Midterm 1 Global Climate Change

Weather

The state of the atmosphere at a given time and place. It is highly variable, changing from day-to-day, year-to-year.

Climate

The accumulation of daily or seasonal weather events over a longer time period. It represents a long-term average of weather but must include extremes.

Meteorology

The study of the atmosphere.

Climatology

The scientific study of climate, which refers to the long-term statistical patterns of weather in a given region globally.

Elements of Weather

Variables/elements include Air temperature, Precipitation/Rainfall, humidity, moisture, wind, Clouds, Visibility, Air pressure.

Mediterranean climate

Characterized by relatively hot, dry summers, and cool, wet winters.

North wind

When winds are blowing from North to South.

West wind

If winds blow from the west.

Wind directions assignment

Winds are referenced by the direction they are BLOWING (COMING) FROM, not GOING to.

Fronts

Boundaries that separate different air masses.

Cold front

A boundary of cold air.

Warm front

A boundary of warm air.

Low pressure

Represented by an 'L' on a weather map.

High pressure

Represented by an 'H' on a weather map.

Hypothesis

A proposed explanation for a phenomenon or some observation.

Theory

A logically self-consistent explanation describing the behavior of natural phenomena (originating from observations).

Climate change

Changes in climate of the past, present or future associated with natural or anthropogenic (human-induced) factors.

Global Warming

Warming of the 20th and 21st century associated with anthropogenic activities.

Miles to kilometers conversion

1 mile is equivalent to 1.6 km.

Kilometers to miles conversion

1 km is equivalent to 0.62 miles.

Miles to kilometers formula

km = miles x 1.6.

miles to kilometers formula

miles = km/1.6.

Celsius to Fahrenheit conversion

(9/5 x ºC) + 32 = ºF.

Fahrenheit to Celsius conversion

(ºF - 32) x 5/9 = ºC.

Temperature scales

Kelvin, Celsius, Fahrenheit.

Absolute zero

0 K = −273.15 °C.

Celsius to Kelvin conversion

K = °C + 273.

Temperature

The measure of the average heat or thermal (kinetic) energy of the particles in a substance.

Composition of the atmosphere

Mainly nitrogen (N2) and oxygen (O2), with small amounts of other gases, called 'trace gases' such as water vapor (H2O) and carbon dioxide (CO2).

Gases and particles exchange

Gases and particles are readily exchanged between the Earth's surface and the atmosphere through physical and biological processes.

Trace gases

Small amounts of other gases in the atmosphere, such as water vapor (H2O) and carbon dioxide (CO2).

Permanent gases

Gases in the atmosphere that have consistent concentrations.

Variable gases

Gases in the atmosphere that can vary in concentration, such as water vapor.

Water vapor

The most abundant variable gas, added or removed from the atmosphere through the hydrologic cycle; a greenhouse gas.

Ozone at high altitudes

Considered 'good' for humans as it protects from harmful UV radiation.

Ozone at low altitudes

Considered 'bad' for humans as it can be harmful to health.

Carbon dioxide

A trace gas accounting for only ~0.039% of the atmosphere's volume.

Sources of Carbon Dioxide

Added to the atmosphere through biologic respiration, volcanic activity, decay, and combustion.

Removal of Carbon Dioxide

Removed from the atmosphere through photosynthesis, where plants convert light energy to chemical energy.

Causes of Sea Rise

Melting of continental ice sheets and glaciers, and thermal expansion of seawater as it warms.

Anthropogenic greenhouse gas

Carbon Dioxide, which has the highest concentration and largest impact on climate, with an approximate atmospheric lifetime of 120 years.

Vertical temperature profiles of the atmosphere

Troposphere, Stratosphere, Mesosphere, Thermosphere.

Weather balloon

A small instrument package suspended below a balloon filled with hydrogen or helium, used to measure the vertical structure of the atmosphere.

Troposphere

The lowest layer of the atmosphere (0 - 11 km) where weather occurs and contains about 80% of all air molecules.

Stratosphere

The layer of the atmosphere (11 - 50 km) with an average temperature of -46 °C and where the ozone layer is found.

Mesosphere

The layer of the atmosphere (50 - 85 km) characterized by transition, -90ºC temperatures, and where meteors burn up.

Thermosphere

The layer of the atmosphere (>85 km) where temperatures exceed 100ºC, it is electrically charged, and it blocks harmful radiation from the sun.

Effect of air rising in height

Cools with height in the troposphere due to the warming of the surface of the Earth.

Temperature lapse rate

The rate at which the air temperature decreases with height.

Average lapse rate in the troposphere

6.5 degrees Celsius (ºC) for every 1000 meters (m).

