1. ATM OCN 100 - Spring 2002 LECTURE 23
UPPER AIR OBSERVATIONS & CHARTS (con’t.)
Introduction
Upper Air Observations
Displaying Upper Air Charts
Interpreting Upper Air Data

2. Letter Grade Exam GradeAB B BC C D
F < 39
Mean = 74
Letter Grade Exam Grade A AB B BC C D
F < 34

3. Announcements Homework 6: Has been posted at
Will be due 1 week from today (3 Dec. 2001)
Homeworks 1-5:
Have been graded and are available up front; please retrieve yours
Answer Keys are posted on the Web at:
2nd Hour Exam:
Has been graded and returned (up front)
The exam stats are posted at:

4. Waves at Duluth Harbor during Tuesday’s Storm

5. MADISON’S CURRENT WEATHER
at 900 AM CST FRI NOV Updated twice an hour at :05 and :25
Sky/Weather: CLOUDY Temperature: 40 F (4 C) Dew Point: 38 F (3 C) Relative Humidity: 93% Wind: N8 MPH Barometer: 29.67F

6. Surface Weather Map from Today with Isobars & Fronts

7. CURRENT IR

8. CURRENT VISIBLE

9. Surface Weather Map from Today with Isobars & Fronts

10. Current Temperatures (oF) & Isotherms

11. Current 5,000 ft. Winds

12. Current 10,000 ft. Winds

13. Current 34,000 ft. Winds & Jet Stream
Trough
Ridge

14. Tomorrow’s 7AM Forecast

15. ATM OCN 100 - Spring 2002 LECTURE 23
UPPER AIR OBSERVATIONS & CHARTS
A. INTRODUCTION
Overview -- What is “upper air”?
The need to know.
For aviation
For weather prediction

16. B. UPPER AIR OBSERVATIONS
Practical Problems
Early Upper Air Observations - The Observing Platforms
Balloons
Kites
Current Upper Air Observations
where…

17. Manned Balloons for Meteorological Observations (late 1800’s)
A balloon equipped for meteorological observations Figure 17 of "Meteorology" by Willis
Milham, 1912 A German balloon ascent in the late 1800's

18. Weather Kites (ca. 1900)
Kite operations at an aerological station

19. Weather Kites (con’t.)
Weather kites were used to bring recording instruments to high levels Temperature,
pressure, humidity and winds were observed from kites
Image ID: wea01100, Historic NWS Collection
Location: Fort Whipple (Fort Myers), Arlington, Virginia
Photo Date: 1894?

20. Weather Kites (con’t.)
A kite equipped for meteorological observations Figure 18 of "Meteorology" by Willis
Milham, 1912 Time, pressure, temperature, and humidity were recorded Recording
instrument was a Marvin Meteorograph

21. Aircraft Observations (ca. 1934)
Navy bi-plane with meteorograph on starboard wing strut Taking meteorological
measurements for pressure, temperature, and humidity Manned flights were inefficient
for routine observations as cost high Manned flights grounded during poor weather,
thus radiosonde balloons replaced However, such flights paved the way for aircraft
weather research projects
Image ID: wea01150, Historic NWS Collection
Location: Washington, D.C.
Photo Date: December 13, 1934

22. THE UPPER AIR WEATHER CHART (con’t.)
Use of Constant Pressure Charts
Pressure always decreases with altitude;
Radiosondes measure pressure not altitude;
Widespread use of pressure altimeters by aviation interests;
Mathematical equations using pressure are easier to use than those with altitude.

23. THE UPPER AIR WEATHER CHART (con’t.)
Plotting of Routine Upper Air Constant Pressure Charts
Upper air analysis involves drawing isopleths on Upper Air Charts:
HEIGHT CONTOURS
ISOTHERMS
ISOTACHS

24. THE UPPER AIR WEATHER CHART (con’t.)
Topography of Constant Pressure Charts
Ridges (Higher heights)
Troughs (Lower heights)
Relationships between:
Height and temperature fields.
Height and wind fields, or specifically, ...

25. Pilot Balloons http://www.photolib.noaa.gov/historic/nws/wea01106.htm
Early testing of hydrogen filled balloons for radiosonde measurements Theodolite used
to track balloon to limit of visibility

26. Radiosonde

27. GOES Satellite

28. C. THE UPPER AIR WEATHER CHART
What is Displayed: Data Set for Upper Air Charts from Radiosonde Observation (RAOB) network
How information is displayed: Operational Upper Air Charts:
Use a constant pressure surface;
Produced twice daily.

29. THE UPPER AIR WEATHER CHART (con’t.)
Typical Constant Pressure Charts

30. An upper air chart example
Current 300 mb Chart

31. THE UPPER AIR WEATHER CHART (con’t.)
Topography of Constant Pressure Charts
Ridges (Higher heights)
Troughs (Lower heights)
Relationships between:
Height and temperature fields.
Height and wind fields, or specifically, ...

32. Recall VERTICAL PRESSURE GRADIENTS - Dependency on density (temperature)

33. THE UPPER AIR WEATHER CHART (con’t.)
HEIGHT & TEMPERATURE FIELDS
Ridges (H): Warm air bubbles
Troughs (L) : Cold air pockets
HEIGHT & WIND FIELDS
Winds parallel height contours;
Lower height (cold air) to left of winds in Northern Hemisphere;
Wind speed inversely proportional to height contour spacing.

34. Waves in the Jet -- A ridge - An intrusion of warm air

35. Waves in the Jet -- A trough - An intrusion of cold air

36. Zonal Circulation Regime Figure 10.10 Moran & Morgan (1997)

37. Meridional Circulation Regime Figure 10.10 Moran & Morgan (1997)

38. Stagnant Circulation Regime with Cut-off Lows & Blocking Highs Figure 10.13 Moran & Morgan (1997)

39. Temperature Structure of Troposphere Figure 10
Temperature Structure of Troposphere Figure Moran & Morgan (1997)

40. Waves in the Westerlies Figure 10.6 Moran & Morgan (1997)