing/"zero" point
114
who developed the Celsius scale and in what year
Anders Celsius ; 1742
115
devised using the decimal scale and a "zero" point; used widely worldwide (except US)
Celsius Scale
116
a degree of celsius is ________ (smaller/larger) than a degree of Fahrenheit by a factor of _____
larger ; 1.8
117
what are the three significant temperatures on the Celsius scale
37 - human body temperature
100 - water's boiling/steam point
0 - freezing point
118
who developed the Kelvin scale and in what year
Lord Kelvin (William Thompson) ; 1848
119
used in scientific formulas/applications ; no negatives on this scale ; the "zero" point is the cessation of molecular motion
Kelvin Scale
120
what are the significant temperatures on the Kelvin scale
273 - freezing point of water
| 373 - water's boiling/steam point
121
temperature scale conversion: Fahrenheit to Celsius
(F - 32) / 1.8 = C
EX: 50 F = 10 C
(50 F - 32) / 1.8 = 18 / 1.8 = 10C
122
temperature scale conversion: Celsius to Fahrenheit
C x 1.8 + 32 = F
EX: 30 C = 86 F
(30 C x 1.8) + 32 = 86 F
123
what are heating/cooling degree days
units of measure ; developed in the early 20th century ; a method of evaluating energy demand and consumption
124
what is the daily mean temperature that marks/determines when to be heating or cooling
65 F / 18.3 C
125
if the average temperature is >65...
CDD
126
if the average temperature is
HDD
127
the degree difference between the average temperature and 65 F tells you...
the number of HDD or CDD
EX: high temp is 90 F , low temp is 60 F ; therefore the average temp is 75 F ; this is 10 F > 65 F ; therefore, it would be a 10 CDD observed for the day
128
CDD season
Jan - Dec
129
HDD season
July 1 - June 30
130
what are the 2 factors of the heat stress index
temperature and humidity
131
85% of body heat loss is from...
top of head to neck/shoulders
132
what are the 2 main factors of the wind chill index
air temperature and wind speed
133
what is the most important compound in the atmosphere
water vapor
134
the amount of water vapor (gas) in the atmosphere is _____ (higher/lower) in the polar regions and _____ (higher/lower) near the equator/tropical regions
lower (near 0%) ; higher (near 4%)
135
water vapor is very important when considering...
atmospheric stability
136
(AKA-water vapor density) ; the weight/mass of the water vapor per volume of air parcel
absolute humidity
137
comparing the weight/mass of the water vapor per volume of air parcel with the total weight/mass of the air in the parcel including the water vapor
specific humidity
138
comparing the weight/mass of the water vapor per volume of air parcel with the weight/mass of the remaining dry air
mixing ratio
139
ratio of the air's actual water vapor content compared with the amount of water vapor required for saturation at a given temp
relative humidity
140
relative humidity can be influenced, or changed, by...
- adding/subtracting moisture to air
| - changing given air temp
141
relative humidity has _______ relationship to temperature
inverse ; so if temperature is getting higher throughout the day, RH is getting low
142
the temperature to which a parcel of air would need to be cooled to (assuming no change in air pressure or moisture content) in order for the given parcel of air to reach saturation
dew point temperature
143
dew point temperature is always __________ air temperature
less than or equal to
144
when dew point temp = air temp...
air is saturated (relative humidity = 100%)
145
relative humidity is lowest when...
there is a greater difference between dew point temp and air temp
146
relative humidity is highest when...
there is a smaller difference between dew point temp and air temp
147
a lower dew point temperature means...
less moisture in air (cold air can hold less water)
148
a higher dew point temperature means...
more moisture in air
149
dew cell
directly measures the air's actual water vapor pressure (used in ASOS/AWOS sensor systems)
150
atmospheric stability refers to...
a state of equilibrium of the atmosphere
151
in order to determine atmospheric stability, we look at...
the temperature of a parcel of air as it rise and/or sinks in the atmosphere and compare that temperature to the temperature of surrounding air
152
when you force a parcel of air to rise...
it expands and cools
153
when you force a parcel of air to sink
it compresses and warms
154
when a given parcel of air expands/cools or compresses/warms with NO interchange of heat with its outside environment
adiabatic process
155
in unsaturated air, air cools/heats at a rate of...
5.5 F / 1000 Ft
156
in saturated air, air cools/heats at a rate of...
3.3 F / 1000 Ft
157
when the ELR is greater than the DALR, the atmosphere is said to be
absolutely unstable
158
when the ELR is greater than the MALR, but less than the DALR, the atmosphere is said to be
conditionally unstable
159
when the ELR is less than the MALR, the atmosphere is said to be
absolutely stable
160
stability is enhanced by...
