CORE PHYSICAL 2.1-2.4

Diurnal Energy Budgets

• An energy budget encompasses energy entering a system, energy leaving, and energy transfers within.
• Energy budgets are considered at global (macro) and local (micro) scales.
• Microclimate describes regional climates like those in urban, coastal, or mountainous areas.
• Climate and weather phenomena vary in spatial and temporal scales, from turbulence to anticyclones and jet streams.
• Jet stream activity, like the Eyjafjallajökull glacier dust dispersal, affects large areas for weeks.
• Different scales of phenomena exist within a hierarchy, where smaller phenomena exist within larger ones.
• Features like latitude, altitude cloud cover, and seasons affect synoptic weather conditions.

Daytime and Night-Time Energy Budgets

• The daytime energy budget has six components: incoming solar radiation (insolation), reflected solar radiation, surface absorption, sensible heat transfer, long-wave radiation, and latent heat.
• The basic formula for the daytime energy budget is, energy available at the surface = incoming solar radiation - (reflected solar radiation + surface absorption + sensible heat transfer + long-wave radiation + latent heat transfers).
• The nighttime energy budget consists of long-wave Earth radiation, latent heat transfer, absorbed energy returned to Earth, and sensible heat transfer.

Incoming (Shortwave) Solar Radiation

• Incoming solar radiation (insolation) is the main energy input, affected by latitude, season, and cloud cover.
• Insolation received depends on the angle of the Sun and cloud type.
• With strato-cumulus clouds, lower Sun angles transmit approximately 23% of radiation, while higher angles transmit approximately 40%.
• Less cloud cover and higher cloud altitudes lead to more radiation reaching the Earth's surface.

Reflected Solar Radiation

• Albedo is the proportion of energy reflected back to the atmosphere.
• Lighter materials are more reflective than dark, with grass reflecting around 20-30% of received radiation.

Surface and Sub-Surface Absorption

• Energy reaching the surface can heat the earth.
• Surface heat conduction depends on the nature of the surface.
• Heat transferred to the soil/bedrock during the day can be released back at night, offsetting cooling.

Sensible Heat Transfer

• Sensible heat transfer involves the movement of air parcels into and out of an area.
• Warmed air may rise (convection), replaced by cooler air (convective transfer), common in warm afternoons.
• Cold air moving in may reduce temperatures, while warm air may supply energy.

Long-Wave Radiation

• Long-wave radiation is energy radiated from the Earth into the atmosphere and space.
• A downward movement of long-wave radiation comes from particles in the atmosphere.
• Net long-wave radiation balance is the difference between outgoing and incoming long-wave radiation.
• A cloudless night results in significant net energy loss due to minimal returned long-wave radiation, which is typical for desert environments.

Latent Heat Transfer (Evaporation and Condensation)

• Heat increases when liquid turns to vapor, and heat is released when water vapor becomes a liquid.
• Water evaporation at a surface consumes a portion of available energy, leaving less for temperature elevation.

Dew

• Dew is condensation on a surface due to saturated air, usually from temperature drops.
• Condensation also occurs when moisture is introduced by sea breezes, with the temperature remaining constant.

Absorbed Energy Returned to The Earth

• Insolation received by the Earth is reradiated as long-wave radiation.
• A portion is absorbed by water vapor and other greenhouse gases, raising the temperature.

Temperature Changes Close to the Surface

• Ground-surface temperatures vary considerably between day and night.
• During the day, the ground heats the air through radiation, conduction, and convection.
• Air close to the ground warms via conduction, with slower air movement near the surface.
• At night, the ground cools via radiation, transferring heat from the air to the ground.

