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

Letter Grade Exam Grade AB 88 - 92 B 80 - 87 BC 73 - 79 C 50 - 72 D 40 - 49 F < 39 Mean = 74 Letter Grade Exam Grade A 90 - 100 AB 86 - 89 B 78 - 85 BC 72 - 77 C 50 - 71 D 34 - 49 F < 34

Announcements Homework 6: Has been posted at http://www.aos.wisc.edu/~hopkins/aos100/homework 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: http://www.aos.wisc.edu/~hopkins/aos100/homework; 2nd Hour Exam: Has been graded and returned (up front) The exam stats are posted at: http://www.aos.wisc.edu/~hopkins/aos100/exams.

Waves at Duluth Harbor during Tuesday’s Storm http://www.duluthshippingnews.com/waves.html

MADISON’S CURRENT WEATHER at 900 AM CST FRI NOV 30 2001 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

Surface Weather Map from Today with Isobars & Fronts

CURRENT IR

CURRENT VISIBLE

Surface Weather Map from Today with Isobars & Fronts

Current Temperatures (oF) & Isotherms

Current 5,000 ft. Winds

Current 10,000 ft. Winds

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

Tomorrow’s 7AM Forecast

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

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

Manned Balloons for Meteorological Observations (late 1800’s) http://www.photolib.noaa.gov/historic/nws/wea01104.htm A balloon equipped for meteorological observations Figure 17 of "Meteorology" by Willis Milham, 1912 A German balloon ascent in the late 1800's

Weather Kites (ca. 1900) http://www.photolib.noaa.gov/historic/nws/wea01103.htm Kite operations at an aerological station

Weather Kites (con’t.) http://www.photolib.noaa.gov/historic/nws/wea01100.htm 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?

Weather Kites (con’t.) http://www.photolib.noaa.gov/historic/nws/wea01102.htm 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

Aircraft Observations (ca. 1934) http://www.photolib.noaa.gov/historic/nws/wea01150.htm 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

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.

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

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, ...

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

Radiosonde

GOES Satellite

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.

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

An upper air chart example Current 300 mb Chart

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, ...

Recall VERTICAL PRESSURE GRADIENTS - Dependency on density (temperature)

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.

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

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

Zonal Circulation Regime Figure 10.10 Moran & Morgan (1997)

Meridional Circulation Regime Figure 10.10 Moran & Morgan (1997)

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

Temperature Structure of Troposphere Figure 10 Temperature Structure of Troposphere Figure 10.17 Moran & Morgan (1997)

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