Ch.+2+E+Atmospheric+Constituents+and+in+Radiative+Forcing

Chapter 2: Changes in Atmospheric Constituents and in Radiative Forcing Section 2.1 Introduction: Ede Forcing agents- Factors which can change the rate of reflection or release of solar radiation.

Radioactive forcing- The difference between received solar radiation and released radiation.

Surface albedo- radiation that is reflected by the surface of the earth.

Since 1750, groups have concerned themselves about the change in our atmosphere (yet, we tend to ignore matter at a full scale until it’s too late). This section focuses on the anthropogenic greenhouse gas changes, aerosol changes and their impact on clouds, surface albedo changes, aviation-induced contrails, cirrus changes, solar, volcanic mechanisms and radioactive forcing.

The study is focused on finding trends in the long lived greenhouse gases such as carbon dioxide, methane, nitrous oxide, chlofluoro-carbons, hydro-chlorofluorocarbons, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride, hereinafter. These will be modeled as forcing agents. These agents have caused global temperature rises and in response that has caused our sea level to rise.



The pie chart above shows the percentage of these long term greenhouse gases in our atmosphere in 2010 (I couldn’t find an earlier version). Further study shows that carbon dioxide breaks up into carbon dioxide from decay of biomass, carbon dioxide (other) and carbon dioxide from fossil fuels which accounts for the majority of the carbon dioxide in our atmosphere (I apologize about repeating carbon dioxide so many times).

1) Tropopause: The interface between the troposphere and the stratosphere. 2)Anthropogenic: Originating in human activity (chiefly of environmental pollution and pollutants) 3)Rf: The chemical element rutherfordium. 4)Percursors: A substance from which another is formed, esp. by metabolic reaction. 5)Perturbation: A cause of such anxiety or uneasiness 6) the study of climate change taken on the scale of the entire history of Earth. It uses... 7)Aerosol: A substance enclosed under pressure and able to be released as a fine spray, typically by means of a propellant gas 8)Solar Irradiance: Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun 9)Cirrus Cloud: A wispy white cloud (usually of fine ice crystals) at a high altitude (4 to 8 miles) 10)Emissions: The production and discharge of something, esp. gas or radiation. Human activity has a lot to do with climate change also contributuing to the change in Earths' overall atmosphere. The amount of Green house gases we produce aswell as aerosols, and the biggest contributer, FOSSIL FUELS. Fossil fuels release carbon dioxide (greenhouse gas) into the atmosphere causing changes in our climate. The most commonly known green house gases are, carbondioxide, methane, nitrous oxide, and halocarbons, when we as humans relase these gases into the environment we create a larger change in the atmosphere than those that natural processes would create. The table below shows the amount of radiative forcing of climate change from 1750-2005 most of which was caused by human activity,(in long-lived gases, ozone, water vapour, surface albedo, aerosols and contrails). The only known natural change between 1750 and 2005 was solar irradiance. Aerosol particles in our atmosphere have an overall negative effect on our planet. human activity since the start of the industrial area has also ad an overall negtive effect on our atmosphere. Some of the human activity has been associated with deforestation, and has somehow had a bad effect on our precipitation. Natural changes in our atmosphereare casue by solar changes aswell as volcanic eruption, but the amount of natural process compared to that of human activity is insanely small. Today, the amount of human activity today plays a much bigger role in the future of our atmosphere than natural processes.
 * Section 2.2 Jade Legarreta**
 * Vocabulary**:
 * 2.2 Summary**:
 * Reflection**: Human activity has had a larger effect on our environment than natural occurances. Our activity has had a larger inpact and more of an atmospheric effect than anything mother nature could have done. Our greenhouse gases have released so many chemicals into our environment that our climate and atmosphere are begininning to change. Natural processes consist of volcanic eruptions and solar radiants, which have not had much of an effect for quite some time. Since the start of the industrial era in 1750 we haven't stopped manipulating our Earths atmosphere.

