Note on Temperature and Wind - GEO 10: Introduction to Meteorology

Page 1

• Course Information

  • Instructor: Thomas Kauzlarich, M.S

  • Semester: Fall 2024

Page 2

• Overview of Module 1

  • Earth's motions affect sunlight distribution.

    • Equator receives the most sunlight; poles receive the least.

    • Variations arise from daylight length and sun angle.

  • Sunlight heats air, influencing temperature.

    • Temperature varies significantly between poles and equator.

Page 3

• Temperature as a Weather Element

  • Temperature is a fundamental aspect of weather and climate.

  • Commonly the first response to weather inquiries.

  • Temperature varies on different time scales:

    • Seasonally

    • Daily

    • Hourly

  • Focus of the module:

    • Factors controlling temperature.

    • Measurement of temperature and its utility.

Page 4

• Today's Agenda

  • Temperature Data and Representation

    • Basic Calculations

    • Isotherms and Isothermal Maps

  • Cycles of Air Temperature

    • Daily and Annual Temperature Cycles

  • Reasons for Temperature Variation

    • Temperature Controls (1-3)

Page 5

• Basic Temperature Calculations

Page 6

• Surface Observing Stations

  • Daily temperature recordings at thousands of weather stations.

  • Data collected by observers or automated systems.

Page 7

• Daily Calculations

  • Daily Mean Temperature: Average of all temperatures in 24 hours.

  • Daily Maximum Temperature: Highest temperature in 24 hours.

  • Daily Minimum Temperature: Lowest temperature in 24 hours.

  • Daily Temperature Range: Difference between maximum and minimum temperatures.

Page 8

• Monthly and Yearly Calculations

  • Monthly Mean Temperature: Average of daily means for the month.

  • Yearly Mean Temperature: Average of 12 monthly means.

  • Yearly Temperature Range: Difference between warmest and coldest monthly means.

Page 9

• Utility of Mean Temperatures

  • Useful for comparisons (e.g., record temperatures).

  • Temperature ranges indicate extremes, essential for understanding local weather and climate.

Page 10

• Isotherms

  • Lines connecting points of equal temperature on a map.

  • Typically represent temperature differences of 5° to 10°.

Page 11

• Isothermal Maps

  • Example of isotherms drawn on a U.S. map.

  • Isotherms do not pass directly through observing stations.

Page 12

• Color-Filled Isothermal Maps

  • Enhances visual representation of temperature ranges.

  • Each color represents a specific temperature range.

Page 13

• Benefits of Isothermal Maps

  • Clearly displays temperature distribution.

  • Identifies areas of low and high temperatures.

  • Visualizes temperature gradients (spacing of isotherms).

Page 14

• Example of Temperature Gradient

  • Illustrates varying temperatures across different locations.

Page 15

• Cycles of Air Temperature

Page 16

• Daily Temperature Cycle

  • Daily temperature fluctuates rhythmically.

    • Decreases overnight, increases with sunrise, decreases at sunset.

  • Weather can disrupt this cycle.

  • Meteograms show changes in meteorological variables over time.

Page 17

• Daily Temperature Cycle Example

  • Chicago meteogram shows typical temperature patterns.

Page 18

• Primary Control of Daily Temperature Cycle

  • Earth's rotation causes day/night cycles.

  • Sun angle affects surface heating.

Page 19

• Energy Gain and Loss

  • More energy gained than lost during the day leads to rising temperatures.

  • More energy lost than gained at night leads to falling temperatures.

Page 20

• Temperature Lag

  • High temperature occurs later in the day (around 4 PM) despite maximum solar heating at noon.

Page 21

• Annual Temperature Cycle

  • Tropics: Warm year-round; midlatitudes: distinct seasons.

  • Seasonal temperature cycles become more pronounced with increasing latitude.

Page 22

• Seasonal Lag in Peak Temperatures

  • Maximum solar radiation in June, but warmest months are July and August.

  • Land and water surfaces respond differently to solar heating.

Page 23

• Example of Seasonal Lag

  • St. Louis vs. San Francisco temperature peaks.

Page 24

• Why Temperatures Vary

Page 25

• Temperature Controls

  • Factors causing temperature variation:

    • Latitude (primary control)

    • Elevation

    • Land and water

    • Ocean currents

    • Geographic positioning and prevailing winds

    • Albedo variations

    • Water vapor and atmospheric circulations

Page 26

• Latitude

  • Primary control of temperature due to sun angle and daylight length.

  • Cities at the same latitude can have different temperatures.

Page 27

• Elevation

  • Secondary control of temperature.

  • Atmospheric pressure and temperature decrease with altitude.

Page 28

• Land and Water

  • Different surfaces affect air temperature.

  • Water heats more slowly than land, leading to temperature variations.

Page 29

• Comparative Monthly Temperature Data

  • Vancouver vs. Winnipeg temperature differences despite similar latitudes.

Page 30

• Hemispheric Temperature Variation

  • Southern Hemisphere has less temperature variation due to more water coverage.