The spatial and temporal variation of acidic precipitation in Newfoundland: from source to receptor
In 1981 between the months of July and December precipitation event samples were s collected at the sites of St. John's, Cape Broyle, Bishop's Falls, Grand Lake, Norris Point, Salmon Dam and Godaleich Pond on the island of Newfoundland in order to determine the acidity of precipitation on...
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| Format: | Thesis |
| Language: | English |
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Memorial University of Newfoundland
1984
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| Online Access: | https://research.library.mun.ca/5527/ https://research.library.mun.ca/5527/1/McCullough_PhilippaMary.pdf https://research.library.mun.ca/5527/3/McCullough_PhilippaMary.pdf |
| Summary: | In 1981 between the months of July and December precipitation event samples were s collected at the sites of St. John's, Cape Broyle, Bishop's Falls, Grand Lake, Norris Point, Salmon Dam and Godaleich Pond on the island of Newfoundland in order to determine the acidity of precipitation on the island. -- The samples were analyzed for pH, conductivity, sulphate, nitrate, ammonium, chloride, sodium, potassium, magnesium and calcium. Those samples which were obviously contaminated were discarded which left 60 samples in total. For these accompanying meteorological conditions were determined, namely weather type (i.e. history of the appropriate low pressure track), trajectory sector (from determination of 850 mbar. back-trajectories), antecedent rainfall duration, rainfall total and rainfall intensity. The combination of rainfall totals and precipitation chemistry results enabled the calculation of deposition values of SO⁼₄, NO⁻₃ and H⁺ --factors considered most important with respect to precipitation acidity. From these results the influence of meteorological variables was determined from subjective and objective analyses in the form of basic and multiple correlation. -- Although in a study of precipitation chemistry variability this sampling period was too short to negate the effects of natural variability, certain patterns did emerge which appear to result from the influence of specific variables. Antecedent rainfall duration, weather type and trajectory sector were the most influential variables on precipitation chemistry, although it is difficult to separate them since they are interdependent to a large extent. The most acidic events both in chemical concentration and total deposition of SO⁼₄, NO⁻₃ and H⁺ were associated with lows that had arrived over the island via Labrador and Quebec. Trajectory Sector 2, which includes high emission areas north of the Great Lakes contained the most acidic events with respect to concentrations (SO⁼₄ 1.66 mg.1⁻¹, NO⁻₃ 0.66 mg.1⁻¹, pH 4.55). However, Sectors 4 (41.6% H⁺) and 3 ... |
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