1. radiational cooling of the earth's surface after sunset
2. cooling of air mass from below as it moves over a colder surface
3. subsidence of an air column
161
instability is enhanced by...
1. intense solar heating
2. heating of air mass from below as moves over a warmer surface
3. forceful lifting of air (orographic and frontal)
4. upward motion with surface air convergence
5. radiational cooling from nocturnal thunderstorm cloudtops
162
parcels rise in _____ (warmer/colder) air
Environmental Lapse Rate ; rate at which air cools with height
163
water that has condensed onto objects near the ground when the temperature of those objects has cooled below the dew point temperature of the surrounding air ; not a form of precipitation, but still an important source of moisture
dew
164
what happens when the air temperature falls below freezing after dew has formed?
frozen dew ; NOT CALLED FROST (frost is produced by deposition - meaning it does not pass through a liquid state)
165
a covering of ice crystals produced by deposition on exposed surfaces when the air temperature falls below the freezing point and the temperature of the exposed objects falls below the surrounding air's dew point temperature
frost
166
what kills more people annually than any other weather-related factors
heat
167
what are the four phases of the hydrologic cycle
evaporation, condensation, transpiration, infiltration
168
hydrolic cycle:
water going through the roots and out through the leaves of the plants
transpiration
169
hydrolic cycle:
soaking into the soil ; aquifer?
infiltration
170
if air temperature and dew point temperature are one degree apart, what is the RH
96%
171
there is a _______ (direct/indirect) relationship between dew point temp and moisture in air
direct ; more moisture in air at higher dew points, and less moisture in air at lower dew points
172
sling psychrometer : dry bulb records
actual air temperature
173
sling psychrometer : wet bulb records
NOT dew point temperature ; after wetting the shoestring and slinging it, the evaporative cooling yields a wet bulb temperature
174
through this we can determine RH & Dew Point Temp using dry and wet bulb temps and psychometric tables
sling psychrometer
175
electronic hygrometer
electrical conductors coated with moisture absorbing chemical (usually carbon); Passage of current varies as Relative Humidity varies; used in Radiosondes / Rawinsondes
176
infrared hygrometer
measures the amount of infrared energy absorbed by water vapor in a given sample of air; used in weather satellites (water vapor imagery)
177
hair hygrometer
based on a hair strand lengthening with higher RH; hair strands attached to an index dial
178
most clouds form as air _____, _______, & _______
rises, expands, and cools
179
a cloud with its base at the earth's surface
fog
180
most common type of fog we see in south central texas ; radiates heat away then cool to dew point temp ; fog forms because air becomes saturated ; little to no wind
radiation fog
181
most common type of fog along west coast ; horizontal wind/movement ; can occur with little wind ;
advection fog
182
latin root : stratus means...
"layer"
183
latin root : nimbus means...
"violent rain"
184
latin root : cumulus means...
"heap"
185
latin root : cirrus means...
"curl of hair"
186
if a parcel is colder than the air temp, what will happen
it will sink to get warmer/compress
187
if a parcel is warmer than the air temp, what will happen
it will rise to get colder/expand
188
when the parcel expands / cools or compresses / warms with interchange of heat with the outside environment
diabatic process ; but we assume adiabatic process
189
thermodynamic diagram : the yellow line is the...
parcel line
190
thermodynamic diagram : compare the yellow line to the...
air temperature line (NOT the dew point temp line)
191
thermodynamic diagram : when the parcel (yellow) line is left of the air temperature line, the atmosphere is...
stable
192
thermodynamic diagram : when the parcel (yellow) line is right of the air temperature line, the atmosphere is...