Section 2.3 Naomi Ruth
In 2.3 they talk about how different things can increase and decrease chemicals in Earth’s atmosphere. CO2 has increase since the industrial revolution because of burning of fossil fuel. CO2 causes a chemical change in the atmosphere causing increasing warmth to us on Earth. But other things like volcanic activity can decrease same the same chemicals that can put us in danger once again. 2.3 also explains how scientist measure the different chemicals. In different locations and different times the take an air sample and measure the levels of CO2 and CH4. From that they compare it to their previous data notice if there is an increase of decrease. If there is a sudden change scientist look for anything that could explain it. Like a volcano eruption or an change in ocean currents. The different increases and decreases in chemical compounds can change how much heat the Earth radiates. The changes cause differences in the water vapor. Since the industrial revolution the small changes in water vapor have weather changes all over the world. Picture of the Industrial Revolution

Figure 2.3. Recent CO2 concentrations and emissions. (a) CO2 concentrations (monthly averages) measured by continuous analysers over the period 1970 to 2005 from Mauna Loa, Hawaii (19°N, black; Keeling and Whorf, 2005) and Baring Head, New Zealand (41°S, blue; following techniques by Manning et al., 1997). In this section I was very confused and had to reread many sections. From what I could understand is that human activity is causing drastic changes in the CO2 and CH4, which causes water vapors to change, leading to climate shifts all over the world. The changes mainly occur above the equator and warmer regions. With the results people should not be surprised by the change in the weather.

Section 2.3 Vocabulary
Contemporaneous: living or occurring during the same period of time; contemporary. Isotope: any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in the nucleus, or different atomic weights. There are 275 isotopes of the 81 stable elements, in addition to over 800 radioactive isotopes, and every element has known isotopic forms. Isotopes of a single element possess almost identical properties. Meticulous: 1.taking or showing extreme care about minute details; precise; thorough: a meticulous craftsman; meticulous personal appearance.2.finicky; fussy: meticulous adherence to technicalities. Logarithmically: pertaining to a logarithm or logarithms. Inaccuracies: something inaccurate; error Unprecedented: without previous instance; never before known or experienced; unexampled or unparalleled: an unprecedented event. Extrapolates: to infer (an unknown) from something that is known; conjecture. Negligible: so small, trifling, or unimportant that it may safely be neglected or disregarded: The extra expenses were negligible.

Sage McKay __Aerosols: __a system of colloidal particles dispersed in a gas, smoke or fog (Dictionary.com) __Radiative: __ giving off radiation (Dictionary.com) __Parameterizations: __to describe (a phenomenon, problem, curve, surface, ect.) by the use of parameters (Dictionary.com) __Temporal: __ of or pertaining to time (Dictionary.com) __Emissions: __an act or instance of emitting (Dictionary.com) __Albedo: __the ratio of the light reflected by a planet or satellite to that received by it (Dictionary.com) __Anthropogenic: __caused or produced by humans (Dictionary.com)
 * __Section 2.4 __**
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Vocabulary: **