The Global Energy Budget: Latitudinal Pattern of Radiation

• The atmosphere is an open energy system receiving energy from the Sun and Earth (insolation).
• The constant receipt of solar energy is balanced by equal outputs.
• Balance is achieved through: radiation (electromagnetic wave emissions), convection (gas/liquid heat transfer), and conduction (contact heat transfer).
• Incoming radiation is absorbed by gases, reflected by the atmosphere, clouds and the planetary surface (albedo).
• Earth reradiates energy at long wavelengths; evaporation and condensation lead to heat loss and heat gain respectively.
• The atmosphere largely is heated from below, where greenhouse gasses function.
• A radiation imbalance exists with an excess in the tropics and a deficit at higher latitudes.
• A horizontal energy transfer from the equator to the poles occurs via winds and ocean currents.
• Areas closer to the equator receive more, concentrated heat compared to the dispersed heat received near the poles.
• Insolation near the poles passes through comparatively more atmosphere, increasing the probability of reflection back.

Annual Temperature Patterns

• Large-scale north-south temperature zones exist; January: max. temperatures over land in Australia and southern Africa; minimum in Siberia, Greenland and the Canadian Arctic.
• A general temperature decline exists northwards from the Tropic of Capricorn, with variations due to the Andes and the Namibia cold current.
• In July, maximum temperatures occur over the Sahara, the Near East, northern India, and parts of the southern USA and Mexico.
• There is little seasonal variation at the equator, but in mid to high latitudes large seasonal differences occur due to changes in insolation and the length of day.
• A lag time exists between the overhead Sun and the period of maximum insolation, because the air is heated from below and oceans are greater.

Atmospheric Transfers

• Pressure variations and ocean currents can influence atmospheric stability.
• Air moves from high to low pressure, redistributing heat; warm/cold currents affect overlying air temperatures.

Pressure Variations

• Pressure is measured in millibars (mb) shown by lines of equal pressure (isobars).
• Pressure is adjusted to mean sea level (MSL).
• MSL pressure is 1013mb, averaging from 1060mb (Siberian winter high) to 940mb.
• Pressure trend is more important than the actual reading; declines indicate poorer weather, rises indicate better conditions

Surface Pressure Belts

• Sea-level pressure differs between hemispheres; northern hemisphere has greater seasonal contrasts compared to more similar southern hemisphere.
• Antarctica has generally high pressure reduced by altitude; differences mainly linked to unequal distribution of land and sea.
• Subtropical high-pressure (STHP) belts exist, continuous at ~30° latitude in the southern hemisphere but are impacted as summers and land temps change.
• Low pressure exists over the equatorial trough (1008-1010mb) coinciding with maximum insolation Zone.

Surface Wind Belts

• Winds coverage at or toward the intertropical convergence zone (ITCZ) or equatorial trough.
• This is an area of low pressure into from which winds blow inwards.
• Rising air releases latent heat stimulating convection.
• Latitudinal ITCZ variations occur with movement of the overhead Sun (greatest over Asia).
• Low Latitude winds between 10-30° are mostly easterlies.
• These are reliable trade winds that make up about a third of the surface of the globe.
• Monsoons are caused wind reverse systems.
• Wind is affected by continent sizes such as that of Asia.

Explaining Variations in Temperature, Pressure and Winds

• Latitude the the most important factor on a global scale in determining temperature.
• Temperature is affected by the angle of the overhead and the sun and the thickness of the atmosphere, in addition.
• Insolation intensity matters.
• However these effects can be offset by day length and seasons.

Factors Affecting Air Movement

• Vertical air motion is important locally.
• Horizontal motion is more widely important from small scale to large scale.
• Basic cause of air motion is unequal heating of the Earth's surface.

Pressure Gradient

• Driving force is the pressure gradient, where there are two pressure points that differ.
• Globally, high pressure exists over Asia in the winter.
• High Pressure dominates a specific latitude.

Coriolis Force

• Coriolis force deflects moving objects caused by easterly rotation of the Earth.
• Airflow from High Pressure to Low Pressure is deflected on it's path in either hemispheres.
• The balance of forces between gradient and Coriolis force yields the best result.

General Circulation Model

• Warm air is transferred poleward, replaced by cold air towards the equator.
• Rising air means Low Pressure, whereas the opposite is for High Pressure.
• Any model should contain meridional heat transfers.
• The Hadley cell occurs from direct heating over the equator, where rising air by convection travels and sinks at higher altitudes.
• The Ferrel cells interlink with the other cell types and rotate the polar cell.

