Geo 2

Gravity effects air because

Air has mass.

Newton's Law of Universal Gravitation

"Any two objects separated in space are attracted to each other by a force proportional to the product of their masses and inversely proportional to the square of the distance between them."

Methane

"Methane is a very strong greenhouse gas. Since 1750, methane concentrations in the atmosphere have increased by more than 150%. The primary sources for the additional methane added to the atmosphere (in order of importance) are: rice cultivation; domestic grazing animals; termites; landfills; coal mining; and, oil and gas extraction. Anaerobic conditions associated with rice paddy flooding results in the formation of methane gas. However, an accurate estimate of how much methane is being produced from rice paddies has been difficult to ascertain. More than 60% of all rice paddies are found in India and China where scientific data concerning emission rates are unavailable."

Nitrogen

"Nitrogen is removed from the atmosphere and deposited at the Earth's surface mainly by specialized nitrogen fixing bacteria, and by way of lightning through precipitation. The addition of this nitrogen to the Earth's surface soils and various water bodies supplies much needed nutrition for plant growth. Nitrogen returns to the atmosphere primarily through biomass combustion and denitrification. "

Oxygen

"Oxygen is exchanged between the atmosphere and life through the processes of photosynthesis and respiration. Photosynthesis produces oxygen when carbon dioxide and water are chemically converted into glucose with the help of sunlight. Respiration is the opposite process of photosynthesis. In respiration, oxygen is combined with glucose to chemically release energy for metabolism. The products of this reaction are water and carbon dioxide."

Ozone

"Ozone's role in the enhancement of the greenhouse effect has been difficult to determine. Accurate measurements of past long-term (more than 25 years in the past) levels of this gas in the atmosphere are currently unavailable. Moreover, concentrations of ozone gas are found in two different regions of the Earth's atmosphere. The majority of the ozone (about 97%) found in the atmosphere is concentrated in the stratosphere at an altitude of 15 to 55 kilometers above the Earth's surface. This stratospheric ozone provides an important service to life on the Earth as it absorbs harmful ultraviolet radiation. In recent years, levels of stratospheric ozone have been decreasing due to the buildup of human created chlorofuorocarbons in the atmosphere. Since the late 1970s, scientists have noticed the development of severe holes in the ozone layer over Antarctica. Satellite measurements have indicated that the zone from 65° North to 65° South latitude has had a 3% decrease in stratospheric ozone since 1978. Ozone is also highly concentrated at the Earth's surface in and around cities. Most of this ozone is created as a by product of human created phtochemical smog. This buildup of ozone is toxic to organisms living at the Earth's surface."

Nitrous Oxide

"The average concentration of the greenhouse gas nitous oxide is now increasing at a rate of 0.2 to 0.3% per year. It has an important role in the artificial fertilization of ecosystems. In extreme cases, this fertilization can lead to the death of forests, eutrophication of aquatic habitats, and species exclusion. Sources for the increase of nitrous oxide in the atmosphere include: land-use conversion; fossil fuel combustion; biomass burning; and soil fertilization. Most of the nitrous oxide added to the atmosphere each year comes from deforestation and the conversion of forest, savanna and grassland ecosystems into agricultural fields and rangeland. Both of these processes reduce the amount of nitrogen stored in living vegetation and soil through the decomposition of organic matter. Nitrous oxide is also released into the atmosphere when fossil fuels and biomass are burned. However, the combined contribution to the increase of this gas in the atmosphere is thought to be minor. The use of nitrate and ammonium fertilizers to enhance plant growth is another source of nitrous oxide. How much is released from this process has been difficult to quantify. Estimates suggest that the contribution from this source represents from 50% to 0.2% of nitrous oxide added to the atmosphere annually."