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Aerosols are categorized into indirect and direct effects. The direct effect is the way aerosols distribute and take up shortwave and longwave radiation, which alters “the radiative balance of the Earth-atmosphere system.” The indirect effect is the way aerosols change “the microphysical and hence the radiative properties, amount and life time of clouds.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">(Figure 2.10 shows “various radiative mechanisms associated with cloud effects”) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Surface based dimensions that are measured of aerosol assets are “size distribution, chemical composition, scattering and absorption.” These are measured using satellites. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Better-quality pictures of “aerosol optical depth in cloud-free regions” have been discovered by using new satellites. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">(Figure 2.11) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Figure 2.11 shows “optical depth” and the “geographical positions of aerosol instrumentation.” The picture quality has greatly improved from the past. Differences in satellite pictures are caused by the movement of clouds. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Advancements in the technology of surface based remote sensing is always improving and there are many different information cites available. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">**Advances in Modelling the Aerosol Direct Effect** <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Results from the many observations and studies have shown “which aerosol parameterizations are poorly constrained and/or understood.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Results are almost always filled with uncertainties. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Atmospheric sulphate aerosol is considered to be made “of sulphuric acid particles that are partly or totally neutralized by ammonia and that are present as liquid droplets or partly crystallized.” Sulphate is mostly spreading aerosol across the solar range. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Organic aerosols “are a mixture of chemical compounds containing carbon-carbon bonds produced from fossil fuels and biofuel burning and natural biogenic emissions.” Organic aerosols are released the same way as normal aerosols. There are hundreds of atmospheric organic mixtures have been found in the atmosphere. Organic aerosols are similar to sulphuric aerosols. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Organic aerosols made from fossil fuels are “relatively weakly absorbing but do absorb solar radiation at some UV and visible wavelengths.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Black carbon is a prime aerosol. When there are incomplete combustion processes, black carbon aerosols are released. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Black carbon takes in solar radiation. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">(Figure 2.12) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Figure 2.12 shows “characteristics aerosol properties related to their radiative effects.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">When sulphate aerosol is fully defused and there is additional ammonia, nitrate aerosol is formed. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Mineral dust comes from heavily harvested places, changes in surface water, and transport practices. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Mineral dust is believed “to be 30% to 50% of the total dust burden in the atmosphere.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">(Figure 2.13) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Figure 2.13 “estimates of the direct aerosol RF” from many different studies. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Aerosol atoms impact how clouds are formed. They do this by interacting with each other. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">“The local impact of anthropogenic aerosols” can decrease cloud droplet sizes and increase cloud droplet sizes. New research has shown the significance “of aerosol particle composition in the activation process and droplet evolution.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The cloud number droplet, temperature, and texture all vary by climate. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Observations are not good enough to estimate the cloud albedo**,** and satellite records are lot long enough. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The many recent enhancements made to the satellite technology are helpful, but the satellites cannot tell the difference between anthropogenic and organic aerosols. An advantage of satellites is that they are able to cover the whole word. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">In the model simulations, there are vast qualms about the total spreading of anthropogenic aerosols. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Other doubts due to model biases are the ability to directly compare results, large differences between models, and the relationships between the particles. The reservations could be caused by the droplet spectral shape. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Although there are restrictions in the current technology used, the advancements in the technology overcomes the restrictments.
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Summary: **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Introduction and Summary of the Third Assessment Report 2.4.1. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Developments Related to Aerosol Observations 2.4.2. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Satellite Retrievals 2.4.2.1. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Satellite retrievals of aerosol optical depth 2.4.2.1.1. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Surface-Based Retrievals 2.4.2.2 **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Estimates of Aerosol Direct Radiative Forcing **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Sulphate Aerosol **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Organic Carbon Aerosol from Fossil Fuels **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Black Carbon Aerosol from Fossil Fuels **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Biomass Burning Aerosol **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Nitrate Aerosol 2.4.4.5. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Mineral Dust Aerosol 2.4.4.6. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Direct RF for Combined Total Aerosol 2.4.4.7. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Aerosol Influence on Clouds 2.4.5. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Link between Aerosol Particles and Cloud Microphysics 2.4.5.1. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Estimates of the Radiative Forcing from Models 2.4.5.2. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Estimates of the Radiative Forcing from Observations and Constrained Models 2.4.5.3. **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">and **Uncertainted in Satellite Estimates 2.4.5.4.**
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Uncertainties Due to Model Biases 2.4.5.5. **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Assessment of the Cloud Albedo Radiative Forcing 2.4.5.6. **


 * <span style="font-family: 'Times New Roman','serif'; font-size: 18px;">Reflection 2.4 **

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">It is very interesting that aerosols alter clouds so immensely. Aerosols are not widely known by the general public, even though they are so important to the formation and “life” of clouds. They affect cloud’s temperature, texture, how much they precipitate, and the size of the rain droplets. It is thought-provoking to wonder how different clouds would be without aerosols influencing them. Clouds would probably be very unlike the way they currently are without the impact of aerosols. Information about how aerosols affect clouds is not only important to know about, but is also important because it happens everywhere. Anywhere there is a cloud, which is basically the whole world, aerosols are affecting clouds.