unstable
193
the quicker it gets colder with height the more ______ (stable/unstable) the parcel is
unstable
194
the slower it gets colder with height or if there are temperature inversions the more _____ (stable/unstable) the parcel is
stable
195
cloud formation process:
1. surface heating and free convection
2. topographic lift
3. widespread lifting (ascent) due to surface convergence
4. uplift along weather fronts (tornado capital causer)
196
Adding more moisture to the air than it can hold (you can see your breath when it is cold)
evaporation/mixing fog
197
Fog that forms when air is forced to move up slowly ; associated with topographic lift
upslope fog
198
cloud classification schemes : who made the first classification and in what year
Lamarck , 1802
199
cloud classification schemes : who made the second modification to the classification and in what year
Howard , 1803
200
cloud classification schemes : who made the last expansion to the classification and in what year
Abercromby & Hildebransson , 1887
201
cloud coverage is measure in what
octas
202
cloud coverage : 0/8
clear sky (CLR/SKC)
203
cloud coverage : 1/8 - 2/8
few clouds (FEW)
204
cloud coverage : 3/8 - 4/8
scattered (SCT)
205
cloud coverage : 5/8 - 7/8
broken (BKN)
206
cloud coverage : 8/8
overcast (OVC)
207
precipitation types
rain, freezing rain, drizzle, freezing drizzle, sleet, hail, snow
208
geostationary satellites
22,500 miles above ground ; images of same geographic area continuously
209
polar orbiting satellites
532 miles above ground ; closely parallel the earth's meridian lines ; they pass over the north and south polar regions with each pass
210
precipitation formation process : collision - coalescence process
warmer temperature process
211
precipitation formation process : bergeron process
colder temperature process
212
what is the water equivalent of snowfall
1" liquid rainfall = 10" snow
213
water equivalent of wet snowfall
1" liquid rainfall = 5" snow
214
water equivalent of dry powdery snow
1" liquid rainfall = 15" snow
215
what are the three types of precipitation measurement
standard rain gauge ; tipping bucket rain gauge ; weighing type rain gauge
216
what are things to remember when measuring snowfall
- avoid areas with drifting/blowing snow
- away from trees/buildings
- measure in 3 places with a ruler and average
217
CLOUD ID: wispy streamers ; lower/shallower near poles ; "mares tales" ; fair weather
cirrus
218
precipitation that does not reach the ground
virga
219
what are the high clouds
cirrus, cirrocumulus, cirrostratus (all at or above 20,000 feet)
220
CLOUD ID: occasional precipitation that doesn't hit the ground (virga); always white ; scales of fish ; small puffs
cirrocumulus
221
CLOUD ID: "halo" -usually transparent to sunlight; shadows are cast ; thin sheet like layer
cirrostratus
222
what are the middle clouds
altocumulus ; altostratus (6,500 - 20,000 ft)
223
CLOUD ID: gray base-distinguishable ; "rising castles" ; common on mornings of severe weather days ;
altocumulus
224
CLOUD ID: gray-blue/gray (NEVER white) ; no shadows cast ;
altostratus
225
what are the low clouds
stratus ; stratocumulus ; nimbostratus
226
CLOUD ID: uniform grey stratified layer ; light drizzle or light snow possible ; very uniform cloud bases
stratus
227
CLOUD ID: lumpy cloud layer ; blue sky visible between cloud elelments
stratocumulus
228
CLOUD ID: dark grey wet-looking cloud ; light to moderate rain (never heavy precipitation) ; bases are normally impossible to identify ; no sun or moon visible through cloud mass
nimbostratus
229
what are the clouds of vertical extent
cumulus ; cumulonimbus
230
CLOUD ID: only out when the sun is ; when they have a flat base, air has reached dew point temp ; dense and well defined ; cotton puffs
cumulus
231
more cloud towering means...
more instability
232
CLOUD ID: large, towering, precipitating ; thunder, lightning and rain ; severe storms
cumulonimbus
233
CLOUD SUBTYPES: lenticularis
lens like
234
CLOUD SUBTYPES: fractus
broken or fractured
235
CLOUD SUBTYPES: humilis
of small size
236
CLOUD SUBTYPES: congestus
to pile up/become congested
237
CLOUD SUBTYPES: undulatus
having waves
238
CLOUD SUBTYPES: translucidus
to shine through
239
CLOUD SUBTYPES: mammatus
bag/pouch like ; mammary (extreme turbulence)
240
CLOUD SUBTYPES: pileus
cap
241
CLOUD SUBTYPES: castellanus
small castles
242
CLOUD SUBTYPES: contrails
condensation trails (behind jets)
243
FORMS OF PRECIPITATION: falls from low stratus clouds ; drops are less than 0.02" ; trace amounts of rainfall
drizzle
244
FORMS OF PRECIPITATION: diameters greater than 0.02"; generally produced by nimbostratus or cumulonimbus clouds; ***intensity is based upon rate of fall
rain
245
what does trace mean
not measurable, but occurs
246
FORMS OF PRECIPITATION: rain that falls in liquid form but freezes upon impact; droplet size greater than 0.02"; ice storms
freezing rain
247
FORMS OF PRECIPITATION: drizzle that falls in liquid form but freezes upon impact; droplet size less than 0.02"; difficult to see-dangerous
freezing drizzle
248
FORMS OF PRECIPITATION: frozen raindrops (freeze in air, not upon impact) ; diameter is 0.2" or less; distinctive sound when hitting ground
ice pellets (sleet)
249
FORMS OF PRECIPITATION: produced through deposition ; up to 0.8" in diameter ; intensity is always based upon visibility
snow
250
FORMS OF PRECIPITATION: always produced by cumulonimbus clouds ; large liquid water contents, large cloud droplet size, and great vertical height are favorable in creating this form of precipitation ; diameter of 1" (size of quarter) or greater is one criteria that classifies a thunderstorm as being "severe"
hail
251
the weight of air above a given surface
air pressure
252
as you climb in elevation, there are fewer air molecules above you, therefore , air pressure always ______ with height
decreses
253
two identical columns of air (fixed width):
if we move air into the column with no temperature change...