Carbon Dioxide

"The volume of this gas has increased by over 35% in the last three hundred years. This increase is primarily due to human induced burning from fossil fuels, deforestation, and other forms of land-use change. Carbon dioxide is an important greenhouse gas. The human-caused increase in its concentration in the atmosphere has strengthened the greenhouse effect and has definitely contributed to global warming over the last 100 years. Carbon dioxide is also naturally exchanged between the atmosphere and life through the processes of photosynthesis and respiration."

Water Vapor

"Water vapor varies in concentration in the atmosphere both spatially and temporally. The highest concentrations of water vapor are found near the equator over the oceans and tropical rain forests. Cold polar areas and subtropical continental deserts are locations where the volume of water vapor can approach zero percent. Water vapor has several very important functional roles on our planet: It redistributes heat energy on the Earth through latent heat energy exchange. The condensation of water vapor creates precipitation that falls to the Earth's surface providing needed fresh water for plants and animals. It helps warm the Earth's atmosphere through the greenhouse effect."

Permanent Gas

% concentrations are relatively constant throughout the lower atmosphere Oxygen 21% --- Nitrogen 78%

Atmosphere at Sea Level

1 Atmosphere

Pascals at Sea Level

101,325 pascals

Millibars at Sea Level***

1013.25 millibars (decreases rapidly above sea level)

1 cm mercury = ____ millibars

13.3 millibars

Atmospheric Pressure at Sea Level

14.7 lbs per square inch

Inches of mercury at Sea Level

29.92 in Hg

On Earth, gravity can be expressed as

A force of acceleration of about 9.8 meters per second per second. As a result, objects falling toward earth increase 9.8m/sec every second. (First sec 9.8m, second sec 19.6 m, etc. until reaching terminal velocity.)

Current concentration of CO2 in atmosphere

About 400ppm

Clouds

Additional important feedback mechanisms involve clouds. Clouds are effective at absorbing infrared radiation and therefore exert a large greenhouse effect, thus warming the Earth. Clouds are also effective at reflecting away incoming solar radiation, thus cooling the Earth. A change in almost any aspect of clouds, such as their type, location, water content, cloud altitude, particle size and shape, or lifetimes, affects the degree to which clouds warm or cool the Earth. Some changes amplify warming while others diminish it. Much research is in progress to better understand how clouds change in response to climate warming, and how these changes affect climate through various feedback mechanisms

Montreal Protocol 1987:

Addressed the hole in the ozone layer - phased out CFCs globally. The on one hole is expected to recover back to the levels they were in the 1980's by the end of this century.

The ozone layer consists of

All other atmospheric gases plus a higher concentration of ozone (10ppm at 30-30km above the surface) Absorbs UV from the sun protecting us from strong radiation Is a pollutant at the surface

The atmosphere behaves

As if it were a single gas

Tropopause

At the top of the Troposphere the temperature stops decreasing. This change in trend signals the Tropopause. Because of this shift, clouds do not tend to form or grow above the Tropopause. Still, there is ample room for thunderstorms to form in the Troposphere, with the tallest clouds being able to grow to 40,000 feet (7.5 miles) or more.

Greenhouse Effect

Based on the fact that certain gases have the quality of absorbing heat easily (Carbon dioxide, methane, ozone, and water vapor.) By absorbing heat, they increase the temperature of the atmosphere. With GHE Earth's annual global temperature is 15 degrees Celsius. Without GHE the annual global temperature would be -18 degrees Celsius.

Gross Primary Productivity

Because all the energy fixed by a plant is converted into sugar, it is theoretically possible to determine a plant's energy uptake by measuring the amount of sugar produced. This quantity is called gross primary productivity. Measurements of the buildup of sugar in the plant reflect gross primary productivity less respiration, or net primary productivity.

