St. Cloud State University
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Session C AbstractsA Predictability Study Using a Non-Divergent Barotropic Vorticity ModelMichael Spinar The accuracy of the initial conditions in describing the current state of the atmosphere has a profound effect on the predictability of a numerical weather prediction model. In this study, a simple nwp model is used to examine the effects of missing data, and thus, imperfect initial conditions upon forecast skill. Presentation Index: C1 Error Analysis of the ASOS HTB PAS During Cold-Weather Precipitation EventsJacob Gontesky The Automated Surface Observing System (ASOS) is widely regarded as one of the great advancements in meteorological technology in recent decades. It has provided detailed, cost effective surface weather observations from a wide range of sites on a frequent basis. However, with the reliance on this technology, some drawbacks have been discovered. The automated instruments have shown some biases over previous manual observations. One of the instruments showing a systematic error is the heated tipping bucket precipitation accumulation sensor. This instrument consists of a heated funnel which collects and melts frozen precipitation. Once collected, the liquid is funneled into the tipping bucket apparatus. The tipping bucket then records the accumulated precipitation. Observations provide strong evidence that the heated tipping bucket instrument under-reports cold-weather precipitation accumulation. This research consists of measurements taken during precipitation events during the 2000-2001 cold season in St. Cloud, Minnesota. ASOS precipitation accumulation data was recorded during each precipitation event. A standard, 4" Tenite rain gauge was mounted approximately 30 meters from the St. Cloud ASOS station. Manual observations were taken from this instrument following each precipitation event. A regression analysis is performed comparing the data from the two gauges. A statistical model is constructed for correction of the ASOS measurements. Presentation Index: C2 Photolysis of Phenylisocyanates and PhenylisothiocyanatesCarrie Link Photochemical study of isocyanates has been very limited even though these molecules are present in the atmosphere, soil fumigants, herbicides, and are released from broccoli and watercress when chewed. Isothiocyanates have shown anti-carcinogenic activity in rodents. Exposure to methyl isocyanate in Bhopal, India killed over 5000 people. For these reasons it is important to understand the ground state and excited state chemistry of these molecules. Research began with photolysis of phenyl isocyanate in a variety of solvents at a maximal absorption of approximately 250 nm. Using techniques such as Thin Layer Chromatography, Nuclear Magnetic Resonance, Infrared Spectroscopy, UV-Visible Spectroscopy, Gas Chromatography-Mass Spectrometry, and Column Chromatography the solutions were analyzed for the formation of a product. Photolysis in cyclopentadiene resulted in reaction of the solvent. No solid product formation was observed. One of the anticipated results was the release of carbon monoxide but as a method for monitoring the elimination of a gas was not feasible for this project, phenyl isothiocyanate was explored. The first photolyses of phenyl isothiocyanate utilized methylene chloride as a solvent and a product was observed with GC-MS. The product is similar to benzonitrile but a rearrangement may occur, resulting in isonitrile. Photolyses were performed with cyclohexene to imitate known episulfide formation on the double bond of isoprene. A product was formed: cyclohexane episulfide. None of the spectra from the starting material showed peaks at the same retention times as any of the products formed; the products are not the result of a contaminating species. The next step will be to use NMR and IR to determine the structure of the isolated products obtained by column chromatography. Cyclohexene should also be distilled in order to ensure purity. The quantum yield should then be established for each product. Presentation Index: C3 Observations of Interstellar OxygenMarcel Goldschen and Brent Williams Ultraviolet spectra from interstellar ionized Oxygen [OII] were obtained from Pine Bluff Observatory, Wisconsin, during the summers of 1999 and 2000 and from Kitt Peak National Observatory, Arizona, during March 2001. The spectra were generated through Fourier analysis of images taken with a Spatial Heterodyne Spectrometer (SHS), which images interference patterns of input light. Data analysis performed at St. Cloud State University will be used in conjunction with results from Wisconsin Hydrogen Alpha Mapper (WHAM) to determine the temperature gradient of diffuse interstellar gas. Such observations will help in understanding the birth and death of stars. Presentation Index: C4 Analysis of Disinfection Byproducts in St. Cloud Drinking WaterSusan Hansen Since 1979 the Environmental Protection Agency (EPA) has regulated the levels of disinfection byproducts in tap water. These byproducts affect the palatability and health of the water. Those of interest are usually carcinogenic, so they present a health risk and affect the taste of the water, which alarms and worries the public. Water has a certain amount of natural organic matter (NOM) that, when mixed with disinfectants such as chlorine, goes through a series of reactions which create the byproducts. Between 50 to 60 percent of the byproducts produced, depending on the technique used, have yet to be identified or tested for. This has prompted researchers to study new and sometimes improved techniques for disinfection and analysis of the byproducts produced. The treatment plant here in St. Cloud uses chloramination as a disinfection technique. This technique produces trihalomethanes (THM's) as the byproducts. These byproducts are carcinogenic and are regulated by the EPA at a level of 80 ppb in tap water. The research that I am doing looks at the THM's in several concentrations within and above the EPA regulated amount in standard solutions. The standards are being tested using a technique called solid-phase microextraction (SPME). SPME is a sampling technique which is used in conjunction with gas chromatography / mass spectrometry (GC/MS). GC/MS is an improvement on the analysis technique widely used today, gas chromatography. SPME uses headspace analysis of the volatile byproducts, which are then identified and quantitated by the GC/MS. The range in concentrations in the standards shows that this analysis method can detect very small levels, 10 ppb, to the larger levels, 100 ppb. Since the regulated amount is below 80 ppb, I am trying to show that this is a viable analysis technique for detection of the THM's in tap water. Presentation Index: C5 |
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