Rossby Waves

• Jet streams come from differences in the Earth as a result of differing temperatures.
• Rossby waves are affected by geographic and mountain features creating large long-lasting patterns.
• Jet Streams and Rossby waves help mix warm and cold air.

Atmospheric Moisture

• Atmospheric moisture exists in all three states: vapor, liquid, and solid.
• Energy and/or pressure may change one state to another.
• Evaporation absorbs heat, while on the other hand, condensation releases it.

Factors Affecting Evaporation

• Occurs when vapor pressure of water surface is greater than that of what is in the atmosphere.
• Its directly impacted by the initial humidity, the supply of heat, and wind strength.

Factors Affecting Condensation

• Occurs when either water masses have evaporated an air enough or the air decreases so that dew point is reached.
• Occurs with radiation, contact, and expansive cooling.
• Is difficult in pure air; needs some sort of nucleus to grab on to.

Other Weather Processes

• Freezing and melting refer to the changing of liquid and solid water.
• Sublimation is the changing of direct conversion of solid to a vapor.

Precipitation

• Refers to the change of forms of the atmosphere.
• Forms of precipitation include: rain, hail, snow and dew.
• The Berger theory states this best, where snow and or rain fall by change of sizes.
• Occurs because of condensation and change of particle sizes on the whole.

Causes of Precipitation

• Related to those that are found in snow-making.
• Its also found in extra-large or electrical states.

Convectional Rainfall

• Rainfall caused by rising hot air and expansion on the atmosphere.
• This is typical of tropical areas because of the ITCZ.

Frontal Cyclonic Rainfall

• Rainfall occurs as warm and cold air converge and warm air is forced upward because warm air is less dense This is typical of mid and higher altitude regions as that is where the different air temps coverage.

Orographic Rainfall

• Occurs as air rises of a barrier.
• Creates rain shadows around the leeward side of slopes; altitude is important in how this process carries out.

Thunderstorms

• Are special cases with heavy precipitation due to unstable conditions Thunderstorm Stages =
• Energy released while updraft occurs
• Then the onset of heavy rains begin.
• Dissipating stage = droughts prevent new cells to happen.

Clouds

• Are millions of small water droplet held in suspension
• Shaped, and formed.
• Its all about there properties.

Dew

• Direct liquid deopsotion onto surfaces.
• Commonly occurs on solid and stable pressures with radiation at night.

Fog

• Commonly called clouds at ground level.
• Mostly comes in radiation changes.
• Also can be a more horizontal change from a land or sea.

The Human Impact - Global warming

• Greenhouse gases are important for life on Earth.
• Without it, there are no human life on the planet
• With it, there are concerns of enhanced.

The Role of the main Greenhouse Gasses

• Carbon Dioxide rates have been on the rise every year.
• Caused by humans actions.
• Other notable gases include: methane, and chlorofluorocarbons (CFCs)

How Human Activities Add to Greenhouse Gasses

• Evidence of this has been taken from glacial data going back thousands of years..
• Other sources include natural and combustion ones.

Complexity of the Problem

• Climate includes various areas.
• It's complex and includes feed back, as well as the scale to which climate occurs.

The Effect of Increased Global Temperatures

• The overall results can be varied with several impacts. This list includes:
  • Rise and displacement from sea level
  • Increase of storm activity
• Change in agricultural activity.

The Stern Review

• There are some potential effects of a high changing climate
• The impact varies with how well temperatures rise.

International Policy to Protect Climate

• First ever conference started in 1977.
• Kyoto protocol provided better goals for better changes.

Urban Climates

• These come from extra heat sources released such as industries.
• Other notable areas come from those different then soil and vegitation, such as albedo, concrete and tar.

Moisture and Humidity

• These changes are impacted by both wet and dry conditions.
• These also are affected by pollution and humans.

Air flow

• Airflow is important in high heat and stable cooling.

Section 2.4 Activities

• Main activities that can be done is finding more ways to understand it all.

London Mini Study

• High temp regions can effect different kinds of temperatures.