The Greenhouse effect impacts

Both weather and Climate

Photosynthesis Product

C6H12O6 + 6O2 carbohydrate glucose and oxygen (which is released into the atmosphere.) All of the sugar glucose is produced in the specialized photosynthetic cells of plants and some other organisms. Glucose is produced by chemically combining carbon dioxide and water with sunlight. This chemical reaction is catalyzed by chlorophyll acting in concert with other pigment, lipid, sugars, protein, and nucleic acid molecules. Sugars created in photosynthesis can be later converted by the plant to starch for storage, or it can be combined with other sugar molecules to form specialized carbohydrates such as cellulose, or it can be combined with other nutrients such as nitrogen, phosphorus, and sulfur, to build complex molecules such as proteins and nucleic acids.

Cause of ozone hole

CFC's / Chlorofluorocarbons (coolants such as freon)

Gravity influences all atmospheric processes. It causes density and pressure of air to ___________ exponentially as one move away from the surface of Earth.

Decrease

In the absence of other forces, as pressure decreases, temperature and density will....

Decrease

Different layers of the atmosphere experience

Different temperature trends and are used to differentiate layers of the atmosphere

Keeling Curve

Each molecule of CO2 has a lifetime of about 100 yrs in the atmosphere. CO2 concentration has increased due to humans burning fossil fuels.

Atmospheric Pressure

Gas molecules are always in motion and exert pressure in all directions

Carbon Dioxide and Methane

Have increased over time

Where the ozone layer is located

The ozone layer is a region of concentration of the ozone molecule (O3) in the Earth's atmosphere. The layer sits at an altitude of about 10-50 kilometers, with a maximum concentration in the stratosphere at an altitude of approximately 25 kilometers.

The Ozone Hole

In recent years, scientists have measured a seasonal thinning of the ozone layer primarily at the South Pole. This phenomenon is being called the ozone hole. Most prevalent above Antartica. Noted since the late 1970's.

If pressure is held constant

It causes the temperature of a gas to be proportional to volume, and inversely proportional to density. Thus, increasing temperature of a unit mass of gas causes its volume to expand and its density to decrease as long as there is no change in pressure.

Aerosols

Liquid droplets or solid particles such as dust or smoke particles suspended in a gas / the air

Barometer

Measures Atmospheric Pressure

Aneroid Barometer

Most common type of barometer used in homes. Inside this instrument is a small, flexible metal capsule called an aneroid cell. In the construction of the device, a vacuum is created inside the capsule so that small changes in outside air pressure cause the capsule to expand or contract. The size of the aneroid cell is then calibrated and any change in its volume is transmitted by springs and levers to an indicating arm that points to the corresponding atmospheric pressure.

Atmospheric Composition Up to an Altitude of 25km * most important for Earth's biosphere

Nitrogen * 78.08% Oxygen * 20.95% Water * 0 to 4% Argon 0.93% Carbon Dioxide * 0.0360% Neon 0.0018% Helium 0.0005% Methane * 0.00017% Hydrogen 0.00005% Nitrous Oxide * 0.0003% Ozone * 0.000004%

These two gasses make up 99% of the Earth's atmosphere

Nitrogen and Oxygen

Another unit of force sometimes used by scientists to measure atmospheric pressure is the newton.

One millibar equals 100 newtons per square meter (N/m2).

Products of Respiration

One of the products of respiration is energy, which is released via the chemical decomposition of glucose. Other products of this chemical reaction are carbon dioxide (CO2) and water (H2O).

Creation and destruction os Ozone

Ozone is created naturally in the stratosphere by the combining of atomic oxygen (O) with molecular oxygen (O2). This process is activated by sunlight. Ozone is destroyed naturally by the absorption of ultraviolet radiation, O3+ UV >>> O2 + O and by the collision of ozone with other atmospheric atoms and molecules. O3 + O ... 2O 2 O3 + O3 ... 3O2

Atmospheric Gases are classified as

Permanent or Variable

Two main processes used by living systems to capture and use energy

Photosynthesis and Respiration

Plant Respiration

Plants absorb CO2 and use water, sun, and nutrients to make Carbohydrates via photosynthesis

