Show:
Instrumentation
Air Masses
Fronts
Synoptic Weather Maps
Miscellaneous
100
What instrument is used to measure temperature?
Thermometer
100
Which 3 characteristics define an air mass?
Pressure, temperature, and moisture.
100
What are the four types of fronts and how are each of them drawn on a weather map?
Cold, Warm, Occluded, and Stationary.
100
Decode the following air pressure measurements from a synoptic weather model: 987, 435, 000 (Include units)
998.7mb, 1043.5mb, 1000.0mb
100
In what part of our atmosphere does weather take place?
The troposphere
200
Which instrument is used to measure air pressure?
Barometer
200
Which type of air mass will most likely form over Canada? Why?
Continental Polar because Canada is relatively far from the equator causing it to be cool and has little moisture available due to the presence of land.
200
When a warm and cold front meet, which air is forced to move up and why?
Warm air is forced upwards due to it being less dense.
200
Encode the following air pressure measurements to be place on a synoptic weather model. 954.3mb, 1000.9mb, 1011.1mb.
543, 009, 111
200
Explain the difference between condensation and evaporation. Indicate the phase change and give an example of each.
Condensation = gas -> liquid, clouds or "sweat" on a glass; Evaporation = liquid -> gas, water "drying" from the ground or moving up in the atmosphere from a lake.
300
Which instrument is used to measure wind speed?
Anemometer.
300
Which type of air mass will usually bring warm and humid (wet) weather? Why? Name a location where this air mass may form.
Maritime tropical because these air masses form over the ocean and relatively close to the equator. A maritime tropical air mass may form in the Gulf of Mexico.
300
What weather and cloud types are associated with cold and warm fronts?
Cold fronts have violent storms with heavy rain and are associated with tall thick cumulonimbus clouds. Warm fronts are associated with light rains and thinner stratus and cirrus clouds.
300
Draw a synoptic weather model to indicate the following conditions: temp = 94 F, dew point = 76 F, air pressure = 999.9 mb, 25% cloud cover, 4 mile visibility, weather = smog, barometric trend = decreased by 5.1mb the past 3 hours and is still falling, wind are from the SW at 15 knots.
Draw answer on board
300
Explain what happens when the air temperature approaches the dew point. Comment on the ensuing weather conditions, the air pressure, and humidity.
The air becomes more humid, the air pressure decreases, and rain or fog follows.
400
Which instrument is used to measure relative humidity or dew point temperature?
Psychrometer
400
Describe the movement of air around a high pressure system in the Northern Hemisphere. Please indicate the vertical and horizontal motions as well as the spinning direction.
High pressure systems spin clockwise and air moves down and out in the center in the Northern Hemisphere.
400
Which type of front causes the same weather to persist for a long period of time, maybe over a few days? Explain your reasoning. You may draw a picture to help show why this is.
A stationary front causes weather to persist for maybe a few days because two air masses are either moving parallel to each other or they both aren't "strong" enough to overtake the other.
400
Draw two synoptic weather models on the boundaries of a cold front (one in front of the front and one behind the front). Indicate weather variables such as temperature, dew point, pressure, present weather, cloudiness and barometric trend.
Should indicate that the temperature and pressure decrease as the cold front approaches, dew point and cloudiness increase and the present weather becomes rainy.
400
Using your knowledge of convection, explain the difference between a land breeze and a sea breeze and when each of these typically occur during the course of 24 hours.
A sea breeze occurs when the land is hotter than a nearby body of water causing air to rise from the land and a breeze to be brought in from the sea. This typically occurs during the day. A land breeze is when a body of water is hotter than nearby land causing air to rise from the ocean and a breeze to be brought in from the land.
500
How is RADAR used to determine the weather?
Radio waves are reflected off the aerosols of precipitation and clouds. This gives information about the intensity and distance of approaching storms.
500
Which type of pressure systems are associated with bad stormy weather and why?
Low pressure systems are associated with stormy weather because air around a low pressure system rises, eventually causing water vapor to condense into water leading to cloud formation and possible rain.
500
Draw the vertical cross section of an occluded front and explain what is happening.
An occluded front is when a cold front overtakes a warm front causing the boundary of the opposing wedges of cold air masses to meet and "squeeze" the warm air forcing it upwards. Draw on the board.
500
Find the dew point of a certain location given that the air temperature is 68 F and its relative humidity is 66%. Use your ESRT. Report your answer in the units used on the synoptic weather models for dew point.
57 - 58 F (14 C)
500
Why does the pressure tend to decrease when moisture is in the air?
Think of molecular masses. N = 14, O = 16. Both diatomic. Water vapor displaces N2 and O2. Atomic mass of water vapor is 18 while N2 is 28 and O2 is 32. Therefore moist air has less mass per unit volume and creates lower pressure.