Notes (09/03)

Weather & Climate

  • Climate does not equal weather

    • Climate = long-term condition in the atmosphere (the expected weather based on what the weather has been over a long period) (avg weather of an area)

    • Weather = short-term condition in the atmosphere (daily temp, daily rain, etc)

  • 2 key variables for both weather & climate:

    • Temperature (hot/cold)

    • Precipitation (dry/wet)

  • What effects temp & precip:

    • Latitude (Global scale)

      • Hot near equator, cold near poles. Some latitudes are wet, others dry

      • Longitude doesn’t play a role, but latitude is important

    • Position within a landmass

      • Temps mild near ocean, temps extreme away from ocean

    • Elevation

      • The higher you go, the colder it gets

      • Wet & dry sides of mountains

      • Rainshadow effect

  • Energy travels in waves

  • Hotter thing = shorter wavelength (wwwww)

    • Radiation from the sun

  • Cooler thing = longer wavelength (~~~~~~)

  • Electro-magnetic energy

    • Transmitted from the Sun or emitted from Earth

      • Comes in a spectrum of wavelengths

      • Sun = Shortwaves (visible, UV, near infrared) // Earth = Longwave (thermal, infrared)

  • The Earth’s atmosphere blocks ultraviolet light (UV rays), but visible light isn’t blocked & can be seen

  • Atmosphere: Gasses surrounding the Earth

  • Main components

    • Permanent gasses (Nitrogen 78%, Oxygen 21%, etc)

      • Primary source of oxygen are plants

    • Variable gasses (Water vapor 0-4%, Carbon Dioxide, etc)

  • Greenhouse effect

    • ex. leaving ur car in the sunlight - visible light can go thru glass so the energy from the sun is heating up the interior, the heat itself is longwave energy

    • Slows the release of longwave energy (heat) from the Earth

      • SW energy comes in from the sun, LW energy goes back to space, Greenhouse gasses slow down escaping LW energy

      • Greenhouse gasses (Carbon Dioxide, Water vapor, etc)

    • Natural process, but humans are adding to the carbon dioxide in the atmosphere

  • Mauna Loa Curve

    • Carbon Dioxide measurements @ Mauna Loa, Hawaii

    • Increasing trend, N. Hem. winter, CO2 increases due to decreased photosynthesis

    • AKA Keeling Curve

  • Seasonality

    • In the Northern Hem. there’s more vegetation, the Southern Hem. has more ocean

Video Points

  • The way energy from the sun moves in&out of the atmosphere

  • The way heat moves around the Earth

  • Insolation

  • Reflection

  • absorbs & re-emits heat

  • Heat is distributed unevenly across the Earth due to the tilt

  • High pressure, low pressure

  • Energy pathways to Earth

    • Insolation — Incoming SW energy from Sun

    • Scattering — Diffuse radiation

    • Reflection (albedo - measure of reflection) — Energy bounced back to space w/o being absorbed

    • Absorption — Energy is observed by the object

  • Clouds reflect a lot of sunlight - clouds reflect the most energy compared to land/water

  • Red - long wavelengths

  • Green - short wavelength

  • Blue - shorter wavelengths

  • Different layers in the atmosphere plays different roles in protecting the Earth

  • Troposphere — Gets colder in the higher you get (bottom layer of the atmosphere)

    • Clouds don’t go past the Troposphere

  • Stratosphere — Gets hotter the higher you get

  • Lapse rate

    • Environmental lapse rate: The real laspe rate for any location

    • Average/normal laspe rate: Avg lapse rate for Earth (6.5*C for every 1000m)

      • Different in different places

  • Continental climates

    • Away from oceans. Greater differences between summer/winter temps (hot summers/cold winters)

  • Marine climates

    • Close to oceans. Less difference between winter/summer temps (mild summer, mild winter)

  • Clockwise pattern in Northern Hemisphere

  • Counter clockwise pattern in Southern Hemisphere

  • More of a continental effect in the North Hemisphere (worse winters bc less ocean influence)