Photosynthesis Process

Plants can capture the electromagnetic energy from the Sun 6CO2 + CH2O + light energy >>> C6H12O6 + 6O2

The ideal gas law says

Pressure = density * temperature * gas constant

Two mathematical equations; Ideal Gas Law

Pressure x Volume = Constant x Temperature and Pressure = Density x Constant x Temperature

The industrial era - The greenhouse effect - and Global Warming

Several components of the climate system, notably the oceans and living things, affect atmospheric concentrations of greenhouse gases. In the industrial era, human activities have added greenhouse gases to the atmosphere, primarily through the burning of fossil fuels and clearing of forests. Adding more of a greenhouse gas, such as CO2, to the atmosphere intensifies the greenhouse effect, thus warming Earth's climate.

Other than gasses, the atmosphere is also composed of

Solids and liquids

Troposphere

Temperature decreases with altitude

Stratospheric inversion

Temperature rises with altitude

Effects of a thinning Ozone layer / increased UV radiation

The ozone layer naturally shields Earth's life from the harmful effects of the Sun's ultraviolet (UV) radiation. A severe decrease in the concentration of ozone in the ozone layer could lead to the following harmful effects: An increase in the incidence of skin cancer (ultraviolet radiation can destroy acids in DNA). A large increase in cataracts and Sun burning. Suppression of immune systems in organisms. Adverse impact on crops and animals. Reduction in the growth of phytoplankton found in the Earth's oceans. Cooling of the Earth's stratosphere and possibly some surface climatic effect.

The greenhouse effect

The Sun powers Earth's climate, radiating energy at very short wavelengths, predominately in the visible or near-visible (e.g., ultraviolet) part of the spectrum. Roughly one-third of the solar energy that reaches the top of Earth's atmosphere is reflected directly back to space. The remaining two-thirds is absorbed by the surface and, to a lesser extent, by the atmosphere. To balance the absorbed incoming energy, the Earth must, on average, radiate the same amount of energy back to space. Because the Earth is much colder than the Sun, it radiates at much longer wavelengths, primarily in the infrared part of the spectrum. Much of this thermal radiation emitted by the land and ocean is absorbed by the atmosphere, including clouds, and reradiated back to Earth. This is called the greenhouse effect.

Evangelista Torricelli Atmospheric Pressure Experiment

The first measurement of atmospheric pressure began with a simple experiment performed by Evangelista Torricelli in 1643. In his experiment, Torricelli immersed a tube, sealed at one end, into a container of mercury (see Figure 7d-2 below). Atmospheric pressure then forced the mercury up into the tube to a level that was considerably higher than the mercury in the container. Torricelli determined from this experiment that the pressure of the atmosphere is approximately 30 inches or 76 centimeters. He also noticed that height of the mercury varied with changes in outside weather conditions.

Respiration

The oxidation of sugar by organisms is called respiration. This process occurs in both plants and animals. In most organisms, respiration releases the energy required for all metabolic processes. This chemical reaction can be described by the following simple equation: C6H12O6 + 6O2 >>> 6CO2 + 6H2O + released energy

Greenhouse Gases

The two most abundant gases in the atmosphere, nitrogen (comprising 78% of the dry atmosphere) and oxygen (comprising 21%), exert almost no greenhouse effect. Instead, the greenhouse effect comes from molecules that are more complex and much less common. Water vapour is the most important greenhouse gas, and carbon dioxide (CO2) is the second-most important one. Methane, nitrous oxide, ozone and several other gases present in the atmosphere in small amounts also contribute to the greenhouse effect.

Weather (clouds and precipitation) occur in the _________.

Troposphere The Troposphere contains about 80% of the atmospheric mass, because gravity's pull on the atmosphere compresses it close to the Earth's surface. This means the atmospheric density and pressure are also highest near the surface of the Earth. The air in the troposphere is heated by the surface of the earth, via radiation, convection and conduction. Consequently, the temperature is highest near the surface, and decreases with altitude in the Troposphere.