surface pressure would increase
254
two identical columns of air (fixed width):
if we move air out of the column with no temperature change...
surface pressure would decrease
255
two identical columns of air (fixed width with same air pressure):
if we warm one column...
the molecules move faster and spread farther apart, the air becomes less dense and the column expands in height
256
two identical columns of air (fixed width with same air pressure):
if we cool one column...
the molecules move more slowly and crowd closer together, the air becomes more dense and the column shrinks in height
257
it takes a ____ (shorter/taller) column of cold, dense air to exert (less, more, same) surface pressure as taller column of warm, less dense air
shorter, same
258
atmospheric pressure decreases more rapidly with elevation in a ______ (warm/cold) column of air
cold
259
true/false: high pressure is always cold
false ; high pressure is not always hot or cold, it depends on where it is in the atmosphere
260
atmospheric pressure decreases more slowly with elevation in a _____ (warm/cold) column of air
warm
261
warmer air aloft is normally associated with ________ (higher/lower) atmospheric pressure aloft
higher (resulting in a more stable atmosphere)
262
colder air aloft is normally associated with _________ (higher/lower) atmospheric pressure aloft
lower (resulting in a more unstable atmosphere)
263
unequal heating of the Earth's surface causes...
the wind to blow (lack of equilibrium)
264
how do we measure air pressure
barometers (mercurial vs. aneroid)
265
corrections must be made for what factors when measuring air pressure
1. temperature
2. instrument
3. gravity
4. sea level
266
atmospheric pressure decreases, on average, ____ inch of ______ for each ______ foot rise in altitude
one ; mercury ; 1000
267
what is the standard surface atmospheric pressure
1013. 2 mb (milibars)
14. 7 lbs/inch
29. 92 " mercury
268
high pressure is also referred to as...
"anticyclone"
269
(rising/sinking) air is more stable ; is this more associated with high or low pressure?
sinking ; high pressure
270
a "mountain" of air above a given location
high pressure
271
a "valley" of air above a given location
low pressure
272
low pressure is also referred to as...
"cyclone"
273
(rising/sinking) air is more unstable ; is this more associated with high or low pressure?
rising ; low pressure
274
storminess is generally brought by (high/low) pressure
low pressure (rising air)
275
low pressure:
warm core lows
tropical ; tropical cyclones
276
low pressure:
cold core lows
extratropical ; frontal lows
277
planes should always take off or land (against/into) the wind
INTO
278
high pressure in the NORTHERN HEMISPHERE always rotates (clockwise/counterclockwise)
clockwise
279
low pressure in the NORTHERN HEMISPHERE always rotates (clockwise/counterclockwise)
counterclockwise
280
if you see a front drawn on a map...
it is a surface weather map
281
troughs = (low/high) pressure
low pressure
282
ridges = (low/high) pressure
high pressure
283
with corrections made to surface pressure readings, surface pressure charts use ______ to depicts lines of _________________________
isobars ; lines of equal surface pressure
284
upper air charts are also called...
constant height charts
285
"ASL"
"above sea level"
286
upper air charts are constructed to show...
height variations along a constant pressure height surface
287
on upper air charts, height contour lines depict...
pressure
288
on upper air charts, higher heights =
higher pressure @ respective height
289
on upper air charts, lower heights =
lower pressure @ respective height
290
850 mb chart
4,000 ft ASL
291
700 mb chart
9,800 ft ASL
292
500 mb chart
18,500 ft ASL
293
300 mb chart
30,000 ft ASL
294
250 mb chart
34,250 ft ASL
295
200 mb chart
38,500 ft ASL
296
Newton's 1st Law of Motion
an object at rest will remain at rest and an object in motion will remain in motion (and will travel at a constant velocity along a straight line) as long as no force is exerted on the object
297
Newton's 2nd Law of Motion
the force exerted on an object equals its mass times the acceleration produced
(F=ma)
298
Newton's 3rd Law of Motion
for every action, there's and opposite and equal reaction
299
hurricanes and tornadoes are (high/low) pressure systems
low pressure systems
300
90% of tornadoes will turn (clockwise/counterclockwise)
counterclockwise (in Northern Hemisphere; because low pressure rotates counterclockwise)
301
pressure gradient force
air will always move from higher to lower pressure
| THINK : tire blowouts
302
define the coriolis force
deflection cause by a rotating object
303
in the northern hemisphere, deflection from the coriolis effect is towards the (left/right)
right
304
coriolis force is ________ at equator and ________ near poles
NEGLIGIBLE at equator and STRONGER near poles
305
coriolis force only affects wind __________, not wind ___________
direction ; NOT speed
306
the amount of deflection depends on...
