Unit 4 Review book Pt. 2 Flashcards
(27 cards)
Six Soil-Forming Factors.
CLORPTH
Climate
Organisms (biological activity)
Relief (topography)
Parent Material
Time
Human influence
Climate
Climate involves differences in temperature and precipitation across the globe, and both heat and water facilitate chemical and biochemical reactions. Seasonal fluctuation of heat and moisture affects processes such as freeze-thaw cycles that weather rock. Climate also helps to determine what organisms grow in a particular location.
Organisms (Biological Activity
Different local conditions support different organisms, which influence the soil in a multitude of ways. Microorganisms perform biochemical functions such as decomposition of organic matter and transformation of minerals into different forms. Animals move soils, consume vegetation, and add nutrients through waste and decomposing bodies. Plants perform physical weathering through root growth, take up soil nutrients and water, alter soil chemistry in various ways, and add nutrients when they die and decompose.
Relief
Topographical relief affects where water moves on the landscape and also the depth of the water table in a given location. Relief similarly affects erosion—which locations are likely to lose surface material through the action of wind and rain, and which locations are likely to accumulate eroded material. Topographical relief also leads to differences in how much sun different locations receive. Through these characteristics, relief influences which organisms grow in a particular location.
Parent Material:
This is the starting point for soil development. Its mineral properties, hardness, and topographical form affect how it is weathered into soil. As parent material varies from location to location, so will the soil that develops at each location. As an example, parent material rich in quartz, such as granite and sandstone, weathers into sandy soil. Shale weathers into soil richer in silt and clay.
Time
More time equals more change! Hard parent material weathers more slowly and softer material more quickly. A flat, stable topographic position develops horizons more quickly than do slopes and depressions where material is lost and gained.
Human influence
The effects of human activity must increasingly be acknowledged as a factor in soil development. Use of fertilizer, pollution, and acid rain alter soil chemistry on a broad scale.
Construction activities such as digging and plowing tend to mix soils and blur the distinctions between horizons. Human activities also lead to compaction (through the traffic of vehicles and machinery), erosion (through removal of stabilizing vegetation), and salinization (increase in salt content, through irrigation and depletion of groundwater).
Troposphere
In the broadest definition, the atmosphere is a layer of gases that’s held close to the Earth by the force of gravity. The inner four layers of the atmosphere reach an altitude that’s just about 12.5% of the Earth’s radius. The layer of gases that lies closest to the Earth is the troposphere; it extends from the Earth’s surface to about, on average, 12 km (7.5 miles) at the poles and 20 km (12.4 miles) at the equator. The troposphere is where all the weather that we experience takes place. The layer also contains 99% of the atmosphere’s water vapor and clouds. Generally, the troposphere is well-mixed from bottom to top—with the exception of periodic temperature inversions. The troposphere gets colder with altitude, decreasing 6.5°C for every kilometer of altitude (or 3.5°F for every thousand feet).
Because of its density, the troposphere contains about 75–80% of the Earth’s atmosphere by mass. You’ve probably heard about the troposphere before in the news because of the greenhouse effect. The troposphere contains the air we breathe, which is made up of 78% nitrogen and 21% oxygen. The remaining 1% includes the so-called “greenhouse” gases (GHGs).
Greenhouse Effect
The troposphere contains the air we breathe, which is made up of 78% nitrogen and 21% oxygen.
The remaining 1% includes the so-called “greenhouse” gases (GHGs).
The proportion of these gases in the troposphere is minuscule, but their effects on conditions on Earth are disproportionately significant. T
he most important of them are water vapor (H2O), carbon dioxide (CO2), and methane (CH4).
As the sun’s rays strike the Earth, some of the solar radiation is reflected back into space; however, greenhouse gases in the troposphere intercept and absorb a lot of this radiation.
This warming effect of greenhouse gases was a good thing, until their concentration in the atmosphere shot up after the Industrial Revolution.
Tropopause
a layer that acts as a buffer between the troposphere and the next layer up, the stratosphere.
This buffer zone is where the jet streams, air currents that are important drivers of weather patterns and important factors in planning airline routes, travel.
stratosphere
sits on top of the tropopause and extends about 20–50 km (7.5–31 miles) above the Earth’s surface.
As opposed to those in the troposphere, gases in the stratosphere are not well mixed and temperatures increase with distance from the Earth.
This warming effect is due to the ozone layer, a thin band of ozone (O3) that exists in the lower half of this layer.
The ozone traps the high-energy radiation of the sun, holding some of the heat and protecting the troposphere and the Earth’s surface from this radiation. The stratosphere is similar to the troposphere in gas composition, only less dense and drier, with a thousand times less water vapor. Commercial jets may also fly in the lower part of this layer.
Mesosphere
extends to about 80 km (50 miles) above the Earth’s surface and is the area where meteors usually burn up.
Temperatures again decrease here, to the coldest point in the atmosphere at the top of this layer, around –90°C (–130°F).
Thermosphere
The thermosphere extends from 80 to around 500 km above the Earth (50– 435 miles). Gases are very thin (rare) and it’s in this layer that the spectacular and colorful auroras (northern lights and southern lights) take place.
The furthest layer is the exosphere, extending to 10,000 km (6,200 miles) or more above the Earth, although the upper limit of this layer is not definitively settled.
The concentration of gases is thinnest here.
Human-made satellites orbit in the exosphere and in the upper thermosphere
The ionosphere
not a distinct layer but dispersed throughout the upper mesosphere, the thermosphere, and the lower exosphere.
The ionosphere comprises regions of ionized gases that absorb most of the energetic charged particles from the sun—the protons and electrons of the solar wind. Interestingly, the ionosphere also reflects radio waves, making long-distance radio communication possible.
