Unit V: Global Processes-Climate and Land Use Chapter 4: Global Climate and Biomes

I. Weather Short term atmospheric conditions-hours to days Temperature, pressure, moisture content, precipitation, cloud cover, wind speed and direction all influence weather. Most weather due to interactions between leading edges of moving masses of warm and cold air.

Atmosphere: Layer closest to the ground is the troposphere-where weather occurs.

II. Climate A region’s general pattern of long-term atmospheric conditions Regional differences in temp and precip are main factors in determining climate and thus which organisms can survive in each region. Latitude and altitude also play a role.

Climate varies in different parts of the Earth because of: Uneven heating of Earth by sun atmospheric convection currents rotation of Earth Earth’s orbit around the sun on a tilted axis ocean currents https://www.youtube.com/watch?v=6LkmD6B2ncs

Explains existence of Tropical, Polar and Temperate regions. 1.Uneven heating of earth’s surface by the sun-variation in angle at which rays strike Earth Air is heated more at the equator, where sun strikes directly than at the poles where sun strikes at angle and spreads over a greater surface area Explains existence of Tropical, Polar and Temperate regions.

Uneven heating of earth’s surface by the sun-the percent of incoming solar radiation that is reflected-ALBEDO or absorbed Higher the albedo of a surface, the more solar energy is reflects and the less it absorbs. White surface high albedo/dark low 30% average /10-20%tropics with dense green foliage and 80-95% in snow covered polar regions

2. Atmospheric Convection Currents Properties of Air Density: cold/more dense sinks; warm/less dense rises Water Vapor Capacity: warm air has a higher capacity for water vapor than cold air Adiabatic Cooling: air rises, pressure decreases, expands in volume and lowers temp of the air. Adiabatic Heating: air sinks, pressure increases, volume decreases and air temp rises Sun’s energy evaporates water and forms vapor/water vapor condenses to a liquid-heat produced. This is latent heat Important because whenever water vapor condenses, air becomes warmer and rises.

Formation of Convection Currents: global patterns of air movement initiated by unequal heating of Earth. Warm humid air in tropics rises, lower pressure and adiabatic cooling, reaches saturation point which leads to condensation, cloud formation and precip. cold, dry air is displaced horizontally N and S of equator where it eventually sinks at 30o N and S. When it reaches Earth surface it is hot and dry-desert.

Hadley Cells: Convection Currents that cycle between equator and 30o N and S. Similar polar cells form at 60o N and S. Between Polar cells and Hadley Cells is air circulation driven by neighboring cells.

3. Earth’s Rotation-Coriolis Effect Earth moves faster at equator because of difference in circumference causing deflection of objects that are moving directly N or S. Prevailing winds produced by a combination of atmospheric convection currents and the Coriolis effect http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/crls.rxml http://www.youtube.com/watch?v=mcPs_OdQOYU

4. Earth’s tilt and the seasons Earth Seasons Earth Video global circulation

5. Ocean Currents Driven by a combination of temperature, gravity, prevailing winds, the Coriolis effect and the location of continents. Warmer equatorial ocean water expands and raises elevation of surface water so that gravity makes water flow away from equator. Gyres: Large scale patterns of water circulation. global prevailing wind patterns play a major role in determining the direction on which ocean surface water moves away from the equator. Thus-oceans distribute heat http://5gyres.org/

Upwelling: Upward movement of water towards the surface Upwelling: Upward movement of water towards the surface. Ocean currents also distribute nutrients and thus determine coastal areas of productivity. Thermohaline circulation: differences in salt concentration and thus density. High cold salty water sinks and warm water near equator rises fuel a deep ocean current that mixes all ocean waters.

National Geographic-El Nino El Nino-Southern Oscillation (ENSO): Ocean/Atmosphere Interaction results from a change in direction of tropical winds-weakened or reversed. Results: every 3-7 years the waters off western coast of South and North America warm and normal upwelling supressed-no mixing of nutrient rich water-thus decreased productivity and decline in fish populations. National Geographic-El Nino

III. Topography and Climate Heat is absorbed and released more slowly by water than by land-create land and sea breezes-moderate climate by oceans and large Mountains and cities create climate patterns that interrupt the flow of prevailing winds and movement of storms. Rainshadow Effect: moist air blowing inland reaches mts- it cools and expands as it rises, dumps moisture on windward side as rain or snow. Leeward side has dry air mass that draws moisture out of plants and soil. Often forms desert EX death valley on leeward side of Cascades Fig. 5-7, p. 104

Urban Heat Island (UHI) A metropolitan area which is significantly warmer than its surrounding rural areas. Cities create microclimates because concrete and asphalt absorb and hold heat & buildings block wind flow; motor vehicles and the climate control systems of buildings release large quantities of heat and pollutants

Land and Sea Breezes Land breezes blow from the land to the water Sea breezes from water to land. Both are caused by uneven heating of earth. During the day the sand will heat faster than the water and blow from the sea to the land/night the sand will cool faster than water and wind will blow from land to water

Land and Sea Breezes

IV. Biomes: Climate and Life on Land Different climates lead to different communities of organisms, especially vegetation. Biomes: large terrestrial regions characterized by similar climate, soil, plants and animals. Temperature: tropical, temperate and polar Precipitation: deserts, grasslands and forests.

V. Aquatic Biomes Freshwater Life Zones: lakes, ponds, streams, rivers and inland wetlands Life in most aquatic systems can be divided into three layers: surface middle and bottom

Eutrophic: a lake with a high level of nutrients; high productivity Oligotrophic: low nutrients; low productivity

Salt Water Ecosystems Salt Marsh: coastal temperate climate; most productive ecosystems; often found in estuaries Mangrove Swamp: tropical and subtropical coasts; contain trees that are salt tolerant and protect coast from erosion; sheltered habitat for fish and shellfish

Intertidal Zone: coastline that exists between high and low tide Intertidal Zone: coastline that exists between high and low tide. Temp, salinity conditions change and organisms must be adapted Coral Reef: warm shallow waters beyond shoreline; most divers marine biome

Coral Reefs Result of mutualistic relationship between polyps and algae; algae provide polyp with food, color and oxygen through photosynthesis; algae get a home and some nutrients Formed by massive colonies of polyps that secrete limestone around their soft body. When polyps die their empty crusts remain as a platform for more reef growth.

Provide Valuable ecosystem services: remove CO2, protect coast from pounding waves, provide habitat, nurseries, fisheries Vulnerable because they grow slowly and are disrupted easily. Threats: Coral bleaching,(stress-algae die-white skeleton of calcium carbonate) coastal development, overfishing

Ocean acidification: name given to the ongoing decrease in the pH and increase in acidity of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide (CO2) from the atmosphere. The CO2 reacts with hydrogen from bicarbonate shells to form carbonic acid CO2 + H2O ↔ H2CO3

Life Zones-Open Ocean