Climate and Terrestrial Biodiversity CHAPTER 6 Weather A

Climate and Terrestrial Biodiversity CHAPTER 6

Weather: A Brief Introduction Weather: result of the atmospheric conditions in a particular area over short periods of time, typically over hours or days Examples: temperature, pressure, moisture content, precipitation, sunshine, cloud cover, and wind direction

Weather: A Brief Introduction Climate: the average pattern of weather for a particular region for a LONG period of time

Warm Fronts A warm front is the boundary between an advancing warm air mass and the cooler one it is replacing. Because warm air is less dense than cool air, an advancing warm front rises up over a mass of cool air. As the warm front rises, its moisture begins condensing into droplets to form layers of clouds at different altitudes.

Cold Fronts A cold front is the leading edge of an advancing mass of cold air. Since cold air is more dense than warm air it moves in low to the ground.

Jet Streams These are hurricane force winds that are blowing around up near the troposphere, these powerful winds rising and falling cause great influence on weather patterns.

What are Highs and Lows? Pressure Changes! Weather is affected by up and down movements of masses of air with high and low atmospheric pressure. Air pressure results from zillions of tiny molecules of gases (mostly nitrogen and oxygen) in the atmosphere zipping around at incredible speeds and hitting and bouncing off anything they encounter.

What are Highs & Lows? An air mass with high pressure, called a high, contains cool, dense air that descends toward the earth’s surface and becomes warmer. An air mass with low pressure, called a low, produces cloudy and sometimes stormy weather.

Weather Godzillas Tornadoes (over land) and tropical storms, cyclones, (form over warm ocean waters and sometimes pass over land) are weather extremes that can cause lots of damage but can sometimes have beneficial ecological effects.

Tornadoes or twisters are swirling funnel shaped clouds that form over land. They can destroy houses and cause other serious damage in areas when they touch down on the earth’s surface. The United States is the world’s most tornado-prone country, followed by Australia.

Tornadoes in the plains of the Midwest usually occur when a large, dry cold air front moving southward from Canada runs into a large mass of humid air moving northward from the Gulf. Most tornadoes occur in the spring when fronts of cold air from north penetrate deeply into the midwestern plains.

Tropical Storms Large and dangerous storms called tropical cyclones are spawned by the formation of low-pressure cells of air over warm tropical seas. Hurricanes are tropical cyclones the form in the Atlantic Ocean; those forming in the Pacific Ocean usually are called typhoons. Gale force winds circle the eye of the storm at speeds of up to 200 miles per hour. Moist surface winds move to the center of the storm

Climate is the long term atmospheric conditions of a region over several decades. The two main factors that determine a regions climate are average temperature and average precipitation.

Determining Air Patterns There are four main factors that determine global air circulation patterns. 1. Uneven heating of the earths surface. EX: Air at the equator has more direct sunlight so it is hotter than air below it and above it

Determining Air Patterns 2. Seasonal changes in temperature and precipitation Ex. The earth is tilted which resulted in some areas being pushed closer to the sun and some being pushed farther.

Determining Air Patterns 3. Rotation of the earth on its axis Ex. This causes prevailing winds which are major surface winds that are continuously blowing and distributing moisture over the earth

Determining Air Patterns 4. Properties of air, water, and land also affect global air circulation.

Seasons in the N and S hemispheres are caused by the tilt of the earths axis. The earths tilt is about 23. 5 degrees.

How does the ocean affect climate? Ocean currents and winds influence climate by redistributing heat received from the sun from one place to another Oceans absorb heat from air patterns

Winds can also affect regional climates and how some forms of ocean life are distributed. The ocean is in a constant flow where the outgoing surface water gets replaced by the upwelling cold nutrient rich water from the bottom.

Wind Currents in the U. S.

El Nino Every few years in the Pacific Ocean normal shore upwelling's are affected by changes in climate patterns called, El Nino Southern Oscillation (ENSO)

El Nino In an ENSO warmer trade winds prevail and warm the ocean waters of the northern and southern waters of the American coasts. This stops the cold nutrient rich waters from reaching the surface and affects marine life populations in the seas. A very strong ENSO can bring about extreme climate changes in two-thirds of the world.

The Natural Greenhouse Effect is water vapor, carbon dioxide, and other gases that influence climate by warming the lower troposphere and the earth’s surface.

The Natural Greenhouse Effect

The Natural Greenhouse Effect Small amounts of certain gases play a key role in determining the earth’s average temperature and thus its climates. These gases include water vapor (H 20), Carbon Dioxide (CO 2), Methane (CH 4), and Nitrous Oxide (N 20)

The Natural Greenhouse Effect

The Natural Greenhouse Effect Together these gases known as greenhouse gases, allow mostly visible light and some infrared radiation and ultraviolet (UV) radiation from the sun to pass through the troposphere.

The Natural Greenhouse Effect The earth’s surface absorbs much of this solar energy. This transforms it to longer-wavelength infrared, which rises into the troposphere.

The Natural Greenhouse Effect Some of this infrared radiation escapes into space and some is absorbed by molecules of greenhouse gases and emitted into the troposphere in all directions as even longer wavelength infrared radiation

The Natural Greenhouse Effect Some of this released energy is radiation into space and some warms the troposphere and the earth’s surface. This natural warming effect of the troposphere is called the greenhouse effect.

Creating Deserts and Warming Cities Mountain and cities affect local and regional climates.

Creating Deserts and Warming Cities When moist air blowing inland from an ocean reaches a mountain range, it cools as it is forced to rise and expand. This causes the air to los most of its moisture as rain and snow on the windward slopes.

