Atmospheric scientists

Following this interplay between observations and theory, many atmospheric scientists began studying chemical reactions of ozone in the upper atmosphere. Chemists duplicated atmospheric conditions in the laboratory and measured how fast various chemical reactions occur. The results of these experiments were used to create theoretical models of the upper atmosphere and predict how the ozone concentration would change as CFCs were... 

Smog contains nitrogen oxides, ozone, and iarger moiecuies. The chemistry of smog is compiex and not fully understood. Atmospheric scientists are studying how smog forms and how it can be prevented. 

Although the great majority of atmospheric scientists believe that the predictions of earth warming from fossil firel burning are valid, there are some that express doubts about the predictions. The National Academy of Sciences indicated in their 1990 book, One Earth One Future that there were indeed uncertainties in the difficult calculations but they noted that if C02 emissions continued to increase, future earth warming may be greater, rather than less than projected. Thus, it does not seem responsible to wait for proof, when it may then not be possible to correct the situation... 

Although this overview of the electrodynamic balance and its applications has been directed to chemical engineers, it is hoped that physicists, chemists, atmospheric scientists, aerosol researchers, and environmental engineers will find something here to interest them. 

In spite of the occurrence of natural events such as the eruption of Krakatoa, scientists are now well aware that human activities can have serious long-term effects on the Earth s atmosphere. The hrst such effect to be noticed historically was the increase in acid precipitation resulting from the combustion of fossil fuels. Acid precipitation is also known as acid rain or acid deposition. The second, discovered in the mid-20th century, was the depletion of stratospheric ozone. More recently, atmospheric scientists established a link between so-called greenhouse gases and global climate change. 

The sources of particles in the atmosphere are of much current interest. This is true from the viewpoint of both the geo-atmospheric scientist and the pollution control specialist. For the atmospheric chemist or geochemist, the identities and the relative contributions of sources are important for understanding 1) atmospheric element cycles and budgets, and 2) the chemical content of precipitation. 

An approach widely used by atmospheric scientists is to infer the imaginary part of the refractive index k from measurements of the absorption coefficient a of particulate samples. Diffuse reflection, the photoacoustic effect, and integrating plates have been used for determining absorption even in the presence of considerable scattering these methods are discussed briefly in the following section. The relation (2.52) between a and k, a - 4nk/, is, of course, strictly valid only for homogeneous media. But under some circum-... 

Practicing atmospheric scientists should find the book useful as a resource, and scientists from other disciplines, such as analytical and physical chemistry, electrical and mechanical engineering, physics, and instrumentation, should find it a good introduction to the field. 

This book is aimed at the physical chemist, spectroscopist, and atmospheric scientist interested in photochemistry. As a reference book it lists about 1200 papers, including some original classic studies and those of recent years up to July 1977. The space limitation and the tremendous amount of publication in the last decade have prevented inclusion of some important papers. I apologize to those whose work has not been quoted. 

Concentrations of atmospheric C02 have increased dramatically in the last 150 years as a result of increased fossil fuel use. Atmospheric scientists worry that global atmospheric warming may occur as a result. 

A 2003 workshop attended by top atmospheric scientists in Berlin concluded that the shielding effect of aerosols may be far greater than previously estimated. Nobel laureate Paul Crutzen said... 

You do constantly experience the pressure exerted by Earth s atmosphere. Scientists estimate that the atmosphere has a mass of 5.1 x 1018 kg. Thus air molecules, which have mass, are being pulled down by gravity and are exerting pressure on all objects on Earth. Figure 11.9 shows how much pressure is exerted by the atmosphere over an area of 1 m2. 

The safety of ultrafine particles remains to be clearly elucidated and requires the collaborative input of toxicologists (animal, cellular, molecular), epidemiologists, clinicians (pulmonary, cardiovascular, neurological), and atmospheric scientists. There are several published studies to indicate that ultrafine particles pose a higher toxicity risk compared with their larger counterparts [258-261], Figure 1 outlines the potential effects of ultrafine particles on respiratory mucosa, the cardiovascular system, and central and peripheral nervous systems, upon inhalation. 

Atmospheric scientists often use mixing ratios to express the concentrations of trace compounds in ain Mixing ratios are often expressed as ppmv (parts per million volume) ... 

For more information, see S. F.lliott and F. S. Rowland, Chlorofluoroearbons and Stratospheric Ozone," J. Cbem. Ed. 64 (19S7) 3S7, and P. S. Zurer, "Ozone Depletion s Recurring Surprises Challenge Atmospheric Scientists," Chon, ami E.iig. News, Mav 24, 1993 , S. 

It is well known that SO2 is a water soluble gas and its oxidation occurs in an oxygen saturated solution namely in the presence of ion metals, which may act as catalysts. A first order rate constant for its conversion to sulphate has been assigned the conversion process in the atmosphere leads however to several oxidation products SO3, H2SO4, NH4HSO4 (NH4)2S04 etc. so that the evaluation of the mechanism and rates of the heterogeneous paths of SO2 oxidation within the troposphere have a great interest for atmospheric scientists. 

This happened because of our investigation of the rate of nucleation of ice in deeply supercooled water. Previous laboratory studies of the freezing of water occurred in substantially warmer water and were blind to the phase of ice obtained. We studied water undergoing nucleation at roughly the temperature of nucleation in cirrus clouds, I believe. I understand that what happens in cirrus clouds has an important effect on the climate. Moreover, we showed directly that the ice first nucleated was the metastable cubic ice, not the ordinary hexagonal ice. Atmospheric scientists had inferred that result from indirect evidence. Previously it had not been possible to carry out experiments like ours in the laboratory, which is why our work attracted the attention of atmospheric scientists. 

C What is the greenhouse effect Why is it a matter of great concent among atmospheric scientists ... 

Atmospheric Scientist National Center for Atmospheric Research... 

Examinations of the solar activity cycle and the unusually cold weather of the Maunder minimum period have spurred significant controversy among astronomers, atmospheric scientists, and climatologists. The period from about 1300-1715 is known as the Little Ice Age in Europe, a period characterized by unusually long and cold winters. This period coincides closely with the time during which the Sun is known to have had time of inactivity, with some of the worst weather occurring squarely during the Maunder minimum. 

Despite the ongoing controversy, for which there is decidedly no definitive answer as of the year 2000, there is no doubt the Maunder minimum years were a time of significant misery in Europe, with the long, harsh winters leading to shortened growing seasons, failed crops, and widespread famine. Whether, or to what degree, the Sun is responsible for this, is an important question for atmospheric scientists and astronomers to tackle over the next few decades. 

Because of their tranendous effect on marry tropical areas, atmospheric scientists corrtinue to study the fomra-... 

Zurer, P.S. Ozone Depletion s Recurring Surprises Challenge Atmospheric Scientists. Chemical cmd Engineering News (May 24,1993) 8-18. 

If too much CO2, water vapour, methane etc., are present, then too much heat is retained, and the effect is to warm up the lower atmosphere. The majority of atmospheric scientists now believe that global warming is occurring, but some believe that the Earth is able to readjust itself to accommodate these changes. (Le Chatelier again.)... 

During the twentieth century, the great increase in our use of fossil fuels caused a significant rise in the concentration of carbon dioxide, CO2, in the atmosphere. Scientists believe that the concentration of atmospheric CO2 could double by early in the 21st century, compared with its level just before the Industrial Revolution. During the last 100 to 200 years, the CO2 concentration has increased by 25%. The curve in Figure (a) shows the recent steady rise in atmospheric CO2 concentration. 

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