Variable Gases

Water Vapor / Humidity (0-4%) Carbon Dioxide (400ppm) Methane (1.8ppm) Ozone (<0.1ppm) in the troposphere and (10ppm) in the stratosphere

The stratosphere differs from the troposphere in 2 major ways (Ozone layer)

While the gases in the Troposphere are well mixed, the Stratosphere holds the ozone layer. The ozone layer is not pure ozone, in fact, only about 10 molecules out of every million are ozone in the vicinity of the ozone layer. However, 10 ppm is a much higher concentration of ozone than found anywhere else in the atmosphere. The other difference with the Stratosphere is that the temperature here increases with altitude. This increase in temperature is because this layer is heated by absorbing ultraviolet rays from the sun. Incoming UV radiation is absorbed by oxygen molecules (O2), causing them to heat up and break apart into two oxygen atoms (O + O). These oxygen atoms then combine with other oxygen molecules to form ozone (O3). Ozone molecules also absorb UV rays, and so the ozone layer is created by atmospheric absorption of UV. Absorbing energy results in an increase in energy in the absorber (in this case ozone and oxygen molecules). Part of this energy goes into breaking apart the molecules, but part goes into heating them up. The higher up in the Stratosphere, the more UV is absorbed, and the higher the temperatures. So unlike the Troposphere, which is heated by the Earth from below, the Stratosphere is directly heated by solar ultraviolet radiation from above

Animals: Indirect Photosynthesis

animals get the energy they need for maintenance of their bodies tissues, growth, and reproduction indirectly from photosynthetic organisms.

Climatology

he study of climate. By its nature it is statistical, though understanding the implications of the statistics requires some understanding of the weather that resulted in the statistics.

Location - The greenhouse effect

in the cold, dry polar regions, the effect of a small increase in CO2 or increases, further intensifying the greenhouse effect. This in turn causes more warming, which causes an additional increase in water vapour, in a self-reinforcing cycle. This water vapour feedback may be strong enough to approximately double the increase in the greenhouse effect due to the added CO2 alone.

Standard sea-level pressure

is said to be 76.0 cm or 29.92 inches or 1013.2 millibars.

Scientists often use ______ as their preferred unit to measure pressure.

kilopascal (kPa). 1 kilopascal is equal to 10 millibars.

Climatologist

looking for big picture information about the Earth-atmosphere system, and is particularly interested in changes that occur. Changes in climate can occur for various reasons and on different time scales. Just like we can have a warm day followed by a cool day, we can have a warm 10 year period followed by a cool one, or a dry period followed by a wet one. However, the driving forces behind a cold decade are quite different than the driving forces behind a cold day.

When temperature is held constant

the density of a gas is proportional to pressure volume is inversely proportional to pressure Accordingly, an increase in pressure will cause an increase in density of the gas and a decrease in its volume.

There are relationships between

temperature, pressure, density and volume, that relate to the Earth's atmosphere.

Without the natural GreenHouse Effect

the average temperature at Earth's surface would be below the freezing point of water.

Climate

the general nature of the weather in a location or region, defined statistically, and based on historical weather measurements - usually over a period of 30 years.

Stratosphere

the layer above the troposphere. Like the lower layer, density and pressure continue to decrease with altitude here in the Stratosphere. By the time you reach the top of the Stratosphere at 30 miles, more than 99% of the atmosphere's gas molecules are between you and the Earth.

If a volume is kept constant

the pressure of a unit mass of gas is proportional to temperature. If temperature increase so will pressure, assuming no change in the volume of the gas.

Meteorology

the study of weather at different scales - local, regional, country wide, and global.

Meteorologist

uses observations of weather variables, and applies his or her knowledge of the forces and mechanisms that cause weather systems to develop, change, and dissipate to predict what the weather will be like in a certain area over a short period of time (hours to weeks).