Meteorology, Climatology, and the Earth’s Atmosphere

1. Meteorology, Climatology, and the Earth’s Atmosphere Global Environmental Change – Lecture 2 Spring 2014

2. What is Meteorology? • One definition is the branch of science that deals with the atmosphere of a planet, particularly that of the earth • Data is analyzed and often plotted on maps to predict, or forecast, the weather for the next few hours to few days • Long-range forecasts, which are more general and less accurate, may be made for a few months • From the Greek, meteōron, of the atmosphere, and logia, study of

3. Climatology • Refers to the study of the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years • Often means much longer, geologically significant, periods • From the Greek klima, place or zone, and logia, study of

4. Climatology Subcategories • Historical - the study of climate as related to human history • Focused only on the last few thousand years • Paleoclimatology - seeks to reconstruct past climates by examining records such as ice cores and tree rings • Tree-ring studies are known as dendroclimatology

5. Climatology Indices • Climate indices based on several climate patterns are used to characterize and understand the various climate mechanisms that culminate in our daily weather • The climate patterns are based on modes of variability, with identifiable characteristics, specific regional effects, and, often. oscillatory behavior

6. Examples of Climatology Indices • Antarctic oscillation (AAO) • Arctic oscillation (AO) • Atlantic multidecadal oscillation (AMO) • El Niño Southern Oscillation (ENSO) • Indian Ocean Dipole (IOD) • Madden–Julian oscillation (MJO) • North Atlantic oscillation (NAO) • Pacific decadal oscillation (PDO)

7. Video Clips • The Board of Atmospheric Sciences and Climate of the National Research Council and National Academy of Sciences has produced a series of Short Videos called, “Climate Change – Lines of Evidence” • Published July 2, 2012

8. Chapter 1:What is Climate?

9. Chapter 2: Is Earth Warming?

10. America’s Climate Choices • In 2008, Congress requested the National Academies to study climate change and report on their findings • The National Academies responded by launching America's Climate Choices, a suite of studies designed to inform and guide responses to climate change across the nation

11. America’s Climate Choices Video

12. The atmosphere is complex Layers and sub layers exist Chemical differences exist between layers Change is continual Change results from uneven heating and cooling, which results in atmospheric circulation The earth's atmosphere is a very thin layer wrapped around a large planet Earth’s Atmosphere In this NASA photo, the troposphere is orange, the stratosphere is white, and the mesosphere is blue

13. Atmospheric Layers Atmospheric layers are denoted by words ending in the suffix –sphere Boundaries are denoted by words ending in –pause Thermal properties are used in defining the atmospheric layers 13

14. Troposphere • Contains about 75% of the mass of the earth’s atmosphere • Weather, major wind systems and clouds occur here • Water vapor, dust, pollen, and soot particles are found here • This layer is turbulent, with storms and atmospheric mixing • The word troposphere comes from Greek tropos, meaning to turn or change, and Greek sphaira, meaning ball; perhaps best rendered as sphere of change • First used in the early 20th century, perhaps coined by French meteorologist Léon-Philippe Teisserenc de Bort (1855-1913)

15. Tropopause • This layer represents an inflection point in a plot of temperature versus altitude • In the troposphere, temperature decreases with altitude • At the tropopause, this changes, and temperature begins to increase with altitude throughout the next highest layer • Near the poles, the altitude of the tropopause is about 10 kilometers • Near the equator, the altitude of the tropopause is about 18 kilometers • The word tropopause comes from Greek tropos, meaning to turn or change, and English pause, meaning discontinuance • The temperature at the tropopause is around - 60°C

16. Stratosphere • The “ozone layer” is found in the stratosphere • Contains about 24% of the mass of the earth’s atmosphere • The word stratosphere comes from Latin stratus, meaning “a spreading out”, and Greek sphaira, meaning ball;perhaps best rendered as sphere of layers • First used in the early 20th century, coined by French meteorologist Léon-Philippe Teisserenc de Bort (1855-1913)

17. Stratospheric Layering • It is stratified in temperature, with warmer layers higher up and cooler layers farther down • This vertical stratification, with warmer layers above and cooler layers below, makes the stratosphere dynamically stable • There is no regular convection and associated turbulence in this part of the atmosphere. • The stratosphere begins at the tropopause and extends upward about 50 kilometers

18. Flying in the Stratosphere • Jets fly in this layer to reduce fuel consumption • Commercial airliners typically cruise at altitudes of 9–12 kilometers in temperate latitudes, which is in the lower reaches of the stratosphere • When the Concorde was flying, it would cruise at mach 2 at about 18 kilometers • The SR-71 would cruise at mach 3 at 26 kilometers (The SR-71 is a later version of the U-2 spy plane, used for atmospheric research)

19. Stratopause • Marks the boundary between the stratosphere and the mesosphere • Like the tropopause, this layer represents an inflection point in a plot of temperature versus altitude • In the stratosphere, temperature is nearly constant for a while, increasing very slowly with altitude • Then it begins to increase quickly, reaching a maximum of around 0°C at the stratopause • In the mesosphere, temperature begins to decrease again

20. Mesosphere • This layer ranges in altitude from 50 to 85 kilometers above the earth • The word mesosphere comes from Greek mesos, meaning middle, and Greek sphaira, meaning ball

21. Mesopause • Marks the boundary between the stratosphere and the mesosphere • The temperature at 85 kilometers above the earth ranges from - 80°C to - 120°C

22. Above about 85 kilometers, the temperature begins to increase again At roughly 100 kilometers altitude, we have a boundary sometimes called the turbopause Below the turbopause, turbulent mixing keeps the gases well-mixed Above the turbopause, residual atmospheric gases sort into strata according to molecular mass Thermosphere

23. Ionosphere • Superimposed on the thermosphere is a layer called the ionosphere, which ranges from about 85 kilometers to 600 kilometers above the earth • Within this layer, absorption of strong solar ultraviolet radiation causes gases to ionize, which makes the layer electrically conductive • Ionized atmospheric gases refract high frequency (HF, or shortwave) radio waves • Because of this property, the ionosphere can be utilized to bounce a transmitted signal down to ground • Transcontinental HF-connections may involve up to 5 bounces

24. Geomagnetic Storms • A temporary, intense disturbance of the Earth's magnetosphere by solar flares • During a geomagnetic storm the F2 layer will become unstable, fragment, and may even disappear completely • In the Northern and Southern pole regions of the Earth aurorae will be observable in the sky • Energy from the sun acts on electrons in the magnetosphere which, energized and accelerated by the solar wind, bombard oxygen molecules in the upper atmosphere, causing them to luminesce • Often, storms and other events on the surface of the sun trigger a burst of auroral activity

25. Aurora Borealis February 11, 2004