Meteorology Revisions


THE EARTH AND ITS ATMOSPHERE (8/25 Lecture)

Weather vs Climate

  • The atmosphere is multiscale. Weather events are measured by size (km) and lifespan ( sec-min, min-hr, hrs-day, days-weeks): how big they are, how long they last

Weather

  • short-term atmospheric conditions

  • conditions of the atmosphere over any short period of time

  • e.g Tornado

Climate

  • long-term atmospheric patterns

  • accumulation of daily and seasonal weather events over a long period of time

  • measured for mean, variations, and extremes

  • e.g Average Global Temperature


Atmospheric Composition

Atmospheric Layers - Stratosphere and Troposphere

General Principles

  • atmosphere gets thinner (fewer molecules) the higher up you go

  • it also gets colder (molecular motion slows down) the higher you go; you can differentiate atmospheric layers by temperature

  • divided into many layers. Most weather happens in the troposphere

Troposphere

  • weather is here

  • lapse rate (change of temp with height) is -6.5C/km or -36F/1000ft

  • Tropopause (upper bound of troposphere) depends on seasons and latitude: higher in equatorial regions, lower in polar regions; higher in summer, lower in winter

Does tropopause height vary based on temperature? If not, why does it change?

Stratosphere

  • above the troposphere

  • stable, no weather

  • temp increases with height, but it’s still colder

  • Ozone layer: 25 km thick, regulates temperature (heats air) and absorbs solar UV radiation

Gases - Variable & Permanent

Permanent gases:

  • comprise most of the atmosphere, with nitrogen and oxygen being the most numerous and notable

  • have only minute changes to concentration


Variable gases:

  • Comprise only a small portion of the atmosphere

  • Change concentration readily and frequently

  • Notable variable gases include water vapor, carbon dioxide, and ozone


Question: Are variable gases more spread out, and permanent gases arranged in layers? I was a bit confused on the wording of “well-mixed” and “heterogenous”



Important Atmospheric Gases

Water vapor (H20) - variable

  • MOST IMPORTANT — humidity, clouds, precip

  • Makes up 4% of air in tropical areas and a very small percentage in cold areas

  • Also a GHG

Carbon Dioxide (C02) - variable

  • GHG (greenhouse gas: traps heat in atmosphere)

  • comes from both natural (carbon cycle) and anthropogenic (human activity) sources

  • very low atmospheric concentration

Ozone (O3) - variable

  • near-surface ozone: BAD, dangerous to organisms

  • stratospheric ozone: GOOD, blocks dangerous UV radiation in the atmosphere

  • Antarctic “ozone hole” created by CFCs in commercial products


Variables, Units, and Measurement

Qualitative vs Quantitative Data

Quantitative: Numerical data

Qualitative: Descriptive data

Mass & Density

Mass: how much matter is in an object

Density: How much mass is in a given volume

Mass Density = mass / volume

Mass is directly proportional to density: more massive objects are more dense, less massive objects are less dense

What are the units of mass, volume, and density? Is it just kg and kg/m or am I missing something? Is L in there somewhere?

Temperature

  • measure of how much matter is moving (average kinetic energy)

  • measure of the average speed/vibration of atoms & molecules

  • higher temperature = matter moving faster on average

  • lower temperature = matter moving slower on average


Units of temperature

  • degrees Celsius

  • degrees Kelvin

  • degrees Fahrenheit


Conversions

C→F

C = 5/9 (F - 32)


C→ K

K = C+ 273.15


Pressure

Pressure: The amount of force exerted over an area

  • air molecules hit each other and produce force

Pressure: force/area


Units

  • millibars (mb) / hectopascals (hPa)

** note: mb = hPa

  • inches of mercury (Hg)

Standard pressure of atmosphere at sea level: 1013.25 mb













HEAT AND REFLECTION CORE CONCEPTS (8/26 Prelab and Lab)