Modeling atmospheric effects of the September 1859 Solar Flare

We have modeled atmospheric effects, especially ozone depletion, due to a solar proton event which probably accompanied the extreme magnetic storm of 1-2 September 1859. We use an inferred proton fluence for this event as estimated from nitrate levels in Greenland ice cores. We present results showing production of odd nitrogen compounds and their impact on ozone. We also compute rainout of nitrate in our model and compare to values from ice core data.Comment: Revised version including improved figures; Accepted for publication in Geophys. Res. Lett, chosen to be highlighted by AG

Stratosphere chemistry in a 2-D model with residual circulation

The objective of this research was to examine the effects of chemical perturbations on the stratosphere using models which can incorporate fully interactive radiative, chemical, and dynamical responses, in the context of a zonally averaged model. Model runs for the unperturbed, chlorine-perturbed and simultaneously chlorine-and CO2-perturbed cases were completed using the JPL-87 chemical kinetics data. The base case was analyzed and submitted for publication. The perturbed cases show substantial sensitivity of the predicted column ozone depletion to the perturbations affecting lower stratosphere temperature, but less to far dynamical perturbations. The column ozone distribution changed substantially when the kinetics data was changed. This implies a greater-than-expected uncertainty in predicted latitude distributions of ozone depletion, due to uncertainty about the accuracy and completeness of the chemical kinetics data set

Direct EPP Affects on the Middle Atmosphere

Energetic precipitating particles (EPPs) can cause significant direct constituent changes in the mesosphere and stratosphere (middle atmosphere) during certain periods. Both protons and electrons can influence the polar middle atmosphere through ionization and dissociation processes. EPPs can enhance HOx (H, OH, HO2) through the formation of positive ions followed by complex ion chemistry and NOx (N, NO, NO2) through the dissociation of molecular nitrogen. The HOx increases result in direct ozone destruction in the mesosphere and upper stratosphere via several catalytic loss cycles. Such middle atmospheric HOx-caused ozone loss is rather short-lived due to the relatively short lifetime (hours) of the HOx constituents. The NOx family has a considerably longer lifetime than the HOx family and can also lead to catalytic ozone destruction. EPP-caused enhancements of the NOx family can affect ozone directly, if produced in the stratosphere. Ozone decreases from the EPPs lead to a reduction in atmospheric heating and, subsequent atmospheric cooling. Conversely, EPPs can cause direct atmospheric heating through Joule heating. Measured HOx constituents OH and HO2 showed increases due to solar protons. Observed NOx constituents NO and NO2 were enhanced due to both solar protons and precipitating electrons. Other hydrogen- and nitrogen-ocntaining constituents were also measured to be directly influenced by EPPs, including N2O, HNO3, HO2NO2, N2OS, H2O2, ClONO2, HCl, and HOCl. Observed constituents ClO and CO were directly affected by EPPs as well. Many measurements indicated significant direct ozone decreases. A significant number of satellites housed instruments, which observed direct EPP-caused atmospheric effects, including Nimbus 4 (BUV), Nimbus 7 (SBUV), several NOAA platforms (SBUV/2), SME, UARS (HALOE, CLAES), SCISAT-1 (ACE-FTS), Odin (OSIRIS), Envisat-l (GOMOS, MIPAS, SCIAMACHY), and Aura (MLS). Measurements by rockets and ground-based radar also indicated EPP direct impacts. Atmospheric models have been used with some success in predicting the direct EPP impacts on the mesosphere and stratosphere. A review of the observed direct effects of EPP on the middle atmosphere will be given in this presentation

An Overview of Energetic Particle Precipitation Effects on the Earth's Atmosphere and (Potentially) Climate

Energetic precipitating particles (EPPs) can cause significant constituent changes in the polar mesosphere and stratosphere (middle atmosphere) during certain periods. Both protons and electrons can influence the polar middle atmosphere through ionization and dissociation processes. EPPs can enhance HOx (H, OH, HO2) through the formation of positive ions followed by complex ion chemistry and NOx (N, NO, NO2) through the dissociation of molecular nitrogen. The solar EPP-created HOx increases can lead to ozone destruction in the mesosphere and upper stratosphere via several catalytic loss cycles. Such middle atmospheric HOx-caused ozone loss is rather short-lived due to the relatively short lifetime (hours) of the HOx constituents. The HOx-caused ozone depletion of greater than 30% has been observed during several large solar proton events (SPEs) in the past 50 years. HOx enhancements due to SPEs were confirmed by observations in solar cycle 23. A number of modeling studies have been undertaken over this time period that show predictions of enhanced HOx accompanied by decreased ozone due to energetic particles. The solar EPP-created NOx family has a longer lifetime than the HOx family and can also lead to catalytic ozone destruction. EPP-caused enhancements of the NOx family can affect ozone promptly, if produced in the stratosphere, or subsequently, if produced in the lower thermosphere or mesosphere and transported to the stratosphere. NOx enhancements due to auroral electrons, medium and high energy electrons, relativistic electron precipitation (REP) events, and SPEs have been measured and/or modeled for decades. Model predictions and measurements show that certain years have significant winter-time meteorological events, which result in the transport of EPP-caused NOx enhancements in the upper mesosphere and lower thermosphere to lower altitudes. The NOx-caused ozone depletion has also been observed during several solar proton events (SPEs) in the past 50 years. Model predictions indicate that the longer-lived SPE-caused polar stratospheric and mesospheric ozone decrease can be >10% for up to five months past the largest events and is statistically significant; however, total ozone measurements do not indicate any long-term SPE impact

Determination for the modal age level for the grades IV and VI of the difficulty of the principle: a body at rest remains at rest, and a body in motion continues to move at constant speed along a straight line, unless the body is acted upon in either case by an unbalanced force.