Climate
The Earth’s atmosphere has physical features that change from day to day as well as patterns that are consistent over a space of many years.
The day-to- day properties such as wind speed and direction, temperature, amount of sunlight, pressure, and humidity are referred to as weather.
The patterns that are constant over many years (30 years or more) are referred to as climate.
The two most important factors in describing climate are average temperature and average precipitation amounts.
Meteorologists are scientists who study weather and climate.
The weather and climate of any given area is the result of the sun unequally warming the Earth (and the gases above it) as well as of the Earth’s rotation.
Reason why earth is unevenly heated - angle, tilt
More of the sun’s rays strike the Earth at the equator in each unit of surface area than strike the poles in the same unit area.
This is because the angle of the sun’s rays strikes the Earth more directly at the equator.
The tilt of the Earth’s axis points regions toward or away from the sun.
When pointed toward the sun, those areas receive more direct or intense light than when pointed away. This causes the seasons.
Coriolis Effect
The Earth’s surface at the equator is moving faster than at the poles, because the circumference is larger but the rotation time is the same.
Because an object or air mass nearer to the equator is moving more rapidly (from east to west), it will maintain this eastward momentum as it moves away from the equator to where the surface is moving more slowly, winding up further east.
Therefore, winds moving north from the equator near the surface are deflected to the right (east), and winds moving south from the equator are deflected to the left (east).
Conversely, winds blowing toward the equator will be deflected to the west because they are moving eastward more slowly than is the surface
in the lower latitudes where they are moving to.
So, in the Northern Hemisphere, this westward deflection will be to the right, and in the Southern Hemisphere, it will be to the left.
The resulting wind patterns are known as the prevailing winds: belts of air that distribute heat and moisture unevenly around the globe.
Convection currents, positive feedback loop
Solar energy warms the Earth’s surface.
The heat is transferred to the atmosphere by radiation heating.
The warmed gases expand, become less dense, and rise, creating vertical air flow called convection currents.
The warm currents can also hold a lot of moisture compared to the surrounding air. As these large masses of warm, moist air rise, cool air flows along the Earth’s surface to occupy the area vacated by the warm air.
This flowing air or horizontal airflow is one way that surface winds are created.
As warm, moist air rises into the cooler atmosphere, it cools to the dew point, the temperature at which water vapor condenses into liquid water.
This condensation creates clouds.
If condensation continues and the water drops get bigger, they can no longer be held up by the convection in the Earth’s atmosphere and they fall as precipitation (which can be frozen or liquid).
This cold, dry air is now denser than the surrounding air.
This air mass then sinks to the Earth’s surface, where it is warmed and can gather more moisture, thus starting the convection cell rotation again.
Convection currents, Hadley cell
On a local level, this phenomenon accounts for land and sea breezes.
On a global scale, these cells are called Hadley cells.
A large Hadley cell starts its cycle over the equator, where the warm, moist air evaporates and rises into the atmosphere.
The precipitation in that region is one cause of the abundant equatorial rainforests.
The cool, dry air then descends about 30 degrees north and south of the equator, forming the belts of deserts occurring around the Earth at those latitudes.
Seasons
The motion of the Earth around the sun and the Earth’s axial tilt of 23.5 degrees together create the seasons that we experience on Earth.
The Earth’s tilt means that sunlight hits most directly, and for the longest number of hours per day, on the parts of the Earth that face the sun most directly, and that which parts those are changes across the Earth’s orbit.
In other words, the main source of energy for a given place on Earth (the sun’s rays) varies depending on latitude and season: season because of the tilt, and latitude because the highest solar radiation per unit area is received at the equator and decreases toward the poles.
Any place will receive the most solar radiation on its longest summer day and the least on its coldest winter day.
Earth’s revolution and rotation
The Earth’s revolution, or trip around the sun, takes 365.25 days.
The calendar that we use is based on the Earth’s revolution around the sun: every four years, we have a leap year with one extra day to account for the accumulation of four quarter-days.
As the Earth revolves around the sun, it iS spinning on its axis; this spinning action is called rotation.
On Earth, it takes 24 hours, or one day, to make a complete rotation.
Interestingly, because of the Earth’s tilt, the sun rises and sets just once a year at the North and South Poles.
Approximately six months of the year at the poles are daytime, while the other six months are nighttime.
Albedo (Reflectance)
nother important property that affects the climates of different regions on Earth is albedo, the percentage of insolation (incoming solar radiation) reflected by a surface.
The lower the surface albedo, the more solar radiation is absorbed.
An albedo value of 0 corresponds to zero reflectance and absorption of all radiation, whereas an albedo value of 1 corresponds to reflection of all incoming radiation.
Snow and ice have high albedo values, while land and trees have lower albedo values.
Changes in albedo can lead to alterations in temperature. For example, snowfall may raise the albedo of an area, leading to an increase in the reflection of solar radiation and a decrease in temperature.
Causes positive feedback loop with melting of polar ice, increasing albedo, increasing melting of ice
Wind basic info
“wind” is widely used to refer to air currents, and we already know that air currents tend to flow from regions of high pressure to regions of low pressure.
wind is air that’s moving as a result of the unequal heating of the Earth’s atmosphere.
It is part of the Earth’s circulatory system and moves heat, moisture, soil, and even pollution around the planet.
Trade winds
named for their ability to quickly propel trading ships across the ocean.
The trade winds that blow between about 30 degrees latitude and the equator are steady and strong, and travel at a speed of about 11 to 13 mph.
They are caused by the surface currents of the Hadley cells, described above, along with the Earth’s direction of rotation (counterclockwise if viewed toward the North Pole).
In the Northern Hemisphere, the trade winds blow from the northeast and are known as the Northeast Trade Winds; in the Southern Hemisphere, the winds blow from the southeast and are called the Southeast Trade Winds.