1. rotation of the earth
2. latitude
3. objects' speed
307
large scale wind systems are associated with...
the coriolis effect
308
generally hurricanes do not form within 5 degrees of __________
the equator
| because the coriolis effect is weak at equator and strong at poles; and large wind systems are associated with CF
309
define friction
wind blowing across Earth's surface and against other air molecules
310
friction causes _____% tilt towards (high/low) pressure
33% ; low pressure
311
Buys-Ballot Rule
says if you stand with your back to the wind and turn to the left 30 degrees, on your right will always be high pressure and on your left low pressure
312
geostrophic wind generally acts in absence of...
friction (because it is found higher up)
313
define geostrophic wind
theoretical horizontal wind blowing in a straight path, parallel to the isobars (constant contour lines) at a constant speed
314
geostrophic wind is caused by an exact balance of _______________ and ___________
pressure gradient force & coriolis force
315
define hydrostatic balance
in the vertical, an exact balance between vertical pressure gradient force and gravity
316
what allows the Earth's atmosphere to remain in place
hydrostatic balance
REMEMBER :
outgoing pressure (geostrophic wind) is balanced by gravity, keeping us from being sucked into space! This is hydrostatic balance
317
wind is characterized by...
1. direction
2. speed
3. gustiness
318
speed vs. gustiness
speed is always based on a two minute average
gustiness is instantaneous and a certain % above sustained wind
319
veering vs. backing wind
veering shifts clockwise
backing shifts counterclockwise
320
back wind shifts (clockwise/counterclockwise)
counterclockwise
321
veneering wind shifts
clockwise
322
what are wind roses/what do they do
graphical device to indicate frequencies of which wind direction is
**USDA and TCEQ
323
who uses wind roses
airport runways and architects
324
what is the average prevailing wind direction in ATX
south
325
wind instrumentation examples
```
wind vane anemometer
ice free wind sensor
aerovane
wind sock
rawinsonde
doppler radar
```
***(located 30 feet above surface)
326
what are the scales of atmospheric motion
microscale, mesoscale, macroscale
327
scales of atmospheric motion:
microscale
- small area/footprint
- close to earth (turbulent flow)
- not very representative
328
scales of atmospheric motion:
mesoscale
- size of several state (regional view)
| - big advancements have been on this scale
329
scales of atmospheric motion:
macroscale - synoptic
- weathermap scale
| - map of US
330
scales of atmospheric motion:
macroscale - global
encompasses most
331
who invented the single cell global atmospheric circulation model and in what year
george hadley ; 1700s
332
describe the single cell global atmospheric circulation model
with higher pressure at the poles, sinking cold air flowed southward from the polar regions...once it got to the Equator, after warming, with lower pressure, air was lifted
**one big circulation cell ; too simple
333
Hadley Cell location
equator 30 degrees north or south latitude
334
what is the ITCZ
Intertropical Convergence Zone ; area around the equator ("Doldrums")
335
in general during the WINTER in the northern hemisphere...higher pressure is over (land/water) and lower pressure over (land/water)
higher pressure is over LAND and lower pressure is over WATER
336
in general during the SUMMER in the northern hemisphere...higher pressure is over (land/water) and lower pressure over (land/water)
higher pressure is over WATER and lower pressure is over LAND
337
the troposphere is _________ (shallower/deeper) near the equator, and (shallower/deeper) near poles
DEEPER at equator, SHALLOW at poles
338
define jet streams
strong, mainly upper level, tropospheric steering wind
339
polar jet streams are found best at
300 mb height
340
subtropical jet streams are found best at
200 mb height
341
low level jet streams are found best at
850 mb to 700 mb heights ; common in central US
342
surface waters of oceans tend to move with the ________
surface wind (upwelling)
343
la nina
colder than average equatorial pacific ocean water temps
344
el nino
warmer than average equatorial pacific ocean water temps
345
notable el nino events:
1982 - 1983
strong event ; $8 billion in damage
346
notable el nino events:
1986 - 1987
weaker event ; ended drought in SE USA
347
notable el nino events:
1991 - 1992
strong event ; severe TX flooding ; 5 year drought ended in CA
348
what are monsoons
season wind shifts that result in heavy rain
349
where are monsoons most common
india/southeastern asia
**baby monsoon - southwestern usa (because of summer thermal low)
350
what are thermal lows
a low pressure circulation created by changes in air temperature
351
katabatic wind
- cold, downslope wind (gravity)
- can be quite destructive
- Greenland, Antarctica
- referred to as a "mistral" in the Alps
352
chinook wind
- warm downslope wind
- referred to as the "snoweater" wind by Native Americans
- eastern slopes Rockies in US/Canada
353
santa ana wind
- warm, dry downslope wind in California
- most common during fall months (october)
- strong surface high pressure over the Great Salt Lake Region
354
desert winds
- dust devils
| - haboob (N. Africa/India)
355
wind shear
rapid change in wind direction and or wind speed in a small area
EX: tornadoes, thunderstorms, cold fronts
356
eddy
small whirlwind of water
357
air masses are characterized by
homogeneous physical properties
-temperature & humidity
358
A or cA
continental arctic
359
cP
continental polar
360
mP
maritime polar
361
mT
maritime tropical
362
cT
continental tropical
363
what air mass is best described by the following:
canada, not as cold as arctic, lake erie modifies temperature upward
continental polar (cP)
364
what air mass is best described by the following:
gulf of mexico, austin, houston, new orleans, ingredient in thunderstorms
maritime tropical (mT)
365
what air mass is best described by the following:
think arctic circle, barrow, alaska, only reached austin a couple of times
continental arctic (A or cA)
366
c =
land
367
m =
water
368
T =
warm
369
P =
cool
370
A =
very cool
371
what air mass is best described by the following:
northern desert in mexico, part of new mexico, and arizona; hot and dry
continental tropical (cT)
372
dry air has a (higher/lower) molecular weight
higher
373
fronts are found
in troughs of low pressure
**surface convergence and upper level divergence
374
what is cyclogenesis
low pressure developing at the surface
375
what causes cyclogenesis
increased surface convergence and upper level divergence (low pressure)
376
what is a front
a boundary between air mass
377
frontolysis
a weakened or dying front
378
frontogenesis
the birth or growth of a new front
379
overrunning
when less dense air mass runs up over a heavier air mass (frizzing drizzle, lots of clouds)
380
cold front
4 - 5 mph
- when cold air ACTIVELY advances into a region formerly occupied by warmer air
- steeper slope
- the most dynamic weather comes from the cold frontal lift
381
a cold front is shown by the color _____ and a line of ________ pointing in the direction that ________________
blue ; triangles ; the front is moving
382
warm front
- when the surface position of a front moves such that warmer air occupies territory formerly occupied by colder air
- more gentle slope
383
a warm front is shown by the color _____ and a line of _________pointing in the way that ____________
red ; semicircles ; the front will move
384
stationary front
- when little forward movement of either air mass, usually upper level winds are parallel to the surface frontal boundary
- causes the floods in TX
385
a stationary front is shown by a line of ___________
ALTERNATING triangles and semicircles
386
occluded front
- when a cold front overtakes a warm front in the vicinity of a surface low
- more common over northern US
387
an occluded front is shown by a line of _____________
triangles and semicircles
| all on one side of the line, unlike stationary fronts where the triangles and semicircles are alternating
388
what do dry lines do
separate two air masses - boundary between cT (hot, dry air) and mT (warm, moist air)
389
true/false: dry lines are a type of front
FALSE ; dry lines are not technically a front
390
the molecular weight of cT air is __________(heavier/lighter) than that of the mT air.....what does this mean?
heavier ; when it charges east a dry line lift occurs which can cause thunderstorms
391
define weather forecasting
predicting how the state of the atmosphere will change with time
392
what resources do we use to "piece together the puzzle" of weather forecasting?
