Rising Air and Sinking Air

• Rising air expands and cools, while sinking air is compressed and warms.

Air Parcel Concept

• An air parcel is an imaginary blob of air contained in a thin, elastic wrap, able to expand or contract freely.
• Neither external air nor heat can mix with the air parcel, maintaining its integrity as it moves.

Rising Air

• As a parcel rises, it encounters lower atmospheric pressure, causing it to expand.
• The molecules inside the parcel use their energy to expand, leading to slower molecular speeds and a lower temperature.
• Rising air always expands and cools.

Sinking Air

• When a parcel sinks, it encounters higher pressure, compressing it back to a smaller size.
• Air molecules rebound faster after striking the collapsing parcel sides, increasing their average speed and warming the parcel.
• Sinking air always warms by compression.

Evaporation and Condensation

• Evaporation cools the air as liquid transforms into vapor.
• Condensation warms the air as vapor transforms into liquid.

Heat Transfer

• Heat is energy transferred due to temperature differences.
• Conduction involves heat transfer through molecule-to-molecule contact, flowing from warmer to colder regions.
• Air is a poor conductor of heat.
• Convection involves the vertical movement of warmer air upwards and cooler air downwards.
• Advection is the horizontal transfer of atmospheric properties by the wind.

Temperature and Molecular Motion

• Temperature reflects the average kinetic energy (speed) of atoms and molecules within a substance.

Convection and Thermals

• Uneven heating of the earth's surface causes convection.
• Air molecules near hot surfaces gain energy and rise.
• The transfer of heat by the mass movement of a fluid such as water and air is called convection.
• Rising bubbles of warm air are known as thermals.

Convective Circulation

• Warm air rises, expands, spreads, and gradually sinks, forming a convective circulation or thermal cell.
• Meteorologists usually restrict the term convection to the rising and sinking parts of the circulation.

Heat Conductivity

• Still air has very low heat conductivity, it measure 0.023 (watts per meter per degree Celcius).
• Silver heat conductivity is 427 (watts per meter per degree Celcius).

Earth's Energy Balance

• High latitudes lose more energy than they receive, while low latitudes gain more.
• Winds and ocean currents transfer heat, preventing extreme temperature changes.

Earth's Orbit and Seasons

• The earth's orbit around the sun is elliptical, bringing it closer in January and farther in July.
• Seasons are regulated by the angle at which sunlight strikes the surface and the duration of daylight.

Angle of Sunlight

• Direct sunlight is more intense than sunlight striking at an angle because it heats a smaller region.

Albedo

• Albedo represents the reflectivity of a surface.
• Thick clouds have high albedo or reflectivity (60 to 90 percent).
• Earth and atmosphere average albedo is 30 percent.

Earth's Annual Energy Budget

• Earth's average temperature remains stable because it emits as much energy as it receives.
• The earth's surface radiates infrared energy, a portion of which is absorbed by greenhouse gases.

Atmospheric Heating

• The atmosphere is primarily heated from the ground upward.
• Sunlight warms the ground, and the air above is then warmed by conduction, convection, and infrared radiation.

Scattering of Light

• Air molecules scatter shorter wavelengths (blue light) more effectively.
• At midday, the sun appears white, while at sunrise and sunset, it appears red or yellow due to scattering.

Solar Constant

• The solar constant is the rate at which radiant energy from the sun is received on a surface at the outer edge of the atmosphere that is perpendicular to the sun's rays.
• It is about 1367 W/m².

Ozone Impact

• Ozone absorbs incoming UV radiation.
• There is only a small amount of ozone in the atmosphere.
• Ozone only has a minor greenhouse effect.
• Depletion of ozone creates an ozone hole.
• The ozone hole is virtually unrelated to global warming.

Atmospheric moisture

• (Hydrological Cycle) water cycle.

Warming the Air

• Air is warmed from the ground upward.
• At the top of the atmosphere, solar energy is a nearly constant rate.

UV Radiation Exposure

• UV-C: 0.20 and 0.29 µm range, are absorbed by ozone in stratosphere.
• UV-B: 0.29 and 0.32 µm range, produce sunburns and can lead to skin cancer.
• UV-A: 0.32 to 0.40 µm range, lead to tanning, skin redness, and long-term skin damage.

Sunscreen and Protection

• Sunscreens block UV rays from reaching the skin, via reflection or absorption.
• Sun Protection Factor (SPF) indicates effectiveness against UV-B radiation.
• The UV Index forecasts daily UV radiation levels.
• Protective measures include sunscreen and limiting direct sunlight exposure, particularly between 11 AM to 3 PM.

Radiation and Equilibrium

• Objects radiate and absorb energy.
• Balance creates constant temperature, imbalance results in a change of temperature.

Earth's Radiation

• The sun radiates energy at short wavelengths
• the earth radiates terrestrial radiation at long wavelengths.

Atmospheric Greenhouse Effect

• It keeps the temperature of our planet at a level where life can survive.
• Without it, air at the surface would be extremely cold.

Key Greenhouse Gasses and Their Impact

• Water Vapor and carbon dioxide absorb infrared radiation, keeping the earth's average surface temperature warmer.
• The concentration of carbon dioxide is increasing primary due to the burning of fossil fuels. and deforestation.
• The earth's surface air temperature has been undergoing warming.
• Other greenhouse gases include methane and nitrous oxide.

Numerical Weather Prediction

• The two potentially largest and least understood feedbacks in the climate system include cloud changes and changes in ocean.
• But it's important to have some uncertainties, unquestionably, the most recent studies on the impact of climate change say that it is primarily worldwide from greenhouse gasses.

Latent Heat and Changes of State

• Heat energy required to change a substance from one state (solid, liquid, gas) to another.
• Evaporation requires heat energy and is a cooling process.
• Condensation releases heat energy and is a warming process.

Methods Of Heat Transer

• Heat transfer flows from warmer to cooler surfaces.
• Materials that easily pass energy from one molecule to another are called good conductors of heat.

Atmospheric Composition

• Molecular nitrogen is at 78%
• Molecular oxygen is at 21%

Atmosphere Layers

Conduction is is heat transfer from the Hot End of the metal pin to the cooler end from molecule to molecule contact.

Types of Thermometers

The Fahrenheit scale was developed in early 1700s by physicist G. Daniel Fahrenheit. Assigning 32 to the temperature where water freezes, and 212 at boiling.

Meterology, what it is

Meterology is a the scientific study of the atmosphere and its phenomena.

Meteroolgy history

-Around the 1920s, the concepts of air masses and weather fronts were formulated in Norway -By the 1940s, daily uppoer balloon air observations of temperature, humity, and pressure gave a 3D view of the atmosphere.