1. Introduction to Meteorology
Geos 114
Introduction to Meteorology

2. Definitions Meteorology Weather Climate Climatology
Study of the atmosphere & the processes that causes weather
Weather
State of the atmosphere at a particular place & time. Described by T, Humidity, Ppt., Wind speed
Climate
Average values of weather conditions at some place for at least 30 years beginning with the first year of a decade (i.e ; average annual and monthly temp, ppt). Tabulation of extreme events during time of record i.e. high/low T, greatests snowfall, most intense rainfall)
Climatology
Study of climate, control, spatial and temporal variability

3. Climatic Zones Tropic Humid (A) Dry Climates (B)
Steppe (BS) and desert (BW)
Subtropical Climates (C)- Mediterranean
Snow Forest Climates (D)- temperate continental (i.e. northeast US)
Polar Climates (E)- poleward of arctic & antarctic circles
Highland Climates (H)- mountanous terrain every 300 meters of altitude is equivalent to 500km of latitude.

4. Climatic Zones

5. Sources of Weather Info
Weather Radio
Low Power VHF High Band FM
Constant weather information
Repeat messages every 4-6 minutes
Transmits all other sorts of emergencies
Cable & Broadcast TV
The Weather Channel
WWW

6. NOAA Weather Radio

7. The Weather Channel

8. Intro to Weather Systems & Maps
ASOS: Automated Surface Observing System (installed at airports) records 24hrs/day
Temp., humidity, dew point, wind speed & direction, Pressure

9. ASOS

10. Pressure Systems
Pressure: weight per unit area of a column of air stretching from the earth’s surface up to through the atmosphere
Highs (anticyclones)
‘H’ on a map
Fair weather systems
Cold or cool, dry air (NW Canada)
Hot, mild, dry air (from land further south)
Clockwise, outward spiral
Lows (cyclones)
‘L’ on a map
Stormy weather systems
Counterclockwise, inward spiral
Highs and lows move with prevailing winds (eastward in North America)

11. Pressure Systems H L

13. Air Masses
Large uniform air mass (temperature and humidity) associated with high pressure system
Cold air masses form at high latitudes
Humid air masses over maritime surfaces
Dry air masses over arid/semi arid regions
Cold & Dry
Cold & Humid
Warm & Dry
Warm & Humid

14. Fronts
Narrow band between 2 air masses that differ in T, humidity, or both
Fronts form where air masses collide
Ppt & cloudiness
Fronts:
Stationary
Cold
Warm

15. Fronts

16. Fronts

17. Vocabulary Max. T (oF; oC) Min. T Dew Point Relative Humidity (%)
Ppt. amount
Air pressure (29.92 inches, 760 millimeters Hg; millibars (mb) mb at sea level)
Wind direction; speed
Sky cover (no clouds; few (1/8-2/8 cloud cover); scattered (3/8-4/8); broken clouds (5/8-7/8); overcast (completely cloud covered))
Weather watch- NWS possibility of hazard
Weather warning- NWS imminent hazard

18. Weather Satellites
GOES (geostationary operational environmental satellite)
36,000km (22,300mi); equatorial, eastward motion, same view 75oW, 135oW
POES (polar-orbiting operational environmental satellite)
N-S orbit km above surface
Measure visible radiation that is scattered or reflected and infrared

19. GOES

20. Weather Radar & Doppler
Complements satellite data
Microwave radiation
Emits pulses that are reflected by rain, snow, hail which appear as blotches known as echoes
Doppler determines velocity of targets moving towards or away from unit depending on frequency bet. Outgoing & returning signal
Monitor circulation of air within a storm system and provide advance warning of severe weather

21. Doppler Radar

22. Sky Watching
Clouds- aggregates of water droplets or ice crystals or both
Fog- ground contact cloud reduces visibility to less than 1000m
Stratiform- horizontal layers, gentle rising of air over broad region ahead of a warm front
Cumuliform- puffy, vigorous ascent of warm air ahead of a cold front

23. Clouds Fair weather cumulus clouds
Storm cumulonimbus clouds produce lightning & thunder
Clouds at different altitudes may move horizontally in different directions and speeds

24. Cloud Types