- satellite
- doppler radar
- rawinsondes
- aircraft data
- lightning data
- buoy data
- weather charts/maps
- numerical weather predictions/comp model
- citizen weather observations
- surface aviation weather observations
- storm spotters/chasers
- looking outside
393
what air mass is best described by the following:
northern pacific/atlantic, foggy, rainy, chilly
*think Seattle
maritime polar (mP)
394
remember that air masses ________ as they move
modify
**meaning they can start off as one type (ex: cT) and modify into another as it travels (ex: mT)
395
severe weather and thunderstorms are associated most with which type of front
cold front
**need dynamic lift
396
define overrunning
less dense air spreading over/occupying more dense air
397
how does warmer air remover colder air
from the top..."eating" its way down
398
what type of front are floods associated with
stationary front
399
what type of front are clouds and fog associated with
occluded front
400
to be able to forecast the weather, what must be known
the current weather information over a large area
401
ASOS/AWOS cannot observe
- hail
- tornadoes
- sleet
- snow depth
402
what is one of the most reflective hydrometers
wet hail
403
humans augment what weather observations
- hail
- tornadoes
- sleet
- snow depth
404
what is the cone of silence
a single sight radar ; when a storm is near or over the radar site, data is unavailable and shows up as this black hole
405
what color representations on a radar are more reflective/less reflective
less reflective = green
| more reflective = red
406
ASOS/AWOS can observe
- temperature
- pressure
- speed
407
how often are rawinsondes released
twice a day at hundred of locations worldwide ( 6-7 am & 6-7pm CST)
408
what do rawinsondes measure with ascension
- temperature
- humidity
- atmospheric pressure
- wind speed/direction
409
what is the average flight of a rawinsonde
60 - 90 minutes
410
how high do rawinsondes travel
as high as 100,00 ft (15 - 20 miles)
411
what are METARS
coded aviation (surface) weather observations that are transmitted globally >hourly ; it is a description of the meteorological elements observed at an airport at a specific time
412
what does WMO stand for
World Meteorological Organization
*it is a UN specialized agency
413
what is the WMO responsible for
the international exchanges of weather data and certifying that the observation process DOES NOT vary between nation since all weather observations must be comparable
414
where do people get their weather forecasts
- radio
- tv
- internet
- newspapers
- AMS/NWA
415
what does it take to be a part of AMS
AMS certified broadcast meteorologist have to pass a test ; joining the AMS/NWA is voluntary because we do not/rarely license meteorologists in the US
416
who issues weather watches/advisories/warnings
the National Weather Service (government)
**this is the SOLE source to issue these
417
which is described below: watch, advisory, or warning?
type of weather specified is imminent or is occurring and is a public inconvenience (smaller to larger geographic area)
advisory
418
which is described below: watch, advisory, or warning?
type of weather specified is imminent or is occurring and is an immediate threat to life and/or property (generally smaller geographic area)
warning
419
which is described below: watch, advisory, or warning?
atmospheric conditions are favorable for the type of weather specified (generally larger geographic area)
watch
420
time span of weather watches
longer time span: 4 - 6 hours up to 24 - 48 hours
421
time span of weather advisory
6 - 24 hours
422
time span of weather warning
.5 - 1 hour
423
what are the different methods of forecasting
- persistence forecasting
- steady state/trend forecasting
- analogue method forecasting
- ensemble forecasting
- climatological forecasting
- "gut" forecasting
424
what type of forecasting method is best described by the following:
looking at similar systems from the past
analogue method forecasting
425
what type of forecasting method is best described by the following:
looking at movement of system
steady state/trend forecasting
426
what type of forecasting method is best described by the following:
tied to numerical weather prediction; several members are run to collect data and test accuracy of model
ensemble forecasting
427
what type of forecasting method is best described by the following:
basing forecast on climate/previous trends of that location and season
climatological forecasting
428
what type of forecasting method is best described by the following:
most valuable in short term, use when pattern is stable
persistence forecasting
429
what type of forecasting method is best described by the following:
go with and make decisions based on your experience/instinct
"gut" forecasting
430
weather forecasting is a ___________ science
non-perfect
431
what method of weather forecasting should be used
all of them! don't just look at one, use a combination
432
what does NWP stand for
Numerical Weather Prediction
433
what is NWP
computer atmospheric models made through programs
434
how often are NWP models run
1-4 times/day
435
what are some problems with the NWP system
- if bad data in, then bad data out
- model make certain assumptions therefore have certain biases
- data sparse areas of the world
- cannot adequately interpret many of the factors that influence surface weather
- small disturbances/errors tend to be amplified with time
436
what does POP forecasting stand for
probability of precipitation
437
true/false: POP forecasting is very misunderstood
true
438
how do we arrive at forecast POP
(forecaster certainty) x (areal coverage expected)
EX: 50% x 20% = 1000 or 10% POP
**it means there's a 10% chance that it will rain AT A GIVEN LOCATION
it does not mean that it will be raining 10% of the time or 10% of the area
439
what is the short term forecast accuracy
80-90% (today/tonight)
440
what is the medium term forecast accuracy
over 80% (2-3 days out)