 * 2.5 and 2.8 Anthropogenic Changes in Surface Albedo and the S.E.B.**

Vocabulary Anthropogenic – Of or relating to human activity Albedo – Reflection coefficient (The reflection value of the planets surface) S.E.B. – The energy or heat “budget” of the earths surface. Heat fluxes – Heat or thermal flux is the rate of heat energy transfer through a given surface RF(Radiative forcing) – Radiative forcing is the difference between radiant energy received by the earth and energy reflected back into space. BC – black carbon is a climate forcing agent formed through the incomplete combustion of fuels and is emitted in both anthropogenic and naturally occurring soot. T.A.R. – IPCC Third Assessment Report Perturb – Upset

Anthropogenic actions can change the physical properties of the land can perturb the climate, both by causing RF and by changing other processes like the fluxes of different heats like latent and sensible, and the transfer of momentum from the atmosphere. In addition to adding to the greenhouse gases and aerosols, anthropogenic changes in the vegetation covering the landscape can change things like surface albedo and other physical properties. The surface albedo of agricultural land can greatly differ from natural land especially if the latter is forest. An area can be fully covered in snow but the trees can disrupt that by growing above the snow, changing the albedo.

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Sage McKay
 * __<span style="font-family: 'Times New Roman','serif'; font-size: 18px;">Section 2.7 Natural Forcings __**

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">**Definitions** <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__irradiance:__ radiant energy per unit area, the fact of shining brightly. (Google) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__faculae:__ a bright region on the surface of the sun (Google) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__empirical:__ based on, concerned with, or verifiable by observation or experience rather than theory or pure logic. (Google) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__tropospheric:__ the lowest atmospheric layer (Google) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__stratosphere:__ the region of the upper atmosphere extending upward from the tropopause to about 30 miles (50 km) above the earth, characterized by little vertical change in temperature (Dictionary.com) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__minima:__ minimum __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">fluctuations: __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> continual change from one point or condition to another (Dictionary.com) __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">empirical: __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> based on observation or experience rather than theory or logic (Google) __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">aerosols: __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> a container under pressure holding a substance (Google)

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">**Summary** <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__Solar Variability 2.7.1__ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Rough calculations of long-term solar "shining" changes have been reexamined and the new research has shown that bright regions on the surface of the sun are probably caused by slighter"irradiance increases." Observations have shown that "since the TAR have strengthened the evidence for solar forcing of climate change" by identifying noticeable low atmospheric layers which are "changes associated with solar variability during the solar system." <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__Satellite measurements of total solar irradiance 2.7.1.1.1.__ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">There are four mechanisms in space that calculate the total solar irradiance, and they send their information to a database that has been around since 1978. The information found by the devices have been used to conduct many experiments for nearly 40 years. Some of the experiments are VIRGO, UARS, and SORCE. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__Observed decadal trends and variability 2.7.1.1.2.__