Creating Deserts and Warming Cities As the drier air mass flows down the leeward slopes, it draws moisture out of the plants and soil over which it passes. The lower precipitation and the resulting semiarid or arid conditions on the leeward side of the high mountains are called rain shadow effect.

Creating Deserts and Warming Cities also create distinct microclimates. Bricks, concrete, asphalt, and other building materials absorb and hold heat, and buildings block wind flow.

Creating Deserts and Warming Cities Motor vehicles and the climate control systems of buildings release large quantities of heat and pollutants. As a result, cities tend to have more haze and smog, higher temperature, and lower wind speeds than the surrounding countryside.

Tropical Temperatures The most important factors for producing the tropical and temperate climates is the average annual precipitation, temperature and soil type.

Navigation Latitude: the distance from the equator Altitude: the elevation above sea level

Deserts A desert is an area where evaporation exceeds precipitation. Deserts have little precipitation and little vegetation and are found in tropical, temperature, and polar regions. Deserts cover about 30% of the earths surface. Deserts are found mostly in tropical and subtropical regions Desert soils have little vegetation so at night the surface rapidly cools

Three Types of Deserts Tropical deserts: hot and dry most of the year, with few plants and hard surfaces

Three Types of Deserts Temperate deserts: has high daytime temps in the summer and low daytime temps in the winter. Vegetation consists of cacti and shrubs

Three Types of Deserts Cold deserts: winters cold and summers are warm with low precipitation.

Semi-deserts In the semiarid zones between deserts and grasslands, we find semi-desert. This biome is dominated by thorn trees and shrubs adapted to long dry spells followed by brief, sometimes heavy rains.

Deserts, Continued Desert plants and animals have a number of strategies for staying cool and getting enough water to survive in hot and dry climates. Beat the heat or DIE!!!

Desert Adaptations Cactuses don’t have leaves which can loose water, also they open their pores at night when its cooler to intake oxygen, they store water in inside them for very dry spells, and finally they have deep roots to tap into ground water supplies.

Grasslands Three Types: Hot, Cold, & Mild Grasslands have enough precipitation to support grasses but not enough to support large stands of trees. Grasslands are found in tropical, temperate and polar regions.

Prairies or Grasslands Prairies or grasslands are mostly found in the interiors on continents. They are formed because of a combination of drought, precipitation, fire and animals grazing that keep large shrubs and trees from growing.

Grasslands in Canada

Savanna Are grasslands that experience very warm temperatures year round. Also they have two dry spells and then rain the rest of the year. They are mainly inhabited by huge herds of hoofed, and grazing animals.

Polar Grasslands are occur south of the polar ice caps. Treeless plains covered in ice and snow most of the year, except for a brief summer period. Has a layer of permafrost just below the soil Inhabited by small herbivores, and small predators.

Chaparral Has a very mild climate with a slightly longer winter rainy season. Located along the oceans in southern California and the Mediterranean. Subject to many fires during the fall followed by flooding and mudslides. Long, hot, dry summers make fires happen very often.

Flooding

Chaparral Plant Life Consists mostly of dense growths of low growing evergreen shrubs Few small trees with leaves that reduce evaporation During summer become dry and flammable.

Tropical Rain Forests Heavy rainfall most days out of the year. Found near the equator. High humidity. Very diverse forms of life. Broadleaf evergreen plants are the main vegetation. Soil has very little plant nutrients. Very little ground plant life.

Temperate Deciduous Grow in places with moderate temperatures. Long warm summers, cold winters, and abundant precipitation. Oak, Hickory, Maple, Popular, and Beech trees dominate the plant life. Diverse ground plant life. Nutrient rich soil.

Temperate Deciduous Animal Life Most popular animal species is the White-Tail Deer, along with squirrels, rabbits, opossums, raccoons, and mice. Used to be home to bears, wolves, foxes, wildcats, and mountain lions. Most of the predators have been killed off, or displaced.

Evergreen Coniferous Forests Found just south of the arctic tundra in the northern regions of North America, Asia, and Europe. Long, dry, and extremely cold winters. Where sunlight is available only 6 -8 hours a day. Summers are short with mild temperatures. Where the sun shines 19 hours a day.

Evergreen Coniferous Forest Plant Life Mostly populated by a few species of coniferous evergreen trees. Spruce, fir, cedar, hemlock, and pine trees. Most keep needles all year long, and are cone bearing.

Evergreen Coniferous Forests Animal Life Many small rabbits and mice. Contain animal species such as moose, wolves, owls, and small birds

Temperate Rain Forests Coastal region support these forests. Huge cone bearing trees such as redwoods and Douglas firs Environment must be cool and moist to support temperate rain forests. Cool summers and winters Trees depend of frequent rains

Mountain Biomes High elevated forests. Often peaks are snow covered. Gradually release water to lower level streams and rivers. Prone to erosion, landslides, and avalanches Make up one fourth on the worlds land surface.

Natural Capital Degradation Clearing and degradation of tropical forests for agriculture, livestock, gazing, and timber harvesting. Clearing of deciduous forests of Europe, Asia and North America, for timber, agriculture, and urban development. Converting diverse forest into non diverse tree plantations.

Natural Capital Degradation Mountains Landless poor migrating uphill to survive. Timber extraction Mineral resource extraction Hydro-electric dams and reservoirs Increasing tourism (such as hiking and skiing) Air pollution Soil damage from off road vehicles