441
what is the monthly or seasonal outlook accuracy
much lower (30-90 days out)
442
what is the longer range forecast accuracy
70% (4-8 days out)
443
what percent of thunderstorms worldwide are classified as severe
less than 5%
444
true/false: straight line winds can cause more damage than tornadoes
true ; straight line winds diverge whereas the winds of tornadoes converge
445
what are the basic requirements for a thunderstorm
- lift
- instability
- moisture
446
how long to most thunderstorms last
about an hour
447
how are thunderstorms brought to an end
the down draft (cold, more dense air) cuts off the updraft and the storm commits atmospheric "suicide"
448
true/false: severe thunderstorms do not last as long as air mass thunderstorms
false ; severe thunderstorms are longer lasting because of an established/well developed wind structure (2 hours longer)
449
where do most severe thunderstorms occur
middle latitudes along cold fronts/dry lines
**cP/mP/mT/cT boundaries
450
what are the criteria for a US severe thunderstorm
- presence of a tornado
- 1 inch or larger diameter hail (@ surface)
- convective wind gusts of 50 knots/58mph
**this is an AND/OR list; only one criteria must be met for it to be considered severe
451
true/false: the presence of an initial tropospheric temperature inversion contributes to thunderstorm development
true
452
define squall lines
a line of thunderstorms
453
what is something you should always remember to look for in a squall line
always watch for the storm at the end of the line
454
what determines the severity of the individual thunderstorms in a squall line
the density of the storms along the line
455
define super cells
long lasting thunderstorms that develop a strong, internal wind structure and that control their atmospheric environment
456
true/false: super cells are always severe
true
457
define mesocyclones
a rotating updraft, usually 3 - 7 miles, within an intense cumulonimbus cloud/severe thunderstorm
458
what percent of mesocyclones produce tornadoes
less than 20%
459
what is a mesoscale convective complex/system
a number of individual thunderstorms that grow in size and arrange and organize into a long lasting convective complex
460
where are mesoscale convective systems commonly found
USA plains and into Mississippi Valley
461
how much larger can mesoscale convective systems be than average air mass thunderstorms
as much as 1000x
462
what does derecho mean
"straight ahead" or "direct"
463
what is a derecho
a widespread and usually fast moving convective wind storm
464
how severe is the reach and damage of a derecho
can produce damaging wind over areas hundreds of miles long and more than 100 miles across
465
true/false: thunderstorms are bad for the environment
false; thunderstorms are good for the environment because they help keep the Earth in electrical balance; they also serve as a great way for the atmosphere to release energy
466
what are the 4 different types of thunderstorms
- single cells
- multicell clusters
- multicell lines
- supercells
467
what are the stages of thunderstorm developement
- cumulus (updrafts dominate)
- mature (updrafts/downdrafts coexist)
- dissipating (downdrafts dominate)
468
lightning won't develop until _____________ develop
downdrafts
469
at any given moment, how many individual thunderstorms are in progress worldwide
2000
470
of the 2000 individual thunderstorms in progress worldwide, what percent are severe or non-severe
over 95% non-severe ; less than 5% severe
471
what are the differences in hail size between severe and non severe thunderstorms
non-severe : hail less than 1" in diameter
| severe: hail equal or greater than 1"
472
what are the differences in formation location between severe and non-severe thunderstorms
non-severe : found WITHIN mT airmass
| severe : found ON boundaries of mT airmass
473
hail size (and thunderstorm severity) is entirely dependent on _____________
thunderstorm updraft and downdraft speed
474
largest hail often falls ________ (NW, NE, SW, SE) of tornadoes
NE
475
what is the number one weather killer in the US
summer heat
476
true/false: flash floods are one of the top weather killers in the US
true ; general public does not understand the power of moving water
**south central texas is considered the flash flood capital of the US
477
what are straight line thunderstorm winds
strong downdraft winds from thunderstorms with a divergent wind pattern
**referred to in general as downbursts
478
where are GOES satellites east and west located
GOES west is at 135 W longitude
| GOES east is at 75 W longitude
479
what are the three different satellite image types
visible, infrared, and water vapor
480
what does the visible satellite image type display
shows what the sun light up, cannot see at night
481
what does the infrared satellite image type display
hotter colors denote colder cloudtops, 24 hrs a day
482
what does the water vapor satellite image type display
mid and upper level atmospheric moisture
483
reflectivity vs. velocity data
reflectivity will show levels of precipitation
velocity will show where it's moving
484
what is clear air mode
when there is high certainty of no precipitation, satellites can enter this mode and not do as much work
485
what is dual pol
horizontal and vertical measurements/waves, this crossection allows us to capture both size and shape of hydrometers
486
ASOS stands for
automated surface observing system
487
AWOS stands for
automated weather observing system
488
an example of an airport that uses human augmentation
austin bergstrom
489
an example of an airport that does not use human augmentation
camp mabry
490
what are the most common lightning types
cloud to cloud & intracloud
491
a bolt of lightning is about the diameter of...
a pencil
492
within the lightning bolt, it is about ___ times the temperature of _______________
5 times the temperature of the outer surface of the sun
493
what about tornadoes kills most people
the flying debris