Thesis (Ed.M.)--Boston Universit

3-D Cinema: Immersive Media Technology

Article exploring 3-D cinema.Copyright © Springer Science+Business Media Dordrecht 20153-D cinema is a largely overlooked media within geographical critique. This omission is notable given both the sustained academic consideration afforded to other popular media, the medium’s significant commercial and popular success, and its status as an ‘affective’ and captivating storytelling medium. With reference to film industry advertisements, the experiential dimensions of the 3-D cinematic encounter and its (popular) framing as an ‘immersive’ consumer experience are explored. In particular, the notion of ‘immersion’ is unpacked with reference to the medium’s engineering and production techniques. In so doing, the intertwinement of the industrial desire for ever more ‘immersive’ and ‘realistic’ consumer experience is explored in relation to the engineering techniques exhibiting perceptual mimicry, or what could be termed ‘mimetic engineering’. The association between 3-D cinema and ‘tactile’ images is then explored with reference to geographic literatures on ‘haptics’ and technologies of touch. A number of recent ‘innovations’ in these fields are drawn upon in order to complicate 3-D cinema’s association with ‘tactility’. In so doing, a technological shift towards the increasingly pervasive and sophisticated engagement of the wider multi-sensory palette is explored. Drawing upon recent media technology ‘innovations’, this persistent and relentless desire for ever more ‘immersive’ and perceptually-convincing media technology is explored in light of developing media geographies

The Impact of New Highways upon Wilderness Areas

Opinions with respect to whether it is in the public interest to construct roads into wilderness areas of Alaska and the Canadian territories are varied. ... Much time has been devoted to impact studies of new or improved highways on urban and rural areas, and much energy has been devoted to studies of the impact of new or improved highways on commercial, residential or recreational developments. ... In Alaska and the Canadian Territories today the stage of development of the countryside at the time of highway construction compares in many ways to that of eastern North America in the early 1800s. ... Concern for the environment through which a highway passed was undreamed of in the early 1800s, and even 150 years later few actually worry about highway impact. ... All authorities agree that changes in the visible landscape do begin with the construction of a highway through a wilderness area of the Arctic or Subarctic. A preponderance of opinion favours the view that the benefits to be derived from new highways do outweigh the undesirable side effects, and plans for future highway construction in Alaska, the Yukon, and Northwest Territories tend to indicate this to be the official view as well. The background of conflicting opinions, claims, and counter-claims which have been building to the present intensity for several years prompted this study. ... During the spring and summer of 1972 approximately 8,000 miles of Alaskan and Yukon Territorial highways were travelled in an effort to gain first-hand knowledge of present conditions along the corridors of highways which had been built through wilderness areas during the past thirty years .... Although the investigation of these Canadian and Alaskan highways was in the nature of a reconnaissance and any conclusions must certainly be validated by further study, it would appear that the construction of a new highway through a wilderness area starts an irreversible series of more or less predictable events. First come the surveyors and the contractors who plan and build the highway. Then there are the hunters and fishermen who want to get in and get theirs before they and others "spoil" the country. On the heels of the sportsmen come guides, outfitters, small enterprises which provide gasoline, tire repairs, groceries, and possibly food and lodging. These small businesses may expand and improve the quality of their services, or others with more capital and experience may provide competition which forces the first comers out of business. ... we must recognize that highways will be built through wilderness areas, and that they can be built in such a way that the changes in the wilderness environment will be acceptable. The greatest environmental problems are created by those who will use the highways for purposes of access and exploitation of a heretofore inaccessible wilderness. It is essential that there be a comprehensive land use plan which would allocate appropriate areas for all activities and allocate the locations for all installations, services and recreational areas in such a way that incompatible activities would not be in too close proximity. Thus by anticipation of conflict and the use of land allocations or zoning it would appear that optimum land utilization can be achieved and the wilderness character of the area preserved

The effects of solar particle events on the middle atmosphere

Solar particle events (SPEs) have been investigated since the late 1960's for possible effects on the middle atmosphere. Solar protons from SPEs produce ionizations, dissociations, dissociative ionizations, and excitations in the middle atmosphere. The production of HO(x) and NO(x) and their subsequent effects on ozone can also be computed using energy deposition and photochemical models. The effects of SPE-produced HO(x) species on the odd nitrogen abundance of the middle atmosphere as well as the SPE-produced long term effects on ozone. Model computations indicate fairly good agreement with ozone data for the SPE-induced ozone depletion caused by NO(y) species connected with the August 1972 SPE. The model computations indicate that NO(y) will not be substantially changed over a solar cycle by SPEs. The changes are mainly at high latitudes and are on time scales of several months, after which the NO(y) drifts back to its ambient levels

Previous model comparisons

The first model comparison workshop examined 14 mathematical models. Issues discussed included: transport methodologies; transport of nuclear test debris; transport algorithms; source gases; NO(y), Cl(x), HO(x), and O3; photolysis rates; diurnal averaging; and rainout. The second model comparison meeting examined 16 models. More real model-model intercomparisons were undertaken and several topics were addressed including: photochemistry and radiation; transport; current atmosphere 1980; and assessment runs. The models computed different values for photolysis rates even when O3 and O2 were fixed, thus more time should be spent at future model comparison meeting on radiation codes