Albedo

The fraction of light reflected by an object or a surface.

High albedo objects

Bright objects that reflect a large amount of sunlight.

Low albedo objects

Dark objects that absorb a large amount of sunlight.

Earth's energy absorption

Earth absorbs more energy from the sun than Venus.

Surface temperature prediction

The atmospheres of the planets are not taken into account.

Venus' atmosphere composition

Venus' atmosphere is mostly CO2 (~ 96%).

Greenhouse effect

The greenhouse effect makes a planet's surface temperature warmer than it would otherwise be.

Earth's surface temperature without greenhouse effect

Very Cold (0°F/-18°C).

Evaporation

Process where a liquid changes into a gas (Phase change of water from liquid to vapor).

Condensation

Process where a gas changes into a liquid (Phase change of water from vapor to liquid).

Precipitation

Any liquid or solid water that falls from the atmosphere to the ground (i.e. RAIN!).

Cloud Condensation Nuclei (CCN)

Non-water particles that help condensing molecules stick together to form cloud droplets.

Examples of CCN

Smoke, Sea Salt, Dust.

Cloud formation

Formation of a cloud requires water vapor in the atmosphere to change phase to liquid water, and further into ice particles under certain circumstances.

Cooling air for condensation

The air has to be cooled sufficiently for the air to reach its condensation and subsequently its freezing point.

Rising air

The easiest way for condensation and freezing processes to occur is through ___.

Albedo effect

Clouds reflect incoming solar radiation, leading to cooling.

Greenhouse effect in clouds

Clouds are good absorbers (and emitters) of longwave (infrared) radiation, leading to warming.

Classification of clouds

Clouds are classified based on Form and Height.

Form of clouds

Cirrus (whispy and thin), Cumulus (globular and puffy), Stratus (layers covering much of the sky).

Height of clouds

High clouds are above 6000 m, Middle clouds range between 2000-6000 m, Low clouds are at altitudes of less than 2000 m.

Clouds of vertical development

Clouds that extend upward to span more than one height range.

Types of clouds based on height

High (cirr-), Middle (alto-), Low (strat-), Vertical Development (cumu-).

Rain-producing clouds

Clouds producing rain have the 'nimb-' root.

Nimbostratus

A type of cloud characterized by thick, dark layers that produce continuous rain.

Cumulonimbus

A type of cloud associated with thunderstorms and severe weather, characterized by towering vertical development.

Cloud Droplets

Small water droplets that form in clouds, typically found in stratiform clouds.

Ice Crystals

Frozen water particles that form in clouds, typically found in cirrus clouds.

Low level clouds

Clouds that appear dark and thick to the observer, but bright at the top, excellent at reflecting solar radiation.

High level clouds

Clouds that appear light and thin to the observer, fair to poor at reflecting solar radiation.

Surface energy budget

The balance between incoming solar energy and outgoing infrared radiation at the Earth's surface.

Increases in low level clouds

Result in cooling of the Earth's surface as the cooling effect outweighs the warming effect.

Effect of Increase of high level clouds in atmosphere

Results in warming of the Earth's surface as the warming effect outweighs the cooling effect.

Net effect of clouds on climate

Clouds generally cool the Earth, but there is more uncertainty about their effect compared to greenhouse gases.

Seasons

Regulated by the amount of solar energy received at the Earth's surface, influenced by sunlight angle and daylight hours.

Austral summer

The summer season in the Southern Hemisphere, occurring in December, January, and February.

Boreal summer

The summer season in the Northern Hemisphere, occurring in June, July, and August.

Insolation

Incoming solar radiation received by the Earth.

Solstice

Days of the year when the sun shines directly overhead at 23.5°S or 23.5°N at noon.

Equinox

Days of the year when the sun shines directly overhead at the equator at noon.

Subsolar point

The latitude at which the sun is directly overhead at noon on a particular day.

June Solstice

Occurs on June 20/21, marking the longest day of the year in the Northern Hemisphere.

December Solstice

Occurs on December 21/22, marking the shortest day of the year in the Northern Hemisphere.

March Equinox

Occurs on March 20, marking the beginning of spring in the Northern Hemisphere.

September Equinox

Occurs on September 22/23, marking the beginning of autumn in the Northern Hemisphere.

Sun's angle of incidence

The angle at which sunlight strikes the Earth's surface, affecting the amount of solar energy received.

Perihelion

The point in Earth's orbit when it is closest to the sun, occurring around January 2-5.

Aphelion

The point in Earth's orbit when it is farthest from the sun, occurring around July 3-6.

Energy

The ability to do work or the capacity to change environmental conditions, such as temperature.

Conduction

The transfer of energy in a substance by means of molecular excitation without any net external motion.