1. 1 NATS 101 Lecture 3 Climate and Weather

2. 2 Review and Missed Items Pressure and Height-Exponential Relationship Temperature Profiles and Atmospheric Layers

3. 3 Exponential Variation Logarithmic Decrease For each 16 km increase in altitude, pressure drops by factor of 10. 48 km - 1 mb 32 km - 10 mb 16 km - 100 mb 0 km - 1000 mb 100 mb 10 mb 1 mb 16 km 32 km 48 km

4. 4 Exponential Variation Logarithmic Decrease For each 5.5 km height increase, pressure drops by factor of 2. 16.5 km - 125 mb 11 km - 250 mb 5.5 km - 500 mb 0 km - 1000 mb

5. 5 Temperature (T) Profile More complex than pressure or density Layers based on Environmental Lapse Rate (ELR), rate at which temperature decreases with height. inversion isothermal 6.5 o C/km

6. 6 Atmospheric Layers Essentials Thermosphere-above 85 km Temps warm w/height Gases settle by molecular weight (Heterosphere) Mesosphere-50 to 85 km Temps decrease w/height Stratosphere-10 to 50 km  Temps increase w/height, very dry Troposphere-0 to 10 km (to the nearest 5 km)  Temps decrease with height Contains “all” H 2 O vapor, weather of public interest

7. 7 Climate and Weather “Climate is what you expect. Weather is what you get.” -Robert A. Heinlein

8. 8 Weather Weather – The state of the atmosphere: for a specific place at a particular time Weather Elements 1) Temperature 2) Pressure 3) Humidity 4) Wind 5) Visibility 6) Clouds 7) Significant Weather

9. 9 Surface Station Model Temperatures Plotted  F in U.S. Sea Level Pressure Leading 10 or 9 is not plotted Examples: 1013.8 plotted as 138 998.7 plotted as 987 1036.0 plotted as 360 Ahrens, p 431 Responsible for boxed parameters

10. 10 Sky Cover and Weather Symbols Ahrens, p 431

11. 11 Pressure Tendency Change in pressure over the past 3 hours is also plotted. Also called barometric tendency Ahrens, p 432

12. 12 Wind Barbs Direction Wind is going towards Westerly Westerly  from the West Speed (accumulated) Each flag is 50 knots Each full barb is 10 knots Each half barb is 5 knots Ahrens, p 432 65 kts from west

13. 13 temperature dew point SLP pressure wind cloud cover Ohio State website

14. 14 Practice Surface Station Temperate ( o F) Pressure (mb) Last Three Digits (tens, ones, tenths) Dew Point (later) Moisture Wind Barb Direction and Speed Cloud Cover Tenths total coverage Ahrens, p 431 72 58 111 Decimal point What are Temp, Dew Point, SLP, Cloud Cover, Wind Speed and Direction?

15. 15 Practice Surface Station Sea Level Pressure Leading 10 or 9 is not plotted Examples: 1013.8 plotted as 138 998.7 plotted as 987 1036.0 plotted as 360 Ahrens, p 431 42 18 998 Decimal point What are Temp, Dew Point, SLP, Cloud Cover, Wind Speed and Direction?

16. 16 Surface Map Symbols Fronts Mark the boundary between different air masses…later Significant weather occurs near fronts Current US Map Ahrens, p 432

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18. 18 Radiosonde Weather balloons, or radiosondes, sample atmospheric to 10 mb. They measure temperature moisture pressure They are tracked to get winds Ahrens, Fig. 1

19. 19 Radiosonde Distribution Radiosondes released at 0000 and at 1200 GMT for a global network of stations. Large gaps in network over oceans and in less affluent nations. Stations ~400 km apart over North America

20. 20 Radiosonde for Tucson Example of data taken by weather balloon released over Tucson Temperature (red) Moisture (green) Winds (white) Note variations of all fields with height UA Tucson 1200 RAOB troposphere stratosphere tropopause temperature profile moisture profile wind profile

21. 21 Upper-Air Model Conditions at specific pressure level Wind Temperature (  C) Moisture (Later) Height above MSL UA 500mb Analysis Ahrens, p 427 Ahrens, p 431 Responsible for boxed parameters

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23. 23 Climate Climate - Average weather and range of weather, computed over many years. Whole year (mean annual precipitation for Tucson, 1970-present) Season (Winter: Dec-Jan-Feb) Month (January rainfall in Tucson) Date (Average, record high and low temperatures for Jan 1 in Tucson)

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26. 26 Climate of Tucson Monthly Averages Individual months can show significant deviations from long-term, monthly means.

27. 27 Average and Record MAX and MIN Temperatures for Date

28. 28 Climate of Tucson Probability of Last Freeze Cool Site: Western Region Climate CenterWestern Region Climate Center

29. 29 Climate of Tucson Probability of Rain Cool Site: Western Region Climate CenterWestern Region Climate Center

30. 30 Climate of Tucson Extreme Rainfall Cool Site: Western Region Climate CenterWestern Region Climate Center

31. 31 Climate of Tucson Snow! Cool Site: Western Region Climate CenterWestern Region Climate Center

32. 32 Summary Weather - atmospheric conditions at specific time and place Weather Maps  Instantaneous Values Climate - average weather and the range of extremes compiled over many years Statistical Quantities  Expected Values

33. 33 Reading Assignment Ahrens Pages 25-30 Problems 2.1-2.4 (2.1  Chapter 2, Problem 1) Don’t Forgot the 4”x 6” Index Cards… I’m getting antsy for a pop quiz. You must be lusting for one too!