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">

<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Figure 2.16 shows the "different composite records of total solar irradiance have been constructed from different combinations of the direct radiometric measurements." The graph shows that the two irradiance records are very similar. "Solar irradiance levels are comparable in the two most recent cycle minima when absolute uncertainties and sensitivity drifts in the measurements are assessed." <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__Measurements of solar spectral irradiance 2.7.1.1.3.__ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Solar Radiation and Climate Experiment (SORCE), the most recent study, has shown that the differences of solar spectral irradiances "occur at all wavelengths, primarily in response to changes in sunspots and faculae." SORCE observations have lengthened the UV spectrum past 120-400 wavelengths.Results about UV spectral irradiance are similar to previous experiments conducted. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The most energy change occurs between 400-500 wavelengths."Broken down by wavelength range these irradiance changes are 1.3% at 200 to 300 nm, 0.2% at 315 to 400 nm, 0.08% at 400 to 700 nm, 0.04% at 700 to 1,000 nm and 0.025% at 1,000 to 1,600 nm." <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Decreased irradiance can be caused by "sunspot blocking," which can take over "facular brightening." SORCE observations have been in concurrence with the original SORCE findings, but the observations have been "too short to provide definitive information about the amplitude of solar spectral irradiance changes during the solar cycle." <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__Reconstructions of past variations in solar irradiance 2.7.1.2.1.__ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Long-term bright spots on the Sun differences have lessened over 300 years. The entire irradiance of the Sun has lessened in recent years. Research has "suggested that the Sun is capable of a broader range of activity than witnessed during recent solar cycles," which can be seen in figure 2.16. Research from the 17th century Maunder Minimum is compared with new information in Table 2.10 (seen below). <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Past research about the Sun's irradiance patterns have been recently thrown up in the air. New studies have proven that " the relationship between solar irradiance and geomagnetic and cosmogenic indices is complex, and not necessarily linear." The new research shows that the amplitude is much less than earlier thought. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">"14C and 10Be cosmogenic isotope records in tree rings and ice cores" are used to discover the Sun's cycles 90 years to over 2,000 years ago. The results allude to the fact that the Sun's current cycles mirror cycles from the 12th century. Solar liveliness has been much higher in the past 70 years <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">__Implications for solar radiative forcing 2.7.1.2.2.__ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">(Table 2.10.) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">“Comparison of the estimates of the increase in RF from the 17th-century Maunder Minimum (MM) to contemporary solar minima, documenting new understanding since the TAR.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">(Figure 2.17) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The total solar irradiance from 1600-2000. “The upper envelope of the shaded regions shows irradiance variations arising from the 11-year activity cycle. The lower envelope is the total irradiance reconstructed by Lean (2000), in which the long-term trend was inferred from brightness changes in Sun-like stars.” __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Indirect Effects of Solar Variability 2.7.1.3. __ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Very little (1%) of the Sun’s glowing “energy is in the UV portion of the spectrum,” and the Earth’s atmosphere absorbs it. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The stratosphere is affected by the troposphere, anthropogenic effect, internal cycles, and natural influence of solar activity. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Numerous observed interactions “have been reported between globally averaged low-level cloud cover and cosmic rays fluxes.” __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Radiative Effects of Volcanic Activity 2.7.2.1 __ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Sulphur gases and volcanic ash are released into the stratosphere when explosive volcanoes erupt. “the stratospheric aerosols resulting from” the volcanic eruptions “yield substantial transitory perturbations to the radiative energy balance of the planet.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The histories of major volcanic eruptions during the history of the world are documented by volcanic “aerosols” conserved in ice when they are transported into the atmosphere. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The eruption of Mt. Pinatubo in 1991 is “the best-documented explosive volcanic event to date.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">By using satellites, volcanic aerosol data is easily found. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Many studies of aerosols are still being conducted. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">(Figure 2.18) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">“Visible (wavelength 0.55 μm) optical depth estimates of stratospheric sulphate aerosols formed in the aftermath of explosive volcanic eruptions that occurred between 1860 and 2000.” __<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Thermal, Dynamical and Chemistry Perturbations Forced by Volcanic Aerosols 2.7.2.2. __ <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Four instruments, altering Earth’s surface temperature, horizontal and vertical heating gradients, internal climate system variability, and surfaces for heterogeneous chemistry, all have their own response design. The mechanisms all “depend on the background state of the climate system.” <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">It is important to decipher aerosol radiative effects. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">“Stratospheric aerosols affect the chemistry and transport processes in the stratosphere.” Studies show the effects of volcanic eruptions “on the stratospheric ozone layer.” Lower stratosphere warming is caused by aerosol effects. Volcanic-aerosols make changes in the atmospheric flow, which causes warming in middle and high latitudes. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The information in 2.7 is interesting because it is remarkable to see how solar irradiance has changed or stayed the same over the past couple of centuries. It is extraordinary that the information has been preserved for so long. It is also fascinating that there are records of all the major volcanic eruptions starting with the first volcanic explosion ever. It is very surprising that there are records of century, even millennia, old information about Earth and that scientists have access to all the information through modern technology. One can only wonder what future technology will be able to tell us about the world.
 * <span style="font-family: 'Times New Roman','serif'; font-size: 18px;">Reflection 2.7 **

Summary
RF’s can change because of human activity. Human activity causes CO2 to change the tropospheric ozone and the stratospheric ozone. Volcanic activity changes RF greatly in a very short amount of time. Everything else has changed but in a slow progressive state, nothing to drastic. Changes in the RF have been changing the climate all over the world. Between the years 1890 and 2000 the radar show how there is an increase in warmth. From what I could tell this section is talking about how different global movements change RF. Certain things change in very quick movements and return normal just as fast, like volcanos. But other things that are changing slowly like the ozone are decreasing which is a why we are having a change in the climate. While some things go up others are going down.



<span style="font-family: 'Calibri','sans-serif'; font-size: 12px;">Figure 2.24. Instantaneous change in the spatial distribution of the net (solar plus longwave) radiative flux (W m–2) due to natural plus anthropogenic forcings between the years 1860 and 2000.



The image above shows the location in which there is air traffic. Aircrafts produce contrails in the upper troposphere. These contrails reflect radiation as it tried to escape and come in. The calculations of the coverage of contrails are uncertain because supersaturated regions of our atmosphere are not well known. It is estimated that contrails account for +0.01 W m-2 (Radioactive Forcing is measured in Watts) in 2005. New changes in an estimate say that the net Radioactive Forcing for a given contrail coverage will decrease by about 20%.-



The image above shows the contrails. Aviation aerosol can lead to changes in cirrus clouds. It is called Aviation-Induced cloudiness which is defined as all changes in cloudiness due to aviation operations. The estimate of Aviation Induced cloudiness includes contrails because as time progresses they lose their linear shape therefore become non distinguishable from background cirrus clouds. It is estimated that the ratio of Aviation-Induced cloudiness cover to persistent linear contrails range from 1.8 to 10. It is assumed that air traffic induces cirrus clouds, but in some places this is false, therefore making the trend inconclusive. But it is found that there is less Radioactive Forcing in places with air traffic compared with +0.03 W m-2 to +0.04 W m-2. Issues with Aviation-Induced cloudiness are that with Aviation-Induced cloudiness the temperatures over the U.S. are warming at a rate of 0.3⁰C per decade. Another problem is that if we stop Aviation-Induced cloudiness the temperatures rise as well as shown when flights were grounded on September 11, 2001. Global aviation operations emit aerosols and aerosol precursors into the troposphere and lower stratosphere. These aerosols have been found to be harmful to the creation of ice clouds. It was found true due to an experiment in a cloud chamber where they could were coated with sulfur (type of aerosol) and found that a decrease in the effectiveness of ice nuclei. Fore hence this essentially reduces snowfall which is necessary to reflect radiation. In overall no estimates have been made if we continue. Reflection: Aerosols in our atmosphere are causing much of the global warming by fracturing the surface albedo. We need to change the way we run our air traffic into something more environmentally friendly. If built an airplane that runs both on fuel and electricity to keep it in air, it would help much of the problem above. Relating to class we had learned about global warming and how pollution of such gasses like aerosols is causing our planet to heat up. Something has to change soon before we are responsible for the extinction of many species and maybe